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Misc updates:

Browse Source 
- Add support for non-rela relocations, in preparation to merge 'recordmcount'
   functionality into objtool.
 
 - Fix assumption that broke under --ffunction-sections (LTO) builds.
 
 - Misc cleanups.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'objtool-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Add support for non-rela relocations, in preparation to merge
   'recordmcount' functionality into objtool

 - Fix assumption that broke under --ffunction-sections (LTO) builds

 - Misc cleanups

* tag 'objtool-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Add support for relocations without addends
  objtool: Rename rela to reloc
  objtool: Use sh_info to find the base for .rela sections
  objtool: Do not assume order of parent/child functions
This commit is contained in:
Linus Torvalds 2020-08-03 14:45:33 -07:00
commit 9dee86896c
8 changed files with 375 additions and 244 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tools/objtool/arch.h
View File

@ -82,7 +82,7 @@ bool arch_callee_saved_reg(unsigned char reg);
unsigned long arch_jump_destination(struct instruction *insn);
unsigned long arch_dest_rela_offset(int addend);
unsigned long arch_dest_reloc_offset(int addend);
const char *arch_nop_insn(int len);

2
tools/objtool/arch/x86/decode.c
View File

@ -67,7 +67,7 @@ bool arch_callee_saved_reg(unsigned char reg)
}
}
unsigned long arch_dest_rela_offset(int addend)
unsigned long arch_dest_reloc_offset(int addend)
{
return addend + 4;
}

