Commit 5e3992fe authored by Josh Poimboeuf's avatar Josh Poimboeuf
Browse files

objtool: Limit unreachable warnings to once per function 



Unreachable instruction warnings are limited to once per object file.
That no longer makes sense for vmlinux validation, which might have
more unreachable instructions lurking in other places.  Change it to
once per function.

Note this affects some other (much rarer) non-fatal warnings as well.
In general I think one-warning-per-function makes sense, as related
warnings can accumulate quickly and we want to eventually get back to
failing the build with -Werror anyway.

Reviewed-by: default avatarMiroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/9d38f881bfc34e031c74e4e90064ccb3e49f599a.1681853186.git.jpoimboe@kernel.org


Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent 89da5a69

tools/objtool/check.c

+3 −2
Original line number Diff line number Diff line
@@ -4514,6 +4514,7 @@ static int validate_sls(struct objtool_file *file) 
static int validate_reachable_instructions(struct objtool_file *file)

{

	struct instruction *insn;

	int warnings = 0;



	if (file->ignore_unreachables)

		return 0;
@@ -4523,10 +4524,10 @@ static int validate_reachable_instructions(struct objtool_file *file) 
			continue;



		WARN_INSN(insn, "unreachable instruction");

		return 1;

		warnings++;

	}



	return 0;

	return warnings;

}



int check(struct objtool_file *file)

tools/objtool/include/objtool/elf.h

+1 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ struct symbol { 
	u8 return_thunk      : 1;

	u8 fentry            : 1;

	u8 profiling_func    : 1;

	u8 warned	     : 1;

	struct list_head pv_target;

	struct list_head reloc_list;

};

tools/objtool/include/objtool/warn.h

+6 −1
Original line number Diff line number Diff line
@@ -55,7 +55,12 @@ static inline char *offstr(struct section *sec, unsigned long offset) 


#define WARN_INSN(insn, format, ...)					\

({									\

	WARN_FUNC(format, insn->sec, insn->offset,  ##__VA_ARGS__);	\

	struct instruction *_insn = (insn);				\

	if (!_insn->sym || !_insn->sym->warned)				\

		WARN_FUNC(format, _insn->sec, _insn->offset,		\

			  ##__VA_ARGS__);				\

	if (_insn->sym)							\

		_insn->sym->warned = 1;					\

})



#define BT_FUNC(format, insn, ...)			\