Commit bd456a1b authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Peter Zijlstra
Browse files

objtool: Separate prefix code from stack validation code 



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

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/d7f31ac2de462d0cd7b1db01b7ecb525c057c8f6.1681331135.git.jpoimboe@kernel.org
parent 6126ed5d

tools/objtool/check.c

+50 −38
Original line number Diff line number Diff line
@@ -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);

		u64 offset;

	insn = find_insn(file, func->sec, func->offset);

	if (!insn)

		return -1;



		if (!prev)

			break;

	for (prev = prev_insn_same_sec(file, insn);

	     prev;

	     prev = prev_insn_same_sec(file, prev)) {

		u64 offset;



		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;



		if (offset > opts.prefix)

			return -1;



		if (offset < opts.prefix)

			continue;



		elf_create_prefix_symbol(file->elf, func, opts.prefix);

			}

		break;

	}

		insn = prev;

	}



	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)