Messages in this thread Patch in this message | | | Subject | Re: [PATCH v3 3/4] LoongArch: Save and restore PERCPU_BASE_KS for ACPI S3 state | From | Tiezhu Yang <> | Date | Fri, 12 Apr 2024 17:30:04 +0800 |
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On 04/12/2024 12:18 PM, Huacai Chen wrote: > Hi, Tiezhu, > > On Thu, Apr 11, 2024 at 9:05 AM Tiezhu Yang <yangtiezhu@loongson.cn> wrote: >> >> Currently, per_cpu_offset(x) is defined as __per_cpu_offset[x]) >> only under CONFIG_SMP in include/asm-generic/percpu.h, that is >> to say, the implementation of loongarch_common_resume() which >> calls per_cpu_offset(0) is not suitable for the case of non-SMP, >> so do not write per_cpu_offset(0) to PERCPU_BASE_KS when resume, >> just save the value of PERCPU_BASE_KS when suspend and restore >> it when resume to make it work well for both SMP and non-SMP. > For non-SMP you need PERCPU_BASE_KS to do what?
The initial aim is to avoid build error under !CONFIG_SMP and it works well on both !CONFIG_SMP and CONFIG_SMP, the changes are similar with the code in hibernate.c.
An alternative way is to do the following simple change, but it seems a little ugly due to the ifdef, let me know what is your preference.
diff --git a/arch/loongarch/power/suspend.c b/arch/loongarch/power/suspend.c index 166d9e06a64b..35191afefcda 100644 --- a/arch/loongarch/power/suspend.c +++ b/arch/loongarch/power/suspend.c @@ -44,7 +44,9 @@ void loongarch_common_resume(void) { sync_counter(); local_flush_tlb_all(); +#ifdef csr_write64(per_cpu_offset(0), PERCPU_BASE_KS); +#endif csr_write64(eentry, LOONGARCH_CSR_EENTRY); csr_write64(eentry, LOONGARCH_CSR_MERRENTRY); csr_write64(tlbrentry, LOONGARCH_CSR_TLBRENTRY); Thanks, Tiezhu
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