* [PATCH] x86/mce: Simplify CPU vendor checks for AMD/Hygon and Intel/Zhaoxin
@ 2022-02-22 15:58 Carlos Bilbao
2022-02-22 16:10 ` Borislav Petkov
0 siblings, 1 reply; 4+ messages in thread
From: Carlos Bilbao @ 2022-02-22 15:58 UTC (permalink / raw)
To: bp, tony.luck, bp
Cc: yazen.ghannam, Smita.KoralahalliChannabasappa, linux-kernel,
linux-edac, Carlos Bilbao
In a number of places across the MCE subsystem we check if we are running
an x86 processor from AMD/Hygon or Intel/Zhaoxin vendors. Simplify these
checks with two mce_flags updated at CPU MCE initialization.
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
---
arch/x86/kernel/cpu/mce/core.c | 22 ++++++++--------------
arch/x86/kernel/cpu/mce/intel.c | 3 +--
arch/x86/kernel/cpu/mce/internal.h | 8 +++++++-
arch/x86/kernel/cpu/mce/severity.c | 3 +--
4 files changed, 17 insertions(+), 19 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 5818b837fd4d..d88c7ba7f67a 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -241,7 +241,7 @@ static void print_mce(struct mce *m)
{
__print_mce(m);
- if (m->cpuvendor != X86_VENDOR_AMD && m->cpuvendor != X86_VENDOR_HYGON)
+ if (!mce_flags.amd_compatible)
pr_emerg_ratelimited(HW_ERR "Run the above through 'mcelog --ascii'\n");
}
@@ -503,8 +503,7 @@ int mce_usable_address(struct mce *m)
return 0;
/* Checks after this one are Intel/Zhaoxin-specific: */
- if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL &&
- boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN)
+ if (!mce_flags.intel_compatible)
return 1;
if (!(m->status & MCI_STATUS_MISCV))
@@ -562,10 +561,7 @@ static bool whole_page(struct mce *m)
bool mce_is_correctable(struct mce *m)
{
- if (m->cpuvendor == X86_VENDOR_AMD && m->status & MCI_STATUS_DEFERRED)
- return false;
-
- if (m->cpuvendor == X86_VENDOR_HYGON && m->status & MCI_STATUS_DEFERRED)
+ if (mce_flags.amd_compatible && m->status & MCI_STATUS_DEFERRED)
return false;
if (m->status & MCI_STATUS_UC)
@@ -1450,8 +1446,7 @@ noinstr void do_machine_check(struct pt_regs *regs)
* Check if this MCE is signaled to only this logical processor,
* on Intel, Zhaoxin only.
*/
- if (m.cpuvendor == X86_VENDOR_INTEL ||
- m.cpuvendor == X86_VENDOR_ZHAOXIN)
+ if (mce_flags.intel_compatible)
lmce = m.mcgstatus & MCG_STATUS_LMCES;
/*
@@ -1910,7 +1905,9 @@ static void __mcheck_cpu_init_early(struct cpuinfo_x86 *c)
mce_flags.succor = !!cpu_has(c, X86_FEATURE_SUCCOR);
mce_flags.smca = !!cpu_has(c, X86_FEATURE_SMCA);
mce_flags.amd_threshold = 1;
- }
+ mce_flags.amd_compatible = 1;
+ } else if (c->x86_vendor == X86_VENDOR_INTEL || c->x86_vendor == X86_VENDOR_ZHAOXIN)
+ mce_flags.intel_compatible = 1;
}
static void mce_centaur_feature_init(struct cpuinfo_x86 *c)
@@ -2277,10 +2274,7 @@ static void vendor_disable_error_reporting(void)
* the socket like the last level cache (LLC), the integrated memory
* controller (iMC), etc.
*/
- if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL ||
- boot_cpu_data.x86_vendor == X86_VENDOR_HYGON ||
- boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
- boot_cpu_data.x86_vendor == X86_VENDOR_ZHAOXIN)
+ if (mce_flags.intel_compatible || mce_flags.amd_compatible)
return;
mce_disable_error_reporting();
diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c
index bb9a46a804bf..169064fa12a9 100644
--- a/arch/x86/kernel/cpu/mce/intel.c
+++ b/arch/x86/kernel/cpu/mce/intel.c
@@ -85,8 +85,7 @@ static int cmci_supported(int *banks)
* initialization is vendor keyed and this
* makes sure none of the backdoors are entered otherwise.
