// SPDX-License-Identifier: GPL-2.0 /* * Kernel Debugger Architecture Dependent Console I/O handler * * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved. * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. */ #include <linux/kdb.h> #include <linux/keyboard.h> #include <linux/ctype.h> #include <linux/io.h> #include "kdb_private.h" /* Keyboard Controller Registers on normal PCs. */ #define KBD_STATUS_REG 0x64 /* Status register (R) */ #define KBD_DATA_REG 0x60 /* Keyboard data register (R/W) */ /* Status Register Bits */ #define KBD_STAT_OBF 0x01 /* Keyboard output buffer full */ #define KBD_STAT_MOUSE_OBF 0x20 /* Mouse output buffer full */ #define CTRL(c) ((c) - 64) static int kbd_exists; static int kbd_last_ret; /* * Check if the keyboard controller has a keypress for us. * Some parts (Enter Release, LED change) are still blocking polled here, * but hopefully they are all short. */ int kdb_get_kbd_char(void) { int scancode, scanstatus; static int shift_lock; /* CAPS LOCK state (0-off, 1-on) */ static int shift_key; /* Shift next keypress */ static int ctrl_key; u_short keychar; if (KDB_FLAG(NO_I8042) || KDB_FLAG(NO_VT_CONSOLE) || (inb(KBD_STATUS_REG) == 0xff && inb(KBD_DATA_REG) == 0xff)) { kbd_exists = 0; return -1; } kbd_exists = 1; if ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0) return -1; /* * Fetch the scancode */ scancode = inb(KBD_DATA_REG); scanstatus = inb(KBD_STATUS_REG); /* * Ignore mouse events. */ if (scanstatus & KBD_STAT_MOUSE_OBF) return -1; /* * Ignore release, trigger on make * (except for shift keys, where we want to * keep the shift state so long as the key is * held down). */ if (((scancode&0x7f) == 0x2a) || ((scancode&0x7f) == 0x36)) { /* * Next key may use shift table */ if ((scancode & 0x80) == 0) shift_key = 1; else shift_key = 0; return -1; } if ((scancode&0x7f) == 0x1d) { /* * Left ctrl key */ if ((scancode & 0x80) == 0) ctrl_key = 1; else ctrl_key = 0; return -1; } if ((scancode & 0x80) != 0) { if (scancode == 0x9c) kbd_last_ret = 0; return -1; } scancode &= 0x7f; /* * Translate scancode */ if (scancode == 0x3a) { /* * Toggle caps lock */ shift_lock ^= 1; #ifdef KDB_BLINK_LED kdb_toggleled(0x4); #endif return -1; } if (scancode == 0x0e) { /* * Backspace */ return 8; } /* Translate special keys to equivalent CTRL control characters */ switch (scancode) { case 0xF: /* Tab */ return CTRL('I'); case 0x53: /* Del */ return CTRL('D'); case 0x47: /* Home */ return CTRL('A'); case 0x4F: /* End */ return CTRL('E'); case 0x4B: /* Left */ return CTRL('B'); case 0x48: /* Up */ return CTRL('P'); case 0x50: /* Down */ return CTRL('N'); case 0x4D: /* Right */ return CTRL('F'); } /* * For Japanese 86/106 keyboards * See comment in drivers/char/pc_keyb.c. * - Masahiro Adegawa */ if (scancode == 0x73) scancode = 0x59; else if (scancode == 0x7d) scancode = 0x7c; if (!shift_lock && !shift_key && !ctrl_key) { keychar = plain_map[scancode]; } else if ((shift_lock || shift_key) && key_maps[1]) { keychar = key_maps[1][scancode]; } else if (ctrl_key && key_maps[4]) { keychar = key_maps[4][scancode]; } else { keychar = 0x0020; kdb_printf("Unknown state/scancode (%d)\n", scancode); } keychar &= 0x0fff; if (keychar == '\t') keychar = ' '; switch (KTYP(keychar)) { case KT_LETTER: case KT_LATIN: switch (keychar) { /* non-printable supported control characters */ case CTRL('A'): /* Home */ case CTRL('B'): /* Left */ case CTRL('D'): /* Del */ case CTRL('E'): /* End */ case CTRL('F'): /* Right */ case CTRL('I'): /* Tab */ case CTRL('N'): /* Down */ case CTRL('P'): /* Up */ return keychar; } if (isprint(keychar)) break; /* printable characters */ fallthrough; case KT_SPEC: if (keychar == K_ENTER) break; fallthrough; default: return -1; /* ignore unprintables */ } if (scancode == 0x1c) { kbd_last_ret = 1; return 13; } return keychar & 0xff; } EXPORT_SYMBOL_GPL(kdb_get_kbd_char); /* * Best effort cleanup of ENTER break codes on leaving KDB. Called on * exiting KDB, when we know we processed an ENTER or KP ENTER scan * code. */ void kdb_kbd_cleanup_state(void) { int scancode, scanstatus; /* * Nothing to clean up, since either * ENTER was never pressed, or has already * gotten cleaned up. */ if (!kbd_last_ret) return; kbd_last_ret = 0; /* * Enter key. Need to absorb the break code here, lest it gets * leaked out if we exit KDB as the result of processing 'g'. * * This has several interesting implications: * + Need to handle KP ENTER, which has break code 0xe0 0x9c. * + Need to handle repeat ENTER and repeat KP ENTER. Repeats * only get a break code at the end of the repeated * sequence. This means we can't propagate the repeated key * press, and must swallow it away. * + Need to handle possible PS/2 mouse input. * + Need to handle mashed keys. */ while (1) { while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0) cpu_relax(); /* * Fetch the scancode. */ scancode = inb(KBD_DATA_REG); scanstatus = inb(KBD_STATUS_REG); /* * Skip mouse input. */ if (scanstatus & KBD_STAT_MOUSE_OBF) continue; /* * If we see 0xe0, this is either a break code for KP * ENTER, or a repeat make for KP ENTER. Either way, * since the second byte is equivalent to an ENTER, * skip the 0xe0 and try again. * * If we see 0x1c, this must be a repeat ENTER or KP * ENTER (and we swallowed 0xe0 before). Try again. * * We can also see make and break codes for other keys * mashed before or after pressing ENTER. Thus, if we * see anything other than 0x9c, we have to try again. * * Note, if you held some key as ENTER was depressed, * that break code would get leaked out. */ if (scancode != 0x9c) continue; return; } }
