// SPDX-License-Identifier: GPL-2.0
/*
* S/390 debug facility
*
* Copyright IBM Corp. 1999, 2020
*
* Author(s): Michael Holzheu (holzheu@de.ibm.com),
* Holger Smolinski (Holger.Smolinski@de.ibm.com)
*
* Bugreports to: <Linux390@de.ibm.com>
*/
#define KMSG_COMPONENT "s390dbf"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/sysctl.h>
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/minmax.h>
#include <linux/debugfs.h>
#include <asm/debug.h>
#define DEBUG_PROLOG_ENTRY -1
#define ALL_AREAS 0 /* copy all debug areas */
#define NO_AREAS 1 /* copy no debug areas */
/* typedefs */
typedef struct file_private_info {
loff_t offset; /* offset of last read in file */
int act_area; /* number of last formated area */
int act_page; /* act page in given area */
int act_entry; /* last formated entry (offset */
/* relative to beginning of last */
/* formated page) */
size_t act_entry_offset; /* up to this offset we copied */
/* in last read the last formated */
/* entry to userland */
char temp_buf[2048]; /* buffer for output */
debug_info_t *debug_info_org; /* original debug information */
debug_info_t *debug_info_snap; /* snapshot of debug information */
struct debug_view *view; /* used view of debug info */
} file_private_info_t;
typedef struct {
char *string;
/*
* This assumes that all args are converted into longs
* on L/390 this is the case for all types of parameter
* except of floats, and long long (32 bit)
*
*/
long args[];
} debug_sprintf_entry_t;
/* internal function prototyes */
static int debug_init(void);
static ssize_t debug_output(struct file *file, char __user *user_buf,
size_t user_len, loff_t *offset);
static ssize_t debug_input(struct file *file, const char __user *user_buf,
size_t user_len, loff_t *offset);
static int debug_open(struct inode *inode, struct file *file);
static int debug_close(struct inode *inode, struct file *file);
static debug_info_t *debug_info_create(const char *name, int pages_per_area,
int nr_areas, int buf_size, umode_t mode);
static void debug_info_get(debug_info_t *);
static void debug_info_put(debug_info_t *);
static int debug_prolog_level_fn(debug_info_t *id,
struct debug_view *view, char *out_buf);
static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
struct file *file, const char __user *user_buf,
size_t user_buf_size, loff_t *offset);
static int debug_prolog_pages_fn(debug_info_t *id,
struct debug_view *view, char *out_buf);
static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
struct file *file, const char __user *user_buf,
size_t user_buf_size, loff_t *offset);
static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
struct file *file, const char __user *user_buf,
size_t user_buf_size, loff_t *offset);
static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
char *out_buf, const char *in_buf);
static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
char *out_buf, const char *inbuf);
static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
static void debug_events_append(debug_info_t *dest, debug_info_t *src);
/* globals */
struct debug_view debug_hex_ascii_view = {
"hex_ascii",
NULL,
&debug_dflt_header_fn,
&debug_hex_ascii_format_fn,
NULL,
NULL
};
EXPORT_SYMBOL(debug_hex_ascii_view);
static struct debug_view debug_level_view = {
"level",
&debug_prolog_level_fn,
NULL,
NULL,
&debug_input_level_fn,
NULL
};
static struct debug_view debug_pages_view = {
"pages",
&debug_prolog_pages_fn,
NULL,
NULL,
&debug_input_pages_fn,
NULL
};
static struct debug_view debug_flush_view = {
"flush",
NULL,
NULL,
NULL,
&debug_input_flush_fn,
NULL
};
struct debug_view debug_sprintf_view = {
"sprintf",
NULL,
&debug_dflt_header_fn,
&debug_sprintf_format_fn,
NULL,
NULL
};
EXPORT_SYMBOL(debug_sprintf_view);
/* used by dump analysis tools to determine version of debug feature */
static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
/* static globals */
static debug_info_t *debug_area_first;
static debug_info_t *debug_area_last;
static DEFINE_MUTEX(debug_mutex);
static int initialized;
static int debug_critical;
static const struct file_operations debug_file_ops = {
.owner = THIS_MODULE,
.read = debug_output,
.write = debug_input,
.open = debug_open,
.release = debug_close,
.llseek = no_llseek,
};
static struct dentry *debug_debugfs_root_entry;
/* functions */
/*
* debug_areas_alloc
* - Debug areas are implemented as a threedimensonal array:
* areas[areanumber][pagenumber][pageoffset]
*/
static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
{
debug_entry_t ***areas;
int i, j;
areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
if (!areas)
goto fail_malloc_areas;
for (i = 0; i < nr_areas; i++) {
/* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
areas[i] = kmalloc_array(pages_per_area,
sizeof(debug_entry_t *),
GFP_KERNEL | __GFP_NOWARN);
if (!areas[i])
goto fail_malloc_areas2;
for (j = 0; j < pages_per_area; j++) {
areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!areas[i][j]) {
for (j--; j >= 0 ; j--)
kfree(areas[i][j]);
kfree(areas[i]);
goto fail_malloc_areas2;
}
}
}
return areas;
fail_malloc_areas2:
for (i--; i >= 0; i--) {
for (j = 0; j < pages_per_area; j++)
kfree(areas[i][j]);
kfree(areas[i]);
}
kfree(areas);
fail_malloc_areas:
return NULL;
}
/*
* debug_info_alloc
* - alloc new debug-info
*/
static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
int nr_areas, int buf_size, int level,
int mode)
{
debug_info_t *rc;
/* alloc everything */
rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
if (!rc)
goto fail_malloc_rc;
rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
if (!rc->active_entries)
goto fail_malloc_active_entries;
rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
if (!rc->active_pages)
goto fail_malloc_active_pages;
if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
if (!rc->areas)
goto fail_malloc_areas;
} else {
rc->areas = NULL;
}
/* initialize members */
spin_lock_init(&rc->lock);
rc->pages_per_area = pages_per_area;
rc->nr_areas = nr_areas;
rc->active_area = 0;
rc->level = level;
rc->buf_size = buf_size;
rc->entry_size = sizeof(debug_entry_t) + buf_size;
strscpy(rc->name, name, sizeof(rc->name));
memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
refcount_set(&(rc->ref_count), 0);
return rc;
fail_malloc_areas:
kfree(rc->active_pages);
fail_malloc_active_pages:
kfree(rc->active_entries);
fail_malloc_active_entries:
kfree(rc);
fail_malloc_rc:
return NULL;
}
/*
* debug_areas_free
* - free all debug areas
*/
static void debug_areas_free(debug_info_t *db_info)
{
int i, j;
if (!db_info->areas)
return;
for (i = 0; i < db_info->nr_areas; i++) {
for (j = 0; j < db_info->pages_per_area; j++)
kfree(db_info->areas[i][j]);
kfree(db_info->areas[i]);
}
kfree(db_info->areas);
db_info->areas = NULL;
}
/*
* debug_info_free
* - free memory debug-info
*/
static void debug_info_free(debug_info_t *db_info)
{
debug_areas_free(db_info);
kfree(db_info->active_entries);
kfree(db_info->active_pages);
kfree(db_info);
}
/*
* debug_info_create
* - create new debug-info
*/
static debug_info_t *debug_info_create(const char *name, int pages_per_area,
int nr_areas, int buf_size, umode_t mode)
{
debug_info_t *rc;
rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
DEBUG_DEFAULT_LEVEL, ALL_AREAS);
if (!rc)
goto out;
rc->mode = mode & ~S_IFMT;
refcount_set(&rc->ref_count, 1);
out:
return rc;
}
/*
* debug_info_copy
* - copy debug-info
*/
static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
{
unsigned long flags;
debug_info_t *rc;
int i, j;
/* get a consistent copy of the debug areas */
do {
rc = debug_info_alloc(in->name, in->pages_per_area,
in->nr_areas, in->buf_size, in->level, mode);
spin_lock_irqsave(&in->lock, flags);
if (!rc)
goto out;
/* has something changed in the meantime ? */
if ((rc->pages_per_area == in->pages_per_area) &&
(rc->nr_areas == in->nr_areas)) {
break;
}
spin_unlock_irqrestore(&in->lock, flags);
debug_info_free(rc);
} while (1);
if (mode == NO_AREAS)
goto out;
for (i = 0; i < in->nr_areas; i++) {
for (j = 0; j < in->pages_per_area; j++)
memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
}
out:
spin_unlock_irqrestore(&in->lock, flags);
return rc;
}
/*
* debug_info_get
* - increments reference count for debug-info
*/
static void debug_info_get(debug_info_t *db_info)
{
if (db_info)
refcount_inc(&db_info->ref_count);
}
/*
* debug_info_put:
* - decreases reference count for debug-info and frees it if necessary
*/
static void debug_info_put(debug_info_t *db_info)
{
if (!db_info)
return;
if (refcount_dec_and_test(&db_info->ref_count))
debug_info_free(db_info);
}
/*
* debug_format_entry:
* - format one debug entry and return size of formated data
*/
static int debug_format_entry(file_private_info_t *p_info)
{
debug_info_t *id_snap = p_info->debug_info_snap;
struct debug_view *view = p_info->view;
debug_entry_t *act_entry;
size_t len = 0;
if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
/* print prolog */
if (view->prolog_proc)
len += view->prolog_proc(id_snap, view, p_info->temp_buf);
goto out;
}
if (!id_snap->areas) /* this is true, if we have a prolog only view */
goto out; /* or if 'pages_per_area' is 0 */
act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
[p_info->act_page] + p_info->act_entry);
if (act_entry->clock == 0LL)
goto out; /* empty entry */
if (view->header_proc)
len += view->header_proc(id_snap, view, p_info->act_area,
act_entry, p_info->temp_buf + len);
if (view->format_proc)
len += view->format_proc(id_snap, view, p_info->temp_buf + len,
DEBUG_DATA(act_entry));
out:
return len;
}
/*
* debug_next_entry:
* - goto next entry in p_info
*/
static inline int debug_next_entry(file_private_info_t *p_info)
{
debug_info_t *id;
id = p_info->debug_info_snap;
if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
