Revert "objtool: Increase per-function WARN_FUNC() rate limit"

This reverts commit 0a7fb6f.

The "skipping duplicate warnings" warning is technically not an actual
warning, which can cause confusion.  This feature isn't all that useful
anyway.  It's exceedingly rare for a function to have more than one
unrelated warning.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/e5abe5e858acf1a9207a5dfa0f37d17ac9dca872.1743481539.git.jpoimboe@kernel.org

Author: jpoimboe

tools/objtool/check.c

@@ -3545,7 +3545,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 
 			WARN("%s() falls through to next function %s()",
 			     func->name, insn_func(insn)->name);
-			func->warnings++;
+			func->warned = 1;
 
 			return 1;
 		}
@@ -4576,7 +4576,7 @@ static void disas_warned_funcs(struct objtool_file *file)
 	char *funcs = NULL, *tmp;
 
 	for_each_sym(file, sym) {
-		if (sym->warnings) {
+		if (sym->warned) {
 			if (!funcs) {
 				funcs = malloc(strlen(sym->name) + 1);
 				if (!funcs) {

tools/objtool/include/objtool/elf.h

@@ -65,11 +65,11 @@ struct symbol {
 	u8 return_thunk      : 1;
 	u8 fentry            : 1;
 	u8 profiling_func    : 1;
+	u8 warned	     : 1;
 	u8 embedded_insn     : 1;
 	u8 local_label       : 1;
 	u8 frame_pointer     : 1;
 	u8 ignore	     : 1;
-	u8 warnings	     : 2;
 	struct list_head pv_target;
 	struct reloc *relocs;
 };

tools/objtool/include/objtool/warn.h

@@ -57,22 +57,14 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 	free(_str);					\
 })
 
-#define WARN_LIMIT 2
-
 #define WARN_INSN(insn, format, ...)					\
 ({									\
 	struct instruction *_insn = (insn);				\
-	BUILD_BUG_ON(WARN_LIMIT > 2);					\
-	if (!_insn->sym || _insn->sym->warnings < WARN_LIMIT) {		\
+	if (!_insn->sym || !_insn->sym->warned)				\
 		WARN_FUNC(format, _insn->sec, _insn->offset,		\
 			  ##__VA_ARGS__);				\
-		if (_insn->sym)						\
-			_insn->sym->warnings++;				\
-	} else if (_insn->sym && _insn->sym->warnings == WARN_LIMIT) {	\
-		WARN_FUNC("skipping duplicate warning(s)",		\
-			  _insn->sec, _insn->offset);			\
-		_insn->sym->warnings++;					\
-	}								\
+	if (_insn->sym)							\
+		_insn->sym->warned = 1;					\
 })
 
 #define BT_INSN(insn, format, ...)				\