202
tools/objtool/check.c
View File

@ -353,7 +353,7 @@ static struct instruction *find_last_insn(struct objtool_file *file,
static int add_dead_ends(struct objtool_file *file)
{
struct section *sec;
struct rela *rela;
struct reloc *reloc;
struct instruction *insn;
/*
@ -371,24 +371,24 @@ static int add_dead_ends(struct objtool_file *file)
if (!sec)
goto reachable;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
if (reloc->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in %s", sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (insn)
insn = list_prev_entry(insn, list);
else if (rela->addend == rela->sym->sec->len) {
insn = find_last_insn(file, rela->sym->sec);
else if (reloc->addend == reloc->sym->sec->len) {
insn = find_last_insn(file, reloc->sym->sec);
if (!insn) {
WARN("can't find unreachable insn at %s+0x%x",
rela->sym->sec->name, rela->addend);
reloc->sym->sec->name, reloc->addend);
return -1;
}
} else {
WARN("can't find unreachable insn at %s+0x%x",
rela->sym->sec->name, rela->addend);
reloc->sym->sec->name, reloc->addend);
return -1;
}
@ -406,24 +406,24 @@ reachable:
if (!sec)
return 0;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
if (reloc->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in %s", sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (insn)
insn = list_prev_entry(insn, list);
else if (rela->addend == rela->sym->sec->len) {
insn = find_last_insn(file, rela->sym->sec);
else if (reloc->addend == reloc->sym->sec->len) {
insn = find_last_insn(file, reloc->sym->sec);
if (!insn) {
WARN("can't find reachable insn at %s+0x%x",
rela->sym->sec->name, rela->addend);
reloc->sym->sec->name, reloc->addend);
return -1;
}
} else {
WARN("can't find reachable insn at %s+0x%x",
rela->sym->sec->name, rela->addend);
reloc->sym->sec->name, reloc->addend);
return -1;
}
@ -441,26 +441,26 @@ static void add_ignores(struct objtool_file *file)
struct instruction *insn;
struct section *sec;
struct symbol *func;
struct rela *rela;
struct reloc *reloc;
sec = find_section_by_name(file->elf, ".rela.discard.func_stack_frame_non_standard");
if (!sec)
return;
list_for_each_entry(rela, &sec->rela_list, list) {
switch (rela->sym->type) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
switch (reloc->sym->type) {
case STT_FUNC:
func = rela->sym;
func = reloc->sym;
break;
case STT_SECTION:
func = find_func_by_offset(rela->sym->sec, rela->addend);
func = find_func_by_offset(reloc->sym->sec, reloc->addend);
if (!func)
continue;
break;
default:
WARN("unexpected relocation symbol type in %s: %d", sec->name, rela->sym->type);
WARN("unexpected relocation symbol type in %s: %d", sec->name, reloc->sym->type);
continue;
}
@ -580,20 +580,20 @@ static void add_uaccess_safe(struct objtool_file *file)
static int add_ignore_alternatives(struct objtool_file *file)
{
struct section *sec;
struct rela *rela;
struct reloc *reloc;
struct instruction *insn;
sec = find_section_by_name(file->elf, ".rela.discard.ignore_alts");
if (!sec)
return 0;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
if (reloc->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in %s", sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (!insn) {
WARN("bad .discard.ignore_alts entry");
return -1;
@ -611,7 +611,7 @@ static int add_ignore_alternatives(struct objtool_file *file)
static int add_jump_destinations(struct objtool_file *file)
{
struct instruction *insn;
struct rela *rela;
struct reloc *reloc;
struct section *dest_sec;
unsigned long dest_off;
@ -622,19 +622,19 @@ static int add_jump_destinations(struct objtool_file *file)
if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET)
continue;
rela = find_rela_by_dest_range(file->elf, insn->sec,
reloc = find_reloc_by_dest_range(file->elf, insn->sec,
insn->offset, insn->len);
if (!rela) {
if (!reloc) {
dest_sec = insn->sec;
dest_off = arch_jump_destination(insn);
} else if (rela->sym->type == STT_SECTION) {
dest_sec = rela->sym->sec;
dest_off = arch_dest_rela_offset(rela->addend);
} else if (rela->sym->sec->idx) {
dest_sec = rela->sym->sec;
dest_off = rela->sym->sym.st_value +
arch_dest_rela_offset(rela->addend);
} else if (strstr(rela->sym->name, "_indirect_thunk_")) {
} else if (reloc->sym->type == STT_SECTION) {
dest_sec = reloc->sym->sec;
dest_off = arch_dest_reloc_offset(reloc->addend);
} else if (reloc->sym->sec->idx) {
dest_sec = reloc->sym->sec;
dest_off = reloc->sym->sym.st_value +
arch_dest_reloc_offset(reloc->addend);
} else if (strstr(reloc->sym->name, "_indirect_thunk_")) {
/*
* Retpoline jumps are really dynamic jumps in
* disguise, so convert them accordingly.
@ -648,7 +648,7 @@ static int add_jump_destinations(struct objtool_file *file)
continue;
} else {
/* external sibling call */
