objtool: warning improvements

index 7c175198d09f..b8de42f6778e 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(),
 };

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 a3e79ae75f2e..b85aa440ee1f 100644
@@ -11,6 +11,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <unistd.h>
 #include <objtool/builtin.h>
 #include <objtool/elf.h>
 

@@ -41,6 +42,41 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 	return str;
 }
 
+static inline void objdump_func(struct section *sec, unsigned long offset)
+{
+	struct symbol *sym = find_func_containing(sec, offset);
+	const char *script_relative = "scripts/objdump-func";
+	bool is_text = (sec->sh.sh_flags & SHF_EXECINSTR);
+	char *cmd, *srctree, *script;
+
+	if (is_text)
+		sym = find_func_containing(sec, offset);
+	if (!sym)
+		sym = find_symbol_containing(sec, offset);
+	if (!sym)
+		return;
+
+	srctree = getenv("abs_srctree");
+	if (!srctree)
+		return;
+
+	script = malloc(strlen(srctree) + strlen(script_relative) + 2);
+	if (!script)
+		return;
+
+	sprintf(script, "%s/%s", srctree, script_relative);
+
+	if (access(script, X_OK))
+		return;
+
+	cmd = malloc(strlen(script) + strlen(objname) + strlen(sym->name) + 10);
+	if (!cmd)
+		return;
+
+	sprintf(cmd, "%s %s %s 1>&2", script, objname, sym->name);
+	system(cmd);
+}
+
 #define WARN(format, ...)				\
 	fprintf(stderr,					\
 		"%s: warning: objtool: " format "\n",	\

@@ -51,6 +87,8 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 	char *_str = offstr(sec, offset);		\
 	WARN("%s: " format, _str, ##__VA_ARGS__);	\
 	free(_str);					\
+	if (opts.verbose)				\
+		objdump_func(sec, offset);		\
 })
 
 #define BT_FUNC(format, insn, ...)			\

index b8de42f6778e..937ba5d78e08 100644
@@ -84,7 +84,6 @@ static const struct option check_options[] = {
 	OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
 
 	OPT_GROUP("Options:"),
-	OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
 	OPT_BOOLEAN(0, "backup", &opts.backup, "create .orig files before modification"),
 	OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
 	OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),

index cae6ac6ff246..a652b9e5c805 100644
@@ -3708,8 +3708,7 @@ 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_FUNC("(alt)", insn);
 					return ret;
 				}
 			}

@@ -3755,8 +3754,7 @@ 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_FUNC("(branch)", insn);
 					return ret;
 				}
 			}

@@ -3855,7 +3853,7 @@ 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)
+		if (ret)
 			BT_FUNC("<=== (hint)", insn);
 		return ret;
 	}

@@ -3914,8 +3912,7 @@ 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_FUNC("(alt)", insn);
 					return ret;
 				}
 			}

@@ -3942,10 +3939,8 @@ 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_FUNC("(branch%s)", insn,
+						insn->type == INSN_JUMP_CONDITIONAL ? "-cond" : "");
 					return ret;
 				}
 

@@ -3967,8 +3962,7 @@ 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_FUNC("(call)", insn);
 				return ret;
 			}
 			/*

@@ -4254,7 +4248,7 @@ 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)
+	if (ret)
 		BT_FUNC("<=== (sym)", insn);
 	return ret;
 }

index fcca6662c8b4..38aef760465e 100644
@@ -28,7 +28,6 @@ struct opts {
 	bool cfi;
 
 	/* options: */
-	bool backtrace;
 	bool backup;
 	bool dryrun;
 	bool link;

index b85aa440ee1f..a9ec1ed6a2e3 100644
@@ -91,12 +91,14 @@ static inline void objdump_func(struct section *sec, unsigned long offset)
 		objdump_func(sec, offset);		\
 })
 
-#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_FUNC(format, insn, ...)				\
+({								\
+	if (opts.verbose) {					\
+		struct instruction *_insn = (insn);		\
+		char *_str = offstr(_insn->sec, _insn->offset); \
+		WARN("  %s: " format, _str, ##__VA_ARGS__);	\
+		free(_str);					\
+	}							\
 })
 
 #define WARN_ELF(format, ...)				\

index a652b9e5c805..73dd091c0075 100644
@@ -4140,8 +4140,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
 	 * It may also insert a UD2 after calling a __noreturn function.
 	 */
 	prev_insn = prev_insn_same_sec(file, insn);
-	if ((prev_insn->dead_end ||
-	     dead_end_function(file, insn_call_dest(prev_insn))) &&
+	if (prev_insn->dead_end &&
 	    (insn->type == INSN_BUG ||
 	     (insn->type == INSN_JUMP_UNCONDITIONAL &&
 	      insn->jump_dest && insn->jump_dest->type == INSN_BUG)))

index 73dd091c0075..67a684225702 100644
@@ -4557,6 +4557,10 @@ static int validate_reachable_instructions(struct objtool_file *file)
 		if (insn->visited || ignore_unreachable_insn(file, insn))
 			continue;
 
+		if (insn->sym->warned)
+			continue;
+		insn->sym->warned = 1;
+
 		WARN_FUNC("unreachable instruction", insn->sec, insn->offset);
 		return 1;
 	}

index ad0024da262b..a668173a5869 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 67a684225702..1ed3024af2b1 100644
@@ -4548,7 +4548,8 @@ 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;
 
 	if (file->ignore_unreachables)
 		return 0;

@@ -4561,8 +4562,19 @@ static int validate_reachable_instructions(struct objtool_file *file)
 			continue;
 		insn->sym->warned = 1;
 
+		prev_insn = prev_insn_same_sec(file, insn);
+		if (prev_insn)
+			call_dest = insn_call_dest(prev_insn);
+		if (prev_insn && prev_insn->dead_end && call_dest) {
+			if (call_dest->warned)
+				continue;
+			call_dest->warned = 1;
+
+			WARN("%s(): missing __noreturn", call_dest->name);
+			continue;
+		}
+
 		WARN_FUNC("unreachable instruction", insn->sec, insn->offset);
-		return 1;
 	}
 
 	return 0;