objtool: warning improvements

index 5b600bbf2389..a00931342c7e 100644
@@ -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)

index e1ca588eb69d..78e2d0fc21ca 100644
@@ -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;
 };

index b1c920dc9516..f195deab456e 100644
@@ -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, ...)			\

index 7c175198d09f..5e21cfb7661d 100644
@@ -93,6 +93,7 @@ static const struct option check_options[] = {
 	OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
 	OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
 	OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
+	OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
 
 	OPT_END(),
 };

@@ -118,6 +119,10 @@ int cmd_parse_options(int argc, const char **argv, const char * const usage[])
 		parse_options(envc, envv, check_options, env_usage, 0);
 	}
 
+	env = getenv("OBJTOOL_VERBOSE");
+	if (env && !strcmp(env, "1"))
+		opts.verbose = true;
+
 	argc = parse_options(argc, argv, check_options, usage, 0);
 	if (argc != 1)
 		usage_with_options(usage, check_options);

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index 2a108e648b7a..fcca6662c8b4 100644
@@ -37,6 +37,7 @@ struct opts {
 	bool no_unreachable;
 	bool sec_address;
 	bool stats;
+	bool verbose;
 };
 
 extern struct opts opts;

index c63e0867daca..aa083296af1e 100644
@@ -3657,8 +3657,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 
 				ret = validate_branch(file, func, alt->insn, state);
 				if (ret) {
-					if (opts.backtrace)
-						BT_FUNC("(alt)", insn);
+					BT_INSN(insn, "(alt)");
 					return ret;
 				}
 			}

@@ -3703,8 +3702,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 				ret = validate_branch(file, func,
 						      insn->jump_dest, state);
 				if (ret) {
-					if (opts.backtrace)
-						BT_FUNC("(branch)", insn);
+					BT_INSN(insn, "(branch)");
 					return ret;
 				}
 			}

@@ -3802,8 +3800,8 @@ static int validate_unwind_hint(struct objtool_file *file,
 {
 	if (insn->hint && !insn->visited && !insn->ignore) {
 		int ret = validate_branch(file, insn_func(insn), insn, *state);
-		if (ret && opts.backtrace)
-			BT_FUNC("<=== (hint)", insn);
+		if (ret)
+			BT_INSN(insn, "<=== (hint)");
 		return ret;
 	}
 

@@ -3861,8 +3859,7 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn)
 
 				ret = validate_unret(file, alt->insn);
 				if (ret) {
-				        if (opts.backtrace)
-						BT_FUNC("(alt)", insn);
+					BT_INSN(insn, "(alt)");
 					return ret;
 				}
 			}

@@ -3888,10 +3885,8 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn)
 				}
 				ret = validate_unret(file, insn->jump_dest);
 				if (ret) {
-					if (opts.backtrace) {
-						BT_FUNC("(branch%s)", insn,
-							insn->type == INSN_JUMP_CONDITIONAL ? "-cond" : "");
-					}
+					BT_INSN(insn, "(branch%s)",
+						insn->type == INSN_JUMP_CONDITIONAL ? "-cond" : "");
 					return ret;
 				}
 

@@ -3913,8 +3908,7 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn)
 
 			ret = validate_unret(file, dest);
 			if (ret) {
-				if (opts.backtrace)
-					BT_FUNC("(call)", insn);
+				BT_INSN(insn, "(call)");
 				return ret;
 			}
 			/*

@@ -4216,8 +4210,8 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
 	state->uaccess = sym->uaccess_safe;
 
 	ret = validate_branch(file, insn_func(insn), insn, *state);
-	if (ret && opts.backtrace)
-		BT_FUNC("<=== (sym)", insn);
+	if (ret)
+		BT_INSN(insn, "<=== (sym)");
 	return ret;
 }
 

index f195deab456e..ac04d3fe4dd9 100644
@@ -63,12 +63,14 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 		_insn->sym->warned = 1;					\
 })
 
-#define BT_FUNC(format, insn, ...)			\
-({							\
-	struct instruction *_insn = (insn);		\
-	char *_str = offstr(_insn->sec, _insn->offset); \
-	WARN("  %s: " format, _str, ##__VA_ARGS__);	\
-	free(_str);					\
+#define BT_INSN(insn, format, ...)				\
+({								\
+	if (opts.verbose || opts.backtrace) {			\
+		struct instruction *_insn = (insn);		\
+		char *_str = offstr(_insn->sec, _insn->offset); \
+		WARN("  %s: " format, _str, ##__VA_ARGS__);	\
+		free(_str);					\
+	}							\
 })
 
