mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-05 10:29:37 +00:00
![Nick Gasson](/assets/img/avatar_default.png)
Fix an issue where addresses in the DWARF line table are offset by -0x40 (GEN_ELF_TEXT_OFFSET). This can be seen with `objdump -S` on the ELF files after perf inject. Committer notes: Ian added this in his Acked-by reply: --- Without too much knowledge this looks good to me. The original code came from oprofile's jit support: https://sourceforge.net/p/oprofile/oprofile/ci/master/tree/opjitconv/debug_line.c#l325 --- Signed-off-by: Nick Gasson <nick.gasson@arm.com> Acked-by: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20200528051916.6722-1-nick.gasson@arm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
609 lines
14 KiB
C
609 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* genelf_debug.c
|
|
* Copyright (C) 2015, Google, Inc
|
|
*
|
|
* Contributed by:
|
|
* Stephane Eranian <eranian@google.com>
|
|
*
|
|
* based on GPLv2 source code from Oprofile
|
|
* @remark Copyright 2007 OProfile authors
|
|
* @author Philippe Elie
|
|
*/
|
|
#include <linux/compiler.h>
|
|
#include <sys/types.h>
|
|
#include <stdio.h>
|
|
#include <getopt.h>
|
|
#include <stddef.h>
|
|
#include <libelf.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
#include <inttypes.h>
|
|
#include <limits.h>
|
|
#include <fcntl.h>
|
|
#include <err.h>
|
|
#include <dwarf.h>
|
|
|
|
#include "genelf.h"
|
|
#include "../util/jitdump.h"
|
|
|
|
#define BUFFER_EXT_DFL_SIZE (4 * 1024)
|
|
|
|
typedef uint32_t uword;
|
|
typedef uint16_t uhalf;
|
|
typedef int32_t sword;
|
|
typedef int16_t shalf;
|
|
typedef uint8_t ubyte;
|
|
typedef int8_t sbyte;
|
|
|
|
struct buffer_ext {
|
|
size_t cur_pos;
|
|
size_t max_sz;
|
|
void *data;
|
|
};
|
|
|
|
static void
|
|
buffer_ext_dump(struct buffer_ext *be, const char *msg)
|
|
{
|
|
size_t i;
|
|
warnx("DUMP for %s", msg);
|
|
for (i = 0 ; i < be->cur_pos; i++)
|
|
warnx("%4zu 0x%02x", i, (((char *)be->data)[i]) & 0xff);
|
|
}
|
|
|
|
static inline int
|
|
buffer_ext_add(struct buffer_ext *be, void *addr, size_t sz)
|
|
{
|
|
void *tmp;
|
|
size_t be_sz = be->max_sz;
|
|
|
|
retry:
|
|
if ((be->cur_pos + sz) < be_sz) {
|
|
memcpy(be->data + be->cur_pos, addr, sz);
|
|
be->cur_pos += sz;
|
|
return 0;
|
|
}
|
|
|
|
if (!be_sz)
|
|
be_sz = BUFFER_EXT_DFL_SIZE;
|
|
else
|
|
be_sz <<= 1;
|
|
|
|
tmp = realloc(be->data, be_sz);
|
|
if (!tmp)
|
|
return -1;
|
|
|
|
be->data = tmp;
|
|
be->max_sz = be_sz;
|
|
|
|
goto retry;
|
|
}
|
|
|
|
static void
|
|
buffer_ext_init(struct buffer_ext *be)
|
|
{
|
|
be->data = NULL;
|
|
be->cur_pos = 0;
|
|
be->max_sz = 0;
|
|
}
|
|
|
|
static inline size_t
|
|
buffer_ext_size(struct buffer_ext *be)
|
|
{
|
|
return be->cur_pos;
|
|
}
|
|
|
|
static inline void *
|
|
buffer_ext_addr(struct buffer_ext *be)
|
|
{
|
|
return be->data;
|
|
}
|
|
|
|
struct debug_line_header {
|
|
// Not counting this field
|
|
uword total_length;
|
|
// version number (2 currently)
|
|
uhalf version;
|
|
// relative offset from next field to
|
|
// program statement
|
|
uword prolog_length;
|
|
ubyte minimum_instruction_length;
|
|
ubyte default_is_stmt;
|
|
// line_base - see DWARF 2 specs
|
|
sbyte line_base;
|
|
// line_range - see DWARF 2 specs
|
|
ubyte line_range;
|
|
// number of opcode + 1
|
|
ubyte opcode_base;
|
|
/* follow the array of opcode args nr: ubytes [nr_opcode_base] */
|
|
/* follow the search directories index, zero terminated string
|
|
* terminated by an empty string.
