/* SPDX-License-Identifier: GPL-2.0 */
/*
 *   S/390 debug facility
 *
 *    Copyright IBM Corp. 1999, 2020
 */
#ifndef _ASM_S390_DEBUG_H
#define _ASM_S390_DEBUG_H

#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/refcount.h>
#include <linux/fs.h>
#include <linux/init.h>

#define DEBUG_MAX_LEVEL            6  /* debug levels range from 0 to 6 */
#define DEBUG_OFF_LEVEL            -1 /* level where debug is switched off */
#define DEBUG_FLUSH_ALL            -1 /* parameter to flush all areas */
#define DEBUG_MAX_VIEWS            10 /* max number of views in proc fs */
#define DEBUG_MAX_NAME_LEN         64 /* max length for a debugfs file name */
#define DEBUG_DEFAULT_LEVEL        3  /* initial debug level */

#define DEBUG_DIR_ROOT "s390dbf" /* name of debug root directory in proc fs */

#define DEBUG_DATA(entry) (char *)(entry + 1) /* data is stored behind */
                                              /* the entry information */

#define __DEBUG_FEATURE_VERSION    3  /* version of debug feature */

struct __debug_entry {
        unsigned long clock     : 60;
        unsigned long exception :  1;
        unsigned long level     :  3;
        void *caller;
        unsigned short cpu;
} __packed;

typedef struct __debug_entry debug_entry_t;

struct debug_view;

typedef struct debug_info {
        struct debug_info *next;
        struct debug_info *prev;
        refcount_t ref_count;
        raw_spinlock_t lock;
        int level;
        int nr_areas;
        int pages_per_area;
        int buf_size;
        int entry_size;
        debug_entry_t ***areas;
        int active_area;
        int *active_pages;
        int *active_entries;
        struct dentry *debugfs_root_entry;
        struct dentry *debugfs_entries[DEBUG_MAX_VIEWS];
        struct debug_view *views[DEBUG_MAX_VIEWS];
        char name[DEBUG_MAX_NAME_LEN];
        umode_t mode;
} debug_info_t;

typedef int (debug_header_proc_t) (debug_info_t *id,
                                   struct debug_view *view,
                                   int area,
                                   debug_entry_t *entry,
                                   char *out_buf, size_t out_buf_size);

typedef int (debug_format_proc_t) (debug_info_t *id,
                                   struct debug_view *view, char *out_buf,
                                   size_t out_buf_size,
                                   const char *in_buf);
typedef int (debug_prolog_proc_t) (debug_info_t *id,
                                   struct debug_view *view,
                                   char *out_buf, size_t out_buf_size);
typedef int (debug_input_proc_t) (debug_info_t *id,
                                  struct debug_view *view,
                                  struct file *file,
                                  const char __user *user_buf,
                                  size_t in_buf_size, loff_t *offset);

int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
                         int area, debug_entry_t *entry,
                         char *out_buf, size_t out_buf_size);

#define DEBUG_SPRINTF_MAX_ARGS 10
int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
                            char *out_buf, size_t out_buf_size,
                            const char *inbuf);
struct debug_view {
        char name[DEBUG_MAX_NAME_LEN];
        debug_prolog_proc_t *prolog_proc;
        debug_header_proc_t *header_proc;
        debug_format_proc_t *format_proc;
        debug_input_proc_t  *input_proc;
        void                *private_data;
};

extern struct debug_view debug_hex_ascii_view;
extern struct debug_view debug_sprintf_view;

/* do NOT use the _common functions */

debug_entry_t *debug_event_common(debug_info_t *id, int level,
                                  const void *data, int length);

debug_entry_t *debug_exception_common(debug_info_t *id, int level,
                                      const void *data, int length);

/* Debug Feature API: */

debug_info_t *debug_register(const char *name, int pages, int nr_areas,
                             int buf_size);

debug_info_t *debug_register_mode(const char *name, int pages, int nr_areas,
                                  int buf_size, umode_t mode, uid_t uid,
                                  gid_t gid);

ssize_t debug_dump(debug_info_t *id, struct debug_view *view,
                   char *buf, size_t buf_size, bool reverse);

void debug_unregister(debug_info_t *id);

void debug_set_level(debug_info_t *id, int new_level);

void debug_set_critical(void);

void debug_stop_all(void);

/**
 * debug_level_enabled() - Returns true if debug events for the specified
 *                         level would be logged. Otherwise returns false.
 *
 * @id:         handle for debug log
 * @level:      debug level
 *
 * Return:
 * - %true if level is less or equal to the current debug level.
 */
static inline bool debug_level_enabled(debug_info_t *id, int level)
{
        return level <= id->level;
}

/**
 * debug_event() - writes binary debug entry to active debug area
 *                 (if level <= actual debug level)
 *
 * @id:         handle for debug log
 * @level:      debug level
 * @data:       pointer to data for debug entry
 * @length:     length of data in bytes
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_event(debug_info_t *id, int level,
                                         void *data, int length)
{
        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_event_common(id, level, data, length);
}

