Contributors: 63
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Rusty Russell |
689 |
19.11% |
10 |
9.62% |
| Zhen Lei |
365 |
10.12% |
3 |
2.88% |
| Alan Maguire |
338 |
9.37% |
1 |
0.96% |
| Paulo Marques |
327 |
9.07% |
2 |
1.92% |
| Stephen Boyd |
200 |
5.55% |
2 |
1.92% |
| Ingo Molnar |
144 |
3.99% |
3 |
2.88% |
| Daniel Borkmann |
135 |
3.74% |
1 |
0.96% |
| Adrian Hunter |
128 |
3.55% |
3 |
2.88% |
| Andrew Morton |
118 |
3.27% |
5 |
4.81% |
| Alexey Dobriyan |
115 |
3.19% |
4 |
3.85% |
| Franck Bui-Huu |
111 |
3.08% |
1 |
0.96% |
| Ard Biesheuvel |
111 |
3.08% |
1 |
0.96% |
| Steven Rostedt |
95 |
2.63% |
4 |
3.85% |
| Jason Wessel |
92 |
2.55% |
1 |
0.96% |
| Sami Tolvanen |
87 |
2.41% |
1 |
0.96% |
| Miguel Ojeda Sandonis |
78 |
2.16% |
1 |
0.96% |
| Namhyung Kim |
53 |
1.47% |
2 |
1.92% |
| Chen Gang S |
52 |
1.44% |
1 |
0.96% |
| Anders H Kaseorg |
51 |
1.41% |
1 |
0.96% |
| Linus Torvalds |
38 |
1.05% |
4 |
3.85% |
| Hugh Dickins |
31 |
0.86% |
1 |
0.96% |
| Linus Torvalds (pre-git) |
27 |
0.75% |
7 |
6.73% |
| Robert S Peterson |
23 |
0.64% |
1 |
0.96% |
| Adam B. Jerome |
19 |
0.53% |
1 |
0.96% |
| Manish Katiyar |
18 |
0.50% |
1 |
0.96% |
| Kai Germaschewski |
13 |
0.36% |
2 |
1.92% |
| Jiri Olsa |
9 |
0.25% |
1 |
0.96% |
| Masahiro Yamada |
8 |
0.22% |
2 |
1.92% |
| Yonghong Song |
8 |
0.22% |
3 |
2.88% |
| Nick Desaulniers |
8 |
0.22% |
1 |
0.96% |
| Andi Kleen |
8 |
0.22% |
1 |
0.96% |
| Rob Jones |
7 |
0.19% |
1 |
0.96% |
| Kees Cook |
7 |
0.19% |
1 |
0.96% |
| Sam Ravnborg |
7 |
0.19% |
1 |
0.96% |
| Vegard Nossum |
6 |
0.17% |
1 |
0.96% |
| Song Liu |
6 |
0.17% |
1 |
0.96% |
| Keith Owens |
5 |
0.14% |
1 |
0.96% |
| Mika Kukkonen |
5 |
0.14% |
1 |
0.96% |
| Marc Zyngier |
5 |
0.14% |
1 |
0.96% |
| Matt Domsch |
5 |
0.14% |
1 |
0.96% |
| Kyle McMartin |
4 |
0.11% |
1 |
0.96% |
| Richard Henderson |
4 |
0.11% |
1 |
0.96% |
| Tejun Heo |
4 |
0.11% |
1 |
0.96% |
| Prasanna S. Panchamukhi |
3 |
0.08% |
1 |
0.96% |
| Rasmus Villemoes |
3 |
0.08% |
1 |
0.96% |
| Denis V. Lunev |
3 |
0.08% |
1 |
0.96% |
| Gideon Israel Dsouza |
3 |
0.08% |
1 |
0.96% |
| David Vernet |
3 |
0.08% |
1 |
0.96% |
| Dmitry Torokhov |
3 |
0.08% |
1 |
0.96% |
| David Howells |
3 |
0.08% |
1 |
0.96% |
| Stephen Brennan |
3 |
0.08% |
1 |
0.96% |
| Helge Deller |
2 |
0.06% |
1 |
0.96% |
| Christoph Hellwig |
2 |
0.06% |
1 |
0.96% |
| Azeem Shaikh |
2 |
0.06% |
1 |
0.96% |
| Joe Perches |
2 |
0.06% |
1 |
0.96% |
| Jan Beulich |
2 |
0.06% |
1 |
0.96% |
| Adrian Bunk |
2 |
0.06% |
1 |
0.96% |
| Simon Kågström |
1 |
0.03% |
1 |
0.96% |
| Martin Peschke |
1 |
0.03% |
1 |
0.96% |
| Thomas Gleixner |
1 |
0.03% |
1 |
0.96% |
| Tim Schmielau |
1 |
0.03% |
1 |
0.96% |
| Arnd Bergmann |
1 |
0.03% |
1 |
0.96% |
| Arjan van de Ven |
1 |
0.03% |
1 |
0.96% |
| Total |
3606 |
|
104 |
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* 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/kprobes.h>
#include <linux/build_bug.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bsearch.h>
#include <linux/btf_ids.h>
#include "kallsyms_internal.h"
/*
* 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 char *tptr;
const u8 *data;
