q3k/linux
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
linux/arch/s390/kernel/debug.c
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop 
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00

1544 lines
35 KiB
C
Raw Blame History

/*
* arch/s390/kernel/debug.c
* S/390 debug facility
*
* Copyright (C) 1999, 2000 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
* 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 <asm/uaccess.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.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, mode_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_raw_format_fn(debug_info_t * id,
struct debug_view *view, char *out_buf,
const char *in_buf);
static int debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
int area, debug_entry_t * entry, char *out_buf);
static int debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
char *out_buf, debug_sprintf_entry_t *curr_event);
/* globals */
struct debug_view debug_raw_view = {
"raw",
NULL,
&debug_raw_header_fn,
&debug_raw_format_fn,
NULL,
NULL
};
struct debug_view debug_hex_ascii_view = {
"hex_ascii",
NULL,
&debug_dflt_header_fn,
&debug_hex_ascii_format_fn,
NULL,
NULL
};
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
};
/* 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 = NULL;
static debug_info_t *debug_area_last = NULL;
static DEFINE_MUTEX(debug_mutex);
static int initialized;
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(nr_areas *
sizeof(debug_entry_t**),
GFP_KERNEL);
if (!areas)
goto fail_malloc_areas;
for (i = 0; i < nr_areas; i++) {
areas[i] = kmalloc(pages_per_area *
sizeof(debug_entry_t*),GFP_KERNEL);
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*));
atomic_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, mode_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;
/* create root directory */
rc->debugfs_root_entry = debugfs_create_dir(rc->name,
debug_debugfs_root_entry);
/* append new element to linked list */
if (!debug_area_first) {
/* first element in list */
debug_area_first = rc;
rc->prev = NULL;
} else {
/* append element to end of list */
debug_area_last->next = rc;
rc->prev = debug_area_last;
}
debug_area_last = rc;
rc->next = NULL;
debug_info_get(rc);
out:
return rc;
}
/*
* debug_info_copy
* - copy debug-info
*/
static debug_info_t*
debug_info_copy(debug_info_t* in, int mode)
{
int i,j;
debug_info_t* rc;
unsigned long flags;
/* 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)
atomic_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)
{
int i;
if (!db_info)
return;
if (atomic_dec_and_test(&db_info->ref_count)) {
for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
if (!db_info->views[i])
continue;
debugfs_remove(db_info->debugfs_entries[i]);
}
debugfs_remove(db_info->debugfs_root_entry);
if(db_info == debug_area_first)
debug_area_first = db_info->next;
if(db_info == debug_area_last)
debug_area_last = db_info->prev;
if(db_info->prev) db_info->prev->next = db_info->next;
if(db_info->next) db_info->next->prev = db_info->prev;
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->id.stck == 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_size;
int formatted_line_residue;
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)
{
int rc = 0;
file_private_info_t *p_info;
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)
{
int i, rc = 0;
file_private_info_t *p_info;
debug_info_t *debug_info, *debug_info_snapshot;
mutex_lock(&debug_mutex);
debug_info = file->f_path.dentry->d_inode->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 */
}
/*
* debug_register_mode:
* - Creates and initializes debug area for the caller
* The mode parameter allows to specify access rights for the s390dbf files
* - Returns handle for debug area
*/
debug_info_t *debug_register_mode(const char *name, int pages_per_area,
