// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/*
 * Hopefully this will be a rather complete VT102 implementation.
 *
 * Beeping thanks to John T Kohl.
 *
 * Virtual Consoles, Screen Blanking, Screen Dumping, Color, Graphics
 *   Chars, and VT100 enhancements by Peter MacDonald.
 *
 * Copy and paste function by Andrew Haylett,
 *   some enhancements by Alessandro Rubini.
 *
 * Code to check for different video-cards mostly by Galen Hunt,
 * <g-hunt@ee.utah.edu>
 *
 * Rudimentary ISO 10646/Unicode/UTF-8 character set support by
 * Markus Kuhn, <mskuhn@immd4.informatik.uni-erlangen.de>.
 *
 * Dynamic allocation of consoles, aeb@cwi.nl, May 1994
 * Resizing of consoles, aeb, 940926
 *
 * Code for xterm like mouse click reporting by Peter Orbaek 20-Jul-94
 * <poe@daimi.aau.dk>
 *
 * User-defined bell sound, new setterm control sequences and printk
 * redirection by Martin Mares <mj@k332.feld.cvut.cz> 19-Nov-95
 *
 * APM screenblank bug fixed Takashi Manabe <manabe@roy.dsl.tutics.tut.jp>
 *
 * Merge with the abstract console driver by Geert Uytterhoeven
 * <geert@linux-m68k.org>, Jan 1997.
 *
 *   Original m68k console driver modifications by
 *
 *     - Arno Griffioen <arno@usn.nl>
 *     - David Carter <carter@cs.bris.ac.uk>
 *
 *   The abstract console driver provides a generic interface for a text
 *   console. It supports VGA text mode, frame buffer based graphical consoles
 *   and special graphics processors that are only accessible through some
 *   registers (e.g. a TMS340x0 GSP).
 *
 *   The interface to the hardware is specified using a special structure
 *   (struct consw) which contains function pointers to console operations
 *   (see <linux/console.h> for more information).
 *
 * Support for changeable cursor shape
 * by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>, August 1997
 *
 * Ported to i386 and con_scrolldelta fixed
 * by Emmanuel Marty <core@ggi-project.org>, April 1998
 *
 * Resurrected character buffers in videoram plus lots of other trickery
 * by Martin Mares <mj@atrey.karlin.mff.cuni.cz>, July 1998
 *
 * Removed old-style timers, introduced console_timer, made timer
 * deletion SMP-safe.  17Jun00, Andrew Morton
 *
 * Removed console_lock, enabled interrupts across all console operations
 * 13 March 2001, Andrew Morton
 *
 * Fixed UTF-8 mode so alternate charset modes always work according
 * to control sequences interpreted in do_con_trol function
 * preserving backward VT100 semigraphics compatibility,
 * malformed UTF sequences represented as sequences of replacement glyphs,
 * original codes or '?' as a last resort if replacement glyph is undefined
 * by Adam Tla/lka <atlka@pg.gda.pl>, Aug 2006
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched/signal.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/hex.h>
#include <linux/kd.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/major.h>
#include <linux/mm.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>
#include <linux/tiocl.h>
#include <linux/kbd_kern.h>
#include <linux/consolemap.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/pm.h>
#include <linux/font.h>
#include <linux/bitops.h>
#include <linux/notifier.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/kdb.h>
#include <linux/ctype.h>
#include <linux/gcd.h>

#define MAX_NR_CON_DRIVER 16

#define CON_DRIVER_FLAG_MODULE 1
#define CON_DRIVER_FLAG_INIT   2
#define CON_DRIVER_FLAG_ATTR   4
#define CON_DRIVER_FLAG_ZOMBIE 8

struct con_driver {
        const struct consw *con;
        const char *desc;
        struct device *dev;
        int node;
        int first;
        int last;
        int flag;
};

static struct con_driver registered_con_driver[MAX_NR_CON_DRIVER];
const struct consw *conswitchp;

/*
 * Here is the default bell parameters: 750HZ, 1/8th of a second
 */
#define DEFAULT_BELL_PITCH      750
#define DEFAULT_BELL_DURATION   (HZ/8)
#define DEFAULT_CURSOR_BLINK_MS 200

struct vc vc_cons [MAX_NR_CONSOLES];
EXPORT_SYMBOL(vc_cons);

static const struct consw *con_driver_map[MAX_NR_CONSOLES];

static int con_open(struct tty_struct *, struct file *);
static void vc_init(struct vc_data *vc, int do_clear);
static void gotoxy(struct vc_data *vc, int new_x, int new_y);
static void restore_cur(struct vc_data *vc);
static void save_cur(struct vc_data *vc);
static void reset_terminal(struct vc_data *vc, int do_clear);
static void con_flush_chars(struct tty_struct *tty);
static int set_vesa_blanking(u8 __user *mode);
static void set_cursor(struct vc_data *vc);
static void hide_cursor(struct vc_data *vc);
static void console_callback(struct work_struct *ignored);
static void con_driver_unregister_callback(struct work_struct *ignored);
static void blank_screen_t(struct timer_list *unused);
static void set_palette(struct vc_data *vc);
static void unblank_screen(void);

#define vt_get_kmsg_redirect() vt_kmsg_redirect(-1)

int default_utf8 = true;
module_param(default_utf8, int, S_IRUGO | S_IWUSR);
int global_cursor_default = -1;
module_param(global_cursor_default, int, S_IRUGO | S_IWUSR);
EXPORT_SYMBOL(global_cursor_default);

static int cur_default = CUR_UNDERLINE;
module_param(cur_default, int, S_IRUGO | S_IWUSR);

/*
 * ignore_poke: don't unblank the screen when things are typed.  This is
 * mainly for the privacy of braille terminal users.
 */
static int ignore_poke;

int do_poke_blanked_console;
int console_blanked;
EXPORT_SYMBOL(console_blanked);

static enum vesa_blank_mode vesa_blank_mode;
static int vesa_off_interval;
static int blankinterval;
core_param(consoleblank, blankinterval, int, 0444);

static DECLARE_WORK(console_work, console_callback);
static DECLARE_WORK(con_driver_unregister_work, con_driver_unregister_callback);

/*
 * fg_console is the current virtual console,
 * last_console is the last used one,
 * want_console is the console we want to switch to,
 */
int fg_console;
EXPORT_SYMBOL(fg_console);
int last_console;
int want_console = -1;

/*
 * For each existing display, we have a pointer to console currently visible
 * on that display, allowing consoles other than fg_console to be refreshed
 * appropriately. Unless the low-level driver supplies its own display_fg
 * variable, we use this one for the "master display".
 */
static struct vc_data *master_display_fg;

/*
 * Unfortunately, we need to delay tty echo when we're currently writing to the
 * console since the code is (and always was) not re-entrant, so we schedule
 * all flip requests to process context with schedule-task() and run it from
 * console_callback().
 */

/*
 * For the same reason, we defer scrollback to the console callback.
 */
static int scrollback_delta;

/*
 * Hook so that the power management routines can (un)blank
 * the console on our behalf.
 */
int (*console_blank_hook)(int);
EXPORT_SYMBOL(console_blank_hook);

static DEFINE_TIMER(console_timer, blank_screen_t);
static int blank_state;
static int blank_timer_expired;
enum {
        blank_off = 0,
        blank_normal_wait,
        blank_vesa_wait,
};

/*
 * /sys/class/tty/tty0/
 *
 * the attribute 'active' contains the name of the current vc
 * console and it supports poll() to detect vc switches
 */
static struct device *tty0dev;

/*
 * Notifier list for console events.
 */
static ATOMIC_NOTIFIER_HEAD(vt_notifier_list);

int register_vt_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&vt_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(register_vt_notifier);

int unregister_vt_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_unregister(&vt_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(unregister_vt_notifier);

static void notify_write(struct vc_data *vc, unsigned int unicode)
{
        struct vt_notifier_param param = { .vc = vc, .c = unicode };
        atomic_notifier_call_chain(&vt_notifier_list, VT_WRITE, &param);
}

static void notify_update(struct vc_data *vc)
{
        struct vt_notifier_param param = { .vc = vc };
        atomic_notifier_call_chain(&vt_notifier_list, VT_UPDATE, &param);
}
/*
 *      Low-Level Functions
 */

static inline bool con_is_fg(const struct vc_data *vc)
{
        return vc->vc_num == fg_console;
}

static inline bool con_should_update(const struct vc_data *vc)
{
        return con_is_visible(vc) && !console_blanked;
}

static inline u16 *screenpos(const struct vc_data *vc, unsigned int offset,
                             bool viewed)
{
        unsigned long origin = viewed ? vc->vc_visible_origin : vc->vc_origin;

        return (u16 *)(origin + offset);
}

static void con_putc(struct vc_data *vc, u16 ca, unsigned int y, unsigned int x)
{
        if (vc->vc_sw->con_putc)
                vc->vc_sw->con_putc(vc, ca, y, x);
        else
                vc->vc_sw->con_putcs(vc, &ca, 1, y, x);
}

/* Called  from the keyboard irq path.. */
static inline void scrolldelta(int lines)
{
        /* FIXME */
        /* scrolldelta needs some kind of consistency lock, but the BKL was
           and still is not protecting versus the scheduled back end */
        scrollback_delta += lines;
        schedule_console_callback();
}

void schedule_console_callback(void)
{
        schedule_work(&console_work);
}

/*
 * Code to manage unicode-based screen buffers
 */

/*
 * Our screen buffer is preceded by an array of line pointers so that
 * scrolling only implies some pointer shuffling.
 */

static u32 **vc_uniscr_alloc(unsigned int cols, unsigned int rows)
{
        u32 **uni_lines;
        void *p;
        unsigned int memsize, i, col_size = cols * sizeof(**uni_lines);

        /* allocate everything in one go */
        memsize = col_size * rows;
        memsize += rows * sizeof(*uni_lines);
        uni_lines = vzalloc(memsize);
        if (!uni_lines)
                return NULL;

        /* initial line pointers */
        p = uni_lines + rows;
        for (i = 0; i < rows; i++) {
                uni_lines[i] = p;
                p += col_size;
        }

        return uni_lines;
}

static void vc_uniscr_free(u32 **uni_lines)
{
        vfree(uni_lines);
}

static void vc_uniscr_set(struct vc_data *vc, u32 **new_uni_lines)
{
        vc_uniscr_free(vc->vc_uni_lines);
        vc->vc_uni_lines = new_uni_lines;
}

static void vc_uniscr_putc(struct vc_data *vc, u32 uc)
{
        if (vc->vc_uni_lines)
                vc->vc_uni_lines[vc->state.y][vc->state.x] = uc;
}

static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)
{
        if (vc->vc_uni_lines) {
                u32 *ln = vc->vc_uni_lines[vc->state.y];
                unsigned int x = vc->state.x, cols = vc->vc_cols;

                memmove(&ln[x + nr], &ln[x], (cols - x - nr) * sizeof(*ln));
                memset32(&ln[x], ' ', nr);
        }
}

static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
{
        if (vc->vc_uni_lines) {
                u32 *ln = vc->vc_uni_lines[vc->state.y];
                unsigned int x = vc->state.x, cols = vc->vc_cols;

                memmove(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
                memset32(&ln[cols - nr], ' ', nr);
        }
}

static void vc_uniscr_clear_line(struct vc_data *vc, unsigned int x,
                                 unsigned int nr)
{
        if (vc->vc_uni_lines)
                memset32(&vc->vc_uni_lines[vc->state.y][x], ' ', nr);
}

static void vc_uniscr_clear_lines(struct vc_data *vc, unsigned int y,
                                  unsigned int nr)
{
        if (vc->vc_uni_lines)
                while (nr--)
                        memset32(vc->vc_uni_lines[y++], ' ', vc->vc_cols);
}

/* juggling array rotation algorithm (complexity O(N), size complexity O(1)) */
static void juggle_array(u32 **array, unsigned int size, unsigned int nr)
{
        unsigned int gcd_idx;

        for (gcd_idx = 0; gcd_idx < gcd(nr, size); gcd_idx++) {
                u32 *gcd_idx_val = array[gcd_idx];
                unsigned int dst_idx = gcd_idx;

                while (1) {
                        unsigned int src_idx = (dst_idx + nr) % size;
                        if (src_idx == gcd_idx)
                                break;

                        array[dst_idx] = array[src_idx];
                        dst_idx = src_idx;
                }

                array[dst_idx] = gcd_idx_val;
        }
}

static void vc_uniscr_scroll(struct vc_data *vc, unsigned int top,
                             unsigned int bottom, enum con_scroll dir,
                             unsigned int nr)
{
        u32 **uni_lines = vc->vc_uni_lines;
        unsigned int size = bottom - top;

        if (!uni_lines)
                return;

        if (dir == SM_DOWN) {
                juggle_array(&uni_lines[top], size, size - nr);
                vc_uniscr_clear_lines(vc, top, nr);
        } else {
                juggle_array(&uni_lines[top], size, nr);
                vc_uniscr_clear_lines(vc, bottom - nr, nr);
        }
}

static u32 vc_uniscr_getc(struct vc_data *vc, int relative_pos)
{
        int pos = vc->state.x + vc->vc_need_wrap + relative_pos;

        if (vc->vc_uni_lines && in_range(pos, 0, vc->vc_cols))
                return vc->vc_uni_lines[vc->state.y][pos];
        return 0;
}

static void vc_uniscr_copy_area(u32 **dst_lines,
                                unsigned int dst_cols,
                                unsigned int dst_rows,
                                u32 **src_lines,
                                unsigned int src_cols,
                                unsigned int src_top_row,
                                unsigned int src_bot_row)
{
        unsigned int dst_row = 0;

        if (!dst_lines)
                return;

        while (src_top_row < src_bot_row) {
                u32 *src_line = src_lines[src_top_row];
                u32 *dst_line = dst_lines[dst_row];

                memcpy(dst_line, src_line, src_cols * sizeof(*src_line));
                if (dst_cols - src_cols)
                        memset32(dst_line + src_cols, ' ', dst_cols - src_cols);
                src_top_row++;
                dst_row++;
        }
        while (dst_row < dst_rows) {
                u32 *dst_line = dst_lines[dst_row];

                memset32(dst_line, ' ', dst_cols);
                dst_row++;
        }
}

/*
 * Called from vcs_read() to make sure unicode screen retrieval is possible.
 * This will initialize the unicode screen buffer if not already done.
 * This returns 0 if OK, or a negative error code otherwise.
 * In particular, -ENODATA is returned if the console is not in UTF-8 mode.
 */
int vc_uniscr_check(struct vc_data *vc)
{
        u32 **uni_lines;
        unsigned short *p;
        int x, y, mask;

        WARN_CONSOLE_UNLOCKED();

        if (!vc->vc_utf)
                return -ENODATA;

        if (vc->vc_uni_lines)
                return 0;

        uni_lines = vc_uniscr_alloc(vc->vc_cols, vc->vc_rows);
        if (!uni_lines)
                return -ENOMEM;

        /*
         * Let's populate it initially with (imperfect) reverse translation.
         * This is the next best thing we can do short of having it enabled
         * from the start even when no users rely on this functionality. True
         * unicode content will be available after a complete screen refresh.
         */
        p = (unsigned short *)vc->vc_origin;
        mask = vc->vc_hi_font_mask | 0xff;
        for (y = 0; y < vc->vc_rows; y++) {
                u32 *line = uni_lines[y];
                for (x = 0; x < vc->vc_cols; x++) {
                        u16 glyph = scr_readw(p++) & mask;
                        line[x] = inverse_translate(vc, glyph, true);
                }
        }

        vc->vc_uni_lines = uni_lines;

        return 0;
}

/*
 * Called from vcs_read() to get the unicode data from the screen.
 * This must be preceded by a successful call to vc_uniscr_check() once
 * the console lock has been taken.
 */
void vc_uniscr_copy_line(const struct vc_data *vc, void *dest, bool viewed,
                         unsigned int row, unsigned int col, unsigned int nr)
{
        u32 **uni_lines = vc->vc_uni_lines;
        int offset = row * vc->vc_size_row + col * 2;
        unsigned long pos;

        if (WARN_ON_ONCE(!uni_lines))
                return;

        pos = (unsigned long)screenpos(vc, offset, viewed);
        if (pos >= vc->vc_origin && pos < vc->vc_scr_end) {
                /*
                 * Desired position falls in the main screen buffer.
                 * However the actual row/col might be different if
                 * scrollback is active.
                 */
                row = (pos - vc->vc_origin) / vc->vc_size_row;
                col = ((pos - vc->vc_origin) % vc->vc_size_row) / 2;
                memcpy(dest, &uni_lines[row][col], nr * sizeof(u32));
        } else {
                /*
                 * Scrollback is active. For now let's simply backtranslate
                 * the screen glyphs until the unicode screen buffer does
                 * synchronize with console display drivers for a scrollback
                 * buffer of its own.
                 */
                u16 *p = (u16 *)pos;
                int mask = vc->vc_hi_font_mask | 0xff;
                u32 *uni_buf = dest;
                while (nr--) {
                        u16 glyph = scr_readw(p++) & mask;
                        *uni_buf++ = inverse_translate(vc, glyph, true);
                }
        }
}

static void con_scroll(struct vc_data *vc, unsigned int top,
                       unsigned int bottom, enum con_scroll dir,
                       unsigned int nr)
{
        unsigned int rows = bottom - top;
        u16 *clear, *dst, *src;

        if (top + nr >= bottom)
                nr = rows - 1;
        if (bottom > vc->vc_rows || top >= bottom || nr < 1)
                return;

        vc_uniscr_scroll(vc, top, bottom, dir, nr);
        if (con_is_visible(vc) &&
                        vc->vc_sw->con_scroll(vc, top, bottom, dir, nr))
                return;

        src = clear = (u16 *)(vc->vc_origin + vc->vc_size_row * top);
        dst = (u16 *)(vc->vc_origin + vc->vc_size_row * (top + nr));

        if (dir == SM_UP) {
                clear = src + (rows - nr) * vc->vc_cols;
                swap(src, dst);
        }
        scr_memmovew(dst, src, (rows - nr) * vc->vc_size_row);
        scr_memsetw(clear, vc->vc_video_erase_char, vc->vc_size_row * nr);
}

static void do_update_region(struct vc_data *vc, unsigned long start, int count)
{
        unsigned int xx, yy, offset;
        u16 *p = (u16 *)start;

        offset = (start - vc->vc_origin) / 2;
        xx = offset % vc->vc_cols;
        yy = offset / vc->vc_cols;

        for(;;) {
                u16 attrib = scr_readw(p) & 0xff00;
                int startx = xx;
                u16 *q = p;
                while (xx < vc->vc_cols && count) {
                        if (attrib != (scr_readw(p) & 0xff00)) {
                                if (p > q)
                                        vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
                                startx = xx;
                                q = p;
                                attrib = scr_readw(p) & 0xff00;
                        }
                        p++;
                        xx++;
                        count--;
                }
                if (p > q)
                        vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
                if (!count)
                        break;
                xx = 0;
                yy++;
        }
}

void update_region(struct vc_data *vc, unsigned long start, int count)
{
        WARN_CONSOLE_UNLOCKED();

        if (con_should_update(vc)) {
                hide_cursor(vc);
                do_update_region(vc, start, count);
                set_cursor(vc);
        }
}
EXPORT_SYMBOL(update_region);