*/
- if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL &&
- boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN)
+ if (!mce_flags.intel_compatible)
return 0;
if (!boot_cpu_has(X86_FEATURE_APIC) || lapic_get_maxlvt() < 6)
diff --git a/arch/x86/kernel/cpu/mce/internal.h b/arch/x86/kernel/cpu/mce/internal.h
index 52c633950b38..562c768ceaf5 100644
--- a/arch/x86/kernel/cpu/mce/internal.h
+++ b/arch/x86/kernel/cpu/mce/internal.h
@@ -170,7 +170,13 @@ struct mce_vendor_flags {
/* SandyBridge IFU quirk */
snb_ifu_quirk : 1,
- __reserved_0 : 57;
+ /* CPUs are from AMD or Hygon */
+ amd_compatible : 1,
+
+ /* CPUs are from Intel or Zhaoxin */
+ intel_compatible : 1,
+
+ __reserved_0 : 55;
};
extern struct mce_vendor_flags mce_flags;
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 7aa2bda93cbb..21aa31bd17a2 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -423,8 +423,7 @@ static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs,
int noinstr mce_severity(struct mce *m, struct pt_regs *regs, int tolerant, char **msg,
bool is_excp)
{
- if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
- boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
+ if (mce_flags.amd_compatible)
return mce_severity_amd(m, regs, tolerant, msg, is_excp);
else
return mce_severity_intel(m, regs, tolerant, msg, is_excp);
--
2.27.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/mce: Simplify CPU vendor checks for AMD/Hygon and Intel/Zhaoxin
2022-02-22 15:58 [PATCH] x86/mce: Simplify CPU vendor checks for AMD/Hygon and Intel/Zhaoxin Carlos Bilbao
@ 2022-02-22 16:10 ` Borislav Petkov
2022-02-22 16:42 ` Carlos Bilbao
0 siblings, 1 reply; 4+ messages in thread
From: Borislav Petkov @ 2022-02-22 16:10 UTC (permalink / raw)
To: Carlos Bilbao
Cc: tony.luck, yazen.ghannam, Smita.KoralahalliChannabasappa,
linux-kernel, linux-edac
On Tue, Feb 22, 2022 at 09:58:58AM -0600, Carlos Bilbao wrote:
> In a number of places across the MCE subsystem we check if we are running
> an x86 processor from AMD/Hygon or Intel/Zhaoxin vendors. Simplify these
> checks with two mce_flags updated at CPU MCE initialization.
... and what's the point of this silliness?
Btw, you don't have to send it to my *two* email addresses - one is
enough. :)
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/mce: Simplify CPU vendor checks for AMD/Hygon and Intel/Zhaoxin
2022-02-22 16:10 ` Borislav Petkov
@ 2022-02-22 16:42 ` Carlos Bilbao
2022-02-22 17:10 ` Borislav Petkov
0 siblings, 1 reply; 4+ messages in thread
From: Carlos Bilbao @ 2022-02-22 16:42 UTC (permalink / raw)
To: Borislav Petkov
Cc: tony.luck, yazen.ghannam, Smita.KoralahalliChannabasappa,
linux-kernel, linux-edac
Hello,
On 2/22/2022 10:10 AM, Borislav Petkov wrote:
> On Tue, Feb 22, 2022 at 09:58:58AM -0600, Carlos Bilbao wrote:
>> In a number of places across the MCE subsystem we check if we are running
>> an x86 processor from AMD/Hygon or Intel/Zhaoxin vendors. Simplify these
>> checks with two mce_flags updated at CPU MCE initialization.
>
> ... and what's the point of this silliness?
>
the point is to simplify the code (as the patch stated). Since we have 57
bits reserved but unused, it also wouldn't cost anything.
> Btw, you don't have to send it to my *two* email addresses - one is
> enough. :)
>
Noted.
Carlos.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/mce: Simplify CPU vendor checks for AMD/Hygon and Intel/Zhaoxin
2022-02-22 16:42 ` Carlos Bilbao
@ 2022-02-22 17:10 ` Borislav Petkov
0 siblings, 0 replies; 4+ messages in thread
From: Borislav Petkov @ 2022-02-22 17:10 UTC (permalink / raw)
To: Carlos Bilbao
Cc: tony.luck, yazen.ghannam, Smita.KoralahalliChannabasappa,
linux-kernel, linux-edac
Hi,
On Tue, Feb 22, 2022 at 10:42:25AM -0600, Carlos Bilbao wrote:
> the point is to simplify the code (as the patch stated).
But it doesn't simplify the code - it makes it obscure.
Also, your "simplification" breaks the moment you need to do something
for the one vendor but *not* for the other.
Because in such cases you'll have to do
if (mce_flags.amd_compatible && m->cpuvendor != X86_VENDOR_HYGON)
which makes me go, "huh what?!"
So no, that's not better.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-02-22 17:11 UTC | newest]
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2022-02-22 15:58 [PATCH] x86/mce: Simplify CPU vendor checks for AMD/Hygon and Intel/Zhaoxin Carlos Bilbao
2022-02-22 16:10 ` Borislav Petkov
2022-02-22 16:42 ` Carlos Bilbao
2022-02-22 17:10 ` Borislav Petkov
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