p_info->act_entry = 0;
p_info->act_page = 0;
goto out;
}
if (!id->areas)
return 1;
p_info->act_entry += id->entry_size;
/* switch to next page, if we reached the end of the page */
if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
/* next page */
p_info->act_entry = 0;
p_info->act_page += 1;
if ((p_info->act_page % id->pages_per_area) == 0) {
/* next area */
p_info->act_area++;
p_info->act_page = 0;
}
if (p_info->act_area >= id->nr_areas)
return 1;
}
out:
return 0;
}
/*
* debug_output:
* - called for user read()
* - copies formated debug entries to the user buffer
*/
static ssize_t debug_output(struct file *file, /* file descriptor */
char __user *user_buf, /* user buffer */
size_t len, /* length of buffer */
loff_t *offset) /* offset in the file */
{
size_t count = 0;
size_t entry_offset;
file_private_info_t *p_info;
p_info = (file_private_info_t *) file->private_data;
if (*offset != p_info->offset)
return -EPIPE;
if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
return 0;
entry_offset = p_info->act_entry_offset;
while (count < len) {
int formatted_line_residue;
int formatted_line_size;
int user_buf_residue;
size_t copy_size;
formatted_line_size = debug_format_entry(p_info);
formatted_line_residue = formatted_line_size - entry_offset;
user_buf_residue = len-count;
copy_size = min(user_buf_residue, formatted_line_residue);
if (copy_size) {
if (copy_to_user(user_buf + count, p_info->temp_buf
+ entry_offset, copy_size))
return -EFAULT;
count += copy_size;
entry_offset += copy_size;
}
if (copy_size == formatted_line_residue) {
entry_offset = 0;
if (debug_next_entry(p_info))
goto out;
}
}
out:
p_info->offset = *offset + count;
p_info->act_entry_offset = entry_offset;
*offset = p_info->offset;
return count;
}
/*
* debug_input:
* - called for user write()
* - calls input function of view
*/
static ssize_t debug_input(struct file *file, const char __user *user_buf,
size_t length, loff_t *offset)
{
file_private_info_t *p_info;
int rc = 0;
mutex_lock(&debug_mutex);
p_info = ((file_private_info_t *) file->private_data);
if (p_info->view->input_proc) {
rc = p_info->view->input_proc(p_info->debug_info_org,
p_info->view, file, user_buf,
length, offset);
} else {
rc = -EPERM;
}
mutex_unlock(&debug_mutex);
return rc; /* number of input characters */
}
/*
* debug_open:
* - called for user open()
* - copies formated output to private_data area of the file
* handle
*/
static int debug_open(struct inode *inode, struct file *file)
{
debug_info_t *debug_info, *debug_info_snapshot;
file_private_info_t *p_info;
int i, rc = 0;
mutex_lock(&debug_mutex);
debug_info = file_inode(file)->i_private;
/* find debug view */
for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
if (!debug_info->views[i])
continue;
else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
goto found; /* found view ! */
}
/* no entry found */
rc = -EINVAL;
goto out;
found:
/* Make snapshot of current debug areas to get it consistent. */
/* To copy all the areas is only needed, if we have a view which */
/* formats the debug areas. */
if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
else
debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
if (!debug_info_snapshot) {
rc = -ENOMEM;
goto out;
}
p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
if (!p_info) {
debug_info_free(debug_info_snapshot);
rc = -ENOMEM;
goto out;
}
p_info->offset = 0;
p_info->debug_info_snap = debug_info_snapshot;
p_info->debug_info_org = debug_info;
p_info->view = debug_info->views[i];
p_info->act_area = 0;
p_info->act_page = 0;
p_info->act_entry = DEBUG_PROLOG_ENTRY;
p_info->act_entry_offset = 0;
file->private_data = p_info;
debug_info_get(debug_info);
nonseekable_open(inode, file);
out:
mutex_unlock(&debug_mutex);
return rc;
}
/*
* debug_close:
* - called for user close()
* - deletes private_data area of the file handle
*/
static int debug_close(struct inode *inode, struct file *file)
{
file_private_info_t *p_info;
p_info = (file_private_info_t *) file->private_data;
if (p_info->debug_info_snap)
debug_info_free(p_info->debug_info_snap);
debug_info_put(p_info->debug_info_org);
kfree(file->private_data);
return 0; /* success */
}
/* Create debugfs entries and add to internal list. */
static void _debug_register(debug_info_t *id)
{
/* create root directory */
id->debugfs_root_entry = debugfs_create_dir(id->name,
debug_debugfs_root_entry);
/* append new element to linked list */
if (!debug_area_first) {
/* first element in list */
debug_area_first = id;
id->prev = NULL;
} else {
/* append element to end of list */
debug_area_last->next = id;
id->prev = debug_area_last;
}
debug_area_last = id;
id->next = NULL;
debug_register_view(id, &debug_level_view);
debug_register_view(id, &debug_flush_view);
debug_register_view(id, &debug_pages_view);
}
/**
* debug_register_mode() - creates and initializes debug area.
