[PATCH 1/3] x86, intel: Output microcode revision v6

Andi Kleen
2011-10-13T00:46:46Z

I got a request to make it easier to determine the microcode update level
on Intel CPUs. This patch adds a new "microcode" field to /proc/cpuinfo.

The microcode level is also outputed on fatal machine checks together
with the other CPUID model information.

I removed the respective code from the microcode update driver, it
just reads the field from cpu_data. Also when the microcode is updated
it fills in the new values too.

I had to add a memory barrier to native_cpuid to prevent it being
optimized away when the result is not used.

This turns out to clean up further code which already got this
information manually. This is done in followon patches.

v2: Lots of updates based on feedback.
v3: Rename cpu_update to microcode. Misc changes from feedback.
v4: minor updates. rebased.
v5: move MSR read to early_intel_init()
v6: Use sync_core() instead of CPUID 1. Drop a white space change.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
arch/x86/include/asm/processor.h | 4 +++-
arch/x86/kernel/cpu/intel.c | 9 +++++++++
arch/x86/kernel/cpu/mcheck/mce.c | 9 +++++++--
arch/x86/kernel/cpu/proc.c | 2 ++
arch/x86/kernel/microcode_intel.c | 14 +++++---------
5 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 0d1171c..b650435 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -111,6 +111,7 @@ struct cpuinfo_x86 {
/* Index into per_cpu list: */
u16 cpu_index;
#endif
+ u32 microcode;
} __attribute__((__aligned__(SMP_CACHE_BYTES)));

#define X86_VENDOR_INTEL 0
@@ -179,7 +180,8 @@ static inline void native_cpuid(unsigned int *eax, unsigned int *ebx,
"=b" (*ebx),
"=c" (*ecx),
"=d" (*edx)
- : "0" (*eax), "2" (*ecx));
+ : "0" (*eax), "2" (*ecx)
+ : "memory");
}

static inline void load_cr3(pgd_t *pgdir)
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index ed6086e..26627a3 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -47,6 +47,15 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
(c->x86 == 0x6 && c->x86_model >= 0x0e))
set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);

+ if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64)) {
+ unsigned lower_word;
+
+ wrmsr(MSR_IA32_UCODE_REV, 0, 0);
+ /* Required by the SDM */
+ sync_core();
+ rdmsr(MSR_IA32_UCODE_REV, lower_word, c->microcode);
+ }
+
/*
* Atom erratum AAE44/AAF40/AAG38/AAH41:
*
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 08363b0..8af6fa4 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -217,8 +217,13 @@ static void print_mce(struct mce *m)
pr_cont("MISC %llx ", m->misc);

pr_cont("\n");
- pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x\n",
- m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid);
+ /*
+ * Note this output is parsed by external tools and old fields
+ * should not be changed.
+ */
+ pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x microcode %u\n",
+ m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid,
+ cpu_data(m->extcpu).microcode);

/*
* Print out human-readable details about the MCE error,
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 62ac8cb..6254fda 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -85,6 +85,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
seq_printf(m, "stepping\t: %d\n", c->x86_mask);
else
seq_printf(m, "stepping\t: unknown\n");
+ if (c->microcode)
+ seq_printf(m, "microcode\t: %u\n", c->microcode);

if (cpu_has(c, X86_FEATURE_TSC)) {
unsigned int freq = cpufreq_quick_get(cpu);
diff --git a/arch/x86/kernel/microcode_intel.c b/arch/x86/kernel/microcode_intel.c
index 1a1b606..3ca42d0 100644
--- a/arch/x86/kernel/microcode_intel.c
+++ b/arch/x86/kernel/microcode_intel.c
@@ -161,12 +161,7 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
csig->pf = 1 << ((val[1] >> 18) & 7);
}

- wrmsr(MSR_IA32_UCODE_REV, 0, 0);
- /* see notes above for revision 1.07. Apparent chip bug */
- sync_core();
- /* get the current revision from MSR 0x8B */
- rdmsr(MSR_IA32_UCODE_REV, val[0], csig->rev);
-
+ csig->rev = c->microcode;
pr_info("CPU%d sig=0x%x, pf=0x%x, revision=0x%x\n",
cpu_num, csig->sig, csig->pf, csig->rev);

@@ -299,9 +294,9 @@ static int apply_microcode(int cpu)
struct microcode_intel *mc_intel;
struct ucode_cpu_info *uci;
unsigned int val[2];
- int cpu_num;
+ int cpu_num = raw_smp_processor_id();
+ struct cpuinfo_x86 *c = &cpu_data(cpu_num);

- cpu_num = raw_smp_processor_id();
uci = ucode_cpu_info + cpu;
mc_intel = uci->mc;

@@ -317,7 +312,7 @@ static int apply_microcode(int cpu)
(unsigned long) mc_intel->bits >> 16 >> 16);
wrmsr(MSR_IA32_UCODE_REV, 0, 0);

- /* see notes above for revision 1.07. Apparent chip bug */
+ /* As documented in the SDM: Do a CPUID 1 here */
sync_core();

/* get the current revision from MSR 0x8B */
@@ -335,6 +330,7 @@ static int apply_microcode(int cpu)
(mc_intel->hdr.date >> 16) & 0xff);

uci->cpu_sig.rev = val[1];
+ c->microcode = val[1];

return 0;
}
--
1.7.4.4