mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Hugh Dickins](/assets/img/avatar_default.png)
sprint_symbol(), itself used when dumping stacks, has been wasting 128 bytes of stack: lookup the symbol directly into the buffer supplied by the caller, instead of using a locally declared namebuf. I believe the name != buffer strcpy() is obsolete: the design here dates from when module symbol lookup pointed into a supposedly const but sadly volatile table; nowadays it copies, but an uncalled strcpy() looks better here than the risk of a recursive BUG_ON(). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
487 lines
12 KiB
C
487 lines
12 KiB
C
/*
|
|
* kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
|
|
*
|
|
* Rewritten and vastly simplified by Rusty Russell for in-kernel
|
|
* module loader:
|
|
* Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
|
|
*
|
|
* ChangeLog:
|
|
*
|
|
* (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
|
|
* Changed the compression method from stem compression to "table lookup"
|
|
* compression (see scripts/kallsyms.c for a more complete description)
|
|
*/
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/err.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/sched.h> /* for cond_resched */
|
|
#include <linux/mm.h>
|
|
#include <linux/ctype.h>
|
|
|
|
#include <asm/sections.h>
|
|
|
|
#ifdef CONFIG_KALLSYMS_ALL
|
|
#define all_var 1
|
|
#else
|
|
#define all_var 0
|
|
#endif
|
|
|
|
/* These will be re-linked against their real values during the second link stage */
|
|
extern const unsigned long kallsyms_addresses[] __attribute__((weak));
|
|
extern const u8 kallsyms_names[] __attribute__((weak));
|
|
|
|
/* tell the compiler that the count isn't in the small data section if the arch
|
|
* has one (eg: FRV)
|
|
*/
|
|
extern const unsigned long kallsyms_num_syms
|
|
__attribute__((weak, section(".rodata")));
|
|
|
|
extern const u8 kallsyms_token_table[] __attribute__((weak));
|
|
extern const u16 kallsyms_token_index[] __attribute__((weak));
|
|
|
|
extern const unsigned long kallsyms_markers[] __attribute__((weak));
|
|
|
|
static inline int is_kernel_inittext(unsigned long addr)
|
|
{
|
|
if (addr >= (unsigned long)_sinittext
|
|
&& addr <= (unsigned long)_einittext)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
static inline int is_kernel_text(unsigned long addr)
|
|
{
|
|
if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
|
|
return 1;
|
|
return in_gate_area_no_task(addr);
|
|
}
|
|
|
|
static inline int is_kernel(unsigned long addr)
|
|
{
|
|
if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
|
|
return 1;
|
|
return in_gate_area_no_task(addr);
|
|
}
|
|
|
|
static int is_ksym_addr(unsigned long addr)
|
|
{
|
|
if (all_var)
|
|
return is_kernel(addr);
|
|
|
|
return is_kernel_text(addr) || is_kernel_inittext(addr);
|
|
}
|
|
|
|
/* expand a compressed symbol data into the resulting uncompressed string,
|
|
given the offset to where the symbol is in the compressed stream */
|
|
static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
|
|
{
|
|
int len, skipped_first = 0;
|
|
const u8 *tptr, *data;
|
|
|
|
/* get the compressed symbol length from the first symbol byte */
|
|
data = &kallsyms_names[off];
|
|
len = *data;
|
|
data++;
|
|
|
|
/* update the offset to return the offset for the next symbol on
|
|
* the compressed stream */
|
|
off += len + 1;
|
|
|
|
/* for every byte on the compressed symbol data, copy the table
|
|
entry for that byte */
|
|
while(len) {
|
|
tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
|
|
data++;
|
|
len--;
|
|
|
|
while (*tptr) {
|
|
if(skipped_first) {
|
|
*result = *tptr;
|
|
result++;
|
|
} else
|
|
skipped_first = 1;
|
|
tptr++;
|
|
}
|
|
}
|
|
|
|
*result = '\0';
|
|
|
|
/* return to offset to the next symbol */
|
|
return off;
|
|
}
|
|
|
|
/* get symbol type information. This is encoded as a single char at the
|
|
* begining of the symbol name */
|
|
static char kallsyms_get_symbol_type(unsigned int off)
|
|
{
|
|
/* get just the first code, look it up in the token table, and return the
|
|
* first char from this token */
|
|
return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
|
|
}
|
|
|
|
|
|
/* find the offset on the compressed stream given and index in the
|
|
* kallsyms array */
|
|
static unsigned int get_symbol_offset(unsigned long pos)
|
|
{
|
|
const u8 *name;
|
|
int i;
|
|
|
|
/* use the closest marker we have. We have markers every 256 positions,
|
|
* so that should be close enough */
|
|
name = &kallsyms_names[ kallsyms_markers[pos>>8] ];
|
|
|
|
/* sequentially scan all the symbols up to the point we're searching for.
