On Fri, Jan 29, 2016 at 04:00:19PM -0800, Tony Luck wrote:
> The Intel Software Developer Manual describes bit 24 in the MCG_CAP
> MSR:
> MCG_SER_P (software error recovery support present) flag,
> bit 24 — Indicates (when set) that the processor supports
> software error recovery
> But only some models with this capability bit set will actually
> generate recoverable machine checks.
>
> Check the model name and set a synthetic capability bit. Provide
> a command line option to set this bit anyway in case the kernel
> doesn't recognise the model name.
>
> Signed-off-by: Tony Luck <[email protected]>
> ---
> Documentation/x86/x86_64/boot-options.txt | 4 ++++
> arch/x86/include/asm/cpufeature.h | 1 +
> arch/x86/include/asm/mce.h | 1 +
> arch/x86/kernel/cpu/mcheck/mce.c | 11 +++++++++++
> 4 files changed, 17 insertions(+)
>
> diff --git a/Documentation/x86/x86_64/boot-options.txt
> b/Documentation/x86/x86_64/boot-options.txt
> index 68ed3114c363..8423c04ae7b3 100644
> --- a/Documentation/x86/x86_64/boot-options.txt
> +++ b/Documentation/x86/x86_64/boot-options.txt
> @@ -60,6 +60,10 @@ Machine check
> threshold to 1. Enabling this may make memory predictive failure
> analysis less effective if the bios sets thresholds for memory
> errors since we will not see details for all errors.
> + mce=recovery
> + Tell the kernel that this system can generate recoverable
> + machine checks (useful when the kernel doesn't recognize
> + the cpuid x86_model_id[])
I'd say "Force-enable generation of recoverable MCEs."
and not mention implementation details in the description text.
> nomce (for compatibility with i386): same as mce=off
>
> diff --git a/arch/x86/include/asm/cpufeature.h
> b/arch/x86/include/asm/cpufeature.h
> index 7ad8c9464297..06c6c2d2fea0 100644
> --- a/arch/x86/include/asm/cpufeature.h
> +++ b/arch/x86/include/asm/cpufeature.h
> @@ -106,6 +106,7 @@
> #define X86_FEATURE_APERFMPERF ( 3*32+28) /* APERFMPERF */
> #define X86_FEATURE_EAGER_FPU ( 3*32+29) /* "eagerfpu" Non lazy FPU
> restore */
> #define X86_FEATURE_NONSTOP_TSC_S3 ( 3*32+30) /* TSC doesn't stop in S3
> state */
> +#define X86_FEATURE_MCE_RECOVERY ( 3*32+31) /* cpu has recoverable machine
> checks */
>
> /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
> #define X86_FEATURE_XMM3 ( 4*32+ 0) /* "pni" SSE-3 */
> diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
> index 2ea4527e462f..18d2ba9c8e44 100644
> --- a/arch/x86/include/asm/mce.h
> +++ b/arch/x86/include/asm/mce.h
> @@ -113,6 +113,7 @@ struct mca_config {
> bool ignore_ce;
> bool disabled;
> bool ser;
> + bool recovery;
> bool bios_cmci_threshold;
> u8 banks;
> s8 bootlog;
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c
> b/arch/x86/kernel/cpu/mcheck/mce.c
> index 905f3070f412..16a3d0e29f84 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1696,6 +1696,15 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c)
> return;
> }
>
> + /*
> + * MCG_CAP.MCG_SER_P is necessary but not sufficient to know
> + * whether this processor will actually generate recoverable
> + * machine checks. Check to see if this is an E7 model Xeon.
> + */
> + if (mca_cfg.recovery || (mca_cfg.ser &&
> + !strncmp(c->x86_model_id, "Intel(R) Xeon(R) CPU E7-", 24)))
Eeww, a model string check :-(
Lemme guess: those E7s can't be represented by a range of
model/steppings, can they?
Similar to AMD_MODEL_RANGE() thing in cpu/amd.c, for example.
In any case, that chunk belongs in the Intel part of
__mcheck_cpu_apply_quirks().
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
