linux-stable/arch/s390/kernel/debug.c
Peter Oberparleiter 70aa5d3982 s390/sclp: add tracing of SCLP interactions
Add tracing of interactions between the SCLP base driver, firmware and
other drivers to support problem determination in case of SCLP-related
issues.

For that purpose this patch introduces two new s390dbf debug areas:

  - sclp: An abbreviated log of all common interactions
  - sclp_err: A full log of failed or abnormal interactions

Tracing of full SCCB contents can be enabled for the sclp area by
setting its debug level to maximum (6).

Overview of added trace events:

  * Firmware interaction:
    - SRV1: Service call about to be issued
    - SRV2: Service call was issued
    - INT:  Interrupt received

  * Driver interaction:
    - RQAD: Request was added
    - RQOK: Request success
    - RQAB: Request aborted
    - RQTM: Request timed out
    - REG:  Event listener registered
    - UREG: Event listener unregistered
    - EVNT: Event callback
    - STCG: State-change callback

  * Abnormal events:
    - TMO:  A timeout occurred
    - UNEX: Unexpected SCCB completion

  * Other (not traced at default level):
    - SYN1: Synchronous wait start
    - SYN2: Synchronous wait end

Since the SCLP interface is used by console drivers this patch also
moves s390dbf printks outside the critical section protected by debug
area locks to prevent a potential deadlock that would otherwise be
introduced between console_owner --> sclp_lock --> sclp_debug.lock.

Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-25 11:03:35 +02:00

1583 lines
38 KiB
C

// 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[0];
} 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, debug_sprintf_entry_t *curr_event);
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_format_proc_t *)&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;
strlcpy(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 s390dbf_dir_table[] = {
{
.procname = "s390dbf",
.maxlen = 0,
.mode = S_IRUGO | S_IXUGO,
.child = s390dbf_table,
},
{ }
};
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, debug_sprintf_entry_t *curr_event)
{
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_table(s390dbf_dir_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);