/* Structure of attributes is hardware-dependent */

static u8 build_attr(struct vc_data *vc, u8 _color,
                enum vc_intensity _intensity, bool _blink, bool _underline,
                bool _reverse, bool _italic)
{
        if (vc->vc_sw->con_build_attr)
                return vc->vc_sw->con_build_attr(vc, _color, _intensity,
                       _blink, _underline, _reverse, _italic);

/*
 * ++roman: I completely changed the attribute format for monochrome
 * mode (!can_do_color). The formerly used MDA (monochrome display
 * adapter) format didn't allow the combination of certain effects.
 * Now the attribute is just a bit vector:
 *  Bit 0..1: intensity (0..2)
 *  Bit 2   : underline
 *  Bit 3   : reverse
 *  Bit 7   : blink
 */
        {
        u8 a = _color;
        if (!vc->vc_can_do_color)
                return _intensity |
                       (_italic    << 1) |
                       (_underline << 2) |
                       (_reverse   << 3) |
                       (_blink     << 7);
        if (_italic)
                a = (a & 0xF0) | vc->vc_itcolor;
        else if (_underline)
                a = (a & 0xf0) | vc->vc_ulcolor;
        else if (_intensity == VCI_HALF_BRIGHT)
                a = (a & 0xf0) | vc->vc_halfcolor;
        if (_reverse)
                a = (a & 0x88) | (((a >> 4) | (a << 4)) & 0x77);
        if (_blink)
                a ^= 0x80;
        if (_intensity == VCI_BOLD)
                a ^= 0x08;
        if (vc->vc_hi_font_mask == 0x100)
                a <<= 1;
        return a;
        }
}

static void update_attr(struct vc_data *vc)
{
        vc->vc_attr = build_attr(vc, vc->state.color, vc->state.intensity,
                      vc->state.blink, vc->state.underline,
                      vc->state.reverse ^ vc->vc_decscnm, vc->state.italic);
        vc->vc_video_erase_char = ' ' | (build_attr(vc, vc->state.color,
                                VCI_NORMAL, vc->state.blink, false,
                                vc->vc_decscnm, false) << 8);
}

/* Note: inverting the screen twice should revert to the original state */
void invert_screen(struct vc_data *vc, int offset, int count, bool viewed)
{
        u16 *p;

        WARN_CONSOLE_UNLOCKED();

        count /= 2;
        p = screenpos(vc, offset, viewed);
        if (vc->vc_sw->con_invert_region) {
                vc->vc_sw->con_invert_region(vc, p, count);
        } else {
                u16 *q = p;
                int cnt = count;
                u16 a;

                if (!vc->vc_can_do_color) {
                        while (cnt--) {
                            a = scr_readw(q);
                            a ^= 0x0800;
                            scr_writew(a, q);
                            q++;
                        }
                } else if (vc->vc_hi_font_mask == 0x100) {
                        while (cnt--) {
                                a = scr_readw(q);
                                a = (a & 0x11ff) |
                                   ((a & 0xe000) >> 4) |
                                   ((a & 0x0e00) << 4);
                                scr_writew(a, q);
                                q++;
                        }
                } else {
                        while (cnt--) {
                                a = scr_readw(q);
                                a = (a & 0x88ff) |
                                   ((a & 0x7000) >> 4) |
                                   ((a & 0x0700) << 4);
                                scr_writew(a, q);
                                q++;
                        }
                }
        }

        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) p, count);
        notify_update(vc);
}

/* used by selection: complement pointer position */
void complement_pos(struct vc_data *vc, int offset)
{
        static int old_offset = -1;
        static unsigned short old;
        static unsigned short oldx, oldy;

        WARN_CONSOLE_UNLOCKED();

        if (old_offset != -1 && old_offset >= 0 &&
            old_offset < vc->vc_screenbuf_size) {
                scr_writew(old, screenpos(vc, old_offset, true));
                if (con_should_update(vc))
                        con_putc(vc, old, oldy, oldx);
                notify_update(vc);
        }

        old_offset = offset;

        if (offset != -1 && offset >= 0 &&
            offset < vc->vc_screenbuf_size) {
                unsigned short new;
                u16 *p = screenpos(vc, offset, true);
                old = scr_readw(p);
                new = old ^ vc->vc_complement_mask;
                scr_writew(new, p);
                if (con_should_update(vc)) {
                        oldx = (offset >> 1) % vc->vc_cols;
                        oldy = (offset >> 1) / vc->vc_cols;
                        con_putc(vc, new, oldy, oldx);
                }
                notify_update(vc);
        }
}

static void insert_char(struct vc_data *vc, unsigned int nr)
{
        unsigned short *p = (unsigned short *) vc->vc_pos;

        vc_uniscr_insert(vc, nr);
        scr_memmovew(p + nr, p, (vc->vc_cols - vc->state.x - nr) * 2);
        scr_memsetw(p, vc->vc_video_erase_char, nr * 2);
        vc->vc_need_wrap = 0;
        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) p,
                        vc->vc_cols - vc->state.x);
}

static void delete_char(struct vc_data *vc, unsigned int nr)
{
        unsigned short *p = (unsigned short *) vc->vc_pos;

        vc_uniscr_delete(vc, nr);
        scr_memmovew(p, p + nr, (vc->vc_cols - vc->state.x - nr) * 2);
        scr_memsetw(p + vc->vc_cols - vc->state.x - nr, vc->vc_video_erase_char,
                        nr * 2);
        vc->vc_need_wrap = 0;
        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) p,
                        vc->vc_cols - vc->state.x);
}

static int softcursor_original = -1;

static void add_softcursor(struct vc_data *vc)
{
        int i = scr_readw((u16 *) vc->vc_pos);
        u32 type = vc->vc_cursor_type;

        if (!(type & CUR_SW))
                return;
        if (softcursor_original != -1)
                return;
        softcursor_original = i;
        i |= CUR_SET(type);
        i ^= CUR_CHANGE(type);
        if ((type & CUR_ALWAYS_BG) &&
                        (softcursor_original & CUR_BG) == (i & CUR_BG))
                i ^= CUR_BG;
        if ((type & CUR_INVERT_FG_BG) && (i & CUR_FG) == ((i & CUR_BG) >> 4))
                i ^= CUR_FG;
        scr_writew(i, (u16 *)vc->vc_pos);
        if (con_should_update(vc))
                con_putc(vc, i, vc->state.y, vc->state.x);
}

static void hide_softcursor(struct vc_data *vc)
{
        if (softcursor_original != -1) {
                scr_writew(softcursor_original, (u16 *)vc->vc_pos);
                if (con_should_update(vc))
                        con_putc(vc, softcursor_original, vc->state.y,
                                 vc->state.x);
                softcursor_original = -1;
        }
}

static void hide_cursor(struct vc_data *vc)
{
        if (vc_is_sel(vc))
                clear_selection();

        vc->vc_sw->con_cursor(vc, false);
        hide_softcursor(vc);
}

static void set_cursor(struct vc_data *vc)
{
        if (!con_is_fg(vc) || console_blanked || vc->vc_mode == KD_GRAPHICS)
                return;
        if (vc->vc_deccm) {
                if (vc_is_sel(vc))
                        clear_selection();
                add_softcursor(vc);
                if (CUR_SIZE(vc->vc_cursor_type) != CUR_NONE)
                        vc->vc_sw->con_cursor(vc, true);
        } else
                hide_cursor(vc);
}

static void set_origin(struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        if (!con_is_visible(vc) ||
            !vc->vc_sw->con_set_origin ||
            !vc->vc_sw->con_set_origin(vc))
                vc->vc_origin = (unsigned long)vc->vc_screenbuf;
        vc->vc_visible_origin = vc->vc_origin;
        vc->vc_scr_end = vc->vc_origin + vc->vc_screenbuf_size;
        vc->vc_pos = vc->vc_origin + vc->vc_size_row * vc->state.y +
                2 * vc->state.x;
}

static void save_screen(struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        if (vc->vc_sw->con_save_screen)
                vc->vc_sw->con_save_screen(vc);
}

static void flush_scrollback(struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        set_origin(vc);
        if (!con_is_visible(vc))
                return;

        /*
         * The legacy way for flushing the scrollback buffer is to use a side
         * effect of the con_switch method. We do it only on the foreground
         * console as background consoles have no scrollback buffers in that
         * case and we obviously don't want to switch to them.
         */
        hide_cursor(vc);
        vc->vc_sw->con_switch(vc);
        set_cursor(vc);
}

/*
 *      Redrawing of screen
 */

void clear_buffer_attributes(struct vc_data *vc)
{
        unsigned short *p = (unsigned short *)vc->vc_origin;
        int count = vc->vc_screenbuf_size / 2;
        int mask = vc->vc_hi_font_mask | 0xff;

        for (; count > 0; count--, p++) {
                scr_writew((scr_readw(p)&mask) | (vc->vc_video_erase_char & ~mask), p);
        }
}

void redraw_screen(struct vc_data *vc, int is_switch)
{
        int redraw = 0;

        WARN_CONSOLE_UNLOCKED();

        if (!vc) {
                /* strange ... */
                /* printk("redraw_screen: tty %d not allocated ??\n", new_console+1); */
                return;
        }

        if (is_switch) {
                struct vc_data *old_vc = vc_cons[fg_console].d;
                if (old_vc == vc)
                        return;
                if (!con_is_visible(vc))
                        redraw = 1;
                *vc->vc_display_fg = vc;
                fg_console = vc->vc_num;
                hide_cursor(old_vc);
                if (!con_is_visible(old_vc)) {
                        save_screen(old_vc);
                        set_origin(old_vc);
                }
                if (tty0dev)
                        sysfs_notify(&tty0dev->kobj, NULL, "active");
        } else {
                hide_cursor(vc);
                redraw = 1;
        }

        if (redraw) {
                bool update;
                int old_was_color = vc->vc_can_do_color;

                set_origin(vc);
                update = vc->vc_sw->con_switch(vc);
                set_palette(vc);
                /*
                 * If console changed from mono<->color, the best we can do
                 * is to clear the buffer attributes. As it currently stands,
                 * rebuilding new attributes from the old buffer is not doable
                 * without overly complex code.
                 */
                if (old_was_color != vc->vc_can_do_color) {
                        update_attr(vc);
                        clear_buffer_attributes(vc);
                }

                if (update && vc->vc_mode != KD_GRAPHICS)
                        do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
        }
        set_cursor(vc);
        if (is_switch) {
                vt_set_leds_compute_shiftstate();
                notify_update(vc);
        }
}
EXPORT_SYMBOL(redraw_screen);

/*
 *      Allocation, freeing and resizing of VTs.
 */

int vc_cons_allocated(unsigned int i)
{
        return (i < MAX_NR_CONSOLES && vc_cons[i].d);
}

static void visual_init(struct vc_data *vc, int num, bool init)
{
        /* ++Geert: vc->vc_sw->con_init determines console size */
        if (vc->vc_sw)
                module_put(vc->vc_sw->owner);
        vc->vc_sw = conswitchp;

        if (con_driver_map[num])
                vc->vc_sw = con_driver_map[num];

        __module_get(vc->vc_sw->owner);
        vc->vc_num = num;
        vc->vc_display_fg = &master_display_fg;
        if (vc->uni_pagedict_loc)
                con_free_unimap(vc);
        vc->uni_pagedict_loc = &vc->uni_pagedict;
        vc->uni_pagedict = NULL;
        vc->vc_hi_font_mask = 0;
        vc->vc_complement_mask = 0;
        vc->vc_can_do_color = 0;
        vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
        vc->vc_sw->con_init(vc, init);
        if (!vc->vc_complement_mask)
                vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
        vc->vc_s_complement_mask = vc->vc_complement_mask;
        vc->vc_size_row = vc->vc_cols << 1;
        vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
}


static void visual_deinit(struct vc_data *vc)
{
        vc->vc_sw->con_deinit(vc);
        module_put(vc->vc_sw->owner);
}

static void vc_port_destruct(struct tty_port *port)
{
        struct vc_data *vc = container_of(port, struct vc_data, port);

        kfree(vc);
}

static const struct tty_port_operations vc_port_ops = {
        .destruct = vc_port_destruct,
};

/*
 * Change # of rows and columns (0 means unchanged/the size of fg_console)
 * [this is to be used together with some user program
 * like resize that changes the hardware videomode]
 */
#define VC_MAXCOL (32767)
#define VC_MAXROW (32767)

int vc_allocate(unsigned int currcons)  /* return 0 on success */
{
        struct vt_notifier_param param;
        struct vc_data *vc;
        int err;

        WARN_CONSOLE_UNLOCKED();

        if (currcons >= MAX_NR_CONSOLES)
                return -ENXIO;

        if (vc_cons[currcons].d)
                return 0;

        /* due to the granularity of kmalloc, we waste some memory here */
        /* the alloc is done in two steps, to optimize the common situation
           of a 25x80 console (structsize=216, screenbuf_size=4000) */
        /* although the numbers above are not valid since long ago, the
           point is still up-to-date and the comment still has its value
           even if only as a historical artifact.  --mj, July 1998 */
        param.vc = vc = kzalloc_obj(struct vc_data);
        if (!vc)
                return -ENOMEM;

        vc_cons[currcons].d = vc;
        tty_port_init(&vc->port);
        vc->port.ops = &vc_port_ops;
        INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);

        visual_init(vc, currcons, true);

        if (!*vc->uni_pagedict_loc)
                con_set_default_unimap(vc);

        err = -EINVAL;
        if (vc->vc_cols > VC_MAXCOL || vc->vc_rows > VC_MAXROW ||
            vc->vc_screenbuf_size > KMALLOC_MAX_SIZE || !vc->vc_screenbuf_size)
                goto err_free;
        err = -ENOMEM;
        vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
        if (!vc->vc_screenbuf)
                goto err_free;

        /* If no drivers have overridden us and the user didn't pass a
           boot option, default to displaying the cursor */
        if (global_cursor_default == -1)
                global_cursor_default = 1;

        vc_init(vc, 1);
        vcs_make_sysfs(currcons);
        atomic_notifier_call_chain(&vt_notifier_list, VT_ALLOCATE, &param);

        return 0;
err_free:
        visual_deinit(vc);
        kfree(vc);
        vc_cons[currcons].d = NULL;
        return err;
}

static inline int resize_screen(struct vc_data *vc, int width, int height,
                                bool from_user)
{
        /* Resizes the resolution of the display adapater */
        int err = 0;

        if (vc->vc_sw->con_resize)
                err = vc->vc_sw->con_resize(vc, width, height, from_user);

        return err;
}

/**
 * vc_do_resize - resizing method for the tty
 * @tty: tty being resized
 * @vc: virtual console private data
 * @cols: columns
 * @lines: lines
 * @from_user: invoked by a user?
 *
 * Resize a virtual console, clipping according to the actual constraints. If
 * the caller passes a tty structure then update the termios winsize
 * information and perform any necessary signal handling.
 *
 * Locking: Caller must hold the console semaphore. Takes the termios rwsem and
 * ctrl.lock of the tty IFF a tty is passed.
 */
static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
                        unsigned int cols, unsigned int lines, bool from_user)
{
        unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0;
        unsigned long end;
        unsigned int old_rows, old_row_size, first_copied_row;
        unsigned int new_cols, new_rows, new_row_size, new_screen_size;
        unsigned short *oldscreen, *newscreen;
        u32 **new_uniscr = NULL;

        WARN_CONSOLE_UNLOCKED();

        if (cols > VC_MAXCOL || lines > VC_MAXROW)
                return -EINVAL;

        new_cols = (cols ? cols : vc->vc_cols);
        new_rows = (lines ? lines : vc->vc_rows);
        new_row_size = new_cols << 1;
        new_screen_size = new_row_size * new_rows;

        if (new_cols == vc->vc_cols && new_rows == vc->vc_rows) {
                /*
                 * This function is being called here to cover the case
                 * where the userspace calls the FBIOPUT_VSCREENINFO twice,
                 * passing the same fb_var_screeninfo containing the fields
                 * yres/xres equal to a number non-multiple of vc_font.height
                 * and yres_virtual/xres_virtual equal to number lesser than the
                 * vc_font.height and yres/xres.
                 * In the second call, the struct fb_var_screeninfo isn't
                 * being modified by the underlying driver because of the
                 * if above, and this causes the fbcon_display->vrows to become
                 * negative and it eventually leads to out-of-bound
                 * access by the imageblit function.
                 * To give the correct values to the struct and to not have
                 * to deal with possible errors from the code below, we call
                 * the resize_screen here as well.
                 */
                return resize_screen(vc, new_cols, new_rows, from_user);
        }

        if (new_screen_size > KMALLOC_MAX_SIZE || !new_screen_size)
                return -EINVAL;
        newscreen = kzalloc(new_screen_size, GFP_USER);
        if (!newscreen)
                return -ENOMEM;

        if (vc->vc_uni_lines) {
                new_uniscr = vc_uniscr_alloc(new_cols, new_rows);
                if (!new_uniscr) {
                        kfree(newscreen);
                        return -ENOMEM;
                }
        }

        if (vc_is_sel(vc))
                clear_selection();

        old_rows = vc->vc_rows;
        old_row_size = vc->vc_size_row;

        err = resize_screen(vc, new_cols, new_rows, from_user);
        if (err) {
                kfree(newscreen);
                vc_uniscr_free(new_uniscr);
                return err;
        }

        vc->vc_rows = new_rows;
        vc->vc_cols = new_cols;
        vc->vc_size_row = new_row_size;
        vc->vc_screenbuf_size = new_screen_size;

        rlth = min(old_row_size, new_row_size);
        rrem = new_row_size - rlth;
        old_origin = vc->vc_origin;
        new_origin = (long) newscreen;
        new_scr_end = new_origin + new_screen_size;

        if (vc->state.y > new_rows) {
                if (old_rows - vc->state.y < new_rows) {
                        /*
                         * Cursor near the bottom, copy contents from the
                         * bottom of buffer
                         */
                        first_copied_row = (old_rows - new_rows);
                } else {
                        /*
                         * Cursor is in no man's land, copy 1/2 screenful
                         * from the top and bottom of cursor position
                         */
                        first_copied_row = (vc->state.y - new_rows/2);
                }
                old_origin += first_copied_row * old_row_size;
        } else
                first_copied_row = 0;
        end = old_origin + old_row_size * min(old_rows, new_rows);

        vc_uniscr_copy_area(new_uniscr, new_cols, new_rows,
                            vc->vc_uni_lines, rlth/2, first_copied_row,
                            min(old_rows, new_rows));
        vc_uniscr_set(vc, new_uniscr);

        update_attr(vc);

        while (old_origin < end) {
                scr_memcpyw((unsigned short *) new_origin,
                            (unsigned short *) old_origin, rlth);
                if (rrem)
                        scr_memsetw((void *)(new_origin + rlth),
                                    vc->vc_video_erase_char, rrem);
                old_origin += old_row_size;
                new_origin += new_row_size;
        }
        if (new_scr_end > new_origin)
                scr_memsetw((void *)new_origin, vc->vc_video_erase_char,
                            new_scr_end - new_origin);
        oldscreen = vc->vc_screenbuf;
        vc->vc_screenbuf = newscreen;
        vc->vc_screenbuf_size = new_screen_size;
        set_origin(vc);
        kfree(oldscreen);

