From c337c849ab528241897ddfb6f334912ead0bfd66 Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Fri, 25 Aug 2023 23:40:38 +0800 Subject: [PATCH] LoongArch: Put the body of play_dead() into arch_cpu_idle_dead() The initial aim is to silence the following objtool warning: arch/loongarch/kernel/process.o: warning: objtool: arch_cpu_idle_dead() falls through to next function start_thread() According to tools/objtool/Documentation/objtool.txt, this is because the last instruction of arch_cpu_idle_dead() is a call to a noreturn function play_dead(). In order to silence the warning, one simple way is to add the noreturn function play_dead() to objtool's hard-coded global_noreturns array, that is to say, just put "NORETURN(play_dead)" into tools/objtool/noreturns.h, it works well. But I noticed that play_dead() is only defined once and only called by arch_cpu_idle_dead(), so put the body of play_dead() into the caller arch_cpu_idle_dead(), then remove the noreturn function play_dead() is an alternative way which can reduce the overhead of the function call at the same time. Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen --- arch/loongarch/include/asm/smp.h | 2 -- arch/loongarch/kernel/process.c | 7 ------- arch/loongarch/kernel/smp.c | 2 +- 3 files changed, 1 insertion(+), 10 deletions(-) diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h index 416b653..66ecb48 100644 --- a/arch/loongarch/include/asm/smp.h +++ b/arch/loongarch/include/asm/smp.h @@ -98,8 +98,6 @@ static inline void __cpu_die(unsigned int cpu) { loongson_cpu_die(cpu); } - -extern void __noreturn play_dead(void); #endif #endif /* __ASM_SMP_H */ diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c index 2e04eb0..4ee1e9d 100644 --- a/arch/loongarch/kernel/process.c +++ b/arch/loongarch/kernel/process.c @@ -61,13 +61,6 @@ EXPORT_SYMBOL(__stack_chk_guard); unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE; EXPORT_SYMBOL(boot_option_idle_override); -#ifdef CONFIG_HOTPLUG_CPU -void __noreturn arch_cpu_idle_dead(void) -{ - play_dead(); -} -#endif - asmlinkage void ret_from_fork(void); asmlinkage void ret_from_kernel_thread(void); diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c index 8ea1bbc..6667b0a 100644 --- a/arch/loongarch/kernel/smp.c +++ b/arch/loongarch/kernel/smp.c @@ -317,7 +317,7 @@ void loongson_cpu_die(unsigned int cpu) mb(); } -void play_dead(void) +void __noreturn arch_cpu_idle_dead(void) { register uint64_t addr; register void (*init_fn)(void); -- 2.7.4