int nr_areas, int buf_size, mode_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_warning("Root becomes the owner of all s390dbf files "
"in sysfs\n");
BUG_ON(!initialized);
mutex_lock(&debug_mutex);
/* create new debug_info */
rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
if(!rc)
goto out;
debug_register_view(rc, &debug_level_view);
debug_register_view(rc, &debug_flush_view);
debug_register_view(rc, &debug_pages_view);
out:
if (!rc){
pr_err("Registering debug feature %s failed\n", name);
}
mutex_unlock(&debug_mutex);
return rc;
}
EXPORT_SYMBOL(debug_register_mode);
/*
* debug_register:
* - creates and initializes debug area for the caller
* - returns handle for debug area
*/
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);
}
/*
* debug_unregister:
* - give back debug area
*/
void
debug_unregister(debug_info_t * id)
{
if (!id)
goto out;
mutex_lock(&debug_mutex);
debug_info_put(id);
mutex_unlock(&debug_mutex);
out:
return;
}
/*
* 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)
{
unsigned long flags;
debug_entry_t *** new_areas;
int rc=0;
if(!id || (nr_areas <= 0) || (pages_per_area < 0))
return -EINVAL;
if(pages_per_area > 0){
new_areas = debug_areas_alloc(pages_per_area, nr_areas);
if(!new_areas) {
pr_info("Allocating memory for %i pages failed\n",
pages_per_area);
rc = -ENOMEM;
goto out;
}
} else {
new_areas = NULL;
}
spin_lock_irqsave(&id->lock,flags);
debug_areas_free(id);
id->areas = new_areas;
id->nr_areas = nr_areas;
id->pages_per_area = pages_per_area;
id->active_area = 0;
memset(id->active_entries,0,sizeof(int)*id->nr_areas);
memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
spin_unlock_irqrestore(&id->lock,flags);
pr_info("%s: set new size (%i pages)\n" ,id->name, pages_per_area);
out:
return rc;
}
/*
* debug_set_level:
* - set actual debug level
*/
void
debug_set_level(debug_info_t* id, int new_level)
{
unsigned long flags;
if(!id)
return;
spin_lock_irqsave(&id->lock,flags);
if(new_level == DEBUG_OFF_LEVEL){
id->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);
} else {
id->level = new_level;
}
spin_unlock_irqrestore(&id->lock,flags);
}
/*
* 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]);
}
/*
* 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)
{
active->id.stck = get_clock();
active->id.fields.cpuid = smp_processor_id();
active->caller = __builtin_return_address(0);
active->id.fields.exception = exception;
active->id.fields.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(ctl_table *table, int write,
void __user *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;
void
debug_stop_all(void)
{
if (debug_stoppable)
debug_active = 0;
}
/*
* 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)
{
unsigned long flags;
debug_entry_t *active;
if (!debug_active || !id->areas)
return NULL;
spin_lock_irqsave(&id->lock, flags);
active = get_active_entry(id);
memset(DEBUG_DATA(active), 0, id->buf_size);
memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
debug_finish_entry(id, active, level, 0);
spin_unlock_irqrestore(&id->lock, flags);
return active;
}
/*
* 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)
{
unsigned long flags;
debug_entry_t *active;
if (!debug_active || !id->areas)
return NULL;
spin_lock_irqsave(&id->lock, flags);
active = get_active_entry(id);
memset(DEBUG_DATA(active), 0, id->buf_size);
memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
debug_finish_entry(id, active, level, 1);
spin_unlock_irqrestore(&id->lock, flags);
return active;
}
/*
* 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,...)
{
va_list ap;
int numargs,idx;
unsigned long flags;
debug_sprintf_entry_t *curr_event;
debug_entry_t *active;
if((!id) || (level > id->level))
return NULL;
if (!debug_active || !id->areas)
return NULL;
numargs=debug_count_numargs(string);
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;
}
/*
* debug_sprintf_exception:
*/
debug_entry_t*
debug_sprintf_exception(debug_info_t* id, int level,char *string,...)
