linux-kernel - [PATCH 08/11] x86/cpu: Mark {hlt,resume}_play_dead() _

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Message-Id: <f28f2dd16f7dcc3951988aa34b47fdf081ae2f36.1680912057.git.jpoimboe@kernel.org>
Date:   Fri,  7 Apr 2023 17:10:01 -0700
From:   Josh Poimboeuf <jpoimboe@...nel.org>
To:     x86@...nel.org
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Miroslav Benes <mbenes@...e.cz>, linux-btrfs@...r.kernel.org,
        Mark Rutland <mark.rutland@....com>,
        linux-scsi@...r.kernel.org, linux-hyperv@...r.kernel.org,
        Arnd Bergmann <arnd@...db.de>,
        "Guilherme G . Piccoli" <gpiccoli@...lia.com>,
        Michael Kelley <mikelley@...rosoft.com>
Subject: [PATCH 08/11] x86/cpu: Mark {hlt,resume}_play_dead() __noreturn

Fixes the following warning:

  vmlinux.o: warning: objtool: resume_play_dead+0x21: unreachable instruction

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 arch/x86/include/asm/smp.h | 2 +-
 arch/x86/kernel/smpboot.c  | 2 +-
 arch/x86/power/cpu.c       | 2 +-
 tools/objtool/check.c      | 2 ++
 4 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index e6d1d2810e38..47ce4c79a3b0 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -125,7 +125,7 @@ int native_cpu_up(unsigned int cpunum, struct task_struct *tidle);
 int native_cpu_disable(void);
 int common_cpu_die(unsigned int cpu);
 void native_cpu_die(unsigned int cpu);
-void hlt_play_dead(void);
+void __noreturn hlt_play_dead(void);
 void native_play_dead(void);
 void play_dead_common(void);
 void wbinvd_on_cpu(int cpu);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 9013bb28255a..a6da3f94b7b6 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1816,7 +1816,7 @@ static inline void mwait_play_dead(void)
 	}
 }
 
-void hlt_play_dead(void)
+void __noreturn hlt_play_dead(void)
 {
 	if (__this_cpu_read(cpu_info.x86) >= 4)
 		wbinvd();
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 236447ee9beb..7a4d5e911415 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -288,7 +288,7 @@ EXPORT_SYMBOL(restore_processor_state);
 #endif
 
 #if defined(CONFIG_HIBERNATION) && defined(CONFIG_HOTPLUG_CPU)
-static void resume_play_dead(void)
+static void __noreturn resume_play_dead(void)
 {
 	play_dead_common();
 	tboot_shutdown(TB_SHUTDOWN_WFS);
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index c5621dd866e1..a926da218c01 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -212,6 +212,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"do_task_dead",
 		"ex_handler_msr_mce",
 		"fortify_panic",
+		"hlt_play_dead",
 		"kthread_complete_and_exit",
 		"kthread_exit",
 		"kunit_try_catch_throw",
@@ -222,6 +223,7 @@ 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",
-- 
2.39.2