/**
 * debug_int_event() - writes unsigned integer debug entry to active debug area
 *                     (if level <= actual debug level)
 *
 * @id:         handle for debug log
 * @level:      debug level
 * @tag:        integer value for debug entry
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_int_event(debug_info_t *id, int level,
                                             unsigned int tag)
{
        unsigned int t = tag;

        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_event_common(id, level, &t, sizeof(unsigned int));
}

/**
 * debug_long_event() - writes unsigned long debug entry to active debug area
 *                     (if level <= actual debug level)
 *
 * @id:         handle for debug log
 * @level:      debug level
 * @tag:        long integer value for debug entry
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_long_event(debug_info_t *id, int level,
                                              unsigned long tag)
{
        unsigned long t = tag;

        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_event_common(id, level, &t, sizeof(unsigned long));
}

/**
 * debug_text_event() - writes string debug entry in ascii format to active
 *                      debug area (if level <= actual debug level)
 *
 * @id:         handle for debug log
 * @level:      debug level
 * @txt:        string for debug entry
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_text_event(debug_info_t *id, int level,
                                              const char *txt)
{
        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_event_common(id, level, txt, strlen(txt));
}

/*
 * IMPORTANT: Use "%s" in sprintf format strings with care! Only pointers are
 * stored in the s390dbf. See Documentation/arch/s390/s390dbf.rst for more details!
 */
extern debug_entry_t *
__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
        __attribute__ ((format(printf, 3, 4)));

/**
 * debug_sprintf_event() - writes debug entry with format string
 *                         and varargs (longs) to active debug area
 *                         (if level $<=$ actual debug level).
 *
 * @_id:        handle for debug log
 * @_level:     debug level
 * @_fmt:       format string for debug entry
 * @...:        varargs used as in sprintf()
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 *
 * floats and long long datatypes cannot be used as varargs.
 */
#define debug_sprintf_event(_id, _level, _fmt, ...)                     \
({                                                                      \
        debug_entry_t *__ret;                                           \
        debug_info_t *__id = _id;                                       \
        int __level = _level;                                           \
                                                                        \
        if ((!__id) || (__level > __id->level))                         \
                __ret = NULL;                                           \
        else                                                            \
                __ret = __debug_sprintf_event(__id, __level,            \
                                              _fmt, ## __VA_ARGS__);    \
        __ret;                                                          \
})

/**
 * debug_exception() - writes binary debug entry to active debug area
 *                     (if level <= actual debug level)
 *                     and switches to next debug area
 *
 * @id:         handle for debug log
 * @level:      debug level
 * @data:       pointer to data for debug entry
 * @length:     length of data in bytes
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_exception(debug_info_t *id, int level,
                                             void *data, int length)
{
        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_exception_common(id, level, data, length);
}

/**
 * debug_int_exception() - writes unsigned int debug entry to active debug area
 *                         (if level <= actual debug level)
 *                         and switches to next debug area
 *
 * @id:         handle for debug log
 * @level:      debug level
 * @tag:        integer value for debug entry
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_int_exception(debug_info_t *id, int level,
                                                 unsigned int tag)
{
        unsigned int t = tag;

        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_exception_common(id, level, &t, sizeof(unsigned int));
}

/**
 * debug_long_exception() - writes long debug entry to active debug area
 *                         (if level <= actual debug level)
 *                         and switches to next debug area
 *
 * @id:         handle for debug log
 * @level:      debug level
 * @tag:        long integer value for debug entry
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_long_exception (debug_info_t *id, int level,
                                                   unsigned long tag)
{
        unsigned long t = tag;

        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_exception_common(id, level, &t, sizeof(unsigned long));
}

/**
 * debug_text_exception() - writes string debug entry in ascii format to active
 *                          debug area (if level <= actual debug level)
 *                          and switches to next debug area
 * area
 *
 * @id: handle for debug log
 * @level:      debug level
 * @txt:        string for debug entry
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 */
static inline debug_entry_t *debug_text_exception(debug_info_t *id, int level,
                                                  const char *txt)
{
        if ((!id) || (level > id->level) || (id->pages_per_area == 0))
                return NULL;
        return debug_exception_common(id, level, txt, strlen(txt));
}

/*
 * IMPORTANT: Use "%s" in sprintf format strings with care! Only pointers are
 * stored in the s390dbf. See Documentation/arch/s390/s390dbf.rst for more details!
 */
extern debug_entry_t *
__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
        __attribute__ ((format(printf, 3, 4)));