|
|
* Every symbol is stored in a [<len>][<len> bytes of data] format, so we
|
|
* just need to add the len to the current pointer for every symbol we
|
|
* wish to skip */
|
|
for(i = 0; i < (pos&0xFF); i++)
|
|
name = name + (*name) + 1;
|
|
|
|
return name - kallsyms_names;
|
|
}
|
|
|
|
/* Lookup the address for this symbol. Returns 0 if not found. */
|
|
unsigned long kallsyms_lookup_name(const char *name)
|
|
{
|
|
char namebuf[KSYM_NAME_LEN];
|
|
unsigned long i;
|
|
unsigned int off;
|
|
|
|
for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
|
|
off = kallsyms_expand_symbol(off, namebuf);
|
|
|
|
if (strcmp(namebuf, name) == 0)
|
|
return kallsyms_addresses[i];
|
|
}
|
|
return module_kallsyms_lookup_name(name);
|
|
}
|
|
|
|
static unsigned long get_symbol_pos(unsigned long addr,
|
|
unsigned long *symbolsize,
|
|
unsigned long *offset)
|
|
{
|
|
unsigned long symbol_start = 0, symbol_end = 0;
|
|
unsigned long i, low, high, mid;
|
|
|
|
/* This kernel should never had been booted. */
|
|
BUG_ON(!kallsyms_addresses);
|
|
|
|
/* do a binary search on the sorted kallsyms_addresses array */
|
|
low = 0;
|
|
high = kallsyms_num_syms;
|
|
|
|
while (high - low > 1) {
|
|
mid = low + (high - low) / 2;
|
|
if (kallsyms_addresses[mid] <= addr)
|
|
low = mid;
|
|
else
|
|
high = mid;
|
|
}
|
|
|
|
/*
|
|
* search for the first aliased symbol. Aliased
|
|
* symbols are symbols with the same address
|
|
*/
|
|
while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
|
|
--low;
|
|
|
|
symbol_start = kallsyms_addresses[low];
|
|
|
|
/* Search for next non-aliased symbol */
|
|
for (i = low + 1; i < kallsyms_num_syms; i++) {
|
|
if (kallsyms_addresses[i] > symbol_start) {
|
|
symbol_end = kallsyms_addresses[i];
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* if we found no next symbol, we use the end of the section */
|
|
if (!symbol_end) {
|
|
if (is_kernel_inittext(addr))
|
|
symbol_end = (unsigned long)_einittext;
|
|
else if (all_var)
|
|
symbol_end = (unsigned long)_end;
|
|
else
|
|
symbol_end = (unsigned long)_etext;
|
|
}
|
|
|
|
if (symbolsize)
|
|
*symbolsize = symbol_end - symbol_start;
|
|
if (offset)
|
|
*offset = addr - symbol_start;
|
|
|
|
return low;
|
|
}
|
|
|
|
/*
|
|
* Lookup an address but don't bother to find any names.