insn->call_dest = rela->sym;
insn->call_dest = reloc->sym;
continue;
}
@ -724,15 +724,15 @@ static int add_call_destinations(struct objtool_file *file)
{
struct instruction *insn;
unsigned long dest_off;
struct rela *rela;
struct reloc *reloc;
for_each_insn(file, insn) {
if (insn->type != INSN_CALL)
continue;
rela = find_rela_by_dest_range(file->elf, insn->sec,
reloc = find_reloc_by_dest_range(file->elf, insn->sec,
insn->offset, insn->len);
if (!rela) {
if (!reloc) {
dest_off = arch_jump_destination(insn);
insn->call_dest = find_func_by_offset(insn->sec, dest_off);
if (!insn->call_dest)
@ -752,19 +752,19 @@ static int add_call_destinations(struct objtool_file *file)
return -1;
}
} else if (rela->sym->type == STT_SECTION) {
dest_off = arch_dest_rela_offset(rela->addend);
insn->call_dest = find_func_by_offset(rela->sym->sec,
} else if (reloc->sym->type == STT_SECTION) {
dest_off = arch_dest_reloc_offset(reloc->addend);
insn->call_dest = find_func_by_offset(reloc->sym->sec,
dest_off);
if (!insn->call_dest) {
WARN_FUNC("can't find call dest symbol at %s+0x%lx",
insn->sec, insn->offset,
rela->sym->sec->name,
reloc->sym->sec->name,
dest_off);
return -1;
}
} else
insn->call_dest = rela->sym;
insn->call_dest = reloc->sym;
/*
* Many compilers cannot disable KCOV with a function attribute
@ -773,9 +773,9 @@ static int add_call_destinations(struct objtool_file *file)
*/
if (insn->sec->noinstr &&
!strncmp(insn->call_dest->name, "__sanitizer_cov_", 16)) {
if (rela) {
rela->type = R_NONE;
elf_write_rela(file->elf, rela);
if (reloc) {
reloc->type = R_NONE;
elf_write_reloc(file->elf, reloc);
}
elf_write_insn(file->elf, insn->sec,
@ -890,7 +890,7 @@ static int handle_group_alt(struct objtool_file *file,
*/
if ((insn->offset != special_alt->new_off ||
(insn->type != INSN_CALL && !is_static_jump(insn))) &&
find_rela_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) {
find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) {
WARN_FUNC("unsupported relocation in alternatives section",
insn->sec, insn->offset);
@ -1036,34 +1036,34 @@ out:
}
static int add_jump_table(struct objtool_file *file, struct instruction *insn,
struct rela *table)
struct reloc *table)
{
struct rela *rela = table;
struct reloc *reloc = table;
struct instruction *dest_insn;
struct alternative *alt;
struct symbol *pfunc = insn->func->pfunc;
unsigned int prev_offset = 0;
/*
* Each @rela is a switch table relocation which points to the target
* Each @reloc is a switch table relocation which points to the target
* instruction.
*/
list_for_each_entry_from(rela, &table->sec->rela_list, list) {
list_for_each_entry_from(reloc, &table->sec->reloc_list, list) {
/* Check for the end of the table: */
if (rela != table && rela->jump_table_start)
if (reloc != table && reloc->jump_table_start)
break;
/* Make sure the table entries are consecutive: */
if (prev_offset && rela->offset != prev_offset + 8)
if (prev_offset && reloc->offset != prev_offset + 8)
break;
/* Detect function pointers from contiguous objects: */
if (rela->sym->sec == pfunc->sec &&
rela->addend == pfunc->offset)
if (reloc->sym->sec == pfunc->sec &&
reloc->addend == pfunc->offset)
break;
dest_insn = find_insn(file, rela->sym->sec, rela->addend);
dest_insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (!dest_insn)
break;
@ -1079,7 +1079,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
alt->insn = dest_insn;
list_add_tail(&alt->list, &insn->alts);
prev_offset = rela->offset;
prev_offset = reloc->offset;
}
if (!prev_offset) {
@ -1134,11 +1134,11 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
*
* NOTE: RETPOLINE made it harder still to decode dynamic jumps.
*/
static struct rela *find_jump_table(struct objtool_file *file,
static struct reloc *find_jump_table(struct objtool_file *file,
struct symbol *func,
struct instruction *insn)
{
struct rela *text_rela, *table_rela;
struct reloc *text_reloc, *table_reloc;
struct instruction *dest_insn, *orig_insn = insn;
struct section *table_sec;
unsigned long table_offset;
@ -1163,16 +1163,16 @@ static struct rela *find_jump_table(struct objtool_file *file,
break;
/* look for a relocation which references .rodata */
text_rela = find_rela_by_dest_range(file->elf, insn->sec,
text_reloc = find_reloc_by_dest_range(file->elf, insn->sec,
insn->offset, insn->len);
if (!text_rela || text_rela->sym->type != STT_SECTION ||
!text_rela->sym->sec->rodata)
if (!text_reloc || text_reloc->sym->type != STT_SECTION ||
!text_reloc->sym->sec->rodata)
continue;
table_offset = text_rela->addend;
table_sec = text_rela->sym->sec;
table_offset = text_reloc->addend;
table_sec = text_reloc->sym->sec;
if (text_rela->type == R_X86_64_PC32)
if (text_reloc->type == R_X86_64_PC32)
table_offset += 4;
/*
