/*
* 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/init.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/kdb.h>
#include <linux/err.h>
#include <linux/proc_fs.h>
#include <linux/sched.h> /* for cond_resched */
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/filter.h>
#include <linux/ftrace.h>
#include <linux/compiler.h>
/*
* These will be re-linked against their real values
* during the second link stage.
*/
extern const unsigned long kallsyms_addresses[] __weak;
extern const int kallsyms_offsets[] __weak;
extern const u8 kallsyms_names[] __weak;
/*
* Tell the compiler that the count isn't in the small data section if the arch
* has one (eg: FRV).
*/
extern const unsigned int kallsyms_num_syms
__attribute__((weak, section(".rodata")));
extern const unsigned long kallsyms_relative_base
__attribute__((weak, section(".rodata")));
extern const u8 kallsyms_token_table[] __weak;
extern const u16 kallsyms_token_index[] __weak;
extern const unsigned int kallsyms_markers[] __weak;
/*
* Expand a compressed symbol data into the resulting uncompressed string,
* if uncompressed string is too long (>= maxlen), it will be truncated,
* given the offset to where the symbol is in the compressed stream.
*/
static unsigned int kallsyms_expand_symbol(unsigned int off,
char *result, size_t maxlen)
{
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) {
if (maxlen <= 1)
goto tail;
*result = *tptr;
result++;
maxlen--;
} else
skipped_first = 1;
tptr++;
}
}
tail:
if (maxlen)
*result = '\0';
/* Return to offset to the next symbol. */
return off;
}
/*
* Get symbol type information. This is encoded as a single char at the
* beginning 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;
}
static unsigned long kallsyms_sym_address(int idx)
{
if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
return kallsyms_addresses[idx];
/* values are unsigned offsets if --absolute-percpu is not in effect */
if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU))
return kallsyms_relative_base + (u32)kallsyms_offsets[idx];
/* ...otherwise, positive offsets are absolute values */
if (kallsyms_offsets[idx] >= 0)
return kallsyms_offsets[idx];
/* ...and negative offsets are relative to kallsyms_relative_base - 1 */
return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
}
/* 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, ARRAY_SIZE(namebuf));
if (strcmp(namebuf, name) == 0)
return kallsyms_sym_address(i);
}
return module_kallsyms_lookup_name(name);
}
EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
unsigned long),
void *data)
{
char namebuf[KSYM_NAME_LEN];
unsigned long i;
unsigned int off;
int ret;
for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
ret = fn(data, namebuf, NULL, kallsyms_sym_address(i));
if (ret != 0)
return ret;
}
return module_kallsyms_on_each_symbol(fn, data);
}
EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);
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. */
if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
BUG_ON(!kallsyms_addresses);
else
BUG_ON(!kallsyms_offsets);
/* 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_sym_address(mid) <= addr)
low = mid;
else
high = mid;
}
/*
* Search for the first aliased symbol. Aliased
* symbols are symbols with the same address.
*/
while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))
--low;
symbol_start = kallsyms_sym_address(low);
/* Search for next non-aliased symbol. */
for (i = low + 1; i < kallsyms_num_syms