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objtool: Separate prefix code from stack validation code

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Simplify the prefix code by moving it after
validate_reachable_instructions().

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/d7f31ac2de462d0cd7b1db01b7ecb525c057c8f6.1681331135.git.jpoimboe@kernel.org
This commit is contained in:
Josh Poimboeuf 2023-04-12 13:26:13 -07:00 committed by Peter Zijlstra
parent 6126ed5dfb
commit bd456a1bed
1 changed files with 50 additions and 38 deletions
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88
tools/objtool/check.c
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@ -4114,54 +4114,61 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
return false;
}
static int add_prefix_symbol(struct objtool_file *file, struct symbol *func,
struct instruction *insn)
static int add_prefix_symbol(struct objtool_file *file, struct symbol *func)
{
if (!opts.prefix)
return 0;
struct instruction *insn, *prev;
for (;;) {
struct instruction *prev = prev_insn_same_sec(file, insn);
insn = find_insn(file, func->sec, func->offset);
if (!insn)
return -1;
for (prev = prev_insn_same_sec(file, insn);
prev;
prev = prev_insn_same_sec(file, prev)) {
u64 offset;
if (!prev)
break;
if (prev->type != INSN_NOP)
break;
return -1;
offset = func->offset - prev->offset;
if (offset >= opts.prefix) {
if (offset == opts.prefix) {
/*
* Since the sec->symbol_list is ordered by
* offset (see elf_add_symbol()) the added
* symbol will not be seen by the iteration in
* validate_section().
*
* Hence the lack of list_for_each_entry_safe()
* there.
*
* The direct concequence is that prefix symbols
* don't get visited (because pointless), except
* for the logic in ignore_unreachable_insn()
* that needs the terminating insn to be visited
* otherwise it will report the hole.
*
* Hence mark the first instruction of the
* prefix symbol as visisted.
*/
prev->visited |= VISITED_BRANCH;
elf_create_prefix_symbol(file->elf, func, opts.prefix);
}
break;
}
insn = prev;
if (offset > opts.prefix)
return -1;
if (offset < opts.prefix)
continue;
elf_create_prefix_symbol(file->elf, func, opts.prefix);
break;
}
if (!prev)
return -1;
return 0;
}
static int add_prefix_symbols(struct objtool_file *file)
{
struct section *sec;
struct symbol *func;
int warnings = 0;
for_each_sec(file, sec) {
if (!(sec->sh.sh_flags & SHF_EXECINSTR))
continue;
sec_for_each_sym(sec, func) {
if (func->type != STT_FUNC)
continue;
add_prefix_symbol(file, func);
}
}
return warnings;
}
static int validate_symbol(struct objtool_file *file, struct section *sec,
struct symbol *sym, struct insn_state *state)
{
@ -4180,8 +4187,6 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
if (!insn || insn->ignore || insn->visited)
return 0;
add_prefix_symbol(file, sym, insn);
state->uaccess = sym->uaccess_safe;
ret = validate_branch(file, insn_func(insn), insn, *state);
@ -4621,6 +4626,13 @@ int check(struct objtool_file *file)
warnings += ret;
}
if (opts.prefix) {
ret = add_prefix_symbols(file);
if (ret < 0)
return ret;
warnings += ret;
}
if (opts.ibt) {
ret = create_ibt_endbr_seal_sections(file);
if (ret < 0)