mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-29 13:53:33 +00:00
Code Issues Releases Wiki Activity

LoongArch: Put the body of play_dead() into arch_cpu_idle_dead()

Browse source 
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 <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Tiezhu Yang 2023-08-25 23:40:38 +08:00 committed by Huacai Chen
parent 8879515e12
commit c337c849ab
3 changed files with 1 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/loongarch/include/asm/smp.h
View file

@ -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 */

7
arch/loongarch/kernel/process.c
View file

@ -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);

2
arch/loongarch/kernel/smp.c
View file

@ -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);