*
* @name: Name of debug log (e.g. used for debugfs entry)
* @pages_per_area: Number of pages, which will be allocated per area
* @nr_areas: Number of debug areas
* @buf_size: Size of data area in each debug entry
* @mode: File mode for debugfs files. E.g. S_IRWXUGO
* @uid: User ID for debugfs files. Currently only 0 is supported.
* @gid: Group ID for debugfs files. Currently only 0 is supported.
*
* Return:
* - Handle for generated debug area
* - %NULL if register failed
*
* Allocates memory for a debug log.
* Must not be called within an interrupt handler.
*/
debug_info_t *debug_register_mode(const char *name, int pages_per_area,
int nr_areas, int buf_size, umode_t mode,
uid_t uid, gid_t gid)
{
debug_info_t *rc = NULL;
/* Since debugfs currently does not support uid/gid other than root, */
/* we do not allow gid/uid != 0 until we get support for that. */
if ((uid != 0) || (gid != 0))
pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
BUG_ON(!initialized);
/* create new debug_info */
rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
if (rc) {
mutex_lock(&debug_mutex);
_debug_register(rc);
mutex_unlock(&debug_mutex);
} else {
pr_err("Registering debug feature %s failed\n", name);
}
return rc;
}
EXPORT_SYMBOL(debug_register_mode);
/**
* debug_register() - creates and initializes debug area with default file mode.
*
* @name: Name of debug log (e.g. used for debugfs entry)
* @pages_per_area: Number of pages, which will be allocated per area
* @nr_areas: Number of debug areas
* @buf_size: Size of data area in each debug entry
*
* Return:
* - Handle for generated debug area
* - %NULL if register failed
*
* Allocates memory for a debug log.
* The debugfs file mode access permissions are read and write for user.
* Must not be called within an interrupt handler.
*/
debug_info_t *debug_register(const char *name, int pages_per_area,
int nr_areas, int buf_size)
{
return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
S_IRUSR | S_IWUSR, 0, 0);
}
EXPORT_SYMBOL(debug_register);
/**
* debug_register_static() - registers a static debug area
*
* @id: Handle for static debug area
* @pages_per_area: Number of pages per area
* @nr_areas: Number of debug areas
*
* Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO.
*
* Note: This function is called automatically via an initcall generated by
* DEFINE_STATIC_DEBUG_INFO.
*/
void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas)
{
unsigned long flags;
debug_info_t *copy;
if (!initialized) {
pr_err("Tried to register debug feature %s too early\n",
id->name);
return;
}
copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
id->level, ALL_AREAS);
if (!copy) {
pr_err("Registering debug feature %s failed\n", id->name);
/* Clear pointers to prevent tracing into released initdata. */
spin_lock_irqsave(&id->lock, flags);
id->areas = NULL;
id->active_pages = NULL;
id->active_entries = NULL;
spin_unlock_irqrestore(&id->lock, flags);
return;
}
/* Replace static trace area with dynamic copy. */
spin_lock_irqsave(&id->lock, flags);
debug_events_append(copy, id);
debug_areas_swap(id, copy);
spin_unlock_irqrestore(&id->lock, flags);
/* Clear pointers to initdata and discard copy. */
copy->areas = NULL;
copy->active_pages = NULL;
copy->active_entries = NULL;
debug_info_free(copy);
mutex_lock(&debug_mutex);
_debug_register(id);
mutex_unlock(&debug_mutex);
}
/* Remove debugfs entries and remove from internal list. */
static void _debug_unregister(debug_info_t *id)
{
int i;
for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
if (!id->views[i])
continue;
debugfs_remove(id->debugfs_entries[i]);
}
debugfs_remove(id->debugfs_root_entry);
if (id == debug_area_first)
debug_area_first = id->next;
if (id == debug_area_last)
debug_area_last = id->prev;
if (id->prev)
id->prev->next = id->next;
if (id->next)
id->next->prev = id->prev;
}
/**
* debug_unregister() - give back debug area.
