Re: [PATCH 3/4] x86,objtool: Mark cpu_startup_entry() __noreturn

From: Josh Poimboeuf
Date: Tue Apr 12 2022 - 11:14:06 EST


On Fri, Apr 08, 2022 at 11:45:55AM +0200, Peter Zijlstra wrote:
> GCC-8 isn't clever enough to figure out that cpu_start_entry() is a
> noreturn while objtool is. This results in code after the call in
> start_secondary(). Give GCC a hand so that they all agree on things.
>
> vmlinux.o: warning: objtool: start_secondary()+0x10e: unreachable
>
> Reported-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> ---
> include/linux/cpu.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/include/linux/cpu.h
> +++ b/include/linux/cpu.h
> @@ -167,7 +167,7 @@ static inline int suspend_disable_second
> static inline void suspend_enable_secondary_cpus(void) { }
> #endif /* !CONFIG_PM_SLEEP_SMP */
>
> -void cpu_startup_entry(enum cpuhp_state state);
> +void __noreturn cpu_startup_entry(enum cpuhp_state state);
>
> void cpu_idle_poll_ctrl(bool enable);

Also needs added to the objtool noreturn list.

--
Josh