Re: [PATCH v2 06/10] x86/mce: Convert multiple if () statements into a switch() statement
From: Sohil Mehta
Date: Wed Oct 23 2024 - 02:48:16 EST
On 10/18/2024 10:46 PM, Zhuo, Qiuxu wrote:
> Convert some hard-coded numbers to VFM macros on top of Tony's patch as shown below.
> Please review it for any errors or omissions.
>
> diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
> index f51fb393d369..3b83efa1ca65 100644
> --- a/arch/x86/kernel/cpu/mce/core.c
> +++ b/arch/x86/kernel/cpu/mce/core.c
> @@ -1924,6 +1924,10 @@ static void apply_quirks_intel(struct cpuinfo_x86 *c)
> struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array);
> struct mca_config *cfg = &mca_cfg;
>
> + /* Older CPUs don't need quirks. */
> + if (c->x86 < 6)
> + return;
> +
As Dave mentioned, change this to make the use of vfm consistent in the
entire function and probably update the comment as well to make it explicit:
/* Older CPUs (prior to family 6) don't need quirks */
if (c->x86_vfm < INTEL_PENTIUM_PRO)
return;
> /*
> * SDM documents that on family 6 bank 0 should not be written
> * because it aliases to another special BIOS controlled
> @@ -1932,23 +1936,21 @@ static void apply_quirks_intel(struct cpuinfo_x86 *c)
> * Don't ignore bank 0 completely because there could be a
> * valid event later, merely don't write CTL0.
> */
> -
> - if (c->x86 == 6 && c->x86_model < 0x1A && this_cpu_read(mce_num_banks) > 0)
> + if (c->x86_vfm < INTEL_NEHALEM_EP && this_cpu_read(mce_num_banks) > 0)
> mce_banks[0].init = false;
>
> /*
> * All newer Intel systems support MCE broadcasting. Enable
> * synchronization with a one second timeout.
> */
> - if ((c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xe)) &&
> - cfg->monarch_timeout < 0)
> + if (c->x86_vfm >= INTEL_CORE_YONAH && cfg->monarch_timeout < 0)
> cfg->monarch_timeout = USEC_PER_SEC;
>
Instead of keeping this open-ended we could tweak this a bit as follows:
if (!(c->x86_vfm < INTEL_CORE_YONAH)) && cfg->monarch_timeout < 0)
cfg->monarch_timeout = USEC_PER_SEC;
Essentially the same: if (new_cpu) vs if (!old_cpu)
Don't have a strong preference. Will leave it to you and Tony.
> /*
> * There are also broken BIOSes on some Pentium M and
> * earlier systems:
> */
> - if (c->x86 == 6 && c->x86_model <= 13 && cfg->bootlog < 0)
> + if (c->x86_vfm < INTEL_CORE_YONAH && cfg->bootlog < 0)
> cfg->bootlog = 0;
>
> if (c->x86_vfm == INTEL_SANDYBRIDGE_X)
>
All the other checks look fine to me.