@ -1189,14 +1189,14 @@ static struct rela *find_jump_table(struct objtool_file *file,
continue;
/*
* Each table entry has a rela associated with it. The rela
* Each table entry has a reloc associated with it. The reloc
* should reference text in the same function as the original
* instruction.
*/
table_rela = find_rela_by_dest(file->elf, table_sec, table_offset);
if (!table_rela)
table_reloc = find_reloc_by_dest(file->elf, table_sec, table_offset);
if (!table_reloc)
continue;
dest_insn = find_insn(file, table_rela->sym->sec, table_rela->addend);
dest_insn = find_insn(file, table_reloc->sym->sec, table_reloc->addend);
if (!dest_insn || !dest_insn->func || dest_insn->func->pfunc != func)
continue;
@ -1205,10 +1205,10 @@ static struct rela *find_jump_table(struct objtool_file *file,
* indicates a rare GCC quirk/bug which can leave dead code
* behind.
*/
if (text_rela->type == R_X86_64_PC32)
if (text_reloc->type == R_X86_64_PC32)
file->ignore_unreachables = true;
return table_rela;
return table_reloc;
}
return NULL;
@ -1222,7 +1222,7 @@ static void mark_func_jump_tables(struct objtool_file *file,
struct symbol *func)
{
struct instruction *insn, *last = NULL;
struct rela *rela;
struct reloc *reloc;
func_for_each_insn(file, func, insn) {
if (!last)
@ -1245,10 +1245,10 @@ static void mark_func_jump_tables(struct objtool_file *file,
if (insn->type != INSN_JUMP_DYNAMIC)
continue;
rela = find_jump_table(file, func, insn);
if (rela) {
rela->jump_table_start = true;
insn->jump_table = rela;
reloc = find_jump_table(file, func, insn);
if (reloc) {
reloc->jump_table_start = true;
insn->jump_table = reloc;
}
}
}
@ -1302,8 +1302,8 @@ static int add_jump_table_alts(struct objtool_file *file)
static int read_unwind_hints(struct objtool_file *file)
{
struct section *sec, *relasec;
struct rela *rela;
struct section *sec, *relocsec;
struct reloc *reloc;
struct unwind_hint *hint;
struct instruction *insn;
struct cfi_reg *cfa;
@ -1313,8 +1313,8 @@ static int read_unwind_hints(struct objtool_file *file)
if (!sec)
return 0;
relasec = sec->rela;
if (!relasec) {
relocsec = sec->reloc;
if (!relocsec) {
WARN("missing .rela.discard.unwind_hints section");
return -1;
}
@ -1329,13 +1329,13 @@ static int read_unwind_hints(struct objtool_file *file)
for (i = 0; i < sec->len / sizeof(struct unwind_hint); i++) {
hint = (struct unwind_hint *)sec->data->d_buf + i;
rela = find_rela_by_dest(file->elf, sec, i * sizeof(*hint));
if (!rela) {
WARN("can't find rela for unwind_hints[%d]", i);
reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint));
if (!reloc) {
WARN("can't find reloc for unwind_hints[%d]", i);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (!insn) {
WARN("can't find insn for unwind_hints[%d]", i);
return -1;
@ -1393,19 +1393,19 @@ static int read_retpoline_hints(struct objtool_file *file)
{
struct section *sec;
struct instruction *insn;
struct rela *rela;
struct reloc *reloc;
sec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe");
if (!sec)
return 0;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
if (reloc->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in %s", sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (!insn) {
WARN("bad .discard.retpoline_safe entry");
return -1;
@ -1428,19 +1428,19 @@ static int read_instr_hints(struct objtool_file *file)
{
struct section *sec;
struct instruction *insn;
struct rela *rela;
struct reloc *reloc;
sec = find_section_by_name(file->elf, ".rela.discard.instr_end");
if (!sec)
return 0;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
if (reloc->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in %s", sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (!insn) {
WARN("bad .discard.instr_end entry");
return -1;
@ -1453,13 +1453,13 @@ static int read_instr_hints(struct objtool_file *file)
if (!sec)
return 0;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
if (reloc->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in %s", sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (!insn) {
WARN("bad .discard.instr_begin entry");
return -1;
@ -1475,22 +1475,22 @@ static int read_intra_function_calls(struct objtool_file *file)
{
struct instruction *insn;
struct section *sec;
struct rela *rela;
struct reloc *reloc;
sec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls");
if (!sec)
return 0;
list_for_each_entry(rela, &sec->rela_list, list) {
list_for_each_entry(reloc, &sec->reloc_list, list) {
unsigned long dest_off;
if (rela->sym->type != STT_SECTION) {
if (reloc->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in %s",
sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
insn = find_insn(file, reloc->sym->sec, reloc->addend);
if (!insn) {
WARN("bad .discard.intra_function_call entry");
return -1;