        /* do part of a reset_terminal() */
        vc->vc_top = 0;
        vc->vc_bottom = vc->vc_rows;
        gotoxy(vc, vc->state.x, vc->state.y);
        save_cur(vc);

        if (tty) {
                /* Rewrite the requested winsize data with the actual
                   resulting sizes */
                struct winsize ws;
                memset(&ws, 0, sizeof(ws));
                ws.ws_row = vc->vc_rows;
                ws.ws_col = vc->vc_cols;
                ws.ws_ypixel = vc->vc_scan_lines;
                tty_do_resize(tty, &ws);
        }

        if (con_is_visible(vc))
                update_screen(vc);
        vt_event_post(VT_EVENT_RESIZE, vc->vc_num, vc->vc_num);
        notify_update(vc);
        return err;
}

/**
 * __vc_resize - resize a VT
 * @vc: virtual console
 * @cols: columns
 * @rows: rows
 * @from_user: invoked by a user?
 *
 * Resize a virtual console as seen from the console end of things. We use the
 * common vc_do_resize() method to update the structures.
 *
 * Locking: The caller must hold the console sem to protect console internals
 * and @vc->port.tty.
 */
int __vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows,
                bool from_user)
{
        return vc_do_resize(vc->port.tty, vc, cols, rows, from_user);
}
EXPORT_SYMBOL(__vc_resize);

/**
 * vt_resize - resize a VT
 * @tty: tty to resize
 * @ws: winsize attributes
 *
 * Resize a virtual terminal. This is called by the tty layer as we register
 * our own handler for resizing. The mutual helper does all the actual work.
 *
 * Locking: Takes the console sem and the called methods then take the tty
 * termios_rwsem and the tty ctrl.lock in that order.
 */
static int vt_resize(struct tty_struct *tty, struct winsize *ws)
{
        struct vc_data *vc = tty->driver_data;

        guard(console_lock)();
        return vc_do_resize(tty, vc, ws->ws_col, ws->ws_row, false);
}

struct vc_data *vc_deallocate(unsigned int currcons)
{
        struct vc_data *vc = NULL;

        WARN_CONSOLE_UNLOCKED();

        if (vc_cons_allocated(currcons)) {
                struct vt_notifier_param param;

                param.vc = vc = vc_cons[currcons].d;
                atomic_notifier_call_chain(&vt_notifier_list, VT_DEALLOCATE, &param);
                vcs_remove_sysfs(currcons);
                visual_deinit(vc);
                con_free_unimap(vc);
                put_pid(vc->vt_pid);
                vc_uniscr_set(vc, NULL);
                kfree(vc->vc_screenbuf);
                vc_cons[currcons].d = NULL;
                if (vc->vc_saved_screen != NULL) {
                        kfree(vc->vc_saved_screen);
                        vc->vc_saved_screen = NULL;
                }
                vc_uniscr_free(vc->vc_saved_uni_lines);
                vc->vc_saved_uni_lines = NULL;
        }
        return vc;
}

/*
 *      VT102 emulator
 */

enum { EPecma = 0, EPdec, EPeq, EPgt, EPlt};

#define set_kbd(vc, x)  vt_set_kbd_mode_bit((vc)->vc_num, (x))
#define clr_kbd(vc, x)  vt_clr_kbd_mode_bit((vc)->vc_num, (x))
#define is_kbd(vc, x)   vt_get_kbd_mode_bit((vc)->vc_num, (x))

#define decarm          VC_REPEAT
#define decckm          VC_CKMODE
#define kbdapplic       VC_APPLIC
#define lnm             VC_CRLF

const unsigned char color_table[] = { 0, 4, 2, 6, 1, 5, 3, 7,
                                       8,12,10,14, 9,13,11,15 };
EXPORT_SYMBOL(color_table);

/* the default colour table, for VGA+ colour systems */
unsigned char default_red[] = {
        0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa,
        0x55, 0xff, 0x55, 0xff, 0x55, 0xff, 0x55, 0xff
};
module_param_array(default_red, byte, NULL, S_IRUGO | S_IWUSR);
EXPORT_SYMBOL(default_red);

unsigned char default_grn[] = {
        0x00, 0x00, 0xaa, 0x55, 0x00, 0x00, 0xaa, 0xaa,
        0x55, 0x55, 0xff, 0xff, 0x55, 0x55, 0xff, 0xff
};
module_param_array(default_grn, byte, NULL, S_IRUGO | S_IWUSR);
EXPORT_SYMBOL(default_grn);

unsigned char default_blu[] = {
        0x00, 0x00, 0x00, 0x00, 0xaa, 0xaa, 0xaa, 0xaa,
        0x55, 0x55, 0x55, 0x55, 0xff, 0xff, 0xff, 0xff
};
module_param_array(default_blu, byte, NULL, S_IRUGO | S_IWUSR);
EXPORT_SYMBOL(default_blu);

/*
 * gotoxy() must verify all boundaries, because the arguments
 * might also be negative. If the given position is out of
 * bounds, the cursor is placed at the nearest margin.
 */
static void gotoxy(struct vc_data *vc, int new_x, int new_y)
{
        int min_y, max_y;

        if (new_x < 0)
                vc->state.x = 0;
        else {
                if (new_x >= vc->vc_cols)
                        vc->state.x = vc->vc_cols - 1;
                else
                        vc->state.x = new_x;
        }

        if (vc->vc_decom) {
                min_y = vc->vc_top;
                max_y = vc->vc_bottom;
        } else {
                min_y = 0;
                max_y = vc->vc_rows;
        }
        if (new_y < min_y)
                vc->state.y = min_y;
        else if (new_y >= max_y)
                vc->state.y = max_y - 1;
        else
                vc->state.y = new_y;
        vc->vc_pos = vc->vc_origin + vc->state.y * vc->vc_size_row +
                (vc->state.x << 1);
        vc->vc_need_wrap = 0;
}

/* for absolute user moves, when decom is set */
static void gotoxay(struct vc_data *vc, int new_x, int new_y)
{
        gotoxy(vc, new_x, vc->vc_decom ? (vc->vc_top + new_y) : new_y);
}

void scrollback(struct vc_data *vc)
{
        scrolldelta(-(vc->vc_rows / 2));
}

void scrollfront(struct vc_data *vc, int lines)
{
        if (!lines)
                lines = vc->vc_rows / 2;
        scrolldelta(lines);
}

static void lf(struct vc_data *vc)
{
        /* don't scroll if above bottom of scrolling region, or
         * if below scrolling region
         */
        if (vc->state.y + 1 == vc->vc_bottom)
                con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_UP, 1);
        else if (vc->state.y < vc->vc_rows - 1) {
                vc->state.y++;
                vc->vc_pos += vc->vc_size_row;
        }
        vc->vc_need_wrap = 0;
        notify_write(vc, '\n');
}

static void ri(struct vc_data *vc)
{
        /* don't scroll if below top of scrolling region, or
         * if above scrolling region
         */
        if (vc->state.y == vc->vc_top)
                con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_DOWN, 1);
        else if (vc->state.y > 0) {
                vc->state.y--;
                vc->vc_pos -= vc->vc_size_row;
        }
        vc->vc_need_wrap = 0;
}

static inline void cr(struct vc_data *vc)
{
        vc->vc_pos -= vc->state.x << 1;
        vc->vc_need_wrap = vc->state.x = 0;
        notify_write(vc, '\r');
}

static inline void bs(struct vc_data *vc)
{
        if (vc->state.x) {
                vc->vc_pos -= 2;
                vc->state.x--;
                vc->vc_need_wrap = 0;
                notify_write(vc, '\b');
        }
}

static inline void del(struct vc_data *vc)
{
        /* ignored */
}

enum CSI_J {
        CSI_J_CURSOR_TO_END     = 0,
        CSI_J_START_TO_CURSOR   = 1,
        CSI_J_VISIBLE           = 2,
        CSI_J_FULL              = 3,
};

static void csi_J(struct vc_data *vc, enum CSI_J vpar)
{
        unsigned short *start;
        unsigned int count;

        switch (vpar) {
        case CSI_J_CURSOR_TO_END:
                vc_uniscr_clear_line(vc, vc->state.x,
                                     vc->vc_cols - vc->state.x);
                vc_uniscr_clear_lines(vc, vc->state.y + 1,
                                      vc->vc_rows - vc->state.y - 1);
                count = (vc->vc_scr_end - vc->vc_pos) >> 1;
                start = (unsigned short *)vc->vc_pos;
                break;
        case CSI_J_START_TO_CURSOR:
                vc_uniscr_clear_line(vc, 0, vc->state.x + 1);
                vc_uniscr_clear_lines(vc, 0, vc->state.y);
                count = ((vc->vc_pos - vc->vc_origin) >> 1) + 1;
                start = (unsigned short *)vc->vc_origin;
                break;
        case CSI_J_FULL:
                flush_scrollback(vc);
                fallthrough;
        case CSI_J_VISIBLE:
                vc_uniscr_clear_lines(vc, 0, vc->vc_rows);
                count = vc->vc_cols * vc->vc_rows;
                start = (unsigned short *)vc->vc_origin;
                break;
        default:
                return;
        }
        scr_memsetw(start, vc->vc_video_erase_char, 2 * count);
        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) start, count);
        vc->vc_need_wrap = 0;
}

enum {
        CSI_K_CURSOR_TO_LINEEND         = 0,
        CSI_K_LINESTART_TO_CURSOR       = 1,
        CSI_K_LINE                      = 2,
};

static void csi_K(struct vc_data *vc)
{
        unsigned int count;
        unsigned short *start = (unsigned short *)vc->vc_pos;
        int offset;

        switch (vc->vc_par[0]) {
        case CSI_K_CURSOR_TO_LINEEND:
                offset = 0;
                count = vc->vc_cols - vc->state.x;
                break;
        case CSI_K_LINESTART_TO_CURSOR:
                offset = -vc->state.x;
                count = vc->state.x + 1;
                break;
        case CSI_K_LINE:
                offset = -vc->state.x;
                count = vc->vc_cols;
                break;
        default:
                return;
        }
        vc_uniscr_clear_line(vc, vc->state.x + offset, count);
        scr_memsetw(start + offset, vc->vc_video_erase_char, 2 * count);
        vc->vc_need_wrap = 0;
        if (con_should_update(vc))
                do_update_region(vc, (unsigned long)(start + offset), count);
}

/* erase the following count positions */
static void csi_X(struct vc_data *vc)
{                                         /* not vt100? */
        unsigned int count = clamp(vc->vc_par[0], 1, vc->vc_cols - vc->state.x);

        vc_uniscr_clear_line(vc, vc->state.x, count);
        scr_memsetw((unsigned short *)vc->vc_pos, vc->vc_video_erase_char, 2 * count);
        if (con_should_update(vc))
                vc->vc_sw->con_clear(vc, vc->state.y, vc->state.x, count);
        vc->vc_need_wrap = 0;
}

static void default_attr(struct vc_data *vc)
{
        vc->state.intensity = VCI_NORMAL;
        vc->state.italic = false;
        vc->state.underline = false;
        vc->state.reverse = false;
        vc->state.blink = false;
        vc->state.color = vc->vc_def_color;
}

struct rgb { u8 r; u8 g; u8 b; };

static void rgb_from_256(unsigned int i, struct rgb *c)
{
        if (i < 8) {            /* Standard colours. */
                c->r = i&1 ? 0xaa : 0x00;
                c->g = i&2 ? 0xaa : 0x00;
                c->b = i&4 ? 0xaa : 0x00;
        } else if (i < 16) {
                c->r = i&1 ? 0xff : 0x55;
                c->g = i&2 ? 0xff : 0x55;
                c->b = i&4 ? 0xff : 0x55;
        } else if (i < 232) {   /* 6x6x6 colour cube. */
                i -= 16;
                c->b = i % 6 * 255 / 6;
                i /= 6;
                c->g = i % 6 * 255 / 6;
                i /= 6;
                c->r = i     * 255 / 6;
        } else                  /* Grayscale ramp. */
                c->r = c->g = c->b = i * 10 - 2312;
}

static void rgb_foreground(struct vc_data *vc, const struct rgb *c)
{
        u8 hue = 0, max = max3(c->r, c->g, c->b);

        if (c->r > max / 2)
                hue |= 4;
        if (c->g > max / 2)
                hue |= 2;
        if (c->b > max / 2)
                hue |= 1;

        if (hue == 7 && max <= 0x55) {
                hue = 0;
                vc->state.intensity = VCI_BOLD;
        } else if (max > 0xaa)
                vc->state.intensity = VCI_BOLD;
        else
                vc->state.intensity = VCI_NORMAL;

        vc->state.color = (vc->state.color & 0xf0) | hue;
}

static void rgb_background(struct vc_data *vc, const struct rgb *c)
{
        /* For backgrounds, err on the dark side. */
        vc->state.color = (vc->state.color & 0x0f)
                | (c->r&0x80) >> 1 | (c->g&0x80) >> 2 | (c->b&0x80) >> 3;
}

/*
 * ITU T.416 Higher colour modes. They break the usual properties of SGR codes
 * and thus need to be detected and ignored by hand. That standard also
 * wants : rather than ; as separators but sequences containing : are currently
 * completely ignored by the parser.
 *
 * Subcommands 3 (CMY) and 4 (CMYK) are so insane there's no point in
 * supporting them.
 */
static int vc_t416_color(struct vc_data *vc, int i,
                void(*set_color)(struct vc_data *vc, const struct rgb *c))
{
        struct rgb c;

        i++;
        if (i > vc->vc_npar)
                return i;

        if (vc->vc_par[i] == 5 && i + 1 <= vc->vc_npar) {
                /* 256 colours */
                i++;
                rgb_from_256(vc->vc_par[i], &c);
        } else if (vc->vc_par[i] == 2 && i + 3 <= vc->vc_npar) {
                /* 24 bit */
                c.r = vc->vc_par[i + 1];
                c.g = vc->vc_par[i + 2];
                c.b = vc->vc_par[i + 3];
                i += 3;
        } else
                return i;

        set_color(vc, &c);

        return i;
}

enum {
        CSI_m_DEFAULT                   = 0,
        CSI_m_BOLD                      = 1,
        CSI_m_HALF_BRIGHT               = 2,
        CSI_m_ITALIC                    = 3,
        CSI_m_UNDERLINE                 = 4,
        CSI_m_BLINK                     = 5,
        CSI_m_REVERSE                   = 7,
        CSI_m_PRI_FONT                  = 10,
        CSI_m_ALT_FONT1                 = 11,
        CSI_m_ALT_FONT2                 = 12,
        CSI_m_DOUBLE_UNDERLINE          = 21,
        CSI_m_NORMAL_INTENSITY          = 22,
        CSI_m_NO_ITALIC                 = 23,
        CSI_m_NO_UNDERLINE              = 24,
        CSI_m_NO_BLINK                  = 25,
        CSI_m_NO_REVERSE                = 27,
        CSI_m_FG_COLOR_BEG              = 30,
        CSI_m_FG_COLOR_END              = 37,
        CSI_m_FG_COLOR                  = 38,
        CSI_m_DEFAULT_FG_COLOR          = 39,
        CSI_m_BG_COLOR_BEG              = 40,
        CSI_m_BG_COLOR_END              = 47,
        CSI_m_BG_COLOR                  = 48,
        CSI_m_DEFAULT_BG_COLOR          = 49,
        CSI_m_BRIGHT_FG_COLOR_BEG       = 90,
        CSI_m_BRIGHT_FG_COLOR_END       = 97,
        CSI_m_BRIGHT_FG_COLOR_OFF       = CSI_m_BRIGHT_FG_COLOR_BEG - CSI_m_FG_COLOR_BEG,
        CSI_m_BRIGHT_BG_COLOR_BEG       = 100,
        CSI_m_BRIGHT_BG_COLOR_END       = 107,
        CSI_m_BRIGHT_BG_COLOR_OFF       = CSI_m_BRIGHT_BG_COLOR_BEG - CSI_m_BG_COLOR_BEG,
};

/* console_lock is held */
static void csi_m(struct vc_data *vc)
{
        int i;

        for (i = 0; i <= vc->vc_npar; i++)
                switch (vc->vc_par[i]) {
                case CSI_m_DEFAULT:     /* all attributes off */
                        default_attr(vc);
                        break;
                case CSI_m_BOLD:
                        vc->state.intensity = VCI_BOLD;
                        break;
                case CSI_m_HALF_BRIGHT:
                        vc->state.intensity = VCI_HALF_BRIGHT;
                        break;
                case CSI_m_ITALIC:
                        vc->state.italic = true;
                        break;
                case CSI_m_DOUBLE_UNDERLINE:
                        /*
                         * No console drivers support double underline, so
                         * convert it to a single underline.
                         */
                case CSI_m_UNDERLINE:
                        vc->state.underline = true;
                        break;
                case CSI_m_BLINK:
                        vc->state.blink = true;
                        break;
                case CSI_m_REVERSE:
                        vc->state.reverse = true;
                        break;
                case CSI_m_PRI_FONT: /* ANSI X3.64-1979 (SCO-ish?)
                          * Select primary font, don't display control chars if
                          * defined, don't set bit 8 on output.
                          */
                        vc->vc_translate = set_translate(vc->state.Gx_charset[vc->state.charset], vc);
                        vc->vc_disp_ctrl = 0;
                        vc->vc_toggle_meta = 0;
                        break;
                case CSI_m_ALT_FONT1: /* ANSI X3.64-1979 (SCO-ish?)
                          * Select first alternate font, lets chars < 32 be
                          * displayed as ROM chars.
                          */
                        vc->vc_translate = set_translate(IBMPC_MAP, vc);
                        vc->vc_disp_ctrl = 1;
                        vc->vc_toggle_meta = 0;
                        break;
                case CSI_m_ALT_FONT2: /* ANSI X3.64-1979 (SCO-ish?)
                          * Select second alternate font, toggle high bit
                          * before displaying as ROM char.
                          */
                        vc->vc_translate = set_translate(IBMPC_MAP, vc);
                        vc->vc_disp_ctrl = 1;
                        vc->vc_toggle_meta = 1;
                        break;
                case CSI_m_NORMAL_INTENSITY:
                        vc->state.intensity = VCI_NORMAL;
                        break;
                case CSI_m_NO_ITALIC:
                        vc->state.italic = false;
                        break;
                case CSI_m_NO_UNDERLINE:
                        vc->state.underline = false;
                        break;
                case CSI_m_NO_BLINK:
                        vc->state.blink = false;
                        break;
                case CSI_m_NO_REVERSE:
                        vc->state.reverse = false;
                        break;
                case CSI_m_FG_COLOR:
                        i = vc_t416_color(vc, i, rgb_foreground);
                        break;
                case CSI_m_BG_COLOR:
                        i = vc_t416_color(vc, i, rgb_background);
                        break;
                case CSI_m_DEFAULT_FG_COLOR:
                        vc->state.color = (vc->vc_def_color & 0x0f) |
                                (vc->state.color & 0xf0);
                        break;
                case CSI_m_DEFAULT_BG_COLOR:
                        vc->state.color = (vc->vc_def_color & 0xf0) |
                                (vc->state.color & 0x0f);
                        break;
                case CSI_m_BRIGHT_FG_COLOR_BEG ... CSI_m_BRIGHT_FG_COLOR_END:
                        vc->state.intensity = VCI_BOLD;
                        vc->vc_par[i] -= CSI_m_BRIGHT_FG_COLOR_OFF;
                        fallthrough;
                case CSI_m_FG_COLOR_BEG ... CSI_m_FG_COLOR_END:
                        vc->vc_par[i] -= CSI_m_FG_COLOR_BEG;
                        vc->state.color = color_table[vc->vc_par[i]] |
                                (vc->state.color & 0xf0);
                        break;
                case CSI_m_BRIGHT_BG_COLOR_BEG ... CSI_m_BRIGHT_BG_COLOR_END:
                        vc->vc_par[i] -= CSI_m_BRIGHT_BG_COLOR_OFF;
                        fallthrough;
                case CSI_m_BG_COLOR_BEG ... CSI_m_BG_COLOR_END:
                        vc->vc_par[i] -= CSI_m_BG_COLOR_BEG;
                        vc->state.color = (color_table[vc->vc_par[i]] << 4) |
                                (vc->state.color & 0x0f);
                        break;
                }
        update_attr(vc);
}

static void respond_string(const char *p, size_t len, struct tty_port *port)
{
        tty_insert_flip_string(port, p, len);
        tty_flip_buffer_push(port);
}

static void cursor_report(struct vc_data *vc, struct tty_struct *tty)
{
        char buf[40];
        int len;

        len = sprintf(buf, "\033[%d;%dR", vc->state.y +
                        (vc->vc_decom ? vc->vc_top + 1 : 1),
                        vc->state.x + 1);
        respond_string(buf, len, tty->port);
}

static inline void status_report(struct tty_struct *tty)
{
        static const char teminal_ok[] = "\033[0n";

        respond_string(teminal_ok, strlen(teminal_ok), tty->port);
}

static inline void respond_ID(struct tty_struct *tty)
{
        /* terminal answer to an ESC-Z or csi0c query. */
        static const char vt102_id[] = "\033[?6c";

        respond_string(vt102_id, strlen(vt102_id), tty->port);
}

void mouse_report(struct tty_struct *tty, int butt, int mrx, int mry)
{
        char buf[8];
        int len;

        len = sprintf(buf, "\033[M%c%c%c", (char)(' ' + butt),
                        (char)('!' + mrx), (char)('!' + mry));
        respond_string(buf, len, tty->port);
}