*
* @id: handle for debug log
*
* Return:
* none
*/
void debug_unregister(debug_info_t *id)
{
if (!id)
return;
mutex_lock(&debug_mutex);
_debug_unregister(id);
mutex_unlock(&debug_mutex);
debug_info_put(id);
}
EXPORT_SYMBOL(debug_unregister);
/*
* debug_set_size:
* - set area size (number of pages) and number of areas
*/
static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
{
debug_info_t *new_id;
unsigned long flags;
if (!id || (nr_areas <= 0) || (pages_per_area < 0))
return -EINVAL;
new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
id->level, ALL_AREAS);
if (!new_id) {
pr_info("Allocating memory for %i pages failed\n",
pages_per_area);
return -ENOMEM;
}
spin_lock_irqsave(&id->lock, flags);
debug_events_append(new_id, id);
debug_areas_swap(new_id, id);
debug_info_free(new_id);
spin_unlock_irqrestore(&id->lock, flags);
pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
return 0;
}
/**
* debug_set_level() - Sets new actual debug level if new_level is valid.
*
* @id: handle for debug log
* @new_level: new debug level
*
* Return:
* none
*/
void debug_set_level(debug_info_t *id, int new_level)
{
unsigned long flags;
if (!id)
return;
if (new_level == DEBUG_OFF_LEVEL) {
pr_info("%s: switched off\n", id->name);
} else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
pr_info("%s: level %i is out of range (%i - %i)\n",
id->name, new_level, 0, DEBUG_MAX_LEVEL);
return;
}
spin_lock_irqsave(&id->lock, flags);
id->level = new_level;
spin_unlock_irqrestore(&id->lock, flags);
}
EXPORT_SYMBOL(debug_set_level);
/*
* proceed_active_entry:
* - set active entry to next in the ring buffer
*/
static inline void proceed_active_entry(debug_info_t *id)
{
if ((id->active_entries[id->active_area] += id->entry_size)
> (PAGE_SIZE - id->entry_size)) {
id->active_entries[id->active_area] = 0;
id->active_pages[id->active_area] =
(id->active_pages[id->active_area] + 1) %
id->pages_per_area;
}
}
/*
* proceed_active_area:
* - set active area to next in the ring buffer
*/
static inline void proceed_active_area(debug_info_t *id)
{
id->active_area++;
id->active_area = id->active_area % id->nr_areas;
}
/*
* get_active_entry:
*/
static inline debug_entry_t *get_active_entry(debug_info_t *id)
{
return (debug_entry_t *) (((char *) id->areas[id->active_area]
[id->active_pages[id->active_area]]) +
id->active_entries[id->active_area]);
}
/* Swap debug areas of a and b. */
static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
{
swap(a->nr_areas, b->nr_areas);
swap(a->pages_per_area, b->pages_per_area);
swap(a->areas, b->areas);
swap(a->active_area, b->active_area);
swap(a->active_pages, b->active_pages);
swap(a->active_entries, b->active_entries);
}
/* Append all debug events in active area from source to destination log. */
static void debug_events_append(debug_info_t *dest, debug_info_t *src)
{
debug_entry_t *from, *to, *last;
if (!src->areas || !dest->areas)
return;
/* Loop over all entries in src, starting with oldest. */
from = get_active_entry(src);
last = from;
do {
if (from->clock != 0LL) {
to = get_active_entry(dest);
memset(to, 0, dest->entry_size);
memcpy(to, from, min(src->entry_size,
dest->entry_size));
proceed_active_entry(dest);
}
proceed_active_entry(src);
from = get_active_entry(src);
} while (from != last);
}
/*
* debug_finish_entry:
* - set timestamp, caller address, cpu number etc.
*/
static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
int level, int exception)
{
unsigned long timestamp;
union tod_clock clk;
store_tod_clock_ext(&clk);
timestamp = clk.us;
timestamp -= TOD_UNIX_EPOCH >> 12;
active->clock = timestamp;
active->cpu = smp_processor_id();
active->caller = __builtin_return_address(0);
active->exception = exception;
active->level = level;
proceed_active_entry(id);
if (exception)
proceed_active_area(id);
}
static int debug_stoppable = 1;
static int debug_active = 1;
#define CTL_S390DBF_STOPPABLE 5678
#define CTL_S390DBF_ACTIVE 5679
/*
* proc handler for the running debug_active sysctl
* always allow read, allow write only if debug_stoppable is set or
* if debug_active is already off
*/
static int s390dbf_procactive(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
if (!write || debug_stoppable || !debug_active)
return proc_dointvec(table, write, buffer, lenp, ppos);
else
return 0;
}
static struct ctl_table s390dbf_table[] = {
{
.procname = "debug_stoppable",
.data = &debug_stoppable,
.maxlen = sizeof(int),
.mode = S_IRUGO | S_IWUSR,
.proc_handler = proc_dointvec,
},
{
.procname = "debug_active",
.data = &debug_active,
.maxlen = sizeof(int),
.mode = S_IRUGO | S_IWUSR,
.proc_handler = s390dbf_procactive,
},
{ }
};
static struct ctl_table_header *s390dbf_sysctl_header;
/**
* debug_stop_all() - stops the debug feature if stopping is allowed.
