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objtool: Classify symbols

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In order to avoid calling str*cmp() on symbol names, over and over, do
them all once upfront and store the result.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120309.658539311@infradead.org
This commit is contained in:
Peter Zijlstra 2021-10-26 14:01:33 +02:00
parent b08cadbd3b
commit 1739c66eb7
2 changed files with 27 additions and 14 deletions
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34
tools/objtool/check.c
View File

@ -1012,8 +1012,7 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn,
* so they need a little help, NOP out any KCOV calls from noinstr
* text.
*/
if (insn->sec->noinstr &&
!strncmp(insn->call_dest->name, "__sanitizer_cov_", 16)) {
if (insn->sec->noinstr && insn->call_dest->kcov) {
if (reloc) {
reloc->type = R_NONE;
elf_write_reloc(file->elf, reloc);
@ -1027,7 +1026,7 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn,
insn->type = sibling ? INSN_RETURN : INSN_NOP;
}
if (mcount && !strcmp(insn->call_dest->name, "__fentry__")) {
if (mcount && insn->call_dest->fentry) {
if (sibling)
WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset);
@ -1077,7 +1076,7 @@ static int add_jump_destinations(struct objtool_file *file)
} else if (reloc->sym->type == STT_SECTION) {
dest_sec = reloc->sym->sec;
dest_off = arch_dest_reloc_offset(reloc->addend);
} else if (arch_is_retpoline(reloc->sym)) {
} else if (reloc->sym->retpoline_thunk) {
/*
* Retpoline jumps are really dynamic jumps in
* disguise, so convert them accordingly.
@ -1218,7 +1217,7 @@ static int add_call_destinations(struct objtool_file *file)
add_call_dest(file, insn, dest, false);
} else if (arch_is_retpoline(reloc->sym)) {
} else if (reloc->sym->retpoline_thunk) {
/*
* Retpoline calls are really dynamic calls in
* disguise, so convert them accordingly.
@ -1907,17 +1906,28 @@ static int read_intra_function_calls(struct objtool_file *file)
return 0;
}
static int read_static_call_tramps(struct objtool_file *file)
static int classify_symbols(struct objtool_file *file)
{
struct section *sec;
struct symbol *func;
for_each_sec(file, sec) {
list_for_each_entry(func, &sec->symbol_list, list) {
if (func->bind == STB_GLOBAL &&
!strncmp(func->name, STATIC_CALL_TRAMP_PREFIX_STR,
if (func->bind != STB_GLOBAL)
continue;
if (!strncmp(func->name, STATIC_CALL_TRAMP_PREFIX_STR,
strlen(STATIC_CALL_TRAMP_PREFIX_STR)))
func->static_call_tramp = true;
if (arch_is_retpoline(func))
func->retpoline_thunk = true;
if (!strcmp(func->name, "__fentry__"))
func->fentry = true;
if (!strncmp(func->name, "__sanitizer_cov_", 16))
func->kcov = true;
}
}
@ -1983,7 +1993,7 @@ static int decode_sections(struct objtool_file *file)
/*
* Must be before add_{jump_call}_destination.
*/
ret = read_static_call_tramps(file);
ret = classify_symbols(file);
if (ret)
return ret;
@ -2041,9 +2051,9 @@ static int decode_sections(struct objtool_file *file)
static bool is_fentry_call(struct instruction *insn)
{
if (insn->type == INSN_CALL && insn->call_dest &&
insn->call_dest->type == STT_NOTYPE &&
!strcmp(insn->call_dest->name, "__fentry__"))
if (insn->type == INSN_CALL &&
insn->call_dest &&
insn->call_dest->fentry)
return true;
return false;

7
tools/objtool/include/objtool/elf.h
View File

@ -54,8 +54,11 @@ struct symbol {
unsigned long offset;
unsigned int len;
struct symbol *pfunc, *cfunc, *alias;
bool uaccess_safe;
bool static_call_tramp;
u8 uaccess_safe : 1;
u8 static_call_tramp : 1;
u8 retpoline_thunk : 1;
u8 fentry : 1;
u8 kcov : 1;
struct list_head pv_target;
};