|
|
*/
|
|
/* follow an array of { filename, LEB128, LEB128, LEB128 }, first is
|
|
* the directory index entry, 0 means current directory, then mtime
|
|
* and filesize, last entry is followed by en empty string.
|
|
*/
|
|
/* follow the first program statement */
|
|
} __packed;
|
|
|
|
/* DWARF 2 spec talk only about one possible compilation unit header while
|
|
* binutils can handle two flavours of dwarf 2, 32 and 64 bits, this is not
|
|
* related to the used arch, an ELF 32 can hold more than 4 Go of debug
|
|
* information. For now we handle only DWARF 2 32 bits comp unit. It'll only
|
|
* become a problem if we generate more than 4GB of debug information.
|
|
*/
|
|
struct compilation_unit_header {
|
|
uword total_length;
|
|
uhalf version;
|
|
uword debug_abbrev_offset;
|
|
ubyte pointer_size;
|
|
} __packed;
|
|
|
|
#define DW_LNS_num_opcode (DW_LNS_set_isa + 1)
|
|
|
|
/* field filled at run time are marked with -1 */
|
|
static struct debug_line_header const default_debug_line_header = {
|
|
.total_length = -1,
|
|
.version = 2,
|
|
.prolog_length = -1,
|
|
.minimum_instruction_length = 1, /* could be better when min instruction size != 1 */
|
|
.default_is_stmt = 1, /* we don't take care about basic block */
|
|
.line_base = -5, /* sensible value for line base ... */
|
|
.line_range = -14, /* ... and line range are guessed statically */
|
|
.opcode_base = DW_LNS_num_opcode
|
|
};
|
|
|
|
static ubyte standard_opcode_length[] =
|
|
{
|
|
0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1
|
|
};
|
|
#if 0
|
|
{
|
|
[DW_LNS_advance_pc] = 1,
|
|
[DW_LNS_advance_line] = 1,
|
|
[DW_LNS_set_file] = 1,
|
|
[DW_LNS_set_column] = 1,
|
|
[DW_LNS_fixed_advance_pc] = 1,
|
|
[DW_LNS_set_isa] = 1,
|
|
};
|
|
#endif
|
|
|
|
/* field filled at run time are marked with -1 */
|
|
static struct compilation_unit_header default_comp_unit_header = {
|
|
.total_length = -1,
|
|
.version = 2,
|
|
.debug_abbrev_offset = 0, /* we reuse the same abbrev entries for all comp unit */
|
|
.pointer_size = sizeof(void *)
|
|
};
|
|
|
|
static void emit_uword(struct buffer_ext *be, uword data)
|
|
{
|
|
buffer_ext_add(be, &data, sizeof(uword));
|
|
}
|
|
|
|
static void emit_string(struct buffer_ext *be, const char *s)
|
|
{
|
|
buffer_ext_add(be, (void *)s, strlen(s) + 1);
|
|
}
|
|
|
|
static void emit_unsigned_LEB128(struct buffer_ext *be,
|
|
unsigned long data)
|
|
{
|
|
do {
|
|
ubyte cur = data & 0x7F;
|
|
data >>= 7;
|
|
if (data)
|
|
cur |= 0x80;
|
|
buffer_ext_add(be, &cur, 1);
|
|
} while (data);
|
|
}
|
|
|
|
static void emit_signed_LEB128(struct buffer_ext *be, long data)
|
|
{
|
|
int more = 1;
|
|
int negative = data < 0;