2
tools/objtool/check.h
View File

@ -37,7 +37,7 @@ struct instruction {
struct symbol *call_dest;
struct instruction *jump_dest;
struct instruction *first_jump_src;
struct rela *jump_table;
struct reloc *jump_table;
struct list_head alts;
struct symbol *func;
struct list_head stack_ops;

308
tools/objtool/elf.c
View File

@ -228,26 +228,26 @@ struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
return NULL;
}
struct rela *find_rela_by_dest_range(const struct elf *elf, struct section *sec,
struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len)
{
struct rela *rela, *r = NULL;
struct reloc *reloc, *r = NULL;
unsigned long o;
if (!sec->rela)
if (!sec->reloc)
return NULL;
sec = sec->rela;
sec = sec->reloc;
for_offset_range(o, offset, offset + len) {
elf_hash_for_each_possible(elf->rela_hash, rela, hash,
elf_hash_for_each_possible(elf->reloc_hash, reloc, hash,
sec_offset_hash(sec, o)) {
if (rela->sec != sec)
if (reloc->sec != sec)
continue;
if (rela->offset >= offset && rela->offset < offset + len) {
if (!r || rela->offset < r->offset)
r = rela;
if (reloc->offset >= offset && reloc->offset < offset + len) {
if (!r || reloc->offset < r->offset)
r = reloc;
}
}
if (r)
@ -257,9 +257,9 @@ struct rela *find_rela_by_dest_range(const struct elf *elf, struct section *sec,
return NULL;
}
struct rela *find_rela_by_dest(const struct elf *elf, struct section *sec, unsigned long offset)
struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset)
{
return find_rela_by_dest_range(elf, sec, offset, 1);
return find_reloc_by_dest_range(elf, sec, offset, 1);
}
static int read_sections(struct elf *elf)
@ -288,7 +288,7 @@ static int read_sections(struct elf *elf)
memset(sec, 0, sizeof(*sec));
INIT_LIST_HEAD(&sec->symbol_list);
INIT_LIST_HEAD(&sec->rela_list);
INIT_LIST_HEAD(&sec->reloc_list);
s = elf_getscn(elf->elf, i);
if (!s) {
@ -434,7 +434,13 @@ static int read_symbols(struct elf *elf)
size_t pnamelen;
if (sym->type != STT_FUNC)
continue;
sym->pfunc = sym->cfunc = sym;
if (sym->pfunc == NULL)
sym->pfunc = sym;
if (sym->cfunc == NULL)
sym->cfunc = sym;
coldstr = strstr(sym->name, ".cold");
if (!coldstr)
continue;
@ -482,72 +488,101 @@ err:
return -1;
}
void elf_add_rela(struct elf *elf, struct rela *rela)
void elf_add_reloc(struct elf *elf, struct reloc *reloc)
{
struct section *sec = rela->sec;
struct section *sec = reloc->sec;
list_add_tail(&rela->list, &sec->rela_list);
elf_hash_add(elf->rela_hash, &rela->hash, rela_hash(rela));
list_add_tail(&reloc->list, &sec->reloc_list);
elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc));
}
static int read_relas(struct elf *elf)
static int read_rel_reloc(struct section *sec, int i, struct reloc *reloc, unsigned int *symndx)
{
if (!gelf_getrel(sec->data, i, &reloc->rel)) {
WARN_ELF("gelf_getrel");
return -1;
}
reloc->type = GELF_R_TYPE(reloc->rel.r_info);
reloc->addend = 0;
reloc->offset = reloc->rel.r_offset;
*symndx = GELF_R_SYM(reloc->rel.r_info);
return 0;
}
static int read_rela_reloc(struct section *sec, int i, struct reloc *reloc, unsigned int *symndx)
{
if (!gelf_getrela(sec->data, i, &reloc->rela)) {
WARN_ELF("gelf_getrela");
return -1;
}
reloc->type = GELF_R_TYPE(reloc->rela.r_info);
reloc->addend = reloc->rela.r_addend;
reloc->offset = reloc->rela.r_offset;
*symndx = GELF_R_SYM(reloc->rela.r_info);
return 0;
}
static int read_relocs(struct elf *elf)
{
struct section *sec;
struct rela *rela;
struct reloc *reloc;
int i;
unsigned int symndx;
unsigned long nr_rela, max_rela = 0, tot_rela = 0;
unsigned long nr_reloc, max_reloc = 0, tot_reloc = 0;
list_for_each_entry(sec, &elf->sections, list) {
if (sec->sh.sh_type != SHT_RELA)
if ((sec->sh.sh_type != SHT_RELA) &&
(sec->sh.sh_type != SHT_REL))
continue;
sec->base = find_section_by_name(elf, sec->name + 5);
sec->base = find_section_by_index(elf, sec->sh.sh_info);
if (!sec->base) {
WARN("can't find base section for rela section %s",
WARN("can't find base section for reloc section %s",
sec->name);
return -1;
}
sec->base->rela = sec;
sec->base->reloc = sec;
nr_rela = 0;
nr_reloc = 0;
for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) {
rela = malloc(sizeof(*rela));
if (!rela) {
reloc = malloc(sizeof(*reloc));
if (!reloc) {
perror("malloc");
return -1;
}
memset(rela, 0, sizeof(*rela));
if (!gelf_getrela(sec->data, i, &rela->rela)) {
WARN_ELF("gelf_getrela");
return -1;
memset(reloc, 0, sizeof(*reloc));
switch (sec->sh.sh_type) {
case SHT_REL:
if (read_rel_reloc(sec, i, reloc, &symndx))
return -1;
break;
case SHT_RELA:
if (read_rela_reloc(sec, i, reloc, &symndx))
return -1;
break;
default: return -1;
}
rela->type = GELF_R_TYPE(rela->rela.r_info);
rela->addend = rela->rela.r_addend;
rela->offset = rela->rela.r_offset;
symndx = GELF_R_SYM(rela->rela.r_info);
rela->sec = sec;
rela->idx = i;
rela->sym = find_symbol_by_index(elf, symndx);
if (!rela->sym) {
WARN("can't find rela entry symbol %d for %s",
reloc->sec = sec;
reloc->idx = i;
reloc->sym = find_symbol_by_index(elf, symndx);
if (!reloc->sym) {
WARN("can't find reloc entry symbol %d for %s",
symndx, sec->name);
return -1;
}
elf_add_rela(elf, rela);
nr_rela++;
elf_add_reloc(elf, reloc);
nr_reloc++;
}
max_rela = max(max_rela, nr_rela);
tot_rela += nr_rela;
max_reloc = max(max_reloc, nr_reloc);
tot_reloc += nr_reloc;
}
if (stats) {
printf("max_rela: %lu\n", max_rela);
printf("tot_rela: %lu\n", tot_rela);
printf("max_reloc: %lu\n", max_reloc);
printf("tot_reloc: %lu\n", tot_reloc);
}
return 0;
@ -573,7 +608,7 @@ struct elf *elf_open_read(const char *name, int flags)
elf_hash_init(elf->symbol_name_hash);
elf_hash_init(elf->section_hash);
elf_hash_init(elf->section_name_hash);
elf_hash_init(elf->rela_hash);
elf_hash_init(elf->reloc_hash);
elf->fd = open(name, flags);
if (elf->fd == -1) {
@ -606,7 +641,7 @@ struct elf *elf_open_read(const char *name, int flags)
if (read_symbols(elf))
goto err;
if (read_relas(elf))
if (read_relocs(elf))
goto err;