/* invoked via ioctl(TIOCLINUX) and through set_selection_user */
int mouse_reporting(void)
{
        return vc_cons[fg_console].d->vc_report_mouse;
}

/* invoked via ioctl(TIOCLINUX) */
static int get_bracketed_paste(struct tty_struct *tty)
{
        struct vc_data *vc = tty->driver_data;

        return vc->vc_bracketed_paste;
}

/* console_lock is held */
static void enter_alt_screen(struct vc_data *vc)
{
        unsigned int size = vc->vc_rows * vc->vc_cols * 2;

        if (vc->vc_saved_screen != NULL)
                return; /* Already inside an alt-screen */
        vc->vc_saved_screen = kmemdup((u16 *)vc->vc_origin, size, GFP_KERNEL);
        if (vc->vc_saved_screen == NULL)
                return;
        vc->vc_saved_uni_lines = vc->vc_uni_lines;
        vc->vc_uni_lines = NULL;
        vc->vc_saved_rows = vc->vc_rows;
        vc->vc_saved_cols = vc->vc_cols;
        save_cur(vc);
        /* clear entire screen */
        csi_J(vc, CSI_J_FULL);
}

/* console_lock is held */
static void leave_alt_screen(struct vc_data *vc)
{
        unsigned int rows = min(vc->vc_saved_rows, vc->vc_rows);
        unsigned int cols = min(vc->vc_saved_cols, vc->vc_cols);
        u16 *src, *dest;

        if (vc->vc_saved_screen == NULL)
                return; /* Not inside an alt-screen */
        for (unsigned int r = 0; r < rows; r++) {
                src = vc->vc_saved_screen + r * vc->vc_saved_cols;
                dest = ((u16 *)vc->vc_origin) + r * vc->vc_cols;
                memcpy(dest, src, 2 * cols);
        }
        /*
         * If the console was resized while in the alternate screen,
         * resize the saved unicode buffer to the current dimensions.
         * On allocation failure new_uniscr is NULL, causing the old
         * buffer to be freed and vc_uni_lines to be lazily rebuilt
         * via vc_uniscr_check() when next needed.
         */
        if (vc->vc_saved_uni_lines &&
            (vc->vc_saved_rows != vc->vc_rows ||
             vc->vc_saved_cols != vc->vc_cols)) {
                u32 **new_uniscr = vc_uniscr_alloc(vc->vc_cols, vc->vc_rows);

                if (new_uniscr)
                        vc_uniscr_copy_area(new_uniscr, vc->vc_cols, vc->vc_rows,
                                            vc->vc_saved_uni_lines, cols, 0, rows);
                vc_uniscr_free(vc->vc_saved_uni_lines);
                vc->vc_saved_uni_lines = new_uniscr;
        }
        vc_uniscr_set(vc, vc->vc_saved_uni_lines);
        vc->vc_saved_uni_lines = NULL;
        restore_cur(vc);
        /* Update the entire screen */
        if (con_should_update(vc))
                do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
        kfree(vc->vc_saved_screen);
        vc->vc_saved_screen = NULL;
}

enum {
        CSI_DEC_hl_CURSOR_KEYS  = 1,    /* CKM: cursor keys send ^[Ox/^[[x */
        CSI_DEC_hl_132_COLUMNS  = 3,    /* COLM: 80/132 mode switch */
        CSI_DEC_hl_REVERSE_VIDEO = 5,   /* SCNM */
        CSI_DEC_hl_ORIGIN_MODE  = 6,    /* OM: origin relative/absolute */
        CSI_DEC_hl_AUTOWRAP     = 7,    /* AWM */
        CSI_DEC_hl_AUTOREPEAT   = 8,    /* ARM */
        CSI_DEC_hl_MOUSE_X10    = 9,
        CSI_DEC_hl_SHOW_CURSOR  = 25,   /* TCEM */
        CSI_DEC_hl_MOUSE_VT200  = 1000,
        CSI_DEC_hl_ALT_SCREEN   = 1049,
        CSI_DEC_hl_BRACKETED_PASTE = 2004,
};

/* console_lock is held */
static void csi_DEC_hl(struct vc_data *vc, bool on_off)
{
        unsigned int i;

        for (i = 0; i <= vc->vc_npar; i++)
                switch (vc->vc_par[i]) {
                case CSI_DEC_hl_CURSOR_KEYS:
                        if (on_off)
                                set_kbd(vc, decckm);
                        else
                                clr_kbd(vc, decckm);
                        break;
                case CSI_DEC_hl_132_COLUMNS:    /* unimplemented */
#if 0
                        vc_resize(deccolm ? 132 : 80, vc->vc_rows);
                        /* this alone does not suffice; some user mode
                           utility has to change the hardware regs */
#endif
                        break;
                case CSI_DEC_hl_REVERSE_VIDEO:
                        if (vc->vc_decscnm != on_off) {
                                vc->vc_decscnm = on_off;
                                invert_screen(vc, 0, vc->vc_screenbuf_size,
                                              false);
                                update_attr(vc);
                        }
                        break;
                case CSI_DEC_hl_ORIGIN_MODE:
                        vc->vc_decom = on_off;
                        gotoxay(vc, 0, 0);
                        break;
                case CSI_DEC_hl_AUTOWRAP:
                        vc->vc_decawm = on_off;
                        break;
                case CSI_DEC_hl_AUTOREPEAT:
                        if (on_off)
                                set_kbd(vc, decarm);
                        else
                                clr_kbd(vc, decarm);
                        break;
                case CSI_DEC_hl_MOUSE_X10:
                        vc->vc_report_mouse = on_off ? 1 : 0;
                        break;
                case CSI_DEC_hl_SHOW_CURSOR:
                        vc->vc_deccm = on_off;
                        break;
                case CSI_DEC_hl_MOUSE_VT200:
                        vc->vc_report_mouse = on_off ? 2 : 0;
                        break;
                case CSI_DEC_hl_BRACKETED_PASTE:
                        vc->vc_bracketed_paste = on_off;
                        break;
                case CSI_DEC_hl_ALT_SCREEN:
                        if (on_off)
                                enter_alt_screen(vc);
                        else
                                leave_alt_screen(vc);
                        break;
                }
}

enum {
        CSI_hl_DISPLAY_CTRL     = 3,    /* handle ansi control chars */
        CSI_hl_INSERT           = 4,    /* IRM: insert/replace */
        CSI_hl_AUTO_NL          = 20,   /* LNM: Enter == CrLf/Lf */
};

/* console_lock is held */
static void csi_hl(struct vc_data *vc, bool on_off)
{
        unsigned int i;

        for (i = 0; i <= vc->vc_npar; i++)
                switch (vc->vc_par[i]) {        /* ANSI modes set/reset */
                case CSI_hl_DISPLAY_CTRL:
                        vc->vc_disp_ctrl = on_off;
                        break;
                case CSI_hl_INSERT:
                        vc->vc_decim = on_off;
                        break;
                case CSI_hl_AUTO_NL:
                        if (on_off)
                                set_kbd(vc, lnm);
                        else
                                clr_kbd(vc, lnm);
                        break;
                }
}

enum CSI_right_square_bracket {
        CSI_RSB_COLOR_FOR_UNDERLINE             = 1,
        CSI_RSB_COLOR_FOR_HALF_BRIGHT           = 2,
        CSI_RSB_MAKE_CUR_COLOR_DEFAULT          = 8,
        CSI_RSB_BLANKING_INTERVAL               = 9,
        CSI_RSB_BELL_FREQUENCY                  = 10,
        CSI_RSB_BELL_DURATION                   = 11,
        CSI_RSB_BRING_CONSOLE_TO_FRONT          = 12,
        CSI_RSB_UNBLANK                         = 13,
        CSI_RSB_VESA_OFF_INTERVAL               = 14,
        CSI_RSB_BRING_PREV_CONSOLE_TO_FRONT     = 15,
        CSI_RSB_CURSOR_BLINK_INTERVAL           = 16,
};

/*
 * csi_RSB - csi+] (Right Square Bracket) handler
 *
 * These are linux console private sequences.
 *
 * console_lock is held
 */
static void csi_RSB(struct vc_data *vc)
{
        switch (vc->vc_par[0]) {
        case CSI_RSB_COLOR_FOR_UNDERLINE:
                if (vc->vc_can_do_color && vc->vc_par[1] < 16) {
                        vc->vc_ulcolor = color_table[vc->vc_par[1]];
                        if (vc->state.underline)
                                update_attr(vc);
                }
                break;
        case CSI_RSB_COLOR_FOR_HALF_BRIGHT:
                if (vc->vc_can_do_color && vc->vc_par[1] < 16) {
                        vc->vc_halfcolor = color_table[vc->vc_par[1]];
                        if (vc->state.intensity == VCI_HALF_BRIGHT)
                                update_attr(vc);
                }
                break;
        case CSI_RSB_MAKE_CUR_COLOR_DEFAULT:
                vc->vc_def_color = vc->vc_attr;
                if (vc->vc_hi_font_mask == 0x100)
                        vc->vc_def_color >>= 1;
                default_attr(vc);
                update_attr(vc);
                break;
        case CSI_RSB_BLANKING_INTERVAL:
                blankinterval = min(vc->vc_par[1], 60U) * 60;
                poke_blanked_console();
                break;
        case CSI_RSB_BELL_FREQUENCY:
                if (vc->vc_npar >= 1)
                        vc->vc_bell_pitch = vc->vc_par[1];
                else
                        vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
                break;
        case CSI_RSB_BELL_DURATION:
                if (vc->vc_npar >= 1)
                        vc->vc_bell_duration = (vc->vc_par[1] < 2000) ?
                                msecs_to_jiffies(vc->vc_par[1]) : 0;
                else
                        vc->vc_bell_duration = DEFAULT_BELL_DURATION;
                break;
        case CSI_RSB_BRING_CONSOLE_TO_FRONT:
                if (vc->vc_par[1] >= 1 && vc_cons_allocated(vc->vc_par[1] - 1))
                        set_console(vc->vc_par[1] - 1);
                break;
        case CSI_RSB_UNBLANK:
                poke_blanked_console();
                break;
        case CSI_RSB_VESA_OFF_INTERVAL:
                vesa_off_interval = min(vc->vc_par[1], 60U) * 60 * HZ;
                break;
        case CSI_RSB_BRING_PREV_CONSOLE_TO_FRONT:
                set_console(last_console);
                break;
        case CSI_RSB_CURSOR_BLINK_INTERVAL:
                if (vc->vc_npar >= 1 && vc->vc_par[1] >= 50 &&
                                vc->vc_par[1] <= USHRT_MAX)
                        vc->vc_cur_blink_ms = vc->vc_par[1];
                else
                        vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
                break;
        }
}

/* console_lock is held */
static void csi_at(struct vc_data *vc, unsigned int nr)
{
        nr = clamp(nr, 1, vc->vc_cols - vc->state.x);
        insert_char(vc, nr);
}

/* console_lock is held */
static void csi_L(struct vc_data *vc)
{
        unsigned int nr = clamp(vc->vc_par[0], 1, vc->vc_rows - vc->state.y);

        con_scroll(vc, vc->state.y, vc->vc_bottom, SM_DOWN, nr);
        vc->vc_need_wrap = 0;
}

/* console_lock is held */
static void csi_P(struct vc_data *vc)
{
        unsigned int nr = clamp(vc->vc_par[0], 1, vc->vc_cols - vc->state.x);

        delete_char(vc, nr);
}

/* console_lock is held */
static void csi_M(struct vc_data *vc)
{
        unsigned int nr = clamp(vc->vc_par[0], 1, vc->vc_rows - vc->state.y);

        con_scroll(vc, vc->state.y, vc->vc_bottom, SM_UP, nr);
        vc->vc_need_wrap = 0;
}

/* console_lock is held (except via vc_init->reset_terminal */
static void save_cur(struct vc_data *vc)
{
        memcpy(&vc->saved_state, &vc->state, sizeof(vc->state));
}

/* console_lock is held */
static void restore_cur(struct vc_data *vc)
{
        memcpy(&vc->state, &vc->saved_state, sizeof(vc->state));

        gotoxy(vc, vc->state.x, vc->state.y);
        vc->vc_translate = set_translate(vc->state.Gx_charset[vc->state.charset],
                        vc);
        update_attr(vc);
        vc->vc_need_wrap = 0;
}

/**
 * enum vc_ctl_state - control characters state of a vt
 *
 * @ESnormal:           initial state, no control characters parsed
 * @ESesc:              ESC parsed
 * @ESsquare:           CSI parsed -- modifiers/parameters/ctrl chars expected
 * @ESgetpars:          CSI parsed -- parameters/ctrl chars expected
 * @ESfunckey:          CSI [ parsed
 * @EShash:             ESC # parsed
 * @ESsetG0:            ESC ( parsed
 * @ESsetG1:            ESC ) parsed
 * @ESpercent:          ESC % parsed
 * @EScsiignore:        CSI [0x20-0x3f] parsed
 * @ESnonstd:           OSC parsed
 * @ESpalette:          OSC P parsed
 * @ESosc:              OSC [0-9] parsed
 * @ESANSI_first:       first state for ignoring ansi control sequences
 * @ESapc:              ESC _ parsed
 * @ESpm:               ESC ^ parsed
 * @ESdcs:              ESC P parsed
 * @ESANSI_last:        last state for ignoring ansi control sequences
 */
enum vc_ctl_state {
        ESnormal,
        ESesc,
        ESsquare,
        ESgetpars,
        ESfunckey,
        EShash,
        ESsetG0,
        ESsetG1,
        ESpercent,
        EScsiignore,
        ESnonstd,
        ESpalette,
        ESosc,
        ESANSI_first = ESosc,
        ESapc,
        ESpm,
        ESdcs,
        ESANSI_last = ESdcs,
};

/* console_lock is held (except via vc_init()) */
static void reset_terminal(struct vc_data *vc, int do_clear)
{
        unsigned int i;

        vc->vc_top              = 0;
        vc->vc_bottom           = vc->vc_rows;
        vc->vc_state            = ESnormal;
        vc->vc_priv             = EPecma;
        vc->vc_translate        = set_translate(LAT1_MAP, vc);
        vc->state.Gx_charset[0] = LAT1_MAP;
        vc->state.Gx_charset[1] = GRAF_MAP;
        vc->state.charset       = 0;
        vc->vc_need_wrap        = 0;
        vc->vc_report_mouse     = 0;
        vc->vc_bracketed_paste  = 0;
        vc->vc_utf              = default_utf8;
        vc->vc_utf_count        = 0;

        vc->vc_disp_ctrl        = 0;
        vc->vc_toggle_meta      = 0;

        vc->vc_decscnm          = 0;
        vc->vc_decom            = 0;
        vc->vc_decawm           = 1;
        vc->vc_deccm            = global_cursor_default;
        vc->vc_decim            = 0;

        if (vc->vc_saved_screen != NULL) {
                kfree(vc->vc_saved_screen);
                vc->vc_saved_screen = NULL;
                vc_uniscr_free(vc->vc_saved_uni_lines);
                vc->vc_saved_uni_lines = NULL;
                vc->vc_saved_rows = 0;
                vc->vc_saved_cols = 0;
        }

        vt_reset_keyboard(vc->vc_num);

        vc->vc_cursor_type = cur_default;
        vc->vc_complement_mask = vc->vc_s_complement_mask;

        default_attr(vc);
        update_attr(vc);

        bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT);
        for (i = 0; i < VC_TABSTOPS_COUNT; i += 8)
                set_bit(i, vc->vc_tab_stop);

        vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
        vc->vc_bell_duration = DEFAULT_BELL_DURATION;
        vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;

        gotoxy(vc, 0, 0);
        save_cur(vc);
        if (do_clear)
            csi_J(vc, CSI_J_VISIBLE);
}

static void vc_setGx(struct vc_data *vc, unsigned int which, u8 c)
{
        unsigned char *charset = &vc->state.Gx_charset[which];

        switch (c) {
        case '0':
                *charset = GRAF_MAP;
                break;
        case 'B':
                *charset = LAT1_MAP;
                break;
        case 'U':
                *charset = IBMPC_MAP;
                break;
        case 'K':
                *charset = USER_MAP;
                break;
        }

        if (vc->state.charset == which)
                vc->vc_translate = set_translate(*charset, vc);
}

static bool ansi_control_string(enum vc_ctl_state state)
{
        return state >= ESANSI_first && state <= ESANSI_last;
}

enum {
        ASCII_NULL              = 0,
        ASCII_BELL              = 7,
        ASCII_BACKSPACE         = 8,
        ASCII_IGNORE_FIRST      = ASCII_BACKSPACE,
        ASCII_HTAB              = 9,
        ASCII_LINEFEED          = 10,
        ASCII_VTAB              = 11,
        ASCII_FORMFEED          = 12,
        ASCII_CAR_RET           = 13,
        ASCII_IGNORE_LAST       = ASCII_CAR_RET,
        ASCII_SHIFTOUT          = 14,
        ASCII_SHIFTIN           = 15,
        ASCII_CANCEL            = 24,
        ASCII_SUBSTITUTE        = 26,
        ASCII_ESCAPE            = 27,
        ASCII_CSI_IGNORE_FIRST  = ' ', /* 0x2x, 0x3a and 0x3c - 0x3f */
        ASCII_CSI_IGNORE_LAST   = '?',
        ASCII_DEL               = 127,
        ASCII_EXT_CSI           = 128 + ASCII_ESCAPE,
};

