x86/mce: Include the PPIN in MCE records when available

Intel Xeons from Ivy Bridge onwards support a processor identification
number set in the factory. To the user this is a handy unique number to
identify a particular CPU. Intel can decode this to the fab/production
run to track errors. On systems that have it, include it in the machine
check record. I'm told that this would be helpful for users that run
large data centers with multi-socket servers to keep track of which CPUs
are seeing errors.

Boris:
* Add some clarifying comments and spacing.
* Mask out [63:2] in the disabled-but-not-locked case
* Call the MSR variable "val" for more readability.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20161123114855.njguoaygp3qnbkia@pd.tnic
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/cpufeatures.h

@@ -193,6 +193,7 @@
 #define X86_FEATURE_HW_PSTATE	( 7*32+ 8) /* AMD HW-PState */
 #define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
 
+#define X86_FEATURE_INTEL_PPIN	( 7*32+14) /* Intel Processor Inventory Number */
 #define X86_FEATURE_INTEL_PT	( 7*32+15) /* Intel Processor Trace */
 #define X86_FEATURE_AVX512_4VNNIW (7*32+16) /* AVX-512 Neural Network Instructions */
 #define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */

arch/x86/include/asm/msr-index.h

@@ -37,6 +37,10 @@
 #define EFER_FFXSR		(1<<_EFER_FFXSR)
 
 /* Intel MSRs. Some also available on other CPUs */
+
+#define MSR_PPIN_CTL			0x0000004e
+#define MSR_PPIN			0x0000004f
+
 #define MSR_IA32_PERFCTR0		0x000000c1
 #define MSR_IA32_PERFCTR1		0x000000c2
 #define MSR_FSB_FREQ			0x000000cd

arch/x86/include/uapi/asm/mce.h

@@ -28,6 +28,7 @@ struct mce {
 	__u64 mcgcap;	/* MCGCAP MSR: machine check capabilities of CPU */
 	__u64 synd;	/* MCA_SYND MSR: only valid on SMCA systems */
 	__u64 ipid;	/* MCA_IPID MSR: only valid on SMCA systems */
+	__u64 ppin;	/* Protected Processor Inventory Number */
 };
 
 #define MCE_GET_RECORD_LEN   _IOR('M', 1, int)

arch/x86/kernel/cpu/mcheck/mce.c

@@ -43,6 +43,7 @@
 #include <linux/export.h>
 #include <linux/jump_label.h>
 
+#include <asm/intel-family.h>
 #include <asm/processor.h>
 #include <asm/traps.h>
 #include <asm/tlbflush.h>
@@ -135,6 +136,9 @@ void mce_setup(struct mce *m)
 	m->socketid = cpu_data(m->extcpu).phys_proc_id;
 	m->apicid = cpu_data(m->extcpu).initial_apicid;
 	rdmsrl(MSR_IA32_MCG_CAP, m->mcgcap);
+
+	if (this_cpu_has(X86_FEATURE_INTEL_PPIN))
+		rdmsrl(MSR_PPIN, m->ppin);
 }
 
 DEFINE_PER_CPU(struct mce, injectm);

arch/x86/kernel/cpu/mcheck/mce_intel.c

@@ -11,6 +11,8 @@
 #include <linux/sched.h>
 #include <linux/cpumask.h>
 #include <asm/apic.h>
+#include <asm/cpufeature.h>
+#include <asm/intel-family.h>
 #include <asm/processor.h>
 #include <asm/msr.h>
 #include <asm/mce.h>
@@ -464,11 +466,46 @@ static void intel_clear_lmce(void)
 	wrmsrl(MSR_IA32_MCG_EXT_CTL, val);
 }
 
+static void intel_ppin_init(struct cpuinfo_x86 *c)
+{
+	unsigned long long val;
+
+	/*
+	 * Even if testing the presence of the MSR would be enough, we don't
+	 * want to risk the situation where other models reuse this MSR for
+	 * other purposes.
+	 */
+	switch (c->x86_model) {
+	case INTEL_FAM6_IVYBRIDGE_X:
+	case INTEL_FAM6_HASWELL_X:
+	case INTEL_FAM6_BROADWELL_XEON_D:
+	case INTEL_FAM6_BROADWELL_X:
+	case INTEL_FAM6_SKYLAKE_X:
+		if (rdmsrl_safe(MSR_PPIN_CTL, &val))
+			return;
+
+		if ((val & 3UL) == 1UL) {
+			/* PPIN available but disabled: */
+			return;
+		}
+
+		/* If PPIN is disabled, but not locked, try to enable: */
+		if (!(val & 3UL)) {
+			wrmsrl_safe(MSR_PPIN_CTL,  val | 2UL);
+			rdmsrl_safe(MSR_PPIN_CTL, &val);
+		}
+
+		if ((val & 3UL) == 2UL)
+			set_cpu_cap(c, X86_FEATURE_INTEL_PPIN);
+	}
+}
+
 void mce_intel_feature_init(struct cpuinfo_x86 *c)
 {
 	intel_init_thermal(c);
 	intel_init_cmci();
 	intel_init_lmce();
+	intel_ppin_init(c);
 }
 
 void mce_intel_feature_clear(struct cpuinfo_x86 *c)