return elf;
@ -632,7 +667,7 @@ struct section *elf_create_section(struct elf *elf, const char *name,
memset(sec, 0, sizeof(*sec));
INIT_LIST_HEAD(&sec->symbol_list);
INIT_LIST_HEAD(&sec->rela_list);
INIT_LIST_HEAD(&sec->reloc_list);
s = elf_newscn(elf->elf);
if (!s) {
@ -719,25 +754,55 @@ struct section *elf_create_section(struct elf *elf, const char *name,
return sec;
}
struct section *elf_create_rela_section(struct elf *elf, struct section *base)
static struct section *elf_create_rel_reloc_section(struct elf *elf, struct section *base)
{
char *relaname;
char *relocname;
struct section *sec;
relaname = malloc(strlen(base->name) + strlen(".rela") + 1);
if (!relaname) {
relocname = malloc(strlen(base->name) + strlen(".rel") + 1);
if (!relocname) {
perror("malloc");
return NULL;
}
strcpy(relaname, ".rela");
strcat(relaname, base->name);
strcpy(relocname, ".rel");
strcat(relocname, base->name);
sec = elf_create_section(elf, relaname, sizeof(GElf_Rela), 0);
free(relaname);
sec = elf_create_section(elf, relocname, sizeof(GElf_Rel), 0);
free(relocname);
if (!sec)
return NULL;
base->rela = sec;
base->reloc = sec;
sec->base = base;
sec->sh.sh_type = SHT_REL;
sec->sh.sh_addralign = 8;
sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
sec->sh.sh_info = base->idx;
sec->sh.sh_flags = SHF_INFO_LINK;
return sec;
}
static struct section *elf_create_rela_reloc_section(struct elf *elf, struct section *base)
{
char *relocname;
struct section *sec;
relocname = malloc(strlen(base->name) + strlen(".rela") + 1);
if (!relocname) {
perror("malloc");
return NULL;
}
strcpy(relocname, ".rela");
strcat(relocname, base->name);
sec = elf_create_section(elf, relocname, sizeof(GElf_Rela), 0);
free(relocname);
if (!sec)
return NULL;
base->reloc = sec;
sec->base = base;
sec->sh.sh_type = SHT_RELA;
@ -749,42 +814,95 @@ struct section *elf_create_rela_section(struct elf *elf, struct section *base)
return sec;
}
int elf_rebuild_rela_section(struct elf *elf, struct section *sec)
struct section *elf_create_reloc_section(struct elf *elf,
struct section *base,
int reltype)
{
struct rela *rela;
int nr, idx = 0, size;
GElf_Rela *relas;
switch (reltype) {
case SHT_REL: return elf_create_rel_reloc_section(elf, base);
case SHT_RELA: return elf_create_rela_reloc_section(elf, base);
default: return NULL;
}
}
nr = 0;
list_for_each_entry(rela, &sec->rela_list, list)
nr++;
static int elf_rebuild_rel_reloc_section(struct section *sec, int nr)
{
struct reloc *reloc;
int idx = 0, size;
GElf_Rel *relocs;
size = nr * sizeof(*relas);
relas = malloc(size);
if (!relas) {
/* Allocate a buffer for relocations */
size = nr * sizeof(*relocs);
relocs = malloc(size);
if (!relocs) {
perror("malloc");
return -1;
}
sec->changed = true;
elf->changed = true;
sec->data->d_buf = relas;
sec->data->d_buf = relocs;
sec->data->d_size = size;
sec->sh.sh_size = size;
idx = 0;
list_for_each_entry(rela, &sec->rela_list, list) {
relas[idx].r_offset = rela->offset;
relas[idx].r_addend = rela->addend;
relas[idx].r_info = GELF_R_INFO(rela->sym->idx, rela->type);
list_for_each_entry(reloc, &sec->reloc_list, list) {
relocs[idx].r_offset = reloc->offset;
relocs[idx].r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
idx++;
}
return 0;
}
static int elf_rebuild_rela_reloc_section(struct section *sec, int nr)
{
struct reloc *reloc;
int idx = 0, size;
GElf_Rela *relocs;
/* Allocate a buffer for relocations with addends */
size = nr * sizeof(*relocs);
relocs = malloc(size);
if (!relocs) {
perror("malloc");
return -1;
}
sec->data->d_buf = relocs;
sec->data->d_size = size;
sec->sh.sh_size = size;
idx = 0;
list_for_each_entry(reloc, &sec->reloc_list, list) {
relocs[idx].r_offset = reloc->offset;
relocs[idx].r_addend = reloc->addend;
relocs[idx].r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
idx++;
}
return 0;
}
int elf_rebuild_reloc_section(struct elf *elf, struct section *sec)
{
struct reloc *reloc;
int nr;
sec->changed = true;
elf->changed = true;
nr = 0;
list_for_each_entry(reloc, &sec->reloc_list, list)
nr++;
switch (sec->sh.sh_type) {
case SHT_REL: return elf_rebuild_rel_reloc_section(sec, nr);
case SHT_RELA: return elf_rebuild_rela_reloc_section(sec, nr);
default: return -1;
}
}
int elf_write_insn(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len,
const char *insn)
@ -804,17 +922,27 @@ int elf_write_insn(struct elf *elf, struct section *sec,
return 0;
}
int elf_write_rela(struct elf *elf, struct rela *rela)
int elf_write_reloc(struct elf *elf, struct reloc *reloc)
{
struct section *sec = rela->sec;
struct section *sec = reloc->sec;
rela->rela.r_info = GELF_R_INFO(rela->sym->idx, rela->type);
rela->rela.r_addend = rela->addend;
rela->rela.r_offset = rela->offset;
if (sec->sh.sh_type == SHT_REL) {
reloc->rel.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
reloc->rel.r_offset = reloc->offset;
if (!gelf_update_rela(sec->data, rela->idx, &rela->rela)) {
WARN_ELF("gelf_update_rela");
return -1;
if (!gelf_update_rel(sec->data, reloc->idx, &reloc->rel)) {
WARN_ELF("gelf_update_rel");
return -1;
}
} else {
reloc->rela.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
reloc->rela.r_addend = reloc->addend;
reloc->rela.r_offset = reloc->offset;
if (!gelf_update_rela(sec->data, reloc->idx, &reloc->rela)) {
WARN_ELF("gelf_update_rela");
return -1;
}
}
elf->changed = true;
@ -862,7 +990,7 @@ void elf_close(struct elf *elf)
{
struct section *sec, *tmpsec;
struct symbol *sym, *tmpsym;
struct rela *rela, *tmprela;
struct reloc *reloc, *tmpreloc;
if (elf->elf)
elf_end(elf->elf);
@ -876,10 +1004,10 @@ void elf_close(struct elf *elf)
hash_del(&sym->hash);
free(sym);
}
list_for_each_entry_safe(rela, tmprela, &sec->rela_list, list) {
list_del(&rela->list);
hash_del(&rela->hash);
free(rela);
list_for_each_entry_safe(reloc, tmpreloc, &sec->reloc_list, list) {
list_del(&reloc->list);
hash_del(&reloc->hash);
free(reloc);
}
list_del(&sec->list);
free(sec);

