Re: [External] Re: [PATCH v12 00/11] Parallel CPU bringup for x86_64

David Woodhouse
2023-02-27T15:30:28Z

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On Mon, 2023-02-27 at 06:14 +0000, Usama Arif wrote:
>
> diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
> index 17bdd6122dca..5d709aa67df4 100644
> --- a/arch/x86/kernel/head_64.S
> +++ b/arch/x86/kernel/head_64.S
> @@ -273,7 +273,11 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify,
> SYM_L_GLOBAL)
>          cmpl    (%rbx,%rcx,4), %edx
>          jz      .Lsetup_cpu
>          inc     %ecx
> +#if (NR_CPUS == 1) || defined(CONFIG_FORCE_NR_CPUS)
> +       cmpl    $NR_CPUS, %ecx
> +#else
>          cmpl    nr_cpu_ids(%rip), %ecx
> +#endif
>          jb      .Lfind_cpunr
>
>          /*  APIC ID not found in the table. Drop the trampoline lock
> and bail. */

The whitespace looks dodgy there but maybe that's just your mail client?

Given this code is already in #ifdef CONFIG_SMP, can NR_CPUS be 1?

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