|
|
int size = sizeof(long) * CHAR_BIT;
|
|
while (more) {
|
|
ubyte cur = data & 0x7F;
|
|
data >>= 7;
|
|
if (negative)
|
|
data |= - (1 << (size - 7));
|
|
if ((data == 0 && !(cur & 0x40)) ||
|
|
(data == -1l && (cur & 0x40)))
|
|
more = 0;
|
|
else
|
|
cur |= 0x80;
|
|
buffer_ext_add(be, &cur, 1);
|
|
}
|
|
}
|
|
|
|
static void emit_extended_opcode(struct buffer_ext *be, ubyte opcode,
|
|
void *data, size_t data_len)
|
|
{
|
|
buffer_ext_add(be, (char *)"", 1);
|
|
|
|
emit_unsigned_LEB128(be, data_len + 1);
|
|
|
|
buffer_ext_add(be, &opcode, 1);
|
|
buffer_ext_add(be, data, data_len);
|
|
}
|
|
|
|
static void emit_opcode(struct buffer_ext *be, ubyte opcode)
|
|
{
|
|
buffer_ext_add(be, &opcode, 1);
|
|
}
|
|
|
|
static void emit_opcode_signed(struct buffer_ext *be,
|
|
ubyte opcode, long data)
|
|
{
|
|
buffer_ext_add(be, &opcode, 1);
|
|
emit_signed_LEB128(be, data);
|
|
}
|
|
|
|
static void emit_opcode_unsigned(struct buffer_ext *be, ubyte opcode,
|
|
unsigned long data)
|
|
{
|
|
buffer_ext_add(be, &opcode, 1);
|
|
emit_unsigned_LEB128(be, data);
|
|
}
|
|
|
|
static void emit_advance_pc(struct buffer_ext *be, unsigned long delta_pc)
|
|
{
|
|
emit_opcode_unsigned(be, DW_LNS_advance_pc, delta_pc);
|
|
}
|
|
|
|
static void emit_advance_lineno(struct buffer_ext *be, long delta_lineno)
|
|
{
|
|
emit_opcode_signed(be, DW_LNS_advance_line, delta_lineno);
|
|
}
|
|
|
|
static void emit_lne_end_of_sequence(struct buffer_ext *be)
|
|
{
|
|
emit_extended_opcode(be, DW_LNE_end_sequence, NULL, 0);
|
|
}
|
|
|
|
static void emit_set_file(struct buffer_ext *be, unsigned long idx)
|
|
{
|
|
emit_opcode_unsigned(be, DW_LNS_set_file, idx);
|
|
}
|
|
|
|
static void emit_lne_define_filename(struct buffer_ext *be,
|
|
const char *filename)
|
|
{
|
|
buffer_ext_add(be, (void *)"", 1);
|
|
|
|
/* LNE field, strlen(filename) + zero termination, 3 bytes for: the dir entry, timestamp, filesize */
|
|
emit_unsigned_LEB128(be, strlen(filename) + 5);
|
|
emit_opcode(be, DW_LNE_define_file);
|
|
emit_string(be, filename);
|
|
/* directory index 0=do not know */
|
|
emit_unsigned_LEB128(be, 0);
|
|
/* last modification date on file 0=do not know */
|
|
emit_unsigned_LEB128(be, 0);
|
|
/* filesize 0=do not know */
|
|
emit_unsigned_LEB128(be, 0);
|
|
}
|
|
|
|
static void emit_lne_set_address(struct buffer_ext *be,
|
|
void *address)
|
|
{
|
|
emit_extended_opcode(be, DW_LNE_set_address, &address, sizeof(unsigned long));
|
|
}
|
|
|
|
static ubyte get_special_opcode(struct debug_entry *ent,
|
|
unsigned int last_line,
|
|
unsigned long last_vma)
|
|
{
|
|
unsigned int temp;
|
|
unsigned long delta_addr;
|
|
|
|
