[tip: objtool/core] cpu: Mark panic_smp_self_stop() __noreturn

[tip-bot2 for Josh Poimboeuf]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     7412a60decec2a6744cf773280ff17a0f89e8395
Gitweb:        https://git.kernel.org/tip/7412a60decec2a6744cf773280ff17a0f89e8395
Author:        Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate:    Wed, 12 Apr 2023 16:49:35 -07:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 14 Apr 2023 17:31:25 +02:00

cpu: Mark panic_smp_self_stop() __noreturn

In preparation for improving objtool's handling of weak noreturn
functions, mark panic_smp_self_stop() __noreturn.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/92d76ab5c8bf660f04fdcd3da1084519212de248.1681342859.git.jpoimboe@xxxxxxxxxx
---
 arch/arm/kernel/smp.c          | 2 +-
 arch/arm64/include/asm/smp.h   | 1 -
 arch/arm64/kernel/smp.c        | 2 +-
 arch/powerpc/kernel/setup_64.c | 2 +-
 include/linux/smp.h            | 2 +-
 kernel/panic.c                 | 2 +-
 tools/objtool/check.c          | 1 +
 7 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index d6be450..f4a4ac0 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -779,7 +779,7 @@ void smp_send_stop(void)
  * kdump fails. So split out the panic_smp_self_stop() and add
  * set_cpu_online(smp_processor_id(), false).
  */
-void panic_smp_self_stop(void)
+void __noreturn panic_smp_self_stop(void)
 {
 	pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
 	         smp_processor_id());
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index 07f4ea1..f2d2623 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -143,7 +143,6 @@ bool cpus_are_stuck_in_kernel(void);
 
 extern void crash_smp_send_stop(void);
 extern bool smp_crash_stop_failed(void);
-extern void panic_smp_self_stop(void);
 
 #endif /* ifndef __ASSEMBLY__ */
 
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 07d156f..05fe797 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -830,7 +830,7 @@ static void __noreturn local_cpu_stop(void)
  * that cpu_online_mask gets correctly updated and smp_send_stop() can skip
  * CPUs that have already stopped themselves.
  */
-void panic_smp_self_stop(void)
+void __noreturn panic_smp_self_stop(void)
 {
 	local_cpu_stop();
 }
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index b2e0d3c..246201d 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -480,7 +480,7 @@ void early_setup_secondary(void)
 
 #endif /* CONFIG_SMP */
 
-void panic_smp_self_stop(void)
+void __noreturn panic_smp_self_stop(void)
 {
 	hard_irq_disable();
 	spin_begin();
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58..2a737b3 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -59,7 +59,7 @@ int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
  * Cpus stopping functions in panic. All have default weak definitions.
  * Architecture-dependent code may override them.
  */
-void panic_smp_self_stop(void);
+void __noreturn panic_smp_self_stop(void);
 void nmi_panic_self_stop(struct pt_regs *regs);
 void crash_smp_send_stop(void);
 
diff --git a/kernel/panic.c b/kernel/panic.c
index 5cfea83..5e4982d 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -141,7 +141,7 @@ EXPORT_SYMBOL(panic_blink);
 /*
  * Stop ourself in panic -- architecture code may override this
  */
-void __weak panic_smp_self_stop(void)
+void __weak __noreturn panic_smp_self_stop(void)
 {
 	while (1)
 		cpu_relax();
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index a436bc1..4b52ed6 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -218,6 +218,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"machine_real_restart",
 		"make_task_dead",
 		"panic",
+		"panic_smp_self_stop",
 		"rest_init",
 		"rewind_stack_and_make_dead",
 		"sev_es_terminate",