/*
 * Handle ascii characters in control sequences and change states accordingly.
 * E.g. ESC sets the state of vc to ESesc.
 *
 * Returns: true if @c handled.
 */
static bool handle_ascii(struct tty_struct *tty, struct vc_data *vc, u8 c)
{
        switch (c) {
        case ASCII_NULL:
                return true;
        case ASCII_BELL:
                if (ansi_control_string(vc->vc_state))
                        vc->vc_state = ESnormal;
                else if (vc->vc_bell_duration)
                        kd_mksound(vc->vc_bell_pitch, vc->vc_bell_duration);
                return true;
        case ASCII_BACKSPACE:
                bs(vc);
                return true;
        case ASCII_HTAB:
                vc->vc_pos -= (vc->state.x << 1);

                vc->state.x = find_next_bit(vc->vc_tab_stop,
                                min(vc->vc_cols - 1, VC_TABSTOPS_COUNT),
                                vc->state.x + 1);
                if (vc->state.x >= VC_TABSTOPS_COUNT)
                        vc->state.x = vc->vc_cols - 1;

                vc->vc_pos += (vc->state.x << 1);
                notify_write(vc, '\t');
                return true;
        case ASCII_LINEFEED:
        case ASCII_VTAB:
        case ASCII_FORMFEED:
                lf(vc);
                if (!is_kbd(vc, lnm))
                        return true;
                fallthrough;
        case ASCII_CAR_RET:
                cr(vc);
                return true;
        case ASCII_SHIFTOUT:
                vc->state.charset = 1;
                vc->vc_translate = set_translate(vc->state.Gx_charset[1], vc);
                vc->vc_disp_ctrl = 1;
                return true;
        case ASCII_SHIFTIN:
                vc->state.charset = 0;
                vc->vc_translate = set_translate(vc->state.Gx_charset[0], vc);
                vc->vc_disp_ctrl = 0;
                return true;
        case ASCII_CANCEL:
        case ASCII_SUBSTITUTE:
                vc->vc_state = ESnormal;
                return true;
        case ASCII_ESCAPE:
                vc->vc_state = ESesc;
                return true;
        case ASCII_DEL:
                del(vc);
                return true;
        case ASCII_EXT_CSI:
                vc->vc_state = ESsquare;
                return true;
        }

        return false;
}

/*
 * Handle a character (@c) following an ESC (when @vc is in the ESesc state).
 * E.g. previous ESC with @c == '[' here yields the ESsquare state (that is:
 * CSI).
 */
static void handle_esc(struct tty_struct *tty, struct vc_data *vc, u8 c)
{
        vc->vc_state = ESnormal;
        switch (c) {
        case '[':
                vc->vc_state = ESsquare;
                break;
        case ']':
                vc->vc_state = ESnonstd;
                break;
        case '_':
                vc->vc_state = ESapc;
                break;
        case '^':
                vc->vc_state = ESpm;
                break;
        case '%':
                vc->vc_state = ESpercent;
                break;
        case 'E':
                cr(vc);
                lf(vc);
                break;
        case 'M':
                ri(vc);
                break;
        case 'D':
                lf(vc);
                break;
        case 'H':
                if (vc->state.x < VC_TABSTOPS_COUNT)
                        set_bit(vc->state.x, vc->vc_tab_stop);
                break;
        case 'P':
                vc->vc_state = ESdcs;
                break;
        case 'Z':
                respond_ID(tty);
                break;
        case '7':
                save_cur(vc);
                break;
        case '8':
                restore_cur(vc);
                break;
        case '(':
                vc->vc_state = ESsetG0;
                break;
        case ')':
                vc->vc_state = ESsetG1;
                break;
        case '#':
                vc->vc_state = EShash;
                break;
        case 'c':
                reset_terminal(vc, 1);
                break;
        case '>':  /* Numeric keypad */
                clr_kbd(vc, kbdapplic);
                break;
        case '=':  /* Appl. keypad */
                set_kbd(vc, kbdapplic);
                break;
        }
}

/*
 * Handle special DEC control sequences ("ESC [ ? parameters char"). Parameters
 * are in @vc->vc_par and the char is in @c here.
 */
static void csi_DEC(struct tty_struct *tty, struct vc_data *vc, u8 c)
{
        switch (c) {
        case 'h':
                csi_DEC_hl(vc, true);
                break;
        case 'l':
                csi_DEC_hl(vc, false);
                break;
        case 'c':
                if (vc->vc_par[0])
                        vc->vc_cursor_type = CUR_MAKE(vc->vc_par[0],
                                                      vc->vc_par[1],
                                                      vc->vc_par[2]);
                else
                        vc->vc_cursor_type = cur_default;
                break;
        case 'm':
                clear_selection();
                if (vc->vc_par[0])
                        vc->vc_complement_mask = vc->vc_par[0] << 8 | vc->vc_par[1];
                else
                        vc->vc_complement_mask = vc->vc_s_complement_mask;
                break;
        case 'n':
                if (vc->vc_par[0] == 5)
                        status_report(tty);
                else if (vc->vc_par[0] == 6)
                        cursor_report(vc, tty);
                break;
        }
}

/*
 * Handle Control Sequence Introducer control characters. That is
 * "ESC [ parameters char". Parameters are in @vc->vc_par and the char is in
 * @c here.
 */
static void csi_ECMA(struct tty_struct *tty, struct vc_data *vc, u8 c)
{
        switch (c) {
        case 'G':
        case '`':
                if (vc->vc_par[0])
                        vc->vc_par[0]--;
                gotoxy(vc, vc->vc_par[0], vc->state.y);
                break;
        case 'A':
                if (!vc->vc_par[0])
                        vc->vc_par[0]++;
                gotoxy(vc, vc->state.x, vc->state.y - vc->vc_par[0]);
                break;
        case 'B':
        case 'e':
                if (!vc->vc_par[0])
                        vc->vc_par[0]++;
                gotoxy(vc, vc->state.x, vc->state.y + vc->vc_par[0]);
                break;
        case 'C':
        case 'a':
                if (!vc->vc_par[0])
                        vc->vc_par[0]++;
                gotoxy(vc, vc->state.x + vc->vc_par[0], vc->state.y);
                break;
        case 'D':
                if (!vc->vc_par[0])
                        vc->vc_par[0]++;
                gotoxy(vc, vc->state.x - vc->vc_par[0], vc->state.y);
                break;
        case 'E':
                if (!vc->vc_par[0])
                        vc->vc_par[0]++;
                gotoxy(vc, 0, vc->state.y + vc->vc_par[0]);
                break;
        case 'F':
                if (!vc->vc_par[0])
                        vc->vc_par[0]++;
                gotoxy(vc, 0, vc->state.y - vc->vc_par[0]);
                break;
        case 'd':
                if (vc->vc_par[0])
                        vc->vc_par[0]--;
                gotoxay(vc, vc->state.x ,vc->vc_par[0]);
                break;
        case 'H':
        case 'f':
                if (vc->vc_par[0])
                        vc->vc_par[0]--;
                if (vc->vc_par[1])
                        vc->vc_par[1]--;
                gotoxay(vc, vc->vc_par[1], vc->vc_par[0]);
                break;
        case 'J':
                csi_J(vc, vc->vc_par[0]);
                break;
        case 'K':
                csi_K(vc);
                break;
        case 'L':
                csi_L(vc);
                break;
        case 'M':
                csi_M(vc);
                break;
        case 'P':
                csi_P(vc);
                break;
        case 'c':
                if (!vc->vc_par[0])
                        respond_ID(tty);
                break;
        case 'g':
                if (!vc->vc_par[0] && vc->state.x < VC_TABSTOPS_COUNT)
                        set_bit(vc->state.x, vc->vc_tab_stop);
                else if (vc->vc_par[0] == 3)
                        bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT);
                break;
        case 'h':
                csi_hl(vc, true);
                break;
        case 'l':
                csi_hl(vc, false);
                break;
        case 'm':
                csi_m(vc);
                break;
        case 'n':
                if (vc->vc_par[0] == 5)
                        status_report(tty);
                else if (vc->vc_par[0] == 6)
                        cursor_report(vc, tty);
                break;
        case 'q': /* DECLL - but only 3 leds */
                /* map 0,1,2,3 to 0,1,2,4 */
                if (vc->vc_par[0] < 4)
                        vt_set_led_state(vc->vc_num,
                                    (vc->vc_par[0] < 3) ? vc->vc_par[0] : 4);
                break;
        case 'r':
                if (!vc->vc_par[0])
                        vc->vc_par[0]++;
                if (!vc->vc_par[1])
                        vc->vc_par[1] = vc->vc_rows;
                /* Minimum allowed region is 2 lines */
                if (vc->vc_par[0] < vc->vc_par[1] &&
                    vc->vc_par[1] <= vc->vc_rows) {
                        vc->vc_top = vc->vc_par[0] - 1;
                        vc->vc_bottom = vc->vc_par[1];
                        gotoxay(vc, 0, 0);
                }
                break;
        case 's':
                save_cur(vc);
                break;
        case 'u':
                restore_cur(vc);
                break;
        case 'X':
                csi_X(vc);
                break;
        case '@':
                csi_at(vc, vc->vc_par[0]);
                break;
        case ']':
                csi_RSB(vc);
                break;
        }

}

static void vc_reset_params(struct vc_data *vc)
{
        memset(vc->vc_par, 0, sizeof(vc->vc_par));
        vc->vc_npar = 0;
}

/* console_lock is held */
static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, u8 c)
{
        /*
         *  Control characters can be used in the _middle_
         *  of an escape sequence, aside from ANSI control strings.
         */
        if (ansi_control_string(vc->vc_state) && c >= ASCII_IGNORE_FIRST &&
            c <= ASCII_IGNORE_LAST)
                return;

        if (handle_ascii(tty, vc, c))
                return;

        switch(vc->vc_state) {
        case ESesc:     /* ESC */
                handle_esc(tty, vc, c);
                return;
        case ESnonstd:  /* ESC ] aka OSC */
                switch (c) {
                case 'P': /* palette escape sequence */
                        vc_reset_params(vc);
                        vc->vc_state = ESpalette;
                        return;
                case 'R': /* reset palette */
                        reset_palette(vc);
                        break;
                case '0' ... '9':
                        vc->vc_state = ESosc;
                        return;
                }
                vc->vc_state = ESnormal;
                return;
        case ESpalette: /* ESC ] P aka OSC P */
                if (isxdigit(c)) {
                        vc->vc_par[vc->vc_npar++] = hex_to_bin(c);
                        if (vc->vc_npar == 7) {
                                int i = vc->vc_par[0] * 3, j = 1;
                                vc->vc_palette[i] = 16 * vc->vc_par[j++];
                                vc->vc_palette[i++] += vc->vc_par[j++];
                                vc->vc_palette[i] = 16 * vc->vc_par[j++];
                                vc->vc_palette[i++] += vc->vc_par[j++];
                                vc->vc_palette[i] = 16 * vc->vc_par[j++];
                                vc->vc_palette[i] += vc->vc_par[j];
                                set_palette(vc);
                                vc->vc_state = ESnormal;
                        }
                } else
                        vc->vc_state = ESnormal;
                return;
        case ESsquare:  /* ESC [ aka CSI, parameters or modifiers expected */
                vc_reset_params(vc);

                vc->vc_state = ESgetpars;
                switch (c) {
                case '[': /* Function key */
                        vc->vc_state = ESfunckey;
                        return;
                case '?':
                        vc->vc_priv = EPdec;
                        return;
                case '>':
                        vc->vc_priv = EPgt;
                        return;
                case '=':
                        vc->vc_priv = EPeq;
                        return;
                case '<':
                        vc->vc_priv = EPlt;
                        return;
                }
                vc->vc_priv = EPecma;
                fallthrough;
        case ESgetpars: /* ESC [ aka CSI, parameters expected */
                switch (c) {
                case ';':
                        if (vc->vc_npar < NPAR - 1) {
                                vc->vc_npar++;
                                return;
                        }
                        break;
                case '0' ... '9':
                        vc->vc_par[vc->vc_npar] *= 10;
                        vc->vc_par[vc->vc_npar] += c - '0';
                        return;
                }
                if (c >= ASCII_CSI_IGNORE_FIRST && c <= ASCII_CSI_IGNORE_LAST) {
                        vc->vc_state = EScsiignore;
                        return;
                }

                /* parameters done, handle the control char @c */

                vc->vc_state = ESnormal;

                switch (vc->vc_priv) {
                case EPdec:
                        csi_DEC(tty, vc, c);
                        return;
                case EPecma:
                        csi_ECMA(tty, vc, c);
                        return;
                default:
                        return;
                }
        case EScsiignore:
                if (c >= ASCII_CSI_IGNORE_FIRST && c <= ASCII_CSI_IGNORE_LAST)
                        return;
                vc->vc_state = ESnormal;
                return;
        case ESpercent: /* ESC % */
                vc->vc_state = ESnormal;
                switch (c) {
                case '@':  /* defined in ISO 2022 */
                        vc->vc_utf = 0;
                        return;
                case 'G':  /* prelim official escape code */
                case '8':  /* retained for compatibility */
                        vc->vc_utf = 1;
                        return;
                }
                return;
        case ESfunckey: /* ESC [ [ aka CSI [ */
                vc->vc_state = ESnormal;
                return;
        case EShash:    /* ESC # */
                vc->vc_state = ESnormal;
                if (c == '8') {
                        /* DEC screen alignment test. kludge :-) */
                        vc->vc_video_erase_char =
                                (vc->vc_video_erase_char & 0xff00) | 'E';
                        csi_J(vc, CSI_J_VISIBLE);
                        vc->vc_video_erase_char =
                                (vc->vc_video_erase_char & 0xff00) | ' ';
                        do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
                }
                return;
        case ESsetG0:   /* ESC ( */
                vc_setGx(vc, 0, c);
                vc->vc_state = ESnormal;
                return;
        case ESsetG1:   /* ESC ) */
                vc_setGx(vc, 1, c);
                vc->vc_state = ESnormal;
                return;
        case ESapc:     /* ESC _ */
                return;
        case ESosc:     /* ESC ] [0-9] aka OSC [0-9] */
                return;
        case ESpm:      /* ESC ^ */
                return;
        case ESdcs:     /* ESC P */
                return;
        default:
                vc->vc_state = ESnormal;
        }
}

struct vc_draw_region {
        unsigned long from, to;
        int x;
};

static void con_flush(struct vc_data *vc, struct vc_draw_region *draw)
{
        if (draw->x < 0)
                return;

        vc->vc_sw->con_putcs(vc, (u16 *)draw->from,
                        (u16 *)draw->to - (u16 *)draw->from, vc->state.y,
                        draw->x);
        draw->x = -1;
}

static inline int vc_translate_ascii(const struct vc_data *vc, int c)
{
        if (IS_ENABLED(CONFIG_CONSOLE_TRANSLATIONS)) {
                if (vc->vc_toggle_meta)
                        c |= 0x80;

                return vc->vc_translate[c];
        }

        return c;
}


/**
 * vc_sanitize_unicode - Replace invalid Unicode code points with ``U+FFFD``
 * @c: the received code point
 */
static inline int vc_sanitize_unicode(const int c)
{
        if (c >= 0xd800 && c <= 0xdfff)
                return 0xfffd;

        return c;
}

/**
 * vc_translate_unicode - Combine UTF-8 into Unicode in &vc_data.vc_utf_char
 * @vc: virtual console
 * @c: UTF-8 byte to translate
 * @rescan: set to true iff @c wasn't consumed here and needs to be re-processed
 *
 * * &vc_data.vc_utf_char is the being-constructed Unicode code point.
 * * &vc_data.vc_utf_count is the number of continuation bytes still expected to
 *   arrive.
 * * &vc_data.vc_npar is the number of continuation bytes arrived so far.
 *
 * Return:
 * * %-1 - Input OK so far, @c consumed, further bytes expected.
 * * %0xFFFD - Possibility 1: input invalid, @c may have been consumed (see
 *             desc. of @rescan). Possibility 2: input OK, @c consumed,
 *             ``U+FFFD`` is the resulting code point. ``U+FFFD`` is valid,
 *             ``REPLACEMENT CHARACTER``.
 * * otherwise - Input OK, @c consumed, resulting code point returned.
 */
static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
{
        static const u32 utf8_length_changes[] = {0x7f, 0x7ff, 0xffff, 0x10ffff};

        /* Continuation byte received */
        if ((c & 0xc0) == 0x80) {
                /* Unexpected continuation byte? */
                if (!vc->vc_utf_count)
                        goto bad_sequence;

                vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
                vc->vc_npar++;
                if (--vc->vc_utf_count)
                        goto need_more_bytes;

                /* Got a whole character */
                c = vc->vc_utf_char;
                /* Reject overlong sequences */
                if (c <= utf8_length_changes[vc->vc_npar - 1] ||
                                c > utf8_length_changes[vc->vc_npar])
                        goto bad_sequence;

                return vc_sanitize_unicode(c);
        }

        /* Single ASCII byte or first byte of a sequence received */
        if (vc->vc_utf_count) {
                /* A continuation byte was expected */
                *rescan = true;
                vc->vc_utf_count = 0;
                goto bad_sequence;
        }

        /* Nothing to do if an ASCII byte was received */
        if (c <= 0x7f)
                return c;

        /* First byte of a multibyte sequence received */
        vc->vc_npar = 0;
        if ((c & 0xe0) == 0xc0) {
                vc->vc_utf_count = 1;
                vc->vc_utf_char = (c & 0x1f);
        } else if ((c & 0xf0) == 0xe0) {
                vc->vc_utf_count = 2;
                vc->vc_utf_char = (c & 0x0f);
        } else if ((c & 0xf8) == 0xf0) {
                vc->vc_utf_count = 3;
                vc->vc_utf_char = (c & 0x07);
        } else {
                goto bad_sequence;
        }

need_more_bytes:
        return -1;

bad_sequence:
        return 0xfffd;
}

static int vc_translate(struct vc_data *vc, int *c, bool *rescan)
{
        /* Do no translation at all in control states */
        if (vc->vc_state != ESnormal)
                return *c;

        if (vc->vc_utf && !vc->vc_disp_ctrl)
                return *c = vc_translate_unicode(vc, *c, rescan);