/*
|
|
* delta from line_base
|
|
*/
|
|
temp = (ent->lineno - last_line) - default_debug_line_header.line_base;
|
|
|
|
if (temp >= default_debug_line_header.line_range)
|
|
return 0;
|
|
|
|
/*
|
|
* delta of addresses
|
|
*/
|
|
delta_addr = (ent->addr - last_vma) / default_debug_line_header.minimum_instruction_length;
|
|
|
|
/* This is not sufficient to ensure opcode will be in [0-256] but
|
|
* sufficient to ensure when summing with the delta lineno we will
|
|
* not overflow the unsigned long opcode */
|
|
|
|
if (delta_addr <= 256 / default_debug_line_header.line_range) {
|
|
unsigned long opcode = temp +
|
|
(delta_addr * default_debug_line_header.line_range) +
|
|
default_debug_line_header.opcode_base;
|
|
|
|
return opcode <= 255 ? opcode : 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void emit_lineno_info(struct buffer_ext *be,
|
|
struct debug_entry *ent, size_t nr_entry,
|
|
unsigned long code_addr)
|
|
{
|
|
size_t i;
|
|
|
|
/*
|
|
* Machine state at start of a statement program
|
|
* address = 0
|
|
* file = 1
|
|
* line = 1
|
|
* column = 0
|
|
* is_stmt = default_is_stmt as given in the debug_line_header
|
|
* basic block = 0
|
|
* end sequence = 0
|
|
*/
|
|
|
|
/* start state of the state machine we take care of */
|
|
unsigned long last_vma = 0;
|
|
char const *cur_filename = NULL;
|
|
unsigned long cur_file_idx = 0;
|
|
int last_line = 1;
|
|
|
|
emit_lne_set_address(be, (void *)code_addr);
|
|
|
|
for (i = 0; i < nr_entry; i++, ent = debug_entry_next(ent)) {
|
|
int need_copy = 0;
|
|
ubyte special_opcode;
|
|
|
|
/*
|
|
* check if filename changed, if so add it
|
|
*/
|
|
if (!cur_filename || strcmp(cur_filename, ent->name)) {
|
|
emit_lne_define_filename(be, ent->name);
|
|
cur_filename = ent->name;
|
|
emit_set_file(be, ++cur_file_idx);
|
|
need_copy = 1;
|
|
}
|
|
|
|
special_opcode = get_special_opcode(ent, last_line, last_vma);
|
|
if (special_opcode != 0) {
|
|
last_line = ent->lineno;
|
|
last_vma = ent->addr;
|
|
emit_opcode(be, special_opcode);
|
|
} else {
|
|
/*
|
|
* lines differ, emit line delta
|
|
*/
|
|
if (last_line != ent->lineno) {
|
|
emit_advance_lineno(be, ent->lineno - last_line);
|
|
last_line = ent->lineno;
|
|
need_copy = 1;
|
|
}
|
|
/*
|
|
* addresses differ, emit address delta
|
|
*/
|
|
if (last_vma != ent->addr) {
|
|
emit_advance_pc(be, ent->addr - last_vma);
|
|
last_vma = ent->addr;
|
|
need_copy = 1;
|
|
}
|
|
/*
|
|
* add new row to matrix
|
|
*/
|
|
if (need_copy)
|
|
emit_opcode(be, DW_LNS_copy);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void add_debug_line(struct buffer_ext *be,
|
|
struct debug_entry *ent, size_t nr_entry,
|
|