*
* Return:
* - none
*
* Currently used in case of a kernel oops.
*/
void debug_stop_all(void)
{
if (debug_stoppable)
debug_active = 0;
}
EXPORT_SYMBOL(debug_stop_all);
/**
* debug_set_critical() - event/exception functions try lock instead of spin.
*
* Return:
* - none
*
* Currently used in case of stopping all CPUs but the current one.
* Once in this state, functions to write a debug entry for an
* event or exception no longer spin on the debug area lock,
* but only try to get it and fail if they do not get the lock.
*/
void debug_set_critical(void)
{
debug_critical = 1;
}
/*
* debug_event_common:
* - write debug entry with given size
*/
debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
int len)
{
debug_entry_t *active;
unsigned long flags;
if (!debug_active || !id->areas)
return NULL;
if (debug_critical) {
if (!spin_trylock_irqsave(&id->lock, flags))
return NULL;
} else {
spin_lock_irqsave(&id->lock, flags);
}
do {
active = get_active_entry(id);
memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
if (len < id->buf_size)
memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
debug_finish_entry(id, active, level, 0);
len -= id->buf_size;
buf += id->buf_size;
} while (len > 0);
spin_unlock_irqrestore(&id->lock, flags);
return active;
}
EXPORT_SYMBOL(debug_event_common);
/*
* debug_exception_common:
* - write debug entry with given size and switch to next debug area
*/
debug_entry_t *debug_exception_common(debug_info_t *id, int level,
const void *buf, int len)
{
debug_entry_t *active;
unsigned long flags;
if (!debug_active || !id->areas)
return NULL;
if (debug_critical) {
if (!spin_trylock_irqsave(&id->lock, flags))
return NULL;
} else {
spin_lock_irqsave(&id->lock, flags);
}
do {
active = get_active_entry(id);
memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
if (len < id->buf_size)
memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
debug_finish_entry(id, active, level, len <= id->buf_size);
len -= id->buf_size;
buf += id->buf_size;
} while (len > 0);
spin_unlock_irqrestore(&id->lock, flags);
return active;
}
EXPORT_SYMBOL(debug_exception_common);
/*
* counts arguments in format string for sprintf view
*/
static inline int debug_count_numargs(char *string)
{
int numargs = 0;
while (*string) {
if (*string++ == '%')
numargs++;
}
return numargs;
}
/*
* debug_sprintf_event:
*/
debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
{
debug_sprintf_entry_t *curr_event;
debug_entry_t *active;
unsigned long flags;
int numargs, idx;
va_list ap;
if (!debug_active || !id->areas)
return NULL;
numargs = debug_count_numargs(string);
if (debug_critical) {
if (!spin_trylock_irqsave(&id->lock, flags))
return NULL;
} else {
spin_lock_irqsave(&id->lock, flags);
}
active = get_active_entry(id);
curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
va_start(ap, string);
curr_event->string = string;
for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
curr_event->args[idx] = va_arg(ap, long);
va_end(ap);
debug_finish_entry(id, active, level, 0);
spin_unlock_irqrestore(&id->lock, flags);
return active;
}
EXPORT_SYMBOL(__debug_sprintf_event);
/*
* debug_sprintf_exception:
*/
debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
{
debug_sprintf_entry_t *curr_event;
debug_entry_t *active;
unsigned long flags;
int numargs, idx;
va_list ap;
if (!debug_active || !id->areas)
return NULL;
numargs = debug_count_numargs(string);
if (debug_critical) {
if (!spin_trylock_irqsave(&id->lock, flags))
return NULL;
} else {
spin_lock_irqsave(&id->lock, flags);
}
active = get_active_entry(id);
curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
va_start(ap, string);
curr_event->string = string;
for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
curr_event->args[idx] = va_arg(ap, long);
va_end(ap);
debug_finish_entry(id, active, level, 1);
spin_unlock_irqrestore(&id->lock, flags);
return active;
}
EXPORT_SYMBOL(__debug_sprintf_exception);
/**
* debug_register_view() - registers new debug view and creates debugfs
* dir entry
*
* @id: handle for debug log
* @view: pointer to debug view struct
*
* Return:
* - 0 : ok
* - < 0: Error