        /* no utf or alternate charset mode */
        return vc_translate_ascii(vc, *c);
}

static inline unsigned char vc_invert_attr(const struct vc_data *vc)
{
        if (!vc->vc_can_do_color)
                return vc->vc_attr ^ 0x08;

        if (vc->vc_hi_font_mask == 0x100)
                return   (vc->vc_attr & 0x11) |
                        ((vc->vc_attr & 0xe0) >> 4) |
                        ((vc->vc_attr & 0x0e) << 4);

        return   (vc->vc_attr & 0x88) |
                ((vc->vc_attr & 0x70) >> 4) |
                ((vc->vc_attr & 0x07) << 4);
}

static bool vc_is_control(struct vc_data *vc, int tc, int c)
{
        /*
         * A bitmap for codes <32. A bit of 1 indicates that the code
         * corresponding to that bit number invokes some special action (such
         * as cursor movement) and should not be displayed as a glyph unless
         * the disp_ctrl mode is explicitly enabled.
         */
        static const u32 CTRL_ACTION = BIT(ASCII_NULL) |
                GENMASK(ASCII_SHIFTIN, ASCII_BELL) | BIT(ASCII_CANCEL) |
                BIT(ASCII_SUBSTITUTE) | BIT(ASCII_ESCAPE);
        /* Cannot be overridden by disp_ctrl */
        static const u32 CTRL_ALWAYS = BIT(ASCII_NULL) | BIT(ASCII_BACKSPACE) |
                BIT(ASCII_LINEFEED) | BIT(ASCII_SHIFTIN) | BIT(ASCII_SHIFTOUT) |
                BIT(ASCII_CAR_RET) | BIT(ASCII_FORMFEED) | BIT(ASCII_ESCAPE);

        if (vc->vc_state != ESnormal)
                return true;

        if (!tc)
                return true;

        /*
         * If the original code was a control character we only allow a glyph
         * to be displayed if the code is not normally used (such as for cursor
         * movement) or if the disp_ctrl mode has been explicitly enabled.
         * Certain characters (as given by the CTRL_ALWAYS bitmap) are always
         * displayed as control characters, as the console would be pretty
         * useless without them; to display an arbitrary font position use the
         * direct-to-font zone in UTF-8 mode.
         */
        if (c < BITS_PER_TYPE(CTRL_ALWAYS)) {
                if (vc->vc_disp_ctrl)
                        return CTRL_ALWAYS & BIT(c);
                else
                        return vc->vc_utf || (CTRL_ACTION & BIT(c));
        }

        if (c == ASCII_DEL && !vc->vc_disp_ctrl)
                return true;

        if (c == ASCII_EXT_CSI)
                return true;

        return false;
}

static void vc_con_rewind(struct vc_data *vc)
{
        if (vc->state.x && !vc->vc_need_wrap) {
                vc->vc_pos -= 2;
                vc->state.x--;
        }
        vc->vc_need_wrap = 0;
}

#define UCS_ZWS         0x200b  /* Zero Width Space */
#define UCS_VS16        0xfe0f  /* Variation Selector 16 */
#define UCS_REPLACEMENT 0xfffd  /* Replacement Character */

static int vc_process_ucs(struct vc_data *vc, int *c, int *tc)
{
        u32 prev_c, curr_c = *c;

        if (ucs_is_double_width(curr_c)) {
                /*
                 * The Unicode screen memory is allocated only when
                 * required. This is one such case as we need to remember
                 * which displayed characters are double-width.
                 */
                vc_uniscr_check(vc);
                return 2;
        }

        if (!ucs_is_zero_width(curr_c))
                return 1;

        /* From here curr_c is known to be zero-width. */

        if (ucs_is_double_width(vc_uniscr_getc(vc, -2))) {
                /*
                 * Let's merge this zero-width code point with the preceding
                 * double-width code point by replacing the existing
                 * zero-width space padding. To do so we rewind one column
                 * and pretend this has a width of 1.
                 * We give the legacy display the same initial space padding.
                 */
                vc_con_rewind(vc);
                *tc = ' ';
                return 1;
        }

        /* From here the preceding character, if any, must be single-width. */
        prev_c = vc_uniscr_getc(vc, -1);

        if (curr_c == UCS_VS16 && prev_c != 0) {
                /*
                 * VS16 (U+FE0F) is special. It typically turns the preceding
                 * single-width character into a double-width one. Let it
                 * have a width of 1 effectively making the combination with
                 * the preceding character double-width.
                 */
                *tc = ' ';
                return 1;
        }

        /* try recomposition */
        prev_c = ucs_recompose(prev_c, curr_c);
        if (prev_c != 0) {
                vc_con_rewind(vc);
                *tc = *c = prev_c;
                return 1;
        }

        /* Otherwise zero-width code points are ignored. */
        return 0;
}

static int vc_get_glyph(struct vc_data *vc, int tc)
{
        int glyph = conv_uni_to_pc(vc, tc);
        u16 charmask = vc->vc_hi_font_mask ? 0x1ff : 0xff;

        if (!(glyph & ~charmask))
                return glyph;

        if (glyph == -1)
                return -1; /* nothing to display */

        /* Glyph not found */
        if ((!vc->vc_utf || vc->vc_disp_ctrl || tc < 128) && !(tc & ~charmask)) {
                /*
                 * In legacy mode use the glyph we get by a 1:1 mapping.
                 * This would make absolutely no sense with Unicode in mind, but do this for
                 * ASCII characters since a font may lack Unicode mapping info and we don't
                 * want to end up with having question marks only.
                 */
                return tc;
        }

        /*
         * The Unicode screen memory is allocated only when required.
         * This is one such case: we're about to "cheat" with the displayed
         * character meaning the simple screen buffer won't hold the original
         * information, whereas the Unicode screen buffer always does.
         */
        vc_uniscr_check(vc);

        /* Try getting a simpler fallback character. */
        tc = ucs_get_fallback(tc);
        if (tc)
                return vc_get_glyph(vc, tc);

        /* Display U+FFFD (Unicode Replacement Character). */
        return conv_uni_to_pc(vc, UCS_REPLACEMENT);
}

static int vc_con_write_normal(struct vc_data *vc, int tc, int c,
                struct vc_draw_region *draw)
{
        int next_c;
        unsigned char vc_attr = vc->vc_attr;
        u16 himask = vc->vc_hi_font_mask;
        u8 width = 1;
        bool inverse = false;

        if (vc->vc_utf && !vc->vc_disp_ctrl) {
                width = vc_process_ucs(vc, &c, &tc);
                if (!width)
                        goto out;
        }

        /* Now try to find out how to display it */
        tc = vc_get_glyph(vc, tc);
        if (tc == -1)
                return -1; /* nothing to display */
        if (tc < 0) {
                inverse = true;
                tc = conv_uni_to_pc(vc, '?');
                if (tc < 0)
                        tc = '?';

                vc_attr = vc_invert_attr(vc);
                con_flush(vc, draw);
        }

        next_c = c;
        while (1) {
                if (vc->vc_need_wrap || vc->vc_decim)
                        con_flush(vc, draw);
                if (vc->vc_need_wrap) {
                        cr(vc);
                        lf(vc);
                }
                if (vc->vc_decim)
                        insert_char(vc, 1);
                vc_uniscr_putc(vc, next_c);

                if (himask)
                        tc = ((tc & 0x100) ? himask : 0) |
                              (tc &  0xff);
                tc |= (vc_attr << 8) & ~himask;

                scr_writew(tc, (u16 *)vc->vc_pos);

                if (con_should_update(vc) && draw->x < 0) {
                        draw->x = vc->state.x;
                        draw->from = vc->vc_pos;
                }
                if (vc->state.x == vc->vc_cols - 1) {
                        vc->vc_need_wrap = vc->vc_decawm;
                        draw->to = vc->vc_pos + 2;
                } else {
                        vc->state.x++;
                        draw->to = (vc->vc_pos += 2);
                }

                if (!--width)
                        break;

                /* A space is printed in the second column */
                tc = conv_uni_to_pc(vc, ' ');
                if (tc < 0)
                        tc = ' ';
                /*
                 * Store a zero-width space in the Unicode screen given that
                 * the previous code point is semantically double width.
                 */
                next_c = UCS_ZWS;
        }

out:
        notify_write(vc, c);

        if (inverse)
                con_flush(vc, draw);

        return 0;
}

/* acquires console_lock */
static int do_con_write(struct tty_struct *tty, const u8 *buf, int count)
{
        struct vc_draw_region draw = {
                .x = -1,
        };
        int c, tc, n = 0;
        unsigned int currcons;
        struct vc_data *vc = tty->driver_data;
        struct vt_notifier_param param;
        bool rescan;

        if (in_interrupt())
                return count;

        guard(console_lock)();
        currcons = vc->vc_num;
        if (!vc_cons_allocated(currcons)) {
                /* could this happen? */
                pr_warn_once("con_write: tty %d not allocated\n", currcons+1);
                return 0;
        }


        /* undraw cursor first */
        if (con_is_fg(vc))
                hide_cursor(vc);

        param.vc = vc;

        while (!tty->flow.stopped && count) {
                u8 orig = *buf;
                buf++;
                n++;
                count--;
rescan_last_byte:
                c = orig;
                rescan = false;

                tc = vc_translate(vc, &c, &rescan);
                if (tc == -1)
                        continue;

                param.c = tc;
                if (atomic_notifier_call_chain(&vt_notifier_list, VT_PREWRITE,
                                        &param) == NOTIFY_STOP)
                        continue;

                if (vc_is_control(vc, tc, c)) {
                        con_flush(vc, &draw);
                        do_con_trol(tty, vc, orig);
                        continue;
                }

                if (vc_con_write_normal(vc, tc, c, &draw) < 0)
                        continue;

                if (rescan)
                        goto rescan_last_byte;
        }
        con_flush(vc, &draw);
        notify_update(vc);

        return n;
}

/*
 * This is the console switching callback.
 *
 * Doing console switching in a process context allows
 * us to do the switches asynchronously (needed when we want
 * to switch due to a keyboard interrupt).  Synchronization
 * with other console code and prevention of re-entrancy is
 * ensured with console_lock.
 */
static void console_callback(struct work_struct *ignored)
{
        guard(console_lock)();

        if (want_console >= 0) {
                if (want_console != fg_console &&
                    vc_cons_allocated(want_console)) {
                        hide_cursor(vc_cons[fg_console].d);
                        change_console(vc_cons[want_console].d);
                        /* we only changed when the console had already
                           been allocated - a new console is not created
                           in an interrupt routine */
                }
                want_console = -1;
        }
        if (do_poke_blanked_console) { /* do not unblank for a LED change */
                do_poke_blanked_console = 0;
                poke_blanked_console();
        }
        if (scrollback_delta) {
                struct vc_data *vc = vc_cons[fg_console].d;
                clear_selection();
                if (vc->vc_mode == KD_TEXT && vc->vc_sw->con_scrolldelta)
                        vc->vc_sw->con_scrolldelta(vc, scrollback_delta);
                scrollback_delta = 0;
        }
        if (blank_timer_expired) {
                do_blank_screen(0);
                blank_timer_expired = 0;
        }
        notify_update(vc_cons[fg_console].d);
}

int set_console(int nr)
{
        struct vc_data *vc = vc_cons[fg_console].d;

        if (!vc_cons_allocated(nr) || vt_dont_switch ||
                (vc->vt_mode.mode == VT_AUTO && vc->vc_mode == KD_GRAPHICS)) {

                /*
                 * Console switch will fail in console_callback() or
                 * change_console() so there is no point scheduling
                 * the callback
                 *
                 * Existing set_console() users don't check the return
                 * value so this shouldn't break anything
                 */
                return -EINVAL;
        }

        want_console = nr;
        schedule_console_callback();

        return 0;
}

struct tty_driver *console_driver;

#ifdef CONFIG_VT_CONSOLE

/**
 * vt_kmsg_redirect() - sets/gets the kernel message console
 * @new: the new virtual terminal number or -1 if the console should stay
 *      unchanged
 *
 * By default, the kernel messages are always printed on the current virtual
 * console. However, the user may modify that default with the
 * %TIOCL_SETKMSGREDIRECT ioctl call.
 *
 * This function sets the kernel message console to be @new. It returns the old
 * virtual console number. The virtual terminal number %0 (both as parameter and
 * return value) means no redirection (i.e. always printed on the currently
 * active console).
 *
 * The parameter -1 means that only the current console is returned, but the
 * value is not modified. You may use the macro vt_get_kmsg_redirect() in that
 * case to make the code more understandable.
 *
 * When the kernel is compiled without %CONFIG_VT_CONSOLE, this function ignores
 * the parameter and always returns %0.
 */
int vt_kmsg_redirect(int new)
{
        static int kmsg_con;

        if (new != -1)
                return xchg(&kmsg_con, new);
        else
                return kmsg_con;
}

/*
 *      Console on virtual terminal
 *
 * The console must be locked when we get here.
 */

static void vt_console_print(struct console *co, const char *b, unsigned count)
{
        struct vc_data *vc = vc_cons[fg_console].d;
        unsigned char c;
        static DEFINE_SPINLOCK(printing_lock);
        const ushort *start;
        ushort start_x, cnt;
        int kmsg_console;

        WARN_CONSOLE_UNLOCKED();

        /* this protects against concurrent oops only */
        if (!spin_trylock(&printing_lock))
                return;

        kmsg_console = vt_get_kmsg_redirect();
        if (kmsg_console && vc_cons_allocated(kmsg_console - 1))
                vc = vc_cons[kmsg_console - 1].d;

        if (!vc_cons_allocated(fg_console)) {
                /* impossible */
                /* printk("vt_console_print: tty %d not allocated ??\n", currcons+1); */
                goto quit;
        }

        if (vc->vc_mode != KD_TEXT)
                goto quit;

        /* undraw cursor first */
        if (con_is_fg(vc))
                hide_cursor(vc);

        start = (ushort *)vc->vc_pos;
        start_x = vc->state.x;
        cnt = 0;
        while (count--) {
                c = *b++;
                if (c == ASCII_LINEFEED || c == ASCII_CAR_RET ||
                    c == ASCII_BACKSPACE || vc->vc_need_wrap) {
                        if (cnt && con_is_visible(vc))
                                vc->vc_sw->con_putcs(vc, start, cnt, vc->state.y, start_x);
                        cnt = 0;
                        if (c == ASCII_BACKSPACE) {
                                bs(vc);
                                start = (ushort *)vc->vc_pos;
                                start_x = vc->state.x;
                                continue;
                        }
                        if (c != ASCII_CAR_RET)
                                lf(vc);
                        cr(vc);
                        start = (ushort *)vc->vc_pos;
                        start_x = vc->state.x;
                        if (c == ASCII_LINEFEED || c == ASCII_CAR_RET)
                                continue;
                }
                vc_uniscr_putc(vc, c);
                scr_writew((vc->vc_attr << 8) + c, (unsigned short *)vc->vc_pos);
                notify_write(vc, c);
                cnt++;
                if (vc->state.x == vc->vc_cols - 1) {
                        vc->vc_need_wrap = 1;
                } else {
                        vc->vc_pos += 2;
                        vc->state.x++;
                }
        }
        if (cnt && con_is_visible(vc))
                vc->vc_sw->con_putcs(vc, start, cnt, vc->state.y, start_x);
        set_cursor(vc);
        notify_update(vc);

quit:
        spin_unlock(&printing_lock);
}

static struct tty_driver *vt_console_device(struct console *c, int *index)
{
        *index = c->index ? c->index-1 : fg_console;
        return console_driver;
}

static int vt_console_setup(struct console *co, char *options)
{
        return co->index >= MAX_NR_CONSOLES ? -EINVAL : 0;
}

static struct console vt_console_driver = {
        .name           = "tty",
        .setup          = vt_console_setup,
        .write          = vt_console_print,
        .device         = vt_console_device,
        .unblank        = unblank_screen,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
};
#endif

/*
 *      Handling of Linux-specific VC ioctls
 */

/*
 * Generally a bit racy with respect to console_lock();.
 *
 * There are some functions which don't need it.
 *
 * There are some functions which can sleep for arbitrary periods
 * (paste_selection) but we don't need the lock there anyway.
 *
 * set_selection_user has locking, and definitely needs it
 */

int tioclinux(struct tty_struct *tty, unsigned long arg)
{
        char type, data;
        char __user *p = (char __user *)arg;
        void __user *param_aligned32 = (u32 __user *)arg + 1;
        void __user *param = (void __user *)arg + 1;
        int lines;
        int ret;

        if (current->signal->tty != tty && !capable(CAP_SYS_ADMIN))
                return -EPERM;
        if (get_user(type, p))
                return -EFAULT;
        ret = 0;

        switch (type) {
        case TIOCL_SETSEL:
                return set_selection_user(param, tty);
        case TIOCL_PASTESEL:
                if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;
                return paste_selection(tty);
        case TIOCL_UNBLANKSCREEN:
                scoped_guard(console_lock)
                        unblank_screen();
                break;
        case TIOCL_SELLOADLUT:
                if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;
                return sel_loadlut(param_aligned32);
        case TIOCL_GETSHIFTSTATE:
                /*
                 * Make it possible to react to Shift+Mousebutton. Note that
                 * 'shift_state' is an undocumented kernel-internal variable;
                 * programs not closely related to the kernel should not use
                 * this.
                 */
                data = vt_get_shift_state();
                return put_user(data, p);
        case TIOCL_GETMOUSEREPORTING:
                scoped_guard(console_lock)      /* May be overkill */
                        data = mouse_reporting();
                return put_user(data, p);
        case TIOCL_SETVESABLANK:
                return set_vesa_blanking(param);
        case TIOCL_GETKMSGREDIRECT:
                data = vt_get_kmsg_redirect();
                return put_user(data, p);
        case TIOCL_SETKMSGREDIRECT:
                if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;

                if (get_user(data, p+1))
                        return -EFAULT;

                vt_kmsg_redirect(data);

                break;
        case TIOCL_GETFGCONSOLE:
                /*
                 * No locking needed as this is a transiently correct return
                 * anyway if the caller hasn't disabled switching.
                 */
                return fg_console;
        case TIOCL_SCROLLCONSOLE:
                if (get_user(lines, (s32 __user *)param_aligned32))
                        return -EFAULT;

                /*
                 * Needs the console lock here. Note that lots of other calls
                 * need fixing before the lock is actually useful!
                 */
                scoped_guard(console_lock)
                        scrollfront(vc_cons[fg_console].d, lines);
                break;
        case TIOCL_BLANKSCREEN: /* until explicitly unblanked, not only poked */
                scoped_guard(console_lock) {
                        ignore_poke = 1;
                        do_blank_screen(0);
                }
                break;
        case TIOCL_BLANKEDSCREEN:
                return console_blanked;
        case TIOCL_GETBRACKETEDPASTE:
                return get_bracketed_paste(tty);
        default:
                return -EINVAL;
        }

        return ret;
}

/*
 * /dev/ttyN handling
 */

static ssize_t con_write(struct tty_struct *tty, const u8 *buf, size_t count)
{
        int     retval;

        retval = do_con_write(tty, buf, count);
        con_flush_chars(tty);

        return retval;
}

static int con_put_char(struct tty_struct *tty, u8 ch)
{
        return do_con_write(tty, &ch, 1);
}

static unsigned int con_write_room(struct tty_struct *tty)
{
        if (tty->flow.stopped)
                return 0;
        return 32768;           /* No limit, really; we're not buffering */
}

