Commit e10cd8fe authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Thomas Gleixner
Browse files

objtool: Refactor function alias logic 



- Add an alias check in validate_functions().  With this change, aliases
  no longer need uaccess_safe set.

- Add an alias check in decode_instructions().  With this change, the
  "if (!insn->func)" check is no longer needed.

- Don't create aliases for zero-length functions, as it can have
  unexpected results.  The next patch will spit out a warning for
  zero-length functions anyway.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/26a99c31426540f19c9a58b9e10727c385a147bc.1563413318.git.jpoimboe@redhat.com
parent c705cecc

tools/objtool/check.c

+9 −7
Original line number Diff line number Diff line
@@ -276,7 +276,7 @@ static int decode_instructions(struct objtool_file *file) 
		}



		list_for_each_entry(func, &sec->symbol_list, list) {

			if (func->type != STT_FUNC)

			if (func->type != STT_FUNC || func->alias != func)

				continue;



			if (!find_insn(file, sec, func->offset)) {
@@ -286,7 +286,6 @@ static int decode_instructions(struct objtool_file *file) 
			}



			func_for_each_insn(file, func, insn)

				if (!insn->func)

				insn->func = func;

		}

	}
@@ -508,7 +507,7 @@ static void add_uaccess_safe(struct objtool_file *file) 
		if (!func)

			continue;



		func->alias->uaccess_safe = true;

		func->uaccess_safe = true;

	}

}
@@ -1887,7 +1886,7 @@ static bool insn_state_match(struct instruction *insn, struct insn_state *state) 
static inline bool func_uaccess_safe(struct symbol *func)

{

	if (func)

		return func->alias->uaccess_safe;

		return func->uaccess_safe;



	return false;

}
@@ -2355,14 +2354,17 @@ static int validate_functions(struct objtool_file *file) 


	for_each_sec(file, sec) {

		list_for_each_entry(func, &sec->symbol_list, list) {

			if (func->type != STT_FUNC || func->pfunc != func)

			if (func->type != STT_FUNC)

				continue;



			if (func->pfunc != func || func->alias != func)

				continue;



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

			if (!insn || insn->ignore || insn->visited)

				continue;



			state.uaccess = func->alias->uaccess_safe;

			state.uaccess = func->uaccess_safe;



			ret = validate_branch(file, func, insn, state);

			if (ret && backtrace)

tools/objtool/elf.c

+1 −1
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ static int read_symbols(struct elf *elf) 
			}



			if (sym->offset == s->offset) {

				if (sym->len == s->len && alias == sym)

				if (sym->len && sym->len == s->len && alias == sym)

					alias = s;



				if (sym->len >= s->len) {

CRA Git | Maintained and supported by SUSTech CRA and CCSE