{
va_list ap;
int numargs,idx;
unsigned long flags;
debug_sprintf_entry_t *curr_event;
debug_entry_t *active;
if((!id) || (level > id->level))
return NULL;
if (!debug_active || !id->areas)
return NULL;
numargs=debug_count_numargs(string);
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;
}
/*
* debug_init:
* - is called exactly once to initialize the debug feature
*/
static int
__init debug_init(void)
{
int rc = 0;
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 rc;
}
/*
* debug_register_view:
*/
int
debug_register_view(debug_info_t * id, struct debug_view *view)
{
int rc = 0;
int i;
unsigned long flags;
mode_t mode;
struct dentry *pde;
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);
if (!pde){
pr_err("Registering view %s/%s failed due to out of "
"memory\n", id->name,view->name);
rc = -1;
goto out;
}
spin_lock_irqsave(&id->lock, flags);
for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
if (!id->views[i])
break;
}
if (i == DEBUG_MAX_VIEWS) {
pr_err("Registering view %s/%s would exceed the maximum "
"number of views %i\n", id->name, view->name, i);
debugfs_remove(pde);
rc = -1;
} else {
id->views[i] = view;
id->debugfs_entries[i] = pde;
}
spin_unlock_irqrestore(&id->lock, flags);
out:
return rc;
}
/*
* debug_unregister_view:
*/
int
debug_unregister_view(debug_info_t * id, struct debug_view *view)
{
int rc = 0;
int i;
unsigned long flags;
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 {
debugfs_remove(id->debugfs_entries[i]);
id->views[i] = NULL;
}
spin_unlock_irqrestore(&id->lock, flags);
out:
return rc;
}
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)
{
char *str;
int rc,new_pages;
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)
{
char *str;
int rc,new_level;
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_warning("%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 header in raw format
*/
static int
debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
int area, debug_entry_t * entry, char *out_buf)
{
int rc;
rc = sizeof(debug_entry_t);
memcpy(out_buf,entry,sizeof(debug_entry_t));
return rc;
}
/*
* prints debug data in raw format
*/
static int
debug_raw_format_fn(debug_info_t * id, struct debug_view *view,
char *out_buf, const char *in_buf)
{
int rc;
rc = id->buf_size;
memcpy(out_buf, in_buf, id->buf_size);
return rc;
}
/*
* 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 (!isprint(c))
rc += sprintf(out_buf + rc, ".");
else
rc += sprintf(out_buf + rc, "%c", c);
}
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)
{
struct timespec time_spec;
char *except_str;
unsigned long caller;
int rc = 0;
unsigned int level;
level = entry->id.fields.level;
stck_to_timespec(entry->id.stck, &time_spec);
if (entry->id.fields.exception)
except_str = "*";
else
except_str = "-";
caller = ((unsigned long) entry->caller) & PSW_ADDR_INSN;
rc += sprintf(out_buf, "%02i %011lu:%06lu %1u %1s %02i %p ",
area, time_spec.tv_sec, time_spec.tv_nsec / 1000, level,
except_str, entry->id.fields.cpuid, (void *) caller);
return rc;
}
/*
* 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;
}
/*
* clean up module
*/
static void __exit debug_exit(void)
{
debugfs_remove(debug_debugfs_root_entry);
unregister_sysctl_table(s390dbf_sysctl_header);
return;
}
/*
* module definitions
*/
postcore_initcall(debug_init);
module_exit(debug_exit);
MODULE_LICENSE("GPL");
EXPORT_SYMBOL(debug_register);
EXPORT_SYMBOL(debug_unregister);
EXPORT_SYMBOL(debug_set_level);
EXPORT_SYMBOL(debug_stop_all);
EXPORT_SYMBOL(debug_register_view);
EXPORT_SYMBOL(debug_unregister_view);
EXPORT_SYMBOL(debug_event_common);
EXPORT_SYMBOL(debug_exception_common);
EXPORT_SYMBOL(debug_hex_ascii_view);
EXPORT_SYMBOL(debug_raw_view);
EXPORT_SYMBOL(debug_dflt_header_fn);
EXPORT_SYMBOL(debug_sprintf_view);
EXPORT_SYMBOL(debug_sprintf_exception);
EXPORT_SYMBOL(debug_sprintf_event);
Reference in a new issue View git blame Copy permalink