29
tools/objtool/elf.h
View File

@ -32,8 +32,8 @@ struct section {
GElf_Shdr sh;
struct rb_root symbol_tree;
struct list_head symbol_list;
struct list_head rela_list;
struct section *base, *rela;
struct list_head reloc_list;
struct section *base, *reloc;
struct symbol *sym;
Elf_Data *data;
char *name;
@ -58,10 +58,13 @@ struct symbol {
bool uaccess_safe;
};
struct rela {
struct reloc {
struct list_head list;
struct hlist_node hash;
GElf_Rela rela;
union {
GElf_Rela rela;
GElf_Rel rel;
};
struct section *sec;
struct symbol *sym;
unsigned long offset;
@ -84,7 +87,7 @@ struct elf {
DECLARE_HASHTABLE(symbol_name_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(section_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(section_name_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(rela_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(reloc_hash, ELF_HASH_BITS);
};
#define OFFSET_STRIDE_BITS 4
@ -111,19 +114,19 @@ static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
return ol;
}
static inline u32 rela_hash(struct rela *rela)
static inline u32 reloc_hash(struct reloc *reloc)
{
return sec_offset_hash(rela->sec, rela->offset);
return sec_offset_hash(reloc->sec, reloc->offset);
}
struct elf *elf_open_read(const char *name, int flags);
struct section *elf_create_section(struct elf *elf, const char *name, size_t entsize, int nr);
struct section *elf_create_rela_section(struct elf *elf, struct section *base);
void elf_add_rela(struct elf *elf, struct rela *rela);
struct section *elf_create_reloc_section(struct elf *elf, struct section *base, int reltype);
void elf_add_reloc(struct elf *elf, struct reloc *reloc);
int elf_write_insn(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len,
const char *insn);
int elf_write_rela(struct elf *elf, struct rela *rela);
int elf_write_reloc(struct elf *elf, struct reloc *reloc);
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
@ -132,11 +135,11 @@ struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
struct rela *find_rela_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
struct rela *find_rela_by_dest_range(const struct elf *elf, struct section *sec,
struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len);
struct symbol *find_func_containing(struct section *sec, unsigned long offset);
int elf_rebuild_rela_section(struct elf *elf, struct section *sec);
int elf_rebuild_reloc_section(struct elf *elf, struct section *sec);
#define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list)