/* Get the compressed symbol length from the first symbol byte. */
data = &kallsyms_names[off];
len = *data;
data++;
off++;
/* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
if ((len & 0x80) != 0) {
len = (len & 0x7F) | (*data << 7);
data++;
off++;
}
/*
* Update the offset to return the offset for the next symbol on
* the compressed stream.
*/
off += len;
/*
* 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, len;
/*
* 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++) {
len = *name;
/*
* If MSB is 1, it is a "big" symbol, so we need to look into
* the next byte (and skip it, too).
*/
if ((len & 0x80) != 0)
len = ((len & 0x7F) | (name[1] << 7)) + 1;
name = name + len + 1;
}
return name - kallsyms_names;
}
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];
}
static void cleanup_symbol_name(char *s)
{
char *res;
if (!IS_ENABLED(CONFIG_LTO_CLANG))
return;
/*
* LLVM appends various suffixes for local functions and variables that
* must be promoted to global scope as part of LTO. This can break
* hooking of static functions with kprobes. '.' is not a valid
* character in an identifier in C. Suffixes only in LLVM LTO observed:
* - foo.llvm.[0-9a-f]+
*/
res = strstr(s, ".llvm.");
if (res)
*res = '\0';
return;
}
static int compare_symbol_name(const char *name, char *namebuf)
{
/* The kallsyms_seqs_of_names is sorted based on names after
* cleanup_symbol_name() (see scripts/kallsyms.c) if clang lto is enabled.
* To ensure correct bisection in kallsyms_lookup_names(), do
* cleanup_symbol_name(namebuf) before comparing name and namebuf.
*/
cleanup_symbol_name(namebuf);
return strcmp(name, namebuf);
}
static unsigned int get_symbol_seq(int index)
{
unsigned int i, seq = 0;
for (i = 0; i < 3; i++)
seq = (seq << 8) | kallsyms_seqs_of_names[3 * index + i];
return seq;
}
static int kallsyms_lookup_names(const char *name,
unsigned int *start,
unsigned int *end)
{
int ret;
int low, mid, high;
unsigned int seq, off;
char namebuf[KSYM_NAME_LEN];
low = 0;
high = kallsyms_num_syms - 1;
while (low <= high) {
mid = low + (high - low) / 2;
seq = get_symbol_seq(mid);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
ret = compare_symbol_name(name, namebuf);
if (ret > 0)
low = mid + 1;
else if (ret < 0)
high = mid - 1;
else
break;
}
if (low > high)
return -ESRCH;
low = mid;
while (low) {
seq = get_symbol_seq(low - 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
if (compare_symbol_name(name, namebuf))
break;
low--;
}
*start = low;
if (end) {
high = mid;
while (high < kallsyms_num_syms - 1) {
seq = get_symbol_seq(high + 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
if (compare_symbol_name(name, namebuf))
break;
high++;
}
*end = high;
}
return 0;
}
/* Lookup the address for this symbol. Returns 0 if not found. */
unsigned long kallsyms_lookup_name(const char *name)
{
int ret;
unsigned int i;
/* Skip the search for empty string. */
if (!*name)
return 0;
ret = kallsyms_lookup_names(name, &i, NULL);
if (!ret)
return kallsyms_sym_address(get_symbol_seq(i));
return module_kallsyms_lookup_name(name);
}
/*
* Iterate over all symbols in vmlinux. For symbols from modules use
* module_kallsyms_on_each_symbol instead.