*/
int debug_register_view(debug_info_t *id, struct debug_view *view)
{
unsigned long flags;
struct dentry *pde;
umode_t mode;
int rc = 0;
int i;
if (!id)
goto out;
mode = (id->mode | S_IFREG) & ~S_IXUGO;
if (!(view->prolog_proc || view->format_proc || view->header_proc))
mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
if (!view->input_proc)
mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
id, &debug_file_ops);
spin_lock_irqsave(&id->lock, flags);
for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
if (!id->views[i])
break;
}
if (i == DEBUG_MAX_VIEWS) {
rc = -1;
} else {
id->views[i] = view;
id->debugfs_entries[i] = pde;
}
spin_unlock_irqrestore(&id->lock, flags);
if (rc) {
pr_err("Registering view %s/%s would exceed the maximum "
"number of views %i\n", id->name, view->name, i);
debugfs_remove(pde);
}
out:
return rc;
}
EXPORT_SYMBOL(debug_register_view);
/**
* debug_unregister_view() - unregisters debug view and removes debugfs
* dir entry
*
* @id: handle for debug log
* @view: pointer to debug view struct
*
* Return:
* - 0 : ok
* - < 0: Error
*/
int debug_unregister_view(debug_info_t *id, struct debug_view *view)
{
struct dentry *dentry = NULL;
unsigned long flags;
int i, rc = 0;
if (!id)
goto out;
spin_lock_irqsave(&id->lock, flags);
for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
if (id->views[i] == view)
break;
}
if (i == DEBUG_MAX_VIEWS) {
rc = -1;
} else {
dentry = id->debugfs_entries[i];
id->views[i] = NULL;
id->debugfs_entries[i] = NULL;
}
spin_unlock_irqrestore(&id->lock, flags);
debugfs_remove(dentry);
out:
return rc;
}
EXPORT_SYMBOL(debug_unregister_view);
static inline char *debug_get_user_string(const char __user *user_buf,
size_t user_len)
{
char *buffer;
buffer = kmalloc(user_len + 1, GFP_KERNEL);
if (!buffer)
return ERR_PTR(-ENOMEM);
if (copy_from_user(buffer, user_buf, user_len) != 0) {
kfree(buffer);
return ERR_PTR(-EFAULT);
}
/* got the string, now strip linefeed. */
if (buffer[user_len - 1] == '\n')
buffer[user_len - 1] = 0;
else
buffer[user_len] = 0;
return buffer;
}
static inline int debug_get_uint(char *buf)
{
int rc;
buf = skip_spaces(buf);
rc = simple_strtoul(buf, &buf, 10);
if (*buf)
rc = -EINVAL;
return rc;
}
/*
* functions for debug-views
***********************************
*/
/*
* prints out actual debug level
*/
static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
char *out_buf)
{
return sprintf(out_buf, "%i\n", id->pages_per_area);
}
/*
* reads new size (number of pages per debug area)
*/
static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
struct file *file, const char __user *user_buf,
size_t user_len, loff_t *offset)
{
int rc, new_pages;
char *str;
if (user_len > 0x10000)
user_len = 0x10000;
if (*offset != 0) {
rc = -EPIPE;
goto out;
}
str = debug_get_user_string(user_buf, user_len);
if (IS_ERR(str)) {
rc = PTR_ERR(str);
goto out;
}
new_pages = debug_get_uint(str);
if (new_pages < 0) {
rc = -EINVAL;
goto free_str;
}
rc = debug_set_size(id, id->nr_areas, new_pages);
if (rc != 0) {
rc = -EINVAL;
goto free_str;
}
rc = user_len;
free_str:
kfree(str);
out:
*offset += user_len;
return rc; /* number of input characters */
}
/*
* prints out actual debug level
*/
static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
char *out_buf)
{
int rc = 0;
if (id->level == DEBUG_OFF_LEVEL)
rc = sprintf(out_buf, "-\n");
else
rc = sprintf(out_buf, "%i\n", id->level);
return rc;
}
/*
* reads new debug level
*/
static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
struct file *file, const char __user *user_buf,
size_t user_len, loff_t *offset)
{
int rc, new_level;
char *str;
if (user_len > 0x10000)
user_len = 0x10000;
if (*offset != 0) {
rc = -EPIPE;
goto out;
}
str = debug_get_user_string(user_buf, user_len);
if (IS_ERR(str)) {
rc = PTR_ERR(str);
goto out;
}
if (str[0] == '-') {
debug_set_level(id, DEBUG_OFF_LEVEL);
rc = user_len;
goto free_str;
} else {
new_level = debug_get_uint(str);
}
if (new_level < 0) {
pr_warn("%s is not a valid level for a debug feature\n", str);
rc = -EINVAL;
} else {
debug_set_level(id, new_level);
rc = user_len;
}
free_str:
kfree(str);
