Messages in this thread | | | Date | Wed, 27 Mar 2024 05:30:58 +0800 | Subject | Re: [PATCH] LoongArch: Give chance to build under !CONFIG_SMP | From | Tiezhu Yang <> |
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Hi Bibo,
On 3/26/24 20:58, maobibo wrote: > > > On 2024/3/26 下午2:21, Tiezhu Yang wrote: >> In the current code, SMP is selected in Kconfig for LoongArch, the users >> can not unset it, this is reasonable for a multiprocessor machine. But as >> the help info of config SMP said, if you have a system with only one CPU, >> say N. On a uniprocessor machine, the kernel will run faster if you say N >> here. >> >> The Loongson-2K0500 is a single-core CPU for applications like industrial >> control, printing terminals, and BMC (Baseboard Management Controller), >> there are many development boards, products and solutions on the market, >> so it is better and necessary to give a chance to build under !CONFIG_SMP >> for a uniprocessor machine.
..
>> +++ b/arch/loongarch/include/asm/smp.h >> @@ -6,6 +6,7 @@ >> #ifndef __ASM_SMP_H >> #define __ASM_SMP_H >> +#ifdef CONFIG_SMP >> #include <linux/atomic.h> >> #include <linux/bitops.h> >> #include <linux/linkage.h> >> @@ -101,4 +102,8 @@ static inline void __cpu_die(unsigned int cpu) >> } >> #endif >> +#else /* !CONFIG_SMP */ >> +#define cpu_logical_map(cpu) 0 > It is unsafe here though physical cpuid of BSP is 0 always. > It is better to use __cpu_logical_map[cpu] or read_csr_cpuid() > >> +#endif
..
>> +++ b/arch/loongarch/power/suspend.c >> @@ -44,7 +44,9 @@ void loongarch_common_resume(void) >> { >> sync_counter(); >> local_flush_tlb_all(); >> +#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA >> csr_write64(per_cpu_offset(0), PERCPU_BASE_KS); >> +#endif > It is another issue, CONFIG_HAVE_SETUP_PER_CPU_AREA should not depend on > NUMA. PERCPU_BASE_KS should be set even for UP.
Thanks for your review and suggestions.
Let me wait for some days, if no more comments, I will address in v3 since the v2 has been sent.
Thanks, Tiezhu
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