unsigned long code_addr)
|
|
{
|
|
struct debug_line_header * dbg_header;
|
|
size_t old_size;
|
|
|
|
old_size = buffer_ext_size(be);
|
|
|
|
buffer_ext_add(be, (void *)&default_debug_line_header,
|
|
sizeof(default_debug_line_header));
|
|
|
|
buffer_ext_add(be, &standard_opcode_length, sizeof(standard_opcode_length));
|
|
|
|
// empty directory entry
|
|
buffer_ext_add(be, (void *)"", 1);
|
|
|
|
// empty filename directory
|
|
buffer_ext_add(be, (void *)"", 1);
|
|
|
|
dbg_header = buffer_ext_addr(be) + old_size;
|
|
dbg_header->prolog_length = (buffer_ext_size(be) - old_size) -
|
|
offsetof(struct debug_line_header, minimum_instruction_length);
|
|
|
|
emit_lineno_info(be, ent, nr_entry, code_addr);
|
|
|
|
emit_lne_end_of_sequence(be);
|
|
|
|
dbg_header = buffer_ext_addr(be) + old_size;
|
|
dbg_header->total_length = (buffer_ext_size(be) - old_size) -
|
|
offsetof(struct debug_line_header, version);
|
|
}
|
|
|
|
static void
|
|
add_debug_abbrev(struct buffer_ext *be)
|
|
{
|
|
emit_unsigned_LEB128(be, 1);
|
|
emit_unsigned_LEB128(be, DW_TAG_compile_unit);
|
|
emit_unsigned_LEB128(be, DW_CHILDREN_yes);
|
|
emit_unsigned_LEB128(be, DW_AT_stmt_list);
|
|
emit_unsigned_LEB128(be, DW_FORM_data4);
|
|
emit_unsigned_LEB128(be, 0);
|
|
emit_unsigned_LEB128(be, 0);
|
|
emit_unsigned_LEB128(be, 0);
|
|
}
|
|
|
|
static void
|
|
add_compilation_unit(struct buffer_ext *be,
|
|
size_t offset_debug_line)
|
|
{
|
|
struct compilation_unit_header *comp_unit_header;
|
|
size_t old_size = buffer_ext_size(be);
|
|
|
|
buffer_ext_add(be, &default_comp_unit_header,
|
|
sizeof(default_comp_unit_header));
|
|
|
|
emit_unsigned_LEB128(be, 1);
|
|
emit_uword(be, offset_debug_line);
|
|
|
|
comp_unit_header = buffer_ext_addr(be) + old_size;
|
|
comp_unit_header->total_length = (buffer_ext_size(be) - old_size) -
|
|
offsetof(struct compilation_unit_header, version);
|
|
}
|
|
|
|
static int
|
|
jit_process_debug_info(uint64_t code_addr,
|
|
void *debug, int nr_debug_entries,
|
|
struct buffer_ext *dl,
|
|
struct buffer_ext *da,
|
|
struct buffer_ext *di)
|
|
{
|
|
struct debug_entry *ent = debug;
|
|
int i;
|
|
|
|
for (i = 0; i < nr_debug_entries; i++) {
|
|
ent->addr = ent->addr - code_addr;
|
|
ent = debug_entry_next(ent);
|
|
}
|
|
add_compilation_unit(di, buffer_ext_size(dl));
|
|
add_debug_line(dl, debug, nr_debug_entries, GEN_ELF_TEXT_OFFSET);
|
|
add_debug_abbrev(da);
|
|
if (0) buffer_ext_dump(da, "abbrev");
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
jit_add_debug_info(Elf *e, uint64_t code_addr, void *debug, int nr_debug_entries)
|
|
{
|
|
Elf_Data *d;
|
|
Elf_Scn *scn;
|
|
Elf_Shdr *shdr;
|
|
struct buffer_ext dl, di, da;
