objtool: Fix validate_branch() return codes

The validate_branch() function should never return a negative value.
Errors are treated as warnings so that even if something goes wrong,
objtool does its best to generate ORC data for the rest of the file.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: baa41469a7b9 ("objtool: Implement stack validation 2.0")
Link: http://lkml.kernel.org/r/d86671cfde823b50477cd2f6f548dfe54871e24d.1502401017.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/objtool/check.c

@@ -1524,7 +1524,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
 	if (insn->alt_group && list_empty(&insn->alts)) {
 		WARN_FUNC("don't know how to handle branch to middle of alternative instruction group",
 			  sec, insn->offset);
-		return -1;
+		return 1;
 	}
 
 	while (1) {
@@ -1543,7 +1543,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
 		if (func && insn->ignore) {
 			WARN_FUNC("BUG: why am I validating an ignored function?",
 				  sec, insn->offset);
-			return -1;
+			return 1;
 		}
 
 		if (insn->visited) {
@@ -1681,7 +1681,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
 
 		case INSN_STACK:
 			if (update_insn_state(insn, &state))
-				return -1;
+				return 1;
 
 			break;