/*
 * con_throttle and con_unthrottle are only used for
 * paste_selection(), which has to stuff in a large number of
 * characters...
 */
static void con_throttle(struct tty_struct *tty)
{
}

static void con_unthrottle(struct tty_struct *tty)
{
        struct vc_data *vc = tty->driver_data;

        wake_up_interruptible(&vc->paste_wait);
}

/*
 * Turn the Scroll-Lock LED on when the tty is stopped
 */
static void con_stop(struct tty_struct *tty)
{
        int console_num;
        if (!tty)
                return;
        console_num = tty->index;
        if (!vc_cons_allocated(console_num))
                return;
        vt_kbd_con_stop(console_num);
}

/*
 * Turn the Scroll-Lock LED off when the console is started
 */
static void con_start(struct tty_struct *tty)
{
        int console_num;
        if (!tty)
                return;
        console_num = tty->index;
        if (!vc_cons_allocated(console_num))
                return;
        vt_kbd_con_start(console_num);
}

static void con_flush_chars(struct tty_struct *tty)
{
        struct vc_data *vc = tty->driver_data;

        if (in_interrupt())     /* from flush_to_ldisc */
                return;

        guard(console_lock)();
        set_cursor(vc);
}

/*
 * Allocate the console screen memory.
 */
static int con_install(struct tty_driver *driver, struct tty_struct *tty)
{
        unsigned int currcons = tty->index;
        struct vc_data *vc;
        int ret;

        guard(console_lock)();
        ret = vc_allocate(currcons);
        if (ret)
                return ret;

        vc = vc_cons[currcons].d;

        /* Still being freed */
        if (vc->port.tty)
                return -ERESTARTSYS;

        ret = tty_port_install(&vc->port, driver, tty);
        if (ret)
                return ret;

        tty->driver_data = vc;
        vc->port.tty = tty;
        tty_port_get(&vc->port);

        if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
                tty->winsize.ws_row = vc_cons[currcons].d->vc_rows;
                tty->winsize.ws_col = vc_cons[currcons].d->vc_cols;
        }
        if (vc->vc_utf)
                tty->termios.c_iflag |= IUTF8;
        else
                tty->termios.c_iflag &= ~IUTF8;

        return 0;
}

static int con_open(struct tty_struct *tty, struct file *filp)
{
        /* everything done in install */
        return 0;
}


static void con_close(struct tty_struct *tty, struct file *filp)
{
        /* Nothing to do - we defer to shutdown */
}

static void con_shutdown(struct tty_struct *tty)
{
        struct vc_data *vc = tty->driver_data;
        BUG_ON(vc == NULL);

        guard(console_lock)();
        vc->port.tty = NULL;
}

static void con_cleanup(struct tty_struct *tty)
{
        struct vc_data *vc = tty->driver_data;

        tty_port_put(&vc->port);
}

/*
 * We can't deal with anything but the N_TTY ldisc,
 * because we can sleep in our write() routine.
 */
static int con_ldisc_ok(struct tty_struct *tty, int ldisc)
{
        return ldisc == N_TTY ? 0 : -EINVAL;
}

static int default_color           = 7; /* white */
static int default_italic_color    = 2; // green (ASCII)
static int default_underline_color = 3; // cyan (ASCII)
module_param_named(color, default_color, int, S_IRUGO | S_IWUSR);
module_param_named(italic, default_italic_color, int, S_IRUGO | S_IWUSR);
module_param_named(underline, default_underline_color, int, S_IRUGO | S_IWUSR);

static void vc_init(struct vc_data *vc, int do_clear)
{
        int j, k ;

        set_origin(vc);
        vc->vc_pos = vc->vc_origin;
        reset_vc(vc);
        for (j=k=0; j<16; j++) {
                vc->vc_palette[k++] = default_red[j] ;
                vc->vc_palette[k++] = default_grn[j] ;
                vc->vc_palette[k++] = default_blu[j] ;
        }
        vc->vc_def_color       = default_color;
        vc->vc_ulcolor         = default_underline_color;
        vc->vc_itcolor         = default_italic_color;
        vc->vc_halfcolor       = 0x08;   /* grey */
        init_waitqueue_head(&vc->paste_wait);
        reset_terminal(vc, do_clear);
}

/*
 * This routine initializes console interrupts, and does nothing
 * else. If you want the screen to clear, call tty_write with
 * the appropriate escape-sequence.
 */

static int __init con_init(void)
{
        const char *display_desc = NULL;
        struct vc_data *vc;
        unsigned int currcons = 0, i;

        console_lock();

        if (!conswitchp)
                conswitchp = &dummy_con;
        display_desc = conswitchp->con_startup();
        if (!display_desc) {
                fg_console = 0;
                console_unlock();
                return 0;
        }

        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                struct con_driver *con_driver = &registered_con_driver[i];

                if (con_driver->con == NULL) {
                        con_driver->con = conswitchp;
                        con_driver->desc = display_desc;
                        con_driver->flag = CON_DRIVER_FLAG_INIT;
                        con_driver->first = 0;
                        con_driver->last = MAX_NR_CONSOLES - 1;
                        break;
                }
        }

        for (i = 0; i < MAX_NR_CONSOLES; i++)
                con_driver_map[i] = conswitchp;

        if (blankinterval) {
                blank_state = blank_normal_wait;
                mod_timer(&console_timer, jiffies + (blankinterval * HZ));
        }

        for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
                vc_cons[currcons].d = vc = kzalloc_obj(struct vc_data,
                                                       GFP_NOWAIT);
                INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
                tty_port_init(&vc->port);
                visual_init(vc, currcons, true);
                /* Assuming vc->vc_{cols,rows,screenbuf_size} are sane here. */
                vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT);
                vc_init(vc, currcons || !vc->vc_sw->con_save_screen);
        }
        currcons = fg_console = 0;
        master_display_fg = vc = vc_cons[currcons].d;
        set_origin(vc);
        save_screen(vc);
        gotoxy(vc, vc->state.x, vc->state.y);
        csi_J(vc, CSI_J_CURSOR_TO_END);
        update_screen(vc);
        pr_info("Console: %s %s %dx%d\n",
                vc->vc_can_do_color ? "colour" : "mono",
                display_desc, vc->vc_cols, vc->vc_rows);

        console_unlock();

#ifdef CONFIG_VT_CONSOLE
        register_console(&vt_console_driver);
#endif
        return 0;
}
console_initcall(con_init);

static const struct tty_operations con_ops = {
        .install = con_install,
        .open = con_open,
        .close = con_close,
        .write = con_write,
        .write_room = con_write_room,
        .put_char = con_put_char,
        .flush_chars = con_flush_chars,
        .ioctl = vt_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl = vt_compat_ioctl,
#endif
        .stop = con_stop,
        .start = con_start,
        .throttle = con_throttle,
        .unthrottle = con_unthrottle,
        .resize = vt_resize,
        .shutdown = con_shutdown,
        .cleanup = con_cleanup,
        .ldisc_ok = con_ldisc_ok,
};

static struct cdev vc0_cdev;

static ssize_t show_tty_active(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "tty%d\n", fg_console + 1);
}
static DEVICE_ATTR(active, S_IRUGO, show_tty_active, NULL);

static struct attribute *vt_dev_attrs[] = {
        &dev_attr_active.attr,
        NULL
};

ATTRIBUTE_GROUPS(vt_dev);

int __init vty_init(const struct file_operations *console_fops)
{
        cdev_init(&vc0_cdev, console_fops);
        if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
            register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
                panic("Couldn't register /dev/tty0 driver\n");
        tty0dev = device_create_with_groups(&tty_class, NULL,
                                            MKDEV(TTY_MAJOR, 0), NULL,
                                            vt_dev_groups, "tty0");
        if (IS_ERR(tty0dev))
                tty0dev = NULL;

        vcs_init();

        console_driver = tty_alloc_driver(MAX_NR_CONSOLES, TTY_DRIVER_REAL_RAW |
                        TTY_DRIVER_RESET_TERMIOS);
        if (IS_ERR(console_driver))
                panic("Couldn't allocate console driver\n");

        console_driver->name = "tty";
        console_driver->name_base = 1;
        console_driver->major = TTY_MAJOR;
        console_driver->minor_start = 1;
        console_driver->type = TTY_DRIVER_TYPE_CONSOLE;
        console_driver->init_termios = tty_std_termios;
        if (default_utf8)
                console_driver->init_termios.c_iflag |= IUTF8;
        tty_set_operations(console_driver, &con_ops);
        if (tty_register_driver(console_driver))
                panic("Couldn't register console driver\n");
        kbd_init();
        console_map_init();
#ifdef CONFIG_MDA_CONSOLE
        mda_console_init();
#endif
        return 0;
}

static const struct class vtconsole_class = {
        .name = "vtconsole",
};

static int do_bind_con_driver(const struct consw *csw, int first, int last,
                           int deflt)
{
        struct module *owner = csw->owner;
        const char *desc = NULL;
        struct con_driver *con_driver;
        int i, j = -1, k = -1, retval = -ENODEV;

        if (!try_module_get(owner))
                return -ENODEV;

        WARN_CONSOLE_UNLOCKED();

        /* check if driver is registered */
        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                con_driver = &registered_con_driver[i];

                if (con_driver->con == csw) {
                        desc = con_driver->desc;
                        retval = 0;
                        break;
                }
        }

        if (retval)
                goto err;

        if (!(con_driver->flag & CON_DRIVER_FLAG_INIT)) {
                csw->con_startup();
                con_driver->flag |= CON_DRIVER_FLAG_INIT;
        }

        if (deflt) {
                if (conswitchp)
                        module_put(conswitchp->owner);

                __module_get(owner);
                conswitchp = csw;
        }

        first = max(first, con_driver->first);
        last = min(last, con_driver->last);

        for (i = first; i <= last; i++) {
                int old_was_color;
                struct vc_data *vc = vc_cons[i].d;

                if (con_driver_map[i])
                        module_put(con_driver_map[i]->owner);
                __module_get(owner);
                con_driver_map[i] = csw;

                if (!vc || !vc->vc_sw)
                        continue;

                j = i;

                if (con_is_visible(vc)) {
                        k = i;
                        save_screen(vc);
                }

                old_was_color = vc->vc_can_do_color;
                vc->vc_sw->con_deinit(vc);
                vc->vc_origin = (unsigned long)vc->vc_screenbuf;
                visual_init(vc, i, false);
                set_origin(vc);
                update_attr(vc);

                /* If the console changed between mono <-> color, then
                 * the attributes in the screenbuf will be wrong.  The
                 * following resets all attributes to something sane.
                 */
                if (old_was_color != vc->vc_can_do_color)
                        clear_buffer_attributes(vc);
        }

        pr_info("Console: switching ");
        if (!deflt)
                pr_cont("consoles %d-%d ", first + 1, last + 1);
        if (j >= 0) {
                struct vc_data *vc = vc_cons[j].d;

                pr_cont("to %s %s %dx%d\n",
                        vc->vc_can_do_color ? "colour" : "mono",
                        desc, vc->vc_cols, vc->vc_rows);

                if (k >= 0) {
                        vc = vc_cons[k].d;
                        update_screen(vc);
                }
        } else {
                pr_cont("to %s\n", desc);
        }

        retval = 0;
err:
        module_put(owner);
        return retval;
};


#ifdef CONFIG_VT_HW_CONSOLE_BINDING
int do_unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
{
        struct module *owner = csw->owner;
        const struct consw *defcsw = NULL;
        struct con_driver *con_driver = NULL, *con_back = NULL;
        int i, retval = -ENODEV;

        if (!try_module_get(owner))
                return -ENODEV;

        WARN_CONSOLE_UNLOCKED();

        /* check if driver is registered and if it is unbindable */
        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                con_driver = &registered_con_driver[i];

                if (con_driver->con == csw &&
                    con_driver->flag & CON_DRIVER_FLAG_MODULE) {
                        retval = 0;
                        break;
                }
        }

        if (retval)
                goto err;

        retval = -ENODEV;

        /* check if backup driver exists */
        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                con_back = &registered_con_driver[i];

                if (con_back->con && con_back->con != csw) {
                        defcsw = con_back->con;
                        retval = 0;
                        break;
                }
        }

        if (retval)
                goto err;

        if (!con_is_bound(csw))
                goto err;

        first = max(first, con_driver->first);
        last = min(last, con_driver->last);

        for (i = first; i <= last; i++) {
                if (con_driver_map[i] == csw) {
                        module_put(csw->owner);
                        con_driver_map[i] = NULL;
                }
        }

        if (!con_is_bound(defcsw)) {
                const struct consw *defconsw = conswitchp;

                defcsw->con_startup();
                con_back->flag |= CON_DRIVER_FLAG_INIT;
                /*
                 * vgacon may change the default driver to point
                 * to dummycon, we restore it here...
                 */
                conswitchp = defconsw;
        }

        if (!con_is_bound(csw))
                con_driver->flag &= ~CON_DRIVER_FLAG_INIT;

        /* ignore return value, binding should not fail */
        do_bind_con_driver(defcsw, first, last, deflt);
err:
        module_put(owner);
        return retval;

}
EXPORT_SYMBOL_GPL(do_unbind_con_driver);

static int vt_bind(struct con_driver *con)
{
        const struct consw *defcsw = NULL, *csw = NULL;
        int i, more = 1, first = -1, last = -1, deflt = 0;

        if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE))
                goto err;

        csw = con->con;

        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                struct con_driver *con = &registered_con_driver[i];

                if (con->con && !(con->flag & CON_DRIVER_FLAG_MODULE)) {
                        defcsw = con->con;
                        break;
                }
        }

        if (!defcsw)
                goto err;

        while (more) {
                more = 0;

                for (i = con->first; i <= con->last; i++) {
                        if (con_driver_map[i] == defcsw) {
                                if (first == -1)
                                        first = i;
                                last = i;
                                more = 1;
                        } else if (first != -1)
                                break;
                }

                if (first == 0 && last == MAX_NR_CONSOLES -1)
                        deflt = 1;

                if (first != -1)
                        do_bind_con_driver(csw, first, last, deflt);

                first = -1;
                last = -1;
                deflt = 0;
        }

err:
        return 0;
}

static int vt_unbind(struct con_driver *con)
{
        const struct consw *csw = NULL;
        int i, more = 1, first = -1, last = -1, deflt = 0;
        int ret;

        if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE))
                goto err;

        csw = con->con;

        while (more) {
                more = 0;

                for (i = con->first; i <= con->last; i++) {
                        if (con_driver_map[i] == csw) {
                                if (first == -1)
                                        first = i;
                                last = i;
                                more = 1;
                        } else if (first != -1)
                                break;
                }

                if (first == 0 && last == MAX_NR_CONSOLES -1)
                        deflt = 1;

                if (first != -1) {
                        ret = do_unbind_con_driver(csw, first, last, deflt);
                        if (ret != 0)
                                return ret;
                }

                first = -1;
                last = -1;
                deflt = 0;
        }

err:
        return 0;
}
#else
static inline int vt_bind(struct con_driver *con)
{
        return 0;
}
static inline int vt_unbind(struct con_driver *con)
{
        return 0;
}
#endif /* CONFIG_VT_HW_CONSOLE_BINDING */

static ssize_t store_bind(struct device *dev, struct device_attribute *attr,
                          const char *buf, size_t count)
{
        struct con_driver *con = dev_get_drvdata(dev);
        int bind = simple_strtoul(buf, NULL, 0);

        guard(console_lock)();

        if (bind)
                vt_bind(con);
        else
                vt_unbind(con);

        return count;
}

static ssize_t show_bind(struct device *dev, struct device_attribute *attr,
                         char *buf)
{
        struct con_driver *con = dev_get_drvdata(dev);
        int bind;

        scoped_guard(console_lock)
                bind = con_is_bound(con->con);

        return sysfs_emit(buf, "%i\n", bind);
}

static ssize_t show_name(struct device *dev, struct device_attribute *attr,
                         char *buf)
{
        struct con_driver *con = dev_get_drvdata(dev);

        return sysfs_emit(buf, "%s %s\n",
                        (con->flag & CON_DRIVER_FLAG_MODULE) ? "(M)" : "(S)",
                         con->desc);

}

static DEVICE_ATTR(bind, S_IRUGO|S_IWUSR, show_bind, store_bind);
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static struct attribute *con_dev_attrs[] = {
        &dev_attr_bind.attr,
        &dev_attr_name.attr,
        NULL
};

ATTRIBUTE_GROUPS(con_dev);

static int vtconsole_init_device(struct con_driver *con)
{
        con->flag |= CON_DRIVER_FLAG_ATTR;
        return 0;
}

static void vtconsole_deinit_device(struct con_driver *con)
{
        con->flag &= ~CON_DRIVER_FLAG_ATTR;
}

/**
 * con_is_bound - checks if driver is bound to the console
 * @csw: console driver
 *
 * RETURNS: zero if unbound, nonzero if bound
 *
 * Drivers can call this and if zero, they should release
 * all resources allocated on &consw.con_startup()
 */
int con_is_bound(const struct consw *csw)
{
        int i, bound = 0;

        WARN_CONSOLE_UNLOCKED();

        for (i = 0; i < MAX_NR_CONSOLES; i++) {
                if (con_driver_map[i] == csw) {
                        bound = 1;
                        break;
                }
        }

        return bound;
}
EXPORT_SYMBOL(con_is_bound);

/**
 * con_is_visible - checks whether the current console is visible
 * @vc: virtual console
 *
 * RETURNS: zero if not visible, nonzero if visible
 */
bool con_is_visible(const struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        return *vc->vc_display_fg == vc;
}
EXPORT_SYMBOL(con_is_visible);

/**
 * con_debug_enter - prepare the console for the kernel debugger
 * @vc: virtual console
 *
 * Called when the console is taken over by the kernel debugger, this
 * function needs to save the current console state, then put the console
 * into a state suitable for the kernel debugger.
 */
void con_debug_enter(struct vc_data *vc)
{
#ifdef CONFIG_KGDB_KDB
        /* Set the initial LINES variable if it is not already set */
        if (vc->vc_rows < 999) {
                int linecount;
                char lns[4];
                const char *setargs[3] = {
                        "set",
                        "LINES",
                        lns,
                };
                if (kdbgetintenv(setargs[0], &linecount)) {
                        snprintf(lns, 4, "%i", vc->vc_rows);
                        kdb_set(2, setargs);
                }
        }
        if (vc->vc_cols < 999) {
                int colcount;
                char cols[4];
                const char *setargs[3] = {
                        "set",
                        "COLUMNS",
                        cols,
                };
                if (kdbgetintenv(setargs[0], &colcount)) {
                        snprintf(cols, 4, "%i", vc->vc_cols);
                        kdb_set(2, setargs);
                }
        }
#endif /* CONFIG_KGDB_KDB */
}
EXPORT_SYMBOL_GPL(con_debug_enter);

/**
 * con_debug_leave - restore console state
 *
 * Restore the console state to what it was before the kernel debugger
 * was invoked.
 */
void con_debug_leave(void)
{ }
EXPORT_SYMBOL_GPL(con_debug_leave);

static int do_register_con_driver(const struct consw *csw, int first, int last)
{
        struct module *owner = csw->owner;
        struct con_driver *con_driver;
        const char *desc;
        int i, retval;

