microcode: use suspend-related CPU hotplug notifications

Make the microcode driver use the suspend-related CPU hotplug notifications
to handle the CPU hotplug events occuring during system-wide suspend and
resume transitions.  Remove the global variable suspend_cpu_hotplug
previously used for this purpose.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 36 insertions, 26 deletions

diff --git a/arch/i386/kernel/microcode.c b/arch/i386/kernel/microcode.c
index 7d934e493e74..83f825f2e2d7 100644
--- a/arch/i386/kernel/microcode.c
+++ b/arch/i386/kernel/microcode.c
@@ -567,7 +567,7 @@ static int cpu_request_microcode(int cpu)
         return error;
 }
 
-static int apply_microcode_on_cpu(int cpu)
+static int apply_microcode_check_cpu(int cpu)
 {
         struct cpuinfo_x86 *c = cpu_data + cpu;
         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -575,8 +575,9 @@ static int apply_microcode_on_cpu(int cpu)
         unsigned int val[2];
         int err = 0;
 
+        /* Check if the microcode is available */
         if (!uci->mc)
-                return -EINVAL;
+                return 0;
 
         old = current->cpus_allowed;
         set_cpus_allowed(current, cpumask_of_cpu(cpu));
@@ -614,7 +615,7 @@ static int apply_microcode_on_cpu(int cpu)
         return err;
 }
 
-static void microcode_init_cpu(int cpu)
+static void microcode_init_cpu(int cpu, int resume)
 {
         cpumask_t old;
         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -624,8 +625,7 @@ 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 &&
-            !suspend_cpu_hotplug)
+        if (uci->valid && system_state == SYSTEM_RUNNING && !resume)
                 cpu_request_microcode(cpu);
         mutex_unlock(&microcode_mutex);
         set_cpus_allowed(current, old);
@@ -702,7 +702,7 @@ static struct attribute_group mc_attr_group = {
         .name = "microcode",
 };
 
-static int mc_sysdev_add(struct sys_device *sys_dev)
+static int __mc_sysdev_add(struct sys_device *sys_dev, int resume)
 {
         int err, cpu = sys_dev->id;
         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -711,39 +711,31 @@ static int mc_sysdev_add(struct sys_device *sys_dev)
                 return 0;
 
         pr_debug("Microcode:CPU %d added\n", cpu);
-        /* 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));
+        memset(uci, 0, sizeof(*uci));
 
         err = sysfs_create_group(&sys_dev->kobj, &mc_attr_group);
         if (err)
                 return err;
 
-        if (!uci->valid)
-                microcode_init_cpu(cpu);
+        microcode_init_cpu(cpu, resume);
 
         return 0;
 }
 
+static int mc_sysdev_add(struct sys_device *sys_dev)
+{
+        return __mc_sysdev_add(sys_dev, 0);
+}
+
 static int mc_sysdev_remove(struct sys_device *sys_dev)
 {
         int cpu = sys_dev->id;
 
         if (!cpu_online(cpu))
                 return 0;
+
         pr_debug("Microcode:CPU %d removed\n", 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);
+        microcode_fini_cpu(cpu);
         sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
         return 0;
 }
@@ -774,16 +766,34 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
 
         sys_dev = get_cpu_sysdev(cpu);
         switch (action) {
+        case CPU_UP_CANCELED_FROZEN:
+                /* The CPU refused to come up during a system resume */
+                microcode_fini_cpu(cpu);
+                break;
         case CPU_ONLINE:
-        case CPU_ONLINE_FROZEN:
         case CPU_DOWN_FAILED:
-        case CPU_DOWN_FAILED_FROZEN:
                 mc_sysdev_add(sys_dev);
                 break;
+        case CPU_ONLINE_FROZEN:
+                /* System-wide resume is in progress, try to apply microcode */
+                if (apply_microcode_check_cpu(cpu)) {
+                        /* The application of microcode failed */
+                        microcode_fini_cpu(cpu);
+                        __mc_sysdev_add(sys_dev, 1);
+                        break;
+                }
+        case CPU_DOWN_FAILED_FROZEN:
+                if (sysfs_create_group(&sys_dev->kobj, &mc_attr_group))
+                        printk(KERN_ERR "Microcode: Failed to create the sysfs "
+                                "group for CPU%d\n", cpu);
+                break;
         case CPU_DOWN_PREPARE:
-        case CPU_DOWN_PREPARE_FROZEN:
                 mc_sysdev_remove(sys_dev);
                 break;
+        case CPU_DOWN_PREPARE_FROZEN:
+                /* Suspend is in progress, only remove the interface */
+                sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
+                break;
         }
         return NOTIFY_OK;
 }