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/*
* 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) / 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);
return NULL;
}
int lookup_symbol_name(unsigned long addr, char *symname)
{
symname[0] = '\0';
symname[KSYM_NAME_LEN - 1] = '\0';
if (is_ksym_addr(addr)) {
unsigned
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