Re: [PATCH 04/10] MIPS: Move mips_smp_ipi_init call after prepare_cpus

Jiaxun Yang
2024-06-18T14:50:54Z

在2024年6月18日六月 上午4:51，Huacai Chen写道：
> On Tue, Jun 18, 2024 at 6:10 AM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>>
>>
>>
>> 在2024年6月17日六月 下午2:53，Huacai Chen写道：
>> > Hi, Jiaxun
>> >
>> > On Mon, Jun 17, 2024 at 5:03 AM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>> >>
>> >> This will give platform code a genuine chance to setup
>> >> IPI IRQ in prepare_cpus.
>> >>
>> >> This is the best place for platforms to setup IPI as smp_setup
>> >> is too early for IRQ subsystem.
>> > mips_smp_ipi_init() is an early_initcall() function, why do you say it
>> > is in smp_setup()?
>>
>> Sorry, I was trying to say that smp_setup is not a good point so we should
>> go prepare_cpus.
> It is not in smp_setup() now, then how do you move it from smp_setup()?
[...]

Well I was trying to justify where should I move it to, not where
does it from.

I should improve the commit message to justify the reason first.

Thanks
- Jiaxun
>
> Huacai
>
>>
>> The intention of this patch is to move mips_smp_ipi_init to a certain point
>> so platform would gain control over it.
>>
>> Thanks
>> - Jiaxun
>>
>> >
>> >
>> > Huacai
>> >>
>> >> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
>> >> ---
>> >> arch/mips/kernel/smp.c | 11 ++++++++++-
>> >> 1 file changed, 10 insertions(+), 1 deletion(-)
>> >>
>> >> diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
>> >> index fe053fe52147..ddf96c28e2f0 100644
>> >> --- a/arch/mips/kernel/smp.c
>> >> +++ b/arch/mips/kernel/smp.c
>> >> @@ -375,7 +375,6 @@ static int __init mips_smp_ipi_init(void)
>> >>
>> >> return 0;
>> >> }
>> >> -early_initcall(mips_smp_ipi_init);
>> >> #endif
>> >>
>> >> /*
>> >> @@ -460,12 +459,22 @@ void __init smp_cpus_done(unsigned int max_cpus)
>> >> /* called from main before smp_init() */
>> >> void __init smp_prepare_cpus(unsigned int max_cpus)
>> >> {
>> >> + int rc;
>> >> +
>> >> init_new_context(current, &init_mm);
>> >> current_thread_info()->cpu = 0;
>> >> mp_ops->prepare_cpus(max_cpus);
>> >> set_cpu_sibling_map(0);
>> >> set_cpu_core_map(0);
>> >> calculate_cpu_foreign_map();
>> >> +#ifdef CONFIG_GENERIC_IRQ_IPI
>> >> + rc = mips_smp_ipi_init();
>> >> + if (rc) {
>> >> + pr_err("Failed to initialize IPI - disabling SMP");
>> >> + init_cpu_present(cpumask_of(0));
>> >> + return;
>> >> + }
>> >> +#endif
>> >> #ifndef CONFIG_HOTPLUG_CPU
>> >> init_cpu_present(cpu_possible_mask);
>> >> #endif
>> >>
>> >> --
>> >> 2.43.0
>> >>
>>
>> --
>> - Jiaxun

--
- Jiaxun