46
tools/objtool/orc_gen.c
View File

@ -80,56 +80,56 @@ int create_orc(struct objtool_file *file)
return 0;
}
static int create_orc_entry(struct elf *elf, struct section *u_sec, struct section *ip_relasec,
static int create_orc_entry(struct elf *elf, struct section *u_sec, struct section *ip_relocsec,
unsigned int idx, struct section *insn_sec,
unsigned long insn_off, struct orc_entry *o)
{
struct orc_entry *orc;
struct rela *rela;
struct reloc *reloc;
/* populate ORC data */
orc = (struct orc_entry *)u_sec->data->d_buf + idx;
memcpy(orc, o, sizeof(*orc));
/* populate rela for ip */
rela = malloc(sizeof(*rela));
if (!rela) {
/* populate reloc for ip */
reloc = malloc(sizeof(*reloc));
if (!reloc) {
perror("malloc");
return -1;
}
memset(rela, 0, sizeof(*rela));
memset(reloc, 0, sizeof(*reloc));
if (insn_sec->sym) {
rela->sym = insn_sec->sym;
rela->addend = insn_off;
reloc->sym = insn_sec->sym;
reloc->addend = insn_off;
} else {
/*
* The Clang assembler doesn't produce section symbols, so we
* have to reference the function symbol instead:
*/
rela->sym = find_symbol_containing(insn_sec, insn_off);
if (!rela->sym) {
reloc->sym = find_symbol_containing(insn_sec, insn_off);
if (!reloc->sym) {
/*
* Hack alert. This happens when we need to reference
* the NOP pad insn immediately after the function.
*/
rela->sym = find_symbol_containing(insn_sec,
reloc->sym = find_symbol_containing(insn_sec,
insn_off - 1);
}
if (!rela->sym) {
if (!reloc->sym) {
WARN("missing symbol for insn at offset 0x%lx\n",
insn_off);
return -1;
}
rela->addend = insn_off - rela->sym->offset;
reloc->addend = insn_off - reloc->sym->offset;
}
rela->type = R_X86_64_PC32;
rela->offset = idx * sizeof(int);
rela->sec = ip_relasec;
reloc->type = R_X86_64_PC32;
reloc->offset = idx * sizeof(int);
reloc->sec = ip_relocsec;
elf_add_rela(elf, rela);
elf_add_reloc(elf, reloc);
return 0;
}
@ -137,7 +137,7 @@ static int create_orc_entry(struct elf *elf, struct section *u_sec, struct secti
int create_orc_sections(struct objtool_file *file)
{
struct instruction *insn, *prev_insn;
struct section *sec, *u_sec, *ip_relasec;
struct section *sec, *u_sec, *ip_relocsec;
unsigned int idx;
struct orc_entry empty = {
@ -181,8 +181,8 @@ int create_orc_sections(struct objtool_file *file)
if (!sec)
return -1;
ip_relasec = elf_create_rela_section(file->elf, sec);
if (!ip_relasec)
ip_relocsec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
if (!ip_relocsec)
return -1;
/* create .orc_unwind section */
@ -200,7 +200,7 @@ int create_orc_sections(struct objtool_file *file)
if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
sizeof(struct orc_entry))) {
if (create_orc_entry(file->elf, u_sec, ip_relasec, idx,
if (create_orc_entry(file->elf, u_sec, ip_relocsec, idx,
insn->sec, insn->offset,
&insn->orc))
return -1;
@ -212,7 +212,7 @@ int create_orc_sections(struct objtool_file *file)
/* section terminator */
if (prev_insn) {
if (create_orc_entry(file->elf, u_sec, ip_relasec, idx,
if (create_orc_entry(file->elf, u_sec, ip_relocsec, idx,
prev_insn->sec,
prev_insn->offset + prev_insn->len,
&empty))
@ -222,7 +222,7 @@ int create_orc_sections(struct objtool_file *file)
}
}
if (elf_rebuild_rela_section(file->elf, ip_relasec))
if (elf_rebuild_reloc_section(file->elf, ip_relocsec))
return -1;
return 0;

28
tools/objtool/special.c
View File

@ -72,7 +72,7 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry,
struct section *sec, int idx,
struct special_alt *alt)
{
struct rela *orig_rela, *new_rela;
struct reloc *orig_reloc, *new_reloc;
unsigned long offset;
offset = idx * entry->size;
@ -118,30 +118,30 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry,
}
}
orig_rela = find_rela_by_dest(elf, sec, offset + entry->orig);
if (!orig_rela) {
WARN_FUNC("can't find orig rela", sec, offset + entry->orig);
orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
if (!orig_reloc) {
WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
return -1;
}
if (orig_rela->sym->type != STT_SECTION) {
WARN_FUNC("don't know how to handle non-section rela symbol %s",
sec, offset + entry->orig, orig_rela->sym->name);
if (orig_reloc->sym->type != STT_SECTION) {
WARN_FUNC("don't know how to handle non-section reloc symbol %s",
sec, offset + entry->orig, orig_reloc->sym->name);
return -1;
}
alt->orig_sec = orig_rela->sym->sec;
alt->orig_off = orig_rela->addend;
alt->orig_sec = orig_reloc->sym->sec;
alt->orig_off = orig_reloc->addend;
if (!entry->group || alt->new_len) {
new_rela = find_rela_by_dest(elf, sec, offset + entry->new);
if (!new_rela) {
WARN_FUNC("can't find new rela",
new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new);
if (!new_reloc) {
WARN_FUNC("can't find new reloc",
sec, offset + entry->new);
return -1;
}
alt->new_sec = new_rela->sym->sec;
alt->new_off = (unsigned int)new_rela->addend;
alt->new_sec = new_reloc->sym->sec;
alt->new_off = (unsigned int)new_reloc->addend;
/* _ASM_EXTABLE_EX hack */
if (alt->new_off >= 0x7ffffff0)