out:
*offset += user_len;
return rc; /* number of input characters */
}
/*
* flushes debug areas
*/
static void debug_flush(debug_info_t *id, int area)
{
unsigned long flags;
int i, j;
if (!id || !id->areas)
return;
spin_lock_irqsave(&id->lock, flags);
if (area == DEBUG_FLUSH_ALL) {
id->active_area = 0;
memset(id->active_entries, 0, id->nr_areas * sizeof(int));
for (i = 0; i < id->nr_areas; i++) {
id->active_pages[i] = 0;
for (j = 0; j < id->pages_per_area; j++)
memset(id->areas[i][j], 0, PAGE_SIZE);
}
} else if (area >= 0 && area < id->nr_areas) {
id->active_entries[area] = 0;
id->active_pages[area] = 0;
for (i = 0; i < id->pages_per_area; i++)
memset(id->areas[area][i], 0, PAGE_SIZE);
}
spin_unlock_irqrestore(&id->lock, flags);
}
/*
* view function: flushes debug areas
*/
static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
struct file *file, const char __user *user_buf,
size_t user_len, loff_t *offset)
{
char input_buf[1];
int rc = user_len;
if (user_len > 0x10000)
user_len = 0x10000;
if (*offset != 0) {
rc = -EPIPE;
goto out;
}
if (copy_from_user(input_buf, user_buf, 1)) {
rc = -EFAULT;
goto out;
}
if (input_buf[0] == '-') {
debug_flush(id, DEBUG_FLUSH_ALL);
goto out;
}
if (isdigit(input_buf[0])) {
int area = ((int) input_buf[0] - (int) '0');
debug_flush(id, area);
goto out;
}
pr_info("Flushing debug data failed because %c is not a valid "
"area\n", input_buf[0]);
out:
*offset += user_len;
return rc; /* number of input characters */
}
/*
* prints debug data in hex/ascii format
*/
static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
char *out_buf, const char *in_buf)
{
int i, rc = 0;
for (i = 0; i < id->buf_size; i++)
rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
rc += sprintf(out_buf + rc, "| ");
for (i = 0; i < id->buf_size; i++) {
unsigned char c = in_buf[i];
if (isascii(c) && isprint(c))
rc += sprintf(out_buf + rc, "%c", c);
else
rc += sprintf(out_buf + rc, ".");
}
rc += sprintf(out_buf + rc, "\n");
return rc;
}
/*
* prints header for debug entry
*/
int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
int area, debug_entry_t *entry, char *out_buf)
{
unsigned long sec, usec;
unsigned long caller;
unsigned int level;
char *except_str;
int rc = 0;
level = entry->level;
sec = entry->clock;
usec = do_div(sec, USEC_PER_SEC);
if (entry->exception)
except_str = "*";
else
except_str = "-";
caller = (unsigned long) entry->caller;
rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px ",
area, sec, usec, level, except_str,
entry->cpu, (void *)caller);
return rc;
}
EXPORT_SYMBOL(debug_dflt_header_fn);
/*
* prints debug data sprintf-formated:
* debug_sprinf_event/exception calls must be used together with this view
*/
#define DEBUG_SPRINTF_MAX_ARGS 10
static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
char *out_buf, const char *inbuf)
{
debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf;
int num_longs, num_used_args = 0, i, rc = 0;
int index[DEBUG_SPRINTF_MAX_ARGS];
/* count of longs fit into one entry */
num_longs = id->buf_size / sizeof(long);
if (num_longs < 1)
goto out; /* bufsize of entry too small */
if (num_longs == 1) {
/* no args, we use only the string */
strcpy(out_buf, curr_event->string);
rc = strlen(curr_event->string);
goto out;
}
/* number of arguments used for sprintf (without the format string) */
num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
for (i = 0; i < num_used_args; i++)
index[i] = i;
rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
curr_event->args[index[1]], curr_event->args[index[2]],
curr_event->args[index[3]], curr_event->args[index[4]],
curr_event->args[index[5]], curr_event->args[index[6]],
curr_event->args[index[7]], curr_event->args[index[8]],
curr_event->args[index[9]]);
out:
return rc;
}
/*
* debug_init:
* - is called exactly once to initialize the debug feature
*/
static int __init debug_init(void)
{
s390dbf_sysctl_header = register_sysctl("s390dbf", s390dbf_table);
mutex_lock(&debug_mutex);
debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
initialized = 1;
mutex_unlock(&debug_mutex);
return 0;
}
postcore_initcall(debug_init);