|
|
*/
|
|
int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
|
|
unsigned long *offset)
|
|
{
|
|
char namebuf[KSYM_NAME_LEN];
|
|
if (is_ksym_addr(addr))
|
|
return !!get_symbol_pos(addr, symbolsize, offset);
|
|
|
|
return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf);
|
|
}
|
|
|
|
/*
|
|
* Lookup an address
|
|
* - modname is set to NULL if it's in the kernel
|
|
* - we guarantee that the returned name is valid until we reschedule even if
|
|
* it resides in a module
|
|
* - we also guarantee that modname will be valid until rescheduled
|
|
*/
|
|
const char *kallsyms_lookup(unsigned long addr,
|
|
unsigned long *symbolsize,
|
|
unsigned long *offset,
|
|
char **modname, char *namebuf)
|
|
{
|
|
namebuf[KSYM_NAME_LEN - 1] = 0;
|
|
namebuf[0] = 0;
|
|
|
|
if (is_ksym_addr(addr)) {
|
|
unsigned long pos;
|
|
|
|
pos = get_symbol_pos(addr, symbolsize, offset);
|
|
/* Grab name */
|
|
kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
|
|
if (modname)
|
|
*modname = NULL;
|
|
return namebuf;
|
|
}
|
|
|
|
/* see if it's in a module */
|
|
return module_address_lookup(addr, symbolsize, offset, modname,
|
|
namebuf);
|
|
}
|
|
|
|
int lookup_symbol_name(unsigned long addr, char *symname)
|
|
{
|
|
symname[0] = '\0';
|
|
symname[KSYM_NAME_LEN - 1] = '\0';
|
|
|
|
if (is_ksym_addr(addr)) {
|
|
unsigned long pos;
|
|
|
|
pos = get_symbol_pos(addr, NULL, NULL);
|
|
/* Grab name */
|
|
kallsyms_expand_symbol(get_symbol_offset(pos), symname);
|
|
return 0;
|
|
}
|
|
/* see if it's in a module */
|
|
return lookup_module_symbol_name(addr, symname);
|
|
}
|
|
|
|
int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
|
|
unsigned long *offset, char *modname, char *name)
|
|
{
|
|
name[0] = '\0';
|
|
name[KSYM_NAME_LEN - 1] = '\0';
|
|
|
|
if (is_ksym_addr(addr)) {
|
|
unsigned long pos;
|
|
|
|
pos = get_symbol_pos(addr, size, offset);
|
|
/* Grab name */
|
|
kallsyms_expand_symbol(get_symbol_offset(pos), name);
|
|
modname[0] = '\0';
|
|
return 0;
|
|
}
|
|
/* see if it's in a module */
|
|
return lookup_module_symbol_attrs(addr, size, offset, modname, name);
|
|
}
|
|
|
|
/* Look up a kernel symbol and return it in a text buffer. */
|
|
int sprint_symbol(char *buffer, unsigned long address)
|
|
{
|
|
char *modname;
|
|
const char *name;
|
|
unsigned long offset, size;
|
|
int len;
|
|
|
|
name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
|
|
if (!name)
|
|
return sprintf(buffer, "0x%lx", address);
|
|
|
|
if (name != buffer)
|
|
strcpy(buffer, name);
|
|
len = strlen(buffer);
|
|
buffer += len;
|
|
|
|
if (modname)
|
|
len += sprintf(buffer, "+%#lx/%#lx [%s]",
|
|
offset, size, modname);
|
|
else
|
|
len += sprintf(buffer, "+%#lx/%#lx", offset, size);
|
|
|
|
return len;
|
|
}
|
|
|
|
/* Look up a kernel symbol and print it to the kernel messages. */
|
|
void __print_symbol(const char *fmt, unsigned long address)
|
|
{
|
|
char buffer[KSYM_SYMBOL_LEN];
|
|
|
|
sprint_symbol(buffer, address);
|
|
|
|
printk(fmt, buffer);
|
|
}
|
|
|
|
/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
|
|
struct kallsym_iter
|
|
{
|
|
loff_t pos;
|
|
unsigned long value;
|
|
unsigned int nameoff; /* If iterating in core kernel symbols */
|
|
char type;
|
|
char name[KSYM_NAME_LEN];
|
|
char module_name[MODULE_NAME_LEN];
|
|
int exported;
|
|
};
|
|
|
|
static int get_ksymbol_mod(struct kallsym_iter *iter)
|
|
{
|
|