*/
int kallsyms_on_each_symbol(int (*fn)(void *, const char *, 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, kallsyms_sym_address(i));
if (ret != 0)
return ret;
cond_resched();
}
return 0;
}
int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
const char *name, void *data)
{
int ret;
unsigned int i, start, end;
ret = kallsyms_lookup_names(name, &start, &end);
if (ret)
return 0;
for (i = start; !ret && i <= end; i++) {
ret = fn(data, kallsyms_sym_address(get_symbol_seq(i)));
cond_resched();
}
return ret;
}
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; i++) {
if (kallsyms_sym_address(i) > symbol_start) {
symbol_end = kallsyms_sym_address(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 (IS_ENABLED(CONFIG_KALLSYMS_ALL))
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)) {
get_symbol_pos(addr, symbolsize, offset);
return 1;
}
return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) ||
!!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
}
static const char *kallsyms_lookup_buildid(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset, char **modname,
const unsigned char **modbuildid, char *namebuf)
{
const char *ret;
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, KSYM_NAME_LEN);
if (modname)
*modname = NULL;
if (modbuildid)
*modbuildid = NULL;
ret = namebuf;
goto found;
}
/* See if it's in a module or a BPF JITed image. */
ret = module_address_lookup(addr, symbolsize, offset,
modname, modbuildid, namebuf);
if (!ret)
ret = bpf_address_lookup(addr, symbolsize,
offset, modname, namebuf);
if (!ret)
ret = ftrace_mod_address_lookup(addr, symbolsize,
offset, modname, namebuf);
found:
cleanup_symbol_name(namebuf);
return ret;
}
/*
* 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)
{
return kallsyms_lookup_buildid(addr, symbolsize, offset, modname,
NULL, namebuf);
}
int lookup_symbol_name(unsigned long addr, char *symname)
{
int res;
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, KSYM_NAME_LEN);
goto found;
}
/* See if it's in a module. */
res = lookup_module_symbol_name(addr, symname);
if (res)
return res;
found:
cleanup_symbol_name(symname);
return 0;
}
/* Look up a kernel symbol and return it in a text buffer. */
static int __sprint_symbol(char *buffer, unsigned long address,
int symbol_offset, int add_offset, int add_buildid)
{
char *modname;
const unsigned char *buildid;
const char *name;
unsigned long offset, size;
int len;
address += symbol_offset;
name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid,
buffer);
if (!name)
return sprintf(buffer, "0x%lx", address - symbol_offset);
if (name != buffer)
strcpy(buffer, name);
len = strlen(buffer);
offset -= symbol_offset;
if (add_offset)
len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
if (modname) {
len += sprintf(buffer + len, " [%s", modname);
#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
if (add_buildid && buildid) {
/* build ID should match length of sprintf */
#if IS_ENABLED(CONFIG_MODULES)
static_assert(sizeof(typeof_member(struct module, build_id)) == 20);
#endif
len += sprintf(buffer + len, " %20phN", buildid);
}
#endif
len += sprintf(buffer + len, "]");
}
return len;
}
/**
* sprint_symbol - Look up a kernel symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function looks up a kernel symbol with @address and stores its name,
* offset, size and module name to @buffer if possible. If no symbol was found,
* just saves its @address as is.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_symbol(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, 0, 1, 0);
}
EXPORT_SYMBOL_GPL(sprint_symbol);
/**
* sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function looks up a kernel symbol with @address and stores its name,
* offset, size, module name and module build ID to @buffer if possible. If no
* symbol was found, just saves its @address as is.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_symbol_build_id(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, 0, 1, 1);
