x86: cpumask: use work_on_cpu in arch/x86/kernel/microcode_core.c

Impact: don't play with current's cpumask

Straightforward indirection through work_on_cpu().  One change is
that the error code from microcode_update_cpu() is now actually
plumbed back to microcode_init_cpu(), so now we printk if it fails
on cpu hotplug.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Cc: Peter Oruba <peter.oruba@amd.com>
LKML-Reference: <200903111632.37279.rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 61 insertions, 45 deletions

diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index c9b721ba968c..9a8dbc000563 100644
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -108,29 +108,40 @@ struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
 EXPORT_SYMBOL_GPL(ucode_cpu_info);
 
 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
+struct update_for_cpu {
+        const void __user *buf;
+        size_t size;
+};
+
+static long update_for_cpu(void *_ufc)
+{
+        struct update_for_cpu *ufc = _ufc;
+        int error;
+
+        error = microcode_ops->request_microcode_user(smp_processor_id(),
+                                                      ufc->buf, ufc->size);
+        if (error < 0)
+                return error;
+        if (!error)
+                microcode_ops->apply_microcode(smp_processor_id());
+        return error;
+}
+
 static int do_microcode_update(const void __user *buf, size_t size)
 {
-        cpumask_t old;
         int error = 0;
         int cpu;
-
-        old = current->cpus_allowed;
+        struct update_for_cpu ufc = { .buf = buf, .size = size };
 
         for_each_online_cpu(cpu) {
                 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
                 if (!uci->valid)
                         continue;
-
-                set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-                error = microcode_ops->request_microcode_user(cpu, buf, size);
+                error = work_on_cpu(cpu, update_for_cpu, &ufc);
                 if (error < 0)
-                        goto out;
-                if (!error)
-                        microcode_ops->apply_microcode(cpu);
+                        break;
         }
-out:
-        set_cpus_allowed_ptr(current, &old);
         return error;
 }
 
@@ -205,11 +216,26 @@ MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
 /* fake device for request_firmware */
 static struct platform_device *microcode_pdev;
 
+static long reload_for_cpu(void *unused)
+{
+        struct ucode_cpu_info *uci = ucode_cpu_info + smp_processor_id();
+        int err = 0;
+
+        mutex_lock(&microcode_mutex);
+        if (uci->valid) {
+                err = microcode_ops->request_microcode_fw(smp_processor_id(),
+                                                          &microcode_pdev->dev);
+                if (!err)
+                        microcode_ops->apply_microcode(smp_processor_id());
+        }
+        mutex_unlock(&microcode_mutex);
+        return err;
+}
+
 static ssize_t reload_store(struct sys_device *dev,
                             struct sysdev_attribute *attr,
                             const char *buf, size_t sz)
 {
-        struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
         char *end;
         unsigned long val = simple_strtoul(buf, &end, 0);
         int err = 0;
@@ -218,21 +244,9 @@ static ssize_t reload_store(struct sys_device *dev,
         if (end == buf)
                 return -EINVAL;
         if (val == 1) {
-                cpumask_t old = current->cpus_allowed;
-
                 get_online_cpus();
-                if (cpu_online(cpu)) {
-                        set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-                        mutex_lock(&microcode_mutex);
-                        if (uci->valid) {
-                                err = microcode_ops->request_microcode_fw(cpu,
-                                                &microcode_pdev->dev);
-                                if (!err)
-                                        microcode_ops->apply_microcode(cpu);
-                        }
-                        mutex_unlock(&microcode_mutex);
-                        set_cpus_allowed_ptr(current, &old);
-                }
+                if (cpu_online(cpu))
+                        err = work_on_cpu(cpu, reload_for_cpu, NULL);
                 put_online_cpus();
         }
         if (err)
@@ -328,9 +342,9 @@ static int microcode_resume_cpu(int cpu)
         return 0;
 }
 
-static void microcode_update_cpu(int cpu)
+static long microcode_update_cpu(void *unused)
 {
-        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+        struct ucode_cpu_info *uci = ucode_cpu_info + smp_processor_id();
         int err = 0;
 
         /*
@@ -338,30 +352,27 @@ static void microcode_update_cpu(int cpu)
          * otherwise just request a firmware:
          */
         if (uci->valid) {
-                err = microcode_resume_cpu(cpu);
+                err = microcode_resume_cpu(smp_processor_id());
         } else {        
-                collect_cpu_info(cpu);
+                collect_cpu_info(smp_processor_id());
                 if (uci->valid && system_state == SYSTEM_RUNNING)
-                        err = microcode_ops->request_microcode_fw(cpu,
+                        err = microcode_ops->request_microcode_fw(
+                                        smp_processor_id(),
                                         &microcode_pdev->dev);
         }
         if (!err)
-                microcode_ops->apply_microcode(cpu);
+                microcode_ops->apply_microcode(smp_processor_id());
+        return err;
 }
 
-static void microcode_init_cpu(int cpu)
+static int microcode_init_cpu(int cpu)
 {
-        cpumask_t old = current->cpus_allowed;
-
-        set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-        /* We should bind the task to the CPU */
-        BUG_ON(raw_smp_processor_id() != cpu);
-
+        int err;
         mutex_lock(&microcode_mutex);
-        microcode_update_cpu(cpu);
+        err = work_on_cpu(cpu, microcode_update_cpu, NULL);
         mutex_unlock(&microcode_mutex);
 
-        set_cpus_allowed_ptr(current, &old);
+        return err;
 }
 
 static int mc_sysdev_add(struct sys_device *sys_dev)
@@ -379,8 +390,11 @@ static int mc_sysdev_add(struct sys_device *sys_dev)
         if (err)
                 return err;
 
-        microcode_init_cpu(cpu);
-        return 0;
+        err = microcode_init_cpu(cpu);
+        if (err)
+                sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
+
+        return err;
 }
 
 static int mc_sysdev_remove(struct sys_device *sys_dev)
@@ -404,7 +418,7 @@ static int mc_sysdev_resume(struct sys_device *dev)
                 return 0;
 
         /* only CPU 0 will apply ucode here */
-        microcode_update_cpu(0);
+        microcode_update_cpu(NULL);
         return 0;
 }
 
@@ -424,7 +438,9 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
         switch (action) {
         case CPU_ONLINE:
         case CPU_ONLINE_FROZEN:
-                microcode_init_cpu(cpu);
+                if (microcode_init_cpu(cpu))
+                        printk(KERN_ERR "microcode: failed to init CPU%d\n",
+                               cpu);
         case CPU_DOWN_FAILED:
         case CPU_DOWN_FAILED_FROZEN:
                 pr_debug("microcode: CPU%d added\n", cpu);