if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value,
|
|
&iter->type, iter->name, iter->module_name,
|
|
&iter->exported) < 0)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/* Returns space to next name. */
|
|
static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
|
|
{
|
|
unsigned off = iter->nameoff;
|
|
|
|
iter->module_name[0] = '\0';
|
|
iter->value = kallsyms_addresses[iter->pos];
|
|
|
|
iter->type = kallsyms_get_symbol_type(off);
|
|
|
|
off = kallsyms_expand_symbol(off, iter->name);
|
|
|
|
return off - iter->nameoff;
|
|
}
|
|
|
|
static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
|
|
{
|
|
iter->name[0] = '\0';
|
|
iter->nameoff = get_symbol_offset(new_pos);
|
|
iter->pos = new_pos;
|
|
}
|
|
|
|
/* Returns false if pos at or past end of file. */
|
|
static int update_iter(struct kallsym_iter *iter, loff_t pos)
|
|
{
|
|
/* Module symbols can be accessed randomly. */
|
|
if (pos >= kallsyms_num_syms) {
|
|
iter->pos = pos;
|
|
return get_ksymbol_mod(iter);
|
|
}
|
|
|
|
/* If we're not on the desired position, reset to new position. */
|
|
if (pos != iter->pos)
|
|
reset_iter(iter, pos);
|
|
|
|
iter->nameoff += get_ksymbol_core(iter);
|
|
iter->pos++;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void *s_next(struct seq_file *m, void *p, loff_t *pos)
|
|
{
|
|
(*pos)++;
|
|
|
|
if (!update_iter(m->private, *pos))
|
|
return NULL;
|
|
return p;
|
|
}
|
|
|
|
static void *s_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
if (!update_iter(m->private, *pos))
|
|
return NULL;
|
|
return m->private;
|
|
}
|
|
|
|
static void s_stop(struct seq_file *m, void *p)
|
|
{
|
|
}
|
|
|
|
static int s_show(struct seq_file *m, void *p)
|
|
{
|
|
struct kallsym_iter *iter = m->private;
|
|
|
|
/* Some debugging symbols have no name. Ignore them. */
|
|
if (!iter->name[0])
|
|
return 0;
|
|
|
|
if (iter->module_name[0]) {
|
|
char type;
|
|
|
|
/* Label it "global" if it is exported,
|
|
* "local" if not exported. */
|
|
type = iter->exported ? toupper(iter->type) :
|
|
tolower(iter->type);
|
|
seq_printf(m, "%0*lx %c %s\t[%s]\n",
|
|
(int)(2*sizeof(void*)),
|
|
iter->value, type, iter->name, iter->module_name);
|
|
} else
|
|
seq_printf(m, "%0*lx %c %s\n",
|
|
(int)(2*sizeof(void*)),
|
|
iter->value, iter->type, iter->name);
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations kallsyms_op = {
|
|
.start = s_start,
|
|
.next = s_next,
|
|
.stop = s_stop,
|
|
.show = s_show
|
|
};
|
|
|
|
static int kallsyms_open(struct inode *inode, struct file *file)
|
|
{
|
|
/* We keep iterator in m->private, since normal case is to
|
|
* s_start from where we left off, so we avoid doing
|
|
* using get_symbol_offset for every symbol */
|
|
struct kallsym_iter *iter;
|
|
int ret;
|
|
|
|
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
return -ENOMEM;
|
|
reset_iter(iter, 0);
|
|
|
|
ret = seq_open(file, &kallsyms_op);
|
|
if (ret == 0)
|
|
((struct seq_file *)file->private_data)->private = iter;
|
|
else
|
|
kfree(iter);
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations kallsyms_operations = {
|
|
.open = kallsyms_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release_private,
|
|
};
|
|
|
|
static int __init kallsyms_init(void)
|
|
{
|
|
proc_create("kallsyms", 0444, NULL, &kallsyms_operations);
|
|
return 0;
|
|
}
|
|
__initcall(kallsyms_init);
|
|
|
|
EXPORT_SYMBOL(__print_symbol);
|
|
EXPORT_SYMBOL_GPL(sprint_symbol);
|