Re: [PATCH 1/4] x86/mce: Define 'SUCCOR' cpuid bit

Borislav Petkov
2015-05-01T10:25:17Z

On Thu, Apr 30, 2015 at 09:49:22AM -0500, Aravind Gopalakrishnan wrote:
> SUCCOR stands for S/W UnCorrectable error COntainment and Recovery.
> It indicates support for data poisoning in HW and deferred error
> interrupts.
>
> Add new bitfield in mce_vendor_flags for this.
> We use this to verify prescence of deferred error interrupts
> before we enable them in mce_amd.c
>
> Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
> ---
> arch/x86/include/asm/mce.h | 3 ++-
> arch/x86/kernel/cpu/mcheck/mce.c | 1 +
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
> index 1f5a86d..dfcb664 100644
> --- a/arch/x86/include/asm/mce.h
> +++ b/arch/x86/include/asm/mce.h
> @@ -118,7 +118,8 @@ struct mca_config {
>
> struct mce_vendor_flags {
> __u64 overflow_recov : 1, /* cpuid_ebx(80000007) */
> - __reserved_0 : 63;
> + succor : 1,

Please add that CPUID bit definition from the commit message here too so
that we know what it means.

> + __reserved_0 : 62;
> };
> extern struct mce_vendor_flags mce_flags;
>
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index e535533..de61f62e 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1640,6 +1640,7 @@ static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c)
> case X86_VENDOR_AMD:
> mce_amd_feature_init(c);
> mce_flags.overflow_recov = cpuid_ebx(0x80000007) & 0x1;
> + mce_flags.succor = (cpuid_ebx(0x80000007) & 0x2) ? 1 : 0;

mce_flags.succor = !!(cpuid_ebx(0x80000007) & BIT(1));

is a common way of assigning truth values from bits in the kernel.

You can change the above one to use BIT(0) too, while at it, and
vertically align the assignments.

Thanks.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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