}
EXPORT_SYMBOL_GPL(sprint_symbol_build_id);
/**
* sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function looks up a kernel symbol with @address and stores its name
* and module name to @buffer if possible. If no symbol was found, just saves
* its @address as is.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_symbol_no_offset(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, 0, 0, 0);
}
EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
/**
* sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function is for stack backtrace and does the same thing as
* sprint_symbol() but with modified/decreased @address. If there is a
* tail-call to the function marked "noreturn", gcc optimized out code after
* the call so that the stack-saved return address could point outside of the
* caller. This function ensures that kallsyms will find the original caller
* by decreasing @address.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_backtrace(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, -1, 1, 0);
}
/**
* sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function is for stack backtrace and does the same thing as
* sprint_symbol() but with modified/decreased @address. If there is a
* tail-call to the function marked "noreturn", gcc optimized out code after
* the call so that the stack-saved return address could point outside of the
* caller. This function ensures that kallsyms will find the original caller
* by decreasing @address. This function also appends the module build ID to
* the @buffer if @address is within a kernel module.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_backtrace_build_id(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, -1, 1, 1);
}
/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
struct kallsym_iter {
loff_t pos;
loff_t pos_mod_end;
loff_t pos_ftrace_mod_end;
loff_t pos_bpf_end;
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;
int show_value;
};
static int get_ksymbol_mod(struct kallsym_iter *iter)
{
int ret = module_get_kallsym(iter->pos - kallsyms_num_syms,
&iter->value, &iter->type,
iter->name, iter->module_name,
&iter->exported);
if (ret < 0) {
iter->pos_mod_end = iter->pos;
return 0;
}
return 1;
}
/*
* ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace
* purposes. In that case "__builtin__ftrace" is used as a module name, even
* though "__builtin__ftrace" is not a module.
*/
static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter)
{
int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,
&iter->value, &iter->type,
iter->name, iter->module_name,
&iter->exported);
if (ret < 0) {
iter->pos_ftrace_mod_end = iter->pos;
return 0;
}
return 1;
}
static int get_ksymbol_bpf(struct kallsym_iter *iter)
{
int ret;
strscpy(iter->module_name, "bpf", MODULE_NAME_LEN);
iter->exported = 0;
ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
&iter->value, &iter->type,
iter->name);
if (ret < 0) {
iter->pos_bpf_end = iter->pos;
return 0;
}
return 1;
}
/*
* This uses "__builtin__kprobes" as a module name for symbols for pages
* allocated for kprobes' purposes, even though "__builtin__kprobes" is not a
* module.
*/
static int get_ksymbol_kprobe(struct kallsym_iter *iter)
{
strscpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
iter->exported = 0;
return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,
&iter->value, &iter->type,
iter->name) < 0 ? 0 : 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_sym_address(iter->pos);
iter->type = kallsyms_get_symbol_type(off);
off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(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;
if (new_pos == 0) {
iter->pos_mod_end = 0;
iter->pos_ftrace_mod_end = 0;
iter->pos_bpf_end = 0;
}
}
/*
* The end position (last + 1) of each additional kallsyms section is recorded
* in iter->pos_..._end as each section is added, and so can be used to
* determine which get_ksymbol_...() function to call next.
