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Subject[tip: ras/core] x86/mce/amd: Add PPIN support for AMD MCE
The following commit has been merged into the ras/core branch of tip:

Commit-ID: 077168e241ec5a3b273652acb1e85f8bc1dc2d81
Gitweb: https://git.kernel.org/tip/077168e241ec5a3b273652acb1e85f8bc1dc2d81
Author: Wei Huang <wei.huang2@amd.com>
AuthorDate: Sat, 21 Mar 2020 14:38:00 -05:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Sun, 22 Mar 2020 11:03:47 +01:00

x86/mce/amd: Add PPIN support for AMD MCE

Newer AMD CPUs support a feature called protected processor
identification number (PPIN). This feature can be detected via
CPUID_Fn80000008_EBX[23].

However, CPUID alone is not enough to read the processor identification
number - MSR_AMD_PPIN_CTL also needs to be configured properly. If, for
any reason, MSR_AMD_PPIN_CTL[PPIN_EN] can not be turned on, such as
disabled in BIOS, the CPU capability bit X86_FEATURE_AMD_PPIN needs to
be cleared.

When the X86_FEATURE_AMD_PPIN capability is available, the
identification number is issued together with the MCE error info in
order to keep track of the source of MCE errors.

[ bp: Massage. ]

Co-developed-by: Smita Koralahalli Channabasappa <smita.koralahallichannabasappa@amd.com>
Signed-off-by: Smita Koralahalli Channabasappa <smita.koralahallichannabasappa@amd.com>
Signed-off-by: Wei Huang <wei.huang2@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200321193800.3666964-1-wei.huang2@amd.com
---
arch/x86/include/asm/cpufeatures.h | 1 +-
arch/x86/kernel/cpu/amd.c | 30 +++++++++++++++++++++++++++++-
arch/x86/kernel/cpu/mce/core.c | 2 ++-
3 files changed, 33 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index f3327cb..4b263ff 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -299,6 +299,7 @@
#define X86_FEATURE_AMD_IBRS (13*32+14) /* "" Indirect Branch Restricted Speculation */
#define X86_FEATURE_AMD_STIBP (13*32+15) /* "" Single Thread Indirect Branch Predictors */
#define X86_FEATURE_AMD_STIBP_ALWAYS_ON (13*32+17) /* "" Single Thread Indirect Branch Predictors always-on preferred */
+#define X86_FEATURE_AMD_PPIN (13*32+23) /* Protected Processor Inventory Number */
#define X86_FEATURE_AMD_SSBD (13*32+24) /* "" Speculative Store Bypass Disable */
#define X86_FEATURE_VIRT_SSBD (13*32+25) /* Virtualized Speculative Store Bypass Disable */
#define X86_FEATURE_AMD_SSB_NO (13*32+26) /* "" Speculative Store Bypass is fixed in hardware. */
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index ac83a0f..a2cd870 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -393,6 +393,35 @@ static void amd_detect_cmp(struct cpuinfo_x86 *c)
per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
}

+static void amd_detect_ppin(struct cpuinfo_x86 *c)
+{
+ unsigned long long val;
+
+ if (!cpu_has(c, X86_FEATURE_AMD_PPIN))
+ return;
+
+ /* When PPIN is defined in CPUID, still need to check PPIN_CTL MSR */
+ if (rdmsrl_safe(MSR_AMD_PPIN_CTL, &val))
+ goto clear_ppin;
+
+ /* PPIN is locked in disabled mode, clear feature bit */
+ if ((val & 3UL) == 1UL)
+ goto clear_ppin;
+
+ /* If PPIN is disabled, try to enable it */
+ if (!(val & 2UL)) {
+ wrmsrl_safe(MSR_AMD_PPIN_CTL, val | 2UL);
+ rdmsrl_safe(MSR_AMD_PPIN_CTL, &val);
+ }
+
+ /* If PPIN_EN bit is 1, return from here; otherwise fall through */
+ if (val & 2UL)
+ return;
+
+clear_ppin:
+ clear_cpu_cap(c, X86_FEATURE_AMD_PPIN);
+}
+
u16 amd_get_nb_id(int cpu)
{
return per_cpu(cpu_llc_id, cpu);
@@ -940,6 +969,7 @@ static void init_amd(struct cpuinfo_x86 *c)
amd_detect_cmp(c);
amd_get_topology(c);
srat_detect_node(c);
+ amd_detect_ppin(c);

init_amd_cacheinfo(c);

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index fe3983d..dd06fce 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -142,6 +142,8 @@ void mce_setup(struct mce *m)

if (this_cpu_has(X86_FEATURE_INTEL_PPIN))
rdmsrl(MSR_PPIN, m->ppin);
+ else if (this_cpu_has(X86_FEATURE_AMD_PPIN))
+ rdmsrl(MSR_AMD_PPIN, m->ppin);

m->microcode = boot_cpu_data.microcode;
}
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