objtool: Refactor sibling call detection logic (0c1ddd33) · Commits · 戴 / test

tools/objtool/check.c

+33 −32

Original line number	Diff line number	Diff line
		@@ -97,6 +97,20 @@ static struct instruction next_insn_same_func(struct objtool_file file,
		for (insn = next_insn_same_sec(file, insn); insn; \
		insn = next_insn_same_sec(file, insn))

		static bool is_sibling_call(struct instruction *insn)
		{
		/* An indirect jump is either a sibling call or a jump to a table. */
		if (insn->type == INSN_JUMP_DYNAMIC)
		return list_empty(&insn->alts);

		if (insn->type != INSN_JUMP_CONDITIONAL &&
		insn->type != INSN_JUMP_UNCONDITIONAL)
		return false;

		/* add_jump_destinations() sets insn->call_dest for sibling calls. */
		return !!insn->call_dest;
		}

		/*
		* This checks to see if the given function is a "noreturn" function.
		*
		@@ -167,36 +181,27 @@ static bool __dead_end_function(struct objtool_file file, struct symbol func,
		* of the sibling call returns.
		*/
		func_for_each_insn_all(file, func, insn) {
		if (insn->type == INSN_JUMP_UNCONDITIONAL) {
		if (is_sibling_call(insn)) {
		struct instruction *dest = insn->jump_dest;

		if (!dest)
		/* sibling call to another file */
		return false;

		if (dest->func && dest->func->pfunc != insn->func->pfunc) {

		/* local sibling call */
		if (recursion == 5) {
		/*
		* Infinite recursion: two functions
		* have sibling calls to each other.
		* This is a very rare case. It means
		* they aren't dead ends.
		* Infinite recursion: two functions have
		* sibling calls to each other. This is a very
		* rare case. It means they aren't dead ends.
		*/
		return false;
		}

		return __dead_end_function(file, dest->func,
		recursion + 1);
		return __dead_end_function(file, dest->func, recursion+1);
		}
		}

		if (insn->type == INSN_JUMP_DYNAMIC && list_empty(&insn->alts))
		/* sibling call */
		return false;
		}

		return true;
		}

		@@ -581,9 +586,8 @@ static int add_jump_destinations(struct objtool_file *file)
		insn->retpoline_safe = true;
		continue;
		} else {
		/* sibling call */
		/* external sibling call */
		insn->call_dest = rela->sym;
		insn->jump_dest = NULL;
		continue;
		}

		@@ -633,9 +637,8 @@ static int add_jump_destinations(struct objtool_file *file)
		} else if (insn->jump_dest->func->pfunc != insn->func->pfunc &&
		insn->jump_dest->offset == insn->jump_dest->func->offset) {

		/* sibling class */
		/* internal sibling call */
		insn->call_dest = insn->jump_dest->func;
		insn->jump_dest = NULL;
		}
		}
		}
		@@ -1889,7 +1892,7 @@ static inline bool func_uaccess_safe(struct symbol *func)
		return false;
		}

		static inline const char insn_dest_name(struct instruction insn)
		static inline const char call_dest_name(struct instruction insn)
		{
		if (insn->call_dest)
		return insn->call_dest->name;
		@@ -1901,13 +1904,13 @@ static int validate_call(struct instruction insn, struct insn_state state)
		{
		if (state->uaccess && !func_uaccess_safe(insn->call_dest)) {
		WARN_FUNC("call to %s() with UACCESS enabled",
		insn->sec, insn->offset, insn_dest_name(insn));
		insn->sec, insn->offset, call_dest_name(insn));
		return 1;
		}

		if (state->df) {
		WARN_FUNC("call to %s() with DF set",
		insn->sec, insn->offset, insn_dest_name(insn));
		insn->sec, insn->offset, call_dest_name(insn));
		return 1;
		}

		@@ -2088,14 +2091,12 @@ static int validate_branch(struct objtool_file file, struct symbol func,

		case INSN_JUMP_CONDITIONAL:
		case INSN_JUMP_UNCONDITIONAL:
		if (func && !insn->jump_dest) {
		if (func && is_sibling_call(insn)) {
		ret = validate_sibling_call(insn, &state);
		if (ret)
		return ret;

		} else if (insn->jump_dest &&
		(!func \|\| !insn->jump_dest->func \|\|
		insn->jump_dest->func->pfunc == func)) {
		} else if (insn->jump_dest) {
		ret = validate_branch(file, func,
		insn->jump_dest, state);
		if (ret) {
		@@ -2111,7 +2112,7 @@ static int validate_branch(struct objtool_file file, struct symbol func,
		break;

		case INSN_JUMP_DYNAMIC:
		if (func && list_empty(&insn->alts)) {
		if (func && is_sibling_call(insn)) {
		ret = validate_sibling_call(insn, &state);
		if (ret)
		return ret;

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