        WARN_CONSOLE_UNLOCKED();

        if (!try_module_get(owner))
                return -ENODEV;

        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                con_driver = &registered_con_driver[i];

                /* already registered */
                if (con_driver->con == csw) {
                        retval = -EBUSY;
                        goto err;
                }
        }

        desc = csw->con_startup();
        if (!desc) {
                retval = -ENODEV;
                goto err;
        }

        retval = -EINVAL;

        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                con_driver = &registered_con_driver[i];

                if (con_driver->con == NULL &&
                    !(con_driver->flag & CON_DRIVER_FLAG_ZOMBIE)) {
                        con_driver->con = csw;
                        con_driver->desc = desc;
                        con_driver->node = i;
                        con_driver->flag = CON_DRIVER_FLAG_MODULE |
                                           CON_DRIVER_FLAG_INIT;
                        con_driver->first = first;
                        con_driver->last = last;
                        retval = 0;
                        break;
                }
        }

        if (retval)
                goto err;

        con_driver->dev =
                device_create_with_groups(&vtconsole_class, NULL,
                                          MKDEV(0, con_driver->node),
                                          con_driver, con_dev_groups,
                                          "vtcon%i", con_driver->node);
        if (IS_ERR(con_driver->dev)) {
                pr_warn("Unable to create device for %s; errno = %ld\n",
                        con_driver->desc, PTR_ERR(con_driver->dev));
                con_driver->dev = NULL;
        } else {
                vtconsole_init_device(con_driver);
        }

err:
        module_put(owner);
        return retval;
}


/**
 * do_unregister_con_driver - unregister console driver from console layer
 * @csw: console driver
 *
 * DESCRIPTION: All drivers that registers to the console layer must
 * call this function upon exit, or if the console driver is in a state
 * where it won't be able to handle console services, such as the
 * framebuffer console without loaded framebuffer drivers.
 *
 * The driver must unbind first prior to unregistration.
 */
int do_unregister_con_driver(const struct consw *csw)
{
        int i;

        /* cannot unregister a bound driver */
        if (con_is_bound(csw))
                return -EBUSY;

        if (csw == conswitchp)
                return -EINVAL;

        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                struct con_driver *con_driver = &registered_con_driver[i];

                if (con_driver->con == csw) {
                        /*
                         * Defer the removal of the sysfs entries since that
                         * will acquire the kernfs s_active lock and we can't
                         * acquire this lock while holding the console lock:
                         * the unbind sysfs entry imposes already the opposite
                         * order. Reset con already here to prevent any later
                         * lookup to succeed and mark this slot as zombie, so
                         * it won't get reused until we complete the removal
                         * in the deferred work.
                         */
                        con_driver->con = NULL;
                        con_driver->flag = CON_DRIVER_FLAG_ZOMBIE;
                        schedule_work(&con_driver_unregister_work);

                        return 0;
                }
        }

        return -ENODEV;
}
EXPORT_SYMBOL_GPL(do_unregister_con_driver);

static void con_driver_unregister_callback(struct work_struct *ignored)
{
        int i;

        guard(console_lock)();

        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                struct con_driver *con_driver = &registered_con_driver[i];

                if (!(con_driver->flag & CON_DRIVER_FLAG_ZOMBIE))
                        continue;

                console_unlock();

                vtconsole_deinit_device(con_driver);
                device_destroy(&vtconsole_class, MKDEV(0, con_driver->node));

                console_lock();

                if (WARN_ON_ONCE(con_driver->con))
                        con_driver->con = NULL;
                con_driver->desc = NULL;
                con_driver->dev = NULL;
                con_driver->node = 0;
                WARN_ON_ONCE(con_driver->flag != CON_DRIVER_FLAG_ZOMBIE);
                con_driver->flag = 0;
                con_driver->first = 0;
                con_driver->last = 0;
        }
}

/*
 *      If we support more console drivers, this function is used
 *      when a driver wants to take over some existing consoles
 *      and become default driver for newly opened ones.
 *
 *      do_take_over_console is basically a register followed by bind
 */
int do_take_over_console(const struct consw *csw, int first, int last, int deflt)
{
        int err;

        err = do_register_con_driver(csw, first, last);
        /*
         * If we get an busy error we still want to bind the console driver
         * and return success, as we may have unbound the console driver
         * but not unregistered it.
         */
        if (err == -EBUSY)
                err = 0;
        if (!err)
                do_bind_con_driver(csw, first, last, deflt);

        return err;
}
EXPORT_SYMBOL_GPL(do_take_over_console);


/*
 * give_up_console is a wrapper to unregister_con_driver. It will only
 * work if driver is fully unbound.
 */
void give_up_console(const struct consw *csw)
{
        guard(console_lock)();
        do_unregister_con_driver(csw);
}
EXPORT_SYMBOL(give_up_console);

static int __init vtconsole_class_init(void)
{
        int i;

        i = class_register(&vtconsole_class);
        if (i)
                pr_warn("Unable to create vt console class; errno = %d\n", i);

        /* Add system drivers to sysfs */
        for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
                struct con_driver *con = &registered_con_driver[i];

                if (con->con && !con->dev) {
                        con->dev =
                                device_create_with_groups(&vtconsole_class, NULL,
                                                          MKDEV(0, con->node),
                                                          con, con_dev_groups,
                                                          "vtcon%i", con->node);

                        if (IS_ERR(con->dev)) {
                                pr_warn("Unable to create device for %s; errno = %ld\n",
                                        con->desc, PTR_ERR(con->dev));
                                con->dev = NULL;
                        } else {
                                vtconsole_init_device(con);
                        }
                }
        }

        return 0;
}
postcore_initcall(vtconsole_class_init);

/*
 *      Screen blanking
 */

static int set_vesa_blanking(u8 __user *mode_user)
{
        u8 mode;

        if (get_user(mode, mode_user))
                return -EFAULT;

        guard(console_lock)();
        vesa_blank_mode = (mode <= VESA_BLANK_MAX) ? mode : VESA_NO_BLANKING;

        return 0;
}

void do_blank_screen(int entering_gfx)
{
        struct vc_data *vc = vc_cons[fg_console].d;
        int i;

        might_sleep();

        WARN_CONSOLE_UNLOCKED();

        if (console_blanked) {
                if (blank_state == blank_vesa_wait) {
                        blank_state = blank_off;
                        vc->vc_sw->con_blank(vc, vesa_blank_mode + 1, 0);
                }
                return;
        }

        /* entering graphics mode? */
        if (entering_gfx) {
                hide_cursor(vc);
                save_screen(vc);
                vc->vc_sw->con_blank(vc, VESA_VSYNC_SUSPEND, 1);
                console_blanked = fg_console + 1;
                blank_state = blank_off;
                set_origin(vc);
                return;
        }

        blank_state = blank_off;

        /* don't blank graphics */
        if (vc->vc_mode != KD_TEXT) {
                console_blanked = fg_console + 1;
                return;
        }

        hide_cursor(vc);
        timer_delete_sync(&console_timer);
        blank_timer_expired = 0;

        save_screen(vc);
        /* In case we need to reset origin, blanking hook returns 1 */
        i = vc->vc_sw->con_blank(vc, vesa_off_interval ? VESA_VSYNC_SUSPEND :
                                 (vesa_blank_mode + 1), 0);
        console_blanked = fg_console + 1;
        if (i)
                set_origin(vc);

        if (console_blank_hook && console_blank_hook(1))
                return;

        if (vesa_off_interval && vesa_blank_mode) {
                blank_state = blank_vesa_wait;
                mod_timer(&console_timer, jiffies + vesa_off_interval);
        }
        vt_event_post(VT_EVENT_BLANK, vc->vc_num, vc->vc_num);
}
EXPORT_SYMBOL(do_blank_screen);

/*
 * Called by timer as well as from vt_console_driver
 */
void do_unblank_screen(int leaving_gfx)
{
        struct vc_data *vc;

        /* This should now always be called from a "sane" (read: can schedule)
         * context for the sake of the low level drivers, except in the special
         * case of oops_in_progress
         */
        if (!oops_in_progress)
                might_sleep();

        WARN_CONSOLE_UNLOCKED();

        ignore_poke = 0;
        if (!console_blanked)
                return;
        if (!vc_cons_allocated(fg_console)) {
                /* impossible */
                pr_warn("unblank_screen: tty %d not allocated ??\n",
                        fg_console + 1);
                return;
        }
        vc = vc_cons[fg_console].d;
        if (vc->vc_mode != KD_TEXT)
                return; /* but leave console_blanked != 0 */

        if (blankinterval) {
                mod_timer(&console_timer, jiffies + (blankinterval * HZ));
                blank_state = blank_normal_wait;
        }

        console_blanked = 0;
        if (vc->vc_sw->con_blank(vc, VESA_NO_BLANKING, leaving_gfx))
                /* Low-level driver cannot restore -> do it ourselves */
                update_screen(vc);
        if (console_blank_hook)
                console_blank_hook(0);
        set_palette(vc);
        set_cursor(vc);
        vt_event_post(VT_EVENT_UNBLANK, vc->vc_num, vc->vc_num);
        notify_update(vc);
}
EXPORT_SYMBOL(do_unblank_screen);

/*
 * This is called by the outside world to cause a forced unblank, mostly for
 * oopses. Currently, I just call do_unblank_screen(0), but we could eventually
 * call it with 1 as an argument and so force a mode restore... that may kill
 * X or at least garbage the screen but would also make the Oops visible...
 */
static void unblank_screen(void)
{
        do_unblank_screen(0);
}

/*
 * We defer the timer blanking to work queue so it can take the console mutex
 * (console operations can still happen at irq time, but only from printk which
 * has the console mutex. Not perfect yet, but better than no locking
 */
static void blank_screen_t(struct timer_list *unused)
{
        blank_timer_expired = 1;
        schedule_work(&console_work);
}

void poke_blanked_console(void)
{
        WARN_CONSOLE_UNLOCKED();

        /* Add this so we quickly catch whoever might call us in a non
         * safe context. Nowadays, unblank_screen() isn't to be called in
         * atomic contexts and is allowed to schedule (with the special case
         * of oops_in_progress, but that isn't of any concern for this
         * function. --BenH.
         */
        might_sleep();

        /* This isn't perfectly race free, but a race here would be mostly harmless,
         * at worst, we'll do a spurious blank and it's unlikely
         */
        timer_delete(&console_timer);
        blank_timer_expired = 0;

        if (ignore_poke || !vc_cons[fg_console].d || vc_cons[fg_console].d->vc_mode == KD_GRAPHICS)
                return;
        if (console_blanked)
                unblank_screen();
        else if (blankinterval) {
                mod_timer(&console_timer, jiffies + (blankinterval * HZ));
                blank_state = blank_normal_wait;
        }
}

/*
 *      Palettes
 */

static void set_palette(struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        if (vc->vc_mode != KD_GRAPHICS && vc->vc_sw->con_set_palette)
                vc->vc_sw->con_set_palette(vc, color_table);
}

/*
 * Load palette into the DAC registers. arg points to a colour
 * map, 3 bytes per colour, 16 colours, range from 0 to 255.
 */

int con_set_cmap(unsigned char __user *arg)
{
        int i, j, k;
        unsigned char colormap[3*16];

        if (copy_from_user(colormap, arg, sizeof(colormap)))
                return -EFAULT;

        guard(console_lock)();
        for (i = k = 0; i < 16; i++) {
                default_red[i] = colormap[k++];
                default_grn[i] = colormap[k++];
                default_blu[i] = colormap[k++];
        }
        for (i = 0; i < MAX_NR_CONSOLES; i++) {
                if (!vc_cons_allocated(i))
                        continue;
                for (j = k = 0; j < 16; j++) {
                        vc_cons[i].d->vc_palette[k++] = default_red[j];
                        vc_cons[i].d->vc_palette[k++] = default_grn[j];
                        vc_cons[i].d->vc_palette[k++] = default_blu[j];
                }
                set_palette(vc_cons[i].d);
        }

        return 0;
}

int con_get_cmap(unsigned char __user *arg)
{
        int i, k;
        unsigned char colormap[3*16];

        scoped_guard(console_lock)
                for (i = k = 0; i < 16; i++) {
                        colormap[k++] = default_red[i];
                        colormap[k++] = default_grn[i];
                        colormap[k++] = default_blu[i];
                }

        if (copy_to_user(arg, colormap, sizeof(colormap)))
                return -EFAULT;

        return 0;
}

void reset_palette(struct vc_data *vc)
{
        int j, k;
        for (j=k=0; j<16; j++) {
                vc->vc_palette[k++] = default_red[j];
                vc->vc_palette[k++] = default_grn[j];
                vc->vc_palette[k++] = default_blu[j];
        }
        set_palette(vc);
}

/*
 *  Font switching
 *
 *  Currently we only support fonts up to 128 pixels wide, at a maximum height
 *  of 128 pixels. Userspace fontdata may have to be stored with 32 bytes
 *  (shorts/ints, depending on width) reserved for each character which is
 *  kinda wasty, but this is done in order to maintain compatibility with the
 *  EGA/VGA fonts. It is up to the actual low-level console-driver convert data
 *  into its favorite format (maybe we should add a `fontoffset' field to the
 *  `display' structure so we won't have to convert the fontdata all the time.
 *  /Jes
 */

#define max_font_width  64
#define max_font_height 128
#define max_font_glyphs 512
#define max_font_size   (max_font_glyphs*max_font_width*max_font_height)

static int con_font_get(struct vc_data *vc, struct console_font_op *op)
{
        struct console_font font;
        int c;
        unsigned int vpitch = op->op == KD_FONT_OP_GET_TALL ? op->height : 32;

        if (vpitch > max_font_height)
                return -EINVAL;

        void *font_data __free(kvfree) = NULL;
        if (op->data) {
                font.data = font_data = kvzalloc(max_font_size, GFP_KERNEL);
                if (!font.data)
                        return -ENOMEM;
        } else
                font.data = NULL;

        scoped_guard(console_lock) {
                if (vc->vc_mode != KD_TEXT)
                        return -EINVAL;
                if (!vc->vc_sw->con_font_get)
                        return -ENOSYS;

                int ret = vc->vc_sw->con_font_get(vc, &font, vpitch);
                if (ret)
                        return ret;
        }

        c = DIV_ROUND_UP(font.width, 8) * vpitch * font.charcount;

        if (op->data && font.charcount > op->charcount)
                return -ENOSPC;
        if (font.width > op->width || font.height > op->height)
                return -ENOSPC;

        op->height = font.height;
        op->width = font.width;
        op->charcount = font.charcount;

        if (op->data && copy_to_user(op->data, font.data, c))
                return -EFAULT;

        return 0;
}

static int con_font_set(struct vc_data *vc, const struct console_font_op *op)
{
        struct console_font font;
        int size;
        unsigned int vpitch = op->op == KD_FONT_OP_SET_TALL ? op->height : 32;

        if (!op->data)
                return -EINVAL;
        if (op->charcount > max_font_glyphs)
                return -EINVAL;
        if (op->width <= 0 || op->width > max_font_width || !op->height ||
            op->height > max_font_height)
                return -EINVAL;
        if (vpitch < op->height)
                return -EINVAL;
        size = DIV_ROUND_UP(op->width, 8) * vpitch * op->charcount;
        if (size > max_font_size)
                return -ENOSPC;

        void *font_data __free(kfree) = font.data = memdup_user(op->data, size);
        if (IS_ERR(font.data))
                return PTR_ERR(font.data);

        font.charcount = op->charcount;
        font.width = op->width;
        font.height = op->height;

        guard(console_lock)();

        if (vc->vc_mode != KD_TEXT)
                return -EINVAL;
        if (!vc->vc_sw->con_font_set)
                return -ENOSYS;

        if (vc_is_sel(vc))
                clear_selection();

        return vc->vc_sw->con_font_set(vc, &font, vpitch, op->flags);
}

static int con_font_default(struct vc_data *vc, struct console_font_op *op)
{
        struct console_font font = {.width = op->width, .height = op->height};
        char name[MAX_FONT_NAME];
        char *s = name;

        if (!op->data)
                s = NULL;
        else if (strncpy_from_user(name, op->data, MAX_FONT_NAME - 1) < 0)
                return -EFAULT;
        else
                name[MAX_FONT_NAME - 1] = 0;

        scoped_guard(console_lock) {
                if (vc->vc_mode != KD_TEXT)
                        return -EINVAL;
                if (!vc->vc_sw->con_font_default)
                        return -ENOSYS;

                if (vc_is_sel(vc))
                        clear_selection();
                int ret = vc->vc_sw->con_font_default(vc, &font, s);
                if (ret)
                        return ret;
        }

        op->width = font.width;
        op->height = font.height;

        return 0;
}

int con_font_op(struct vc_data *vc, struct console_font_op *op)
{
        switch (op->op) {
        case KD_FONT_OP_SET:
        case KD_FONT_OP_SET_TALL:
                return con_font_set(vc, op);
        case KD_FONT_OP_GET:
        case KD_FONT_OP_GET_TALL:
                return con_font_get(vc, op);
        case KD_FONT_OP_SET_DEFAULT:
                return con_font_default(vc, op);
        case KD_FONT_OP_COPY:
                /* was buggy and never really used */
                return -EINVAL;
        }
        return -ENOSYS;
}

/*
 *      Interface exported to selection and vcs.
 */

/* used by selection */
u16 screen_glyph(const struct vc_data *vc, int offset)
{
        u16 w = scr_readw(screenpos(vc, offset, true));
        u16 c = w & 0xff;

        if (w & vc->vc_hi_font_mask)
                c |= 0x100;
        return c;
}
EXPORT_SYMBOL_GPL(screen_glyph);

u32 screen_glyph_unicode(const struct vc_data *vc, int n)
{
        u32 **uni_lines = vc->vc_uni_lines;

        if (uni_lines)
                return uni_lines[n / vc->vc_cols][n % vc->vc_cols];

        return inverse_translate(vc, screen_glyph(vc, n * 2), true);
}
EXPORT_SYMBOL_GPL(screen_glyph_unicode);

/* used by vcs - note the word offset */
unsigned short *screen_pos(const struct vc_data *vc, int w_offset, bool viewed)
{
        return screenpos(vc, 2 * w_offset, viewed);
}
EXPORT_SYMBOL_GPL(screen_pos);

void getconsxy(const struct vc_data *vc, unsigned char xy[static 2])
{
        /* clamp values if they don't fit */
        xy[0] = min(vc->state.x, 0xFFu);
        xy[1] = min(vc->state.y, 0xFFu);
}

void putconsxy(struct vc_data *vc, unsigned char xy[static const 2])
{
        hide_cursor(vc);
        gotoxy(vc, xy[0], xy[1]);
        set_cursor(vc);
}

u16 vcs_scr_readw(const struct vc_data *vc, const u16 *org)
{
        if ((unsigned long)org == vc->vc_pos && softcursor_original != -1)
                return softcursor_original;
        return scr_readw(org);
}

void vcs_scr_writew(struct vc_data *vc, u16 val, u16 *org)
{
        scr_writew(val, org);
        if ((unsigned long)org == vc->vc_pos) {
                softcursor_original = -1;
                add_softcursor(vc);
        }
}

void vcs_scr_updated(struct vc_data *vc)
{
        notify_update(vc);
}