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SubjectRe: [PATCH 3/5] x86, AMD: cleanup: merge common code in early microcode loading
On Tue, Jul 23, 2013 at 11:00:26PM +0200, Torsten Kaiser wrote:
> Extract common checks and initialisations from load_ucode_ap() and
> save_microcode_in_initrd_amd() to load_microcode_amd_early().
> load_ucode_ap() gets a quick exit for !cpu, because for the BSP there is
> already a different function dealing with its update.
>
> The original code already didn't anything, because without load_microcode_amd()
> getting called apply_microcode_amd() could not do anything.
>
> Signed-off-by: Torsten Kaiser <just.for.lkml@googlemail.com>
>
> --- a/arch/x86/kernel/microcode_amd_early.c 2013-07-22 06:22:32.000000000 +0200
> +++ b/arch/x86/kernel/microcode_amd_early.c 2013-07-23 20:00:04.889508712 +0200
> @@ -196,6 +196,23 @@ void __init load_ucode_amd_bsp(void)
> apply_ucode_in_initrd(cd.data, cd.size);
> }
>
> +static int load_microcode_amd_early(void)
> +{
> + enum ucode_state ret;
> + void *ucode;
> +
> + if (ucode_loaded || !ucode_size || !initrd_start)
> + return 0;
> +
> + ucode = (void *)(initrd_start + ucode_offset);
> + ret = load_microcode_amd(0, ucode, ucode_size);
> + if (ret != UCODE_OK)
> + return -EINVAL;
> +
> + ucode_loaded = true;
> + return 0;
> +}
> +
> #ifdef CONFIG_X86_32
> u8 amd_bsp_mpb[MPB_MAX_SIZE];
>
> @@ -258,17 +275,13 @@ void load_ucode_amd_ap(void)
>
> collect_cpu_info_amd_early(&cpu_data(cpu), ucode_cpu_info + cpu);
>
> - if (cpu && !ucode_loaded) {
> - void *ucode;
> -
> - if (!ucode_size || !initrd_start)
> - return;
> + /* BSP via load_ucode_amd_bsp() */
> + if (!cpu)
> + return;

Ok, this is really misleading. Fenghua, what's the reason for calling
load_ucode_ap() on the BSP too?

We have on the one hand:

x86_64_start_kernel
|->load_ucode_bsp

and on the other:

x86_64_start_kernel
|-> x86_64_start_reservations
|-> start_kernel
|-> trap_init
|-> cpu_init
|-> load_ucode_ap()

so we attempt to load the ucode twice on the BSP.

IMO, we should do this in cpu_init:

if (cpu)
load_ucode_ap();

no?

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
--


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