*/
static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
{
iter->pos = pos;
if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&
get_ksymbol_mod(iter))
return 1;
if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&
get_ksymbol_ftrace_mod(iter))
return 1;
if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) &&
get_ksymbol_bpf(iter))
return 1;
return get_ksymbol_kprobe(iter);
}
/* 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)
return update_iter_mod(iter, pos);
/* 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)
{
void *value;
struct kallsym_iter *iter = m->private;
/* Some debugging symbols have no name. Ignore them. */
if (!iter->name[0])
return 0;
value = iter->show_value ? (void *)iter->value : NULL;
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, "%px %c %s\t[%s]\n", value,
type, iter->name, iter->module_name);
} else
seq_printf(m, "%px %c %s\n", 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
};
#ifdef CONFIG_BPF_SYSCALL
struct bpf_iter__ksym {
__bpf_md_ptr(struct bpf_iter_meta *, meta);
__bpf_md_ptr(struct kallsym_iter *, ksym);
};
static int ksym_prog_seq_show(struct seq_file *m, bool in_stop)
{
struct bpf_iter__ksym ctx;
struct bpf_iter_meta meta;
struct bpf_prog *prog;
meta.seq = m;
prog = bpf_iter_get_info(&meta, in_stop);
if (!prog)
return 0;
ctx.meta = &meta;
ctx.ksym = m ? m->private : NULL;
return bpf_iter_run_prog(prog, &ctx);
}
static int bpf_iter_ksym_seq_show(struct seq_file *m, void *p)
{
return ksym_prog_seq_show(m, false);
}
static void bpf_iter_ksym_seq_stop(struct seq_file *m, void *p)
{
if (!p)
(void) ksym_prog_seq_show(m, true);
else
s_stop(m, p);
}
static const struct seq_operations bpf_iter_ksym_ops = {
.start = s_start,
.next = s_next,
.stop = bpf_iter_ksym_seq_stop,
.show = bpf_iter_ksym_seq_show,
};
static int bpf_iter_ksym_init(void *priv_data, struct bpf_iter_aux_info *aux)
{
struct kallsym_iter *iter = priv_data;
reset_iter(iter, 0);
/* cache here as in kallsyms_open() case; use current process
* credentials to tell BPF iterators if values should be shown.
*/
iter->show_value = kallsyms_show_value(current_cred());
return 0;
}
DEFINE_BPF_ITER_FUNC(ksym, struct bpf_iter_meta *meta, struct kallsym_iter *ksym)
static const struct bpf_iter_seq_info ksym_iter_seq_info = {
.seq_ops = &bpf_iter_ksym_ops,
.init_seq_private = bpf_iter_ksym_init,
.fini_seq_private = NULL,
.seq_priv_size = sizeof(struct kallsym_iter),
};
static struct bpf_iter_reg ksym_iter_reg_info = {
.target = "ksym",
.feature = BPF_ITER_RESCHED,
.ctx_arg_info_size = 1,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__ksym, ksym),
PTR_TO_BTF_ID_OR_NULL },
},
.seq_info = &ksym_iter_seq_info,
};
BTF_ID_LIST(btf_ksym_iter_id)
BTF_ID(struct, kallsym_iter)
static int __init bpf_ksym_iter_register(void)
{
ksym_iter_reg_info.ctx_arg_info[0].btf_id = *btf_ksym_iter_id;
return bpf_iter_reg_target(&ksym_iter_reg_info);
}
late_initcall(bpf_ksym_iter_register);
#endif /* CONFIG_BPF_SYSCALL */
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;
iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter));
if (!iter)
return -ENOMEM;
reset_iter(iter, 0);
/*
* Instead of checking this on every s_show() call, cache
* the result here at open time.
*/
iter->show_value = kallsyms_show_value(file->f_cred);
return 0;
}
#ifdef CONFIG_KGDB_KDB
const char *kdb_walk_kallsyms(loff_t *pos)
{
static struct kallsym_iter kdb_walk_kallsyms_iter;
if (*pos == 0) {
memset(&kdb_walk_kallsyms_iter, 0,
sizeof(kdb_walk_kallsyms_iter));
reset_iter(&kdb_walk_kallsyms_iter, 0);
}
while (1) {
if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
return NULL;
++*pos;
/* Some debugging symbols have no name. Ignore them. */
if (kdb_walk_kallsyms_iter.name[0])
return kdb_walk_kallsyms_iter.name;
}
}
#endif /* CONFIG_KGDB_KDB */
static const struct proc_ops kallsyms_proc_ops = {
.proc_open = kallsyms_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = seq_release_private,
};
static int __init kallsyms_init(void)
{
proc_create("kallsyms", 0444, NULL, &kallsyms_proc_ops);
return 0;
}
device_initcall(kallsyms_init);