|
|
int ret;
|
|
|
|
buffer_ext_init(&dl);
|
|
buffer_ext_init(&di);
|
|
buffer_ext_init(&da);
|
|
|
|
ret = jit_process_debug_info(code_addr, debug, nr_debug_entries, &dl, &da, &di);
|
|
if (ret)
|
|
return -1;
|
|
/*
|
|
* setup .debug_line section
|
|
*/
|
|
scn = elf_newscn(e);
|
|
if (!scn) {
|
|
warnx("cannot create section");
|
|
return -1;
|
|
}
|
|
|
|
d = elf_newdata(scn);
|
|
if (!d) {
|
|
warnx("cannot get new data");
|
|
return -1;
|
|
}
|
|
|
|
d->d_align = 1;
|
|
d->d_off = 0LL;
|
|
d->d_buf = buffer_ext_addr(&dl);
|
|
d->d_type = ELF_T_BYTE;
|
|
d->d_size = buffer_ext_size(&dl);
|
|
d->d_version = EV_CURRENT;
|
|
|
|
shdr = elf_getshdr(scn);
|
|
if (!shdr) {
|
|
warnx("cannot get section header");
|
|
return -1;
|
|
}
|
|
|
|
shdr->sh_name = 52; /* .debug_line */
|
|
shdr->sh_type = SHT_PROGBITS;
|
|
shdr->sh_addr = 0; /* must be zero or == sh_offset -> dynamic object */
|
|
shdr->sh_flags = 0;
|
|
shdr->sh_entsize = 0;
|
|
|
|
/*
|
|
* setup .debug_info section
|
|
*/
|
|
scn = elf_newscn(e);
|
|
if (!scn) {
|
|
warnx("cannot create section");
|
|
return -1;
|
|
}
|
|
|
|
d = elf_newdata(scn);
|
|
if (!d) {
|
|
warnx("cannot get new data");
|
|
return -1;
|
|
}
|
|
|
|
d->d_align = 1;
|
|
d->d_off = 0LL;
|
|
d->d_buf = buffer_ext_addr(&di);
|
|
d->d_type = ELF_T_BYTE;
|
|
d->d_size = buffer_ext_size(&di);
|
|
d->d_version = EV_CURRENT;
|
|
|
|
shdr = elf_getshdr(scn);
|
|
if (!shdr) {
|
|
warnx("cannot get section header");
|
|
return -1;
|
|
}
|
|
|
|
shdr->sh_name = 64; /* .debug_info */
|
|
shdr->sh_type = SHT_PROGBITS;
|
|
shdr->sh_addr = 0; /* must be zero or == sh_offset -> dynamic object */
|
|
shdr->sh_flags = 0;
|
|
shdr->sh_entsize = 0;
|
|
|
|
/*
|
|
* setup .debug_abbrev section
|
|
*/
|
|
scn = elf_newscn(e);
|
|
if (!scn) {
|
|
warnx("cannot create section");
|
|
return -1;
|
|
}
|
|
|
|
d = elf_newdata(scn);
|
|
if (!d) {
|
|
warnx("cannot get new data");
|
|
return -1;
|
|
}
|
|
|
|
d->d_align = 1;
|
|
d->d_off = 0LL;
|
|
d->d_buf = buffer_ext_addr(&da);
|
|
d->d_type = ELF_T_BYTE;
|
|
d->d_size = buffer_ext_size(&da);
|
|
d->d_version = EV_CURRENT;
|
|
|
|
shdr = elf_getshdr(scn);
|
|
if (!shdr) {
|
|
warnx("cannot get section header");
|
|
return -1;
|
|
}
|
|
|
|
shdr->sh_name = 76; /* .debug_info */
|
|
shdr->sh_type = SHT_PROGBITS;
|
|
shdr->sh_addr = 0; /* must be zero or == sh_offset -> dynamic object */
|
|
shdr->sh_flags = 0;
|
|
shdr->sh_entsize = 0;
|
|
|
|
/*
|
|
* now we update the ELF image with all the sections
|
|
*/
|
|
if (elf_update(e, ELF_C_WRITE) < 0) {
|
|
warnx("elf_update debug failed");
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|