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From:   Josh Poimboeuf <jpoimboe@kernel.org>
To:     x86@kernel.org
Cc:     linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        Miroslav Benes <mbenes@suse.cz>, linux-btrfs@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        linux-scsi@vger.kernel.org, linux-hyperv@vger.kernel.org,
        Arnd Bergmann <arnd@arndb.de>,
        "Guilherme G . Piccoli" <gpiccoli@igalia.com>,
        Michael Kelley <mikelley@microsoft.com>
Subject: [PATCH 01/11] init: Mark [arch_call_]rest_init() __noreturn
Date:   Fri,  7 Apr 2023 17:09:54 -0700
Message-Id: <b24a972397061a67d46ff5a98657e352040f427a.1680912057.git.jpoimboe@kernel.org>
In-Reply-To: <cover.1680912057.git.jpoimboe@kernel.org>
References: <cover.1680912057.git.jpoimboe@kernel.org>
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Fixes the following warning:

  init/main.o: warning: objtool: start_kernel+0x4ad: unreachable instruction

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 arch/s390/kernel/setup.c     | 2 +-
 include/linux/start_kernel.h | 4 ++--
 init/main.c                  | 4 ++--
 tools/objtool/check.c        | 2 ++
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 8ec5cdf9dadc..4259b6c50516 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -396,7 +396,7 @@ int __init arch_early_irq_init(void)
 	return 0;
 }
 
-void __init arch_call_rest_init(void)
+void __init __noreturn arch_call_rest_init(void)
 {
 	unsigned long stack;
 
diff --git a/include/linux/start_kernel.h b/include/linux/start_kernel.h
index 8b369a41c03c..864921e54c92 100644
--- a/include/linux/start_kernel.h
+++ b/include/linux/start_kernel.h
@@ -9,7 +9,7 @@
    up something else. */
 
 extern asmlinkage void __init start_kernel(void);
-extern void __init arch_call_rest_init(void);
-extern void __ref rest_init(void);
+extern void __init __noreturn arch_call_rest_init(void);
+extern void __ref __noreturn rest_init(void);
 
 #endif /* _LINUX_START_KERNEL_H */
diff --git a/init/main.c b/init/main.c
index 4425d1783d5c..161ed956d738 100644
--- a/init/main.c
+++ b/init/main.c
@@ -683,7 +683,7 @@ static void __init setup_command_line(char *command_line)
 
 static __initdata DECLARE_COMPLETION(kthreadd_done);
 
-noinline void __ref rest_init(void)
+noinline void __ref __noreturn rest_init(void)
 {
 	struct task_struct *tsk;
 	int pid;
@@ -889,7 +889,7 @@ static int __init early_randomize_kstack_offset(char *buf)
 early_param("randomize_kstack_offset", early_randomize_kstack_offset);
 #endif
 
-void __init __weak arch_call_rest_init(void)
+void __init __weak __noreturn arch_call_rest_init(void)
 {
 	rest_init();
 }
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index cae6ac6ff246..e7442e7ad676 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -202,6 +202,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"__reiserfs_panic",
 		"__stack_chk_fail",
 		"__ubsan_handle_builtin_unreachable",
+		"arch_call_rest_init",
 		"arch_cpu_idle_dead",
 		"cpu_bringup_and_idle",
 		"cpu_startup_entry",
@@ -217,6 +218,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"machine_real_restart",
 		"make_task_dead",
 		"panic",
+		"rest_init",
 		"rewind_stack_and_make_dead",
 		"sev_es_terminate",
 		"snp_abort",
-- 
2.39.2