Merge branch 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RAS fixes from Thomas Gleixner:
 "Two small fixes for RAS/MCE:

   - Serialize sysfs changes to avoid concurrent modificaiton of
     underlying data

   - Add microcode revision to Machine Check records. This should have
     been there forever, but now with the broken microcode versions in
     the wild it has become important"

* 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/MCE: Serialize sysfs changes
  x86/MCE: Save microcode revision in machine check records

2 files changed, 25 insertions, 2 deletions

diff --git a/arch/x86/include/uapi/asm/mce.h b/arch/x86/include/uapi/asm/mce.h
index 91723461dc1f..435db58a7bad 100644
--- a/arch/x86/include/uapi/asm/mce.h
+++ b/arch/x86/include/uapi/asm/mce.h
@@ -30,6 +30,7 @@ struct mce {
         __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 */
+        __u32 microcode;/* Microcode revision */
 };
 
 #define MCE_GET_RECORD_LEN   _IOR('M', 1, int)
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 8ff94d1e2dce..466f47301334 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -56,6 +56,9 @@
 
 static DEFINE_MUTEX(mce_log_mutex);
 
+/* sysfs synchronization */
+static DEFINE_MUTEX(mce_sysfs_mutex);
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/mce.h>
 
@@ -130,6 +133,8 @@ void mce_setup(struct mce *m)
 
         if (this_cpu_has(X86_FEATURE_INTEL_PPIN))
                 rdmsrl(MSR_PPIN, m->ppin);
+
+        m->microcode = boot_cpu_data.microcode;
 }
 
 DEFINE_PER_CPU(struct mce, injectm);
@@ -262,7 +267,7 @@ static void __print_mce(struct mce *m)
          */
         pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x microcode %x\n",
                 m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid,
-                cpu_data(m->extcpu).microcode);
+                m->microcode);
 }
 
 static void print_mce(struct mce *m)
@@ -2086,6 +2091,7 @@ static ssize_t set_ignore_ce(struct device *s,
         if (kstrtou64(buf, 0, &new) < 0)
                 return -EINVAL;
 
+        mutex_lock(&mce_sysfs_mutex);
         if (mca_cfg.ignore_ce ^ !!new) {
                 if (new) {
                         /* disable ce features */
@@ -2098,6 +2104,8 @@ static ssize_t set_ignore_ce(struct device *s,
                         on_each_cpu(mce_enable_ce, (void *)1, 1);
                 }
         }
+        mutex_unlock(&mce_sysfs_mutex);
+
         return size;
 }
 
@@ -2110,6 +2118,7 @@ static ssize_t set_cmci_disabled(struct device *s,
         if (kstrtou64(buf, 0, &new) < 0)
                 return -EINVAL;
 
+        mutex_lock(&mce_sysfs_mutex);
         if (mca_cfg.cmci_disabled ^ !!new) {
                 if (new) {
                         /* disable cmci */
@@ -2121,6 +2130,8 @@ static ssize_t set_cmci_disabled(struct device *s,
                         on_each_cpu(mce_enable_ce, NULL, 1);
                 }
         }
+        mutex_unlock(&mce_sysfs_mutex);
+
         return size;
 }
 
@@ -2128,8 +2139,19 @@ static ssize_t store_int_with_restart(struct device *s,
                                       struct device_attribute *attr,
                                       const char *buf, size_t size)
 {
-        ssize_t ret = device_store_int(s, attr, buf, size);
+        unsigned long old_check_interval = check_interval;
+        ssize_t ret = device_store_ulong(s, attr, buf, size);
+
+        if (check_interval == old_check_interval)
+                return ret;
+
+        if (check_interval < 1)
+                check_interval = 1;
+
+        mutex_lock(&mce_sysfs_mutex);
         mce_restart();
+        mutex_unlock(&mce_sysfs_mutex);
+
         return ret;
 }