 #define WARN_ELF(format, ...)				\

index aa083296af1e..dd10128ab013 100644
@@ -4507,7 +4507,8 @@ static int validate_sls(struct objtool_file *file)
 
 static int validate_reachable_instructions(struct objtool_file *file)
 {
-	struct instruction *insn;
+	struct instruction *insn, *prev_insn;
+	struct symbol *call_dest;
 	int warnings = 0;
 
 	if (file->ignore_unreachables)

@@ -4517,6 +4518,17 @@ static int validate_reachable_instructions(struct objtool_file *file)
 		if (insn->visited || ignore_unreachable_insn(file, insn))
 			continue;
 
+		prev_insn = prev_insn_same_sec(file, insn);
+		if (prev_insn && prev_insn->dead_end) {
+			call_dest = insn_call_dest(prev_insn);
+			if (call_dest) {
+				WARN_INSN(insn, "%s() is missing a __noreturn annotation",
+					  call_dest->name);
+				warnings++;
+				continue;
+			}
+		}
+
 		WARN_INSN(insn, "unreachable instruction");
 		warnings++;
 	}

index dd10128ab013..1cace399d32a 100644
@@ -4505,6 +4505,35 @@ static int validate_sls(struct objtool_file *file)
 	return warnings;
 }
 
+static bool ignore_noreturn_call(struct instruction *insn)
+{
+	struct symbol *call_dest = insn_call_dest(insn);
+
+	/*
+	 * FIXME: hack, we need a real noreturn solution
+	 *
+	 * Problem is, exc_double_fault() may or may not return, depending on
+	 * whether CONFIG_X86_ESPFIX64 is set.  But objtool has no visibility
+	 * to the kernel config.
+	 *
+	 * Other potential ways to fix it:
+	 *
+	 *   - have compiler communicate __noreturn functions somehow
+	 *   - remove CONFIG_X86_ESPFIX64
+	 *   - read the .config file
+	 *   - add a cmdline option
+	 *   - create a generic objtool annotation format (vs a bunch of custom
+	 *     formats) and annotate it
+	 */
+	if (!strcmp(call_dest->name, "exc_double_fault")) {
+		/* prevent further unreachable warnings for the caller */
+		insn->sym->warned = 1;
+		return true;
+	}
+
+	return false;
+}
+
 static int validate_reachable_instructions(struct objtool_file *file)
 {
 	struct instruction *insn, *prev_insn;

@@ -4521,7 +4550,7 @@ static int validate_reachable_instructions(struct objtool_file *file)
 		prev_insn = prev_insn_same_sec(file, insn);
 		if (prev_insn && prev_insn->dead_end) {
 			call_dest = insn_call_dest(prev_insn);
-			if (call_dest) {
+			if (call_dest && !ignore_noreturn_call(prev_insn)) {
 				WARN_INSN(insn, "%s() is missing a __noreturn annotation",
 					  call_dest->name);
 				warnings++;

index 1cace399d32a..2047a6d5339b 100644
@@ -217,7 +217,6 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"kthread_complete_and_exit",
 		"kthread_exit",
 		"kunit_try_catch_throw",
-		"lbug_with_loc",
 		"machine_real_restart",
 		"make_task_dead",
 		"mpt_halt_firmware",

@@ -225,7 +224,6 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"panic",
 		"panic_smp_self_stop",
 		"rest_init",
-		"resume_play_dead",
 		"rewind_stack_and_make_dead",
 		"sev_es_terminate",
 		"snp_abort",

index 41b9b942504d..8e9147358a28 100644
@@ -6,10 +6,6 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-#ifndef NORETURN
-#define NORETURN __attribute__((__noreturn__))
-#endif
-
 enum parse_opt_type {
 	/* special types */
 	OPTION_END,

@@ -183,9 +179,9 @@ extern int parse_options_subcommand(int argc, const char **argv,
 				const char *const subcommands[],
 				const char *usagestr[], int flags);
 
-extern NORETURN void usage_with_options(const char * const *usagestr,
+extern __noreturn void usage_with_options(const char * const *usagestr,
                                         const struct option *options);
-extern NORETURN __attribute__((format(printf,3,4)))
+extern __noreturn __attribute__((format(printf,3,4)))
 void usage_with_options_msg(const char * const *usagestr,
 			    const struct option *options,
 			    const char *fmt, ...);

index b2aec04fce8f..dfac76e35ac7 100644
@@ -5,8 +5,7 @@
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
-
-#define NORETURN __attribute__((__noreturn__))
+#include <linux/compiler.h>
 
 static inline void report(const char *prefix, const char *err, va_list params)
 {

@@ -15,7 +14,7 @@ static inline void report(const char *prefix, const char *err, va_list params)
 	fprintf(stderr, " %s%s\n", prefix, msg);
 }
 
-static NORETURN inline void die(const char *err, ...)
+static __noreturn inline void die(const char *err, ...)
 {
 	va_list params;
 

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