1 files changed, 67 insertions, 4 deletions

diff --git a/arch/i386/kernel/microcode.c b/arch/i386/kernel/microcode.c
index b8f16633a6ec..cbe7ec8dbb9f 100644
--- a/arch/i386/kernel/microcode.c
+++ b/arch/i386/kernel/microcode.c
@@ -567,6 +567,53 @@ static int cpu_request_microcode(int cpu)
         return error;
 }
 
+static int apply_microcode_on_cpu(int cpu)
+{
+        struct cpuinfo_x86 *c = cpu_data + cpu;
+        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+        cpumask_t old;
+        unsigned int val[2];
+        int err = 0;
+
+        if (!uci->mc)
+                return -EINVAL;
+
+        old = current->cpus_allowed;
+        set_cpus_allowed(current, cpumask_of_cpu(cpu));
+
+        /* Check if the microcode we have in memory matches the CPU */
+        if (c->x86_vendor != X86_VENDOR_INTEL || c->x86 < 6 ||
+            cpu_has(c, X86_FEATURE_IA64) || uci->sig != cpuid_eax(0x00000001))
+                err = -EINVAL;
+
+        if (!err && ((c->x86_model >= 5) || (c->x86 > 6))) {
+                /* get processor flags from MSR 0x17 */
+                rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
+                if (uci->pf != (1 << ((val[1] >> 18) & 7)))
+                        err = -EINVAL;
+        }
+
+        if (!err) {
+                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], val[1]);
+                if (uci->rev != val[1])
+                        err = -EINVAL;
+        }
+
+        if (!err)
+                apply_microcode(cpu);
+        else
+                printk(KERN_ERR "microcode: Could not apply microcode to CPU%d:"
+                        " sig=0x%x, pf=0x%x, rev=0x%x\n",
+                        cpu, uci->sig, uci->pf, uci->rev);
+
+        set_cpus_allowed(current, old);
+        return err;
+}
+
 static void microcode_init_cpu(int cpu)
 {
         cpumask_t old;
@@ -577,7 +624,8 @@ static void microcode_init_cpu(int cpu)
         set_cpus_allowed(current, cpumask_of_cpu(cpu));
         mutex_lock(&microcode_mutex);
         collect_cpu_info(cpu);
-        if (uci->valid && system_state == SYSTEM_RUNNING)
+        if (uci->valid && system_state == SYSTEM_RUNNING &&
+            !suspend_cpu_hotplug)
                 cpu_request_microcode(cpu);
         mutex_unlock(&microcode_mutex);
         set_cpus_allowed(current, old);
@@ -663,13 +711,24 @@ static int mc_sysdev_add(struct sys_device *sys_dev)
                 return 0;
 
         pr_debug("Microcode:CPU %d added\n", cpu);
-        memset(uci, 0, sizeof(*uci));
+        /* If suspend_cpu_hotplug is set, the system is resuming and we should
+         * use the data from before the suspend.
+         */
+        if (suspend_cpu_hotplug) {
+                err = apply_microcode_on_cpu(cpu);
+                if (err)
+                        microcode_fini_cpu(cpu);
+        }
+        if (!uci->valid)
+                memset(uci, 0, sizeof(*uci));
 
         err = sysfs_create_group(&sys_dev->kobj, &mc_attr_group);
         if (err)
                 return err;
 
-        microcode_init_cpu(cpu);
+        if (!uci->valid)
+                microcode_init_cpu(cpu);
+
         return 0;
 }
 
@@ -680,7 +739,11 @@ static int mc_sysdev_remove(struct sys_device *sys_dev)
         if (!cpu_online(cpu))
                 return 0;
         pr_debug("Microcode:CPU %d removed\n", cpu);
-        microcode_fini_cpu(cpu);
+        /* If suspend_cpu_hotplug is set, the system is suspending and we should
+         * keep the microcode in memory for the resume.
+         */
+        if (!suspend_cpu_hotplug)
+                microcode_fini_cpu(cpu);
         sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
         return 0;
 }