/**
 * debug_sprintf_exception() - writes debug entry with format string and
 *                             varargs (longs) to active debug area
 *                             (if level <= actual debug level)
 *                             and switches to next debug area.
 *
 * @_id:        handle for debug log
 * @_level:     debug level
 * @_fmt:       format string for debug entry
 * @...:        varargs used as in sprintf()
 *
 * Return:
 * - Address of written debug entry
 * - %NULL if error
 *
 * floats and long long datatypes cannot be used as varargs.
 */
#define debug_sprintf_exception(_id, _level, _fmt, ...)                 \
({                                                                      \
        debug_entry_t *__ret;                                           \
        debug_info_t *__id = _id;                                       \
        int __level = _level;                                           \
                                                                        \
        if ((!__id) || (__level > __id->level))                         \
                __ret = NULL;                                           \
        else                                                            \
                __ret = __debug_sprintf_exception(__id, __level,        \
                                                  _fmt, ## __VA_ARGS__);\
        __ret;                                                          \
})

int debug_register_view(debug_info_t *id, struct debug_view *view);

int debug_unregister_view(debug_info_t *id, struct debug_view *view);

#ifndef MODULE

/*
 * Note: Initial page and area numbers must be fixed to allow static
 * initialization. This enables very early tracing. Changes to these values
 * must be reflected in __DEFINE_STATIC_AREA.
 */
#define EARLY_PAGES             8
#define EARLY_AREAS             1

#define VNAME(var, suffix)      __##var##_##suffix

/*
 * Define static areas for early trace data. During boot debug_register_static()
 * will replace these with dynamically allocated areas to allow custom page and
 * area sizes, and dynamic resizing.
 */
#define __DEFINE_STATIC_AREA(var)                                       \
static char VNAME(var, data)[EARLY_PAGES][PAGE_SIZE] __initdata;        \
static debug_entry_t *VNAME(var, pages)[EARLY_PAGES] __initdata = {     \
        (debug_entry_t *)VNAME(var, data)[0],                           \
        (debug_entry_t *)VNAME(var, data)[1],                           \
        (debug_entry_t *)VNAME(var, data)[2],                           \
        (debug_entry_t *)VNAME(var, data)[3],                           \
        (debug_entry_t *)VNAME(var, data)[4],                           \
        (debug_entry_t *)VNAME(var, data)[5],                           \
        (debug_entry_t *)VNAME(var, data)[6],                           \
        (debug_entry_t *)VNAME(var, data)[7],                           \
};                                                                      \
static debug_entry_t **VNAME(var, areas)[EARLY_AREAS] __initdata = {    \
        (debug_entry_t **)VNAME(var, pages),                            \
};                                                                      \
static int VNAME(var, active_pages)[EARLY_AREAS] __initdata;            \
static int VNAME(var, active_entries)[EARLY_AREAS] __initdata

#define __DEBUG_INFO_INIT(var, _name, _buf_size) {                      \
        .next = NULL,                                                   \
        .prev = NULL,                                                   \
        .ref_count = REFCOUNT_INIT(1),                                  \
        .lock = __RAW_SPIN_LOCK_UNLOCKED(var.lock),                     \
        .level = DEBUG_DEFAULT_LEVEL,                                   \
        .nr_areas = EARLY_AREAS,                                        \
        .pages_per_area = EARLY_PAGES,                                  \
        .buf_size = (_buf_size),                                        \
        .entry_size = sizeof(debug_entry_t) + (_buf_size),              \
        .areas = VNAME(var, areas),                                     \
        .active_area = 0,                                               \
        .active_pages = VNAME(var, active_pages),                       \
        .active_entries = VNAME(var, active_entries),                   \
        .debugfs_root_entry = NULL,                                     \
        .debugfs_entries = { NULL },                                    \
        .views = { NULL },                                              \
        .name = (_name),                                                \
        .mode = 0600,                                                   \
}

#define __REGISTER_STATIC_DEBUG_INFO(var, name, pages, areas, view)     \
static int __init VNAME(var, reg)(void)                                 \
{                                                                       \
        debug_register_static(&var, (pages), (areas));                  \
        debug_register_view(&var, (view));                              \
        return 0;                                                       \
}                                                                       \
arch_initcall(VNAME(var, reg))

/**
 * DEFINE_STATIC_DEBUG_INFO - Define static debug_info_t
 *
 * @var: Name of debug_info_t variable
 * @name: Name of debug log (e.g. used for debugfs entry)
 * @pages: Number of pages per area
 * @nr_areas: Number of debug areas
 * @buf_size: Size of data area in each debug entry
 * @view: Pointer to debug view struct
 *
 * Define a static debug_info_t for early tracing. The associated debugfs log
 * is automatically registered with the specified debug view.
 *
 * Important: Users of this macro must not call any of the
 * debug_register/_unregister() functions for this debug_info_t!
 *
 * Note: Tracing will start with a fixed number of initial pages and areas.
 * The debug area will be changed to use the specified numbers during
 * arch_initcall.
 */
#define DEFINE_STATIC_DEBUG_INFO(var, name, pages, nr_areas, buf_size, view) \
__DEFINE_STATIC_AREA(var);                                              \
static debug_info_t __refdata var =                                     \
        __DEBUG_INFO_INIT(var, (name), (buf_size));                     \
__REGISTER_STATIC_DEBUG_INFO(var, name, pages, nr_areas, view)

void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas);

#endif /* MODULE */

#endif /* _ASM_S390_DEBUG_H */