1 files changed, 36 insertions, 148 deletions

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 7019d4b2df0c..6a41cee242f6 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -55,7 +55,7 @@ LIST_HEAD(microcode_cache);
  * All non cpu-hotplug-callback call sites use:
  *
  * - microcode_mutex to synchronize with each other;
- * - get/put_online_cpus() to synchronize with
+ * - cpus_read_lock/unlock() to synchronize with
  *   the cpu-hotplug-callback call sites.
  *
  * We guarantee that only a single cpu is being
@@ -140,25 +140,6 @@ static bool __init check_loader_disabled_bsp(void)
 	return *res;
 }
 
-extern struct builtin_fw __start_builtin_fw[];
-extern struct builtin_fw __end_builtin_fw[];
-
-bool get_builtin_firmware(struct cpio_data *cd, const char *name)
-{
-#ifdef CONFIG_FW_LOADER
-	struct builtin_fw *b_fw;
-
-	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
-		if (!strcmp(name, b_fw->name)) {
-			cd->size = b_fw->size;
-			cd->data = b_fw->data;
-			return true;
-		}
-	}
-#endif
-	return false;
-}
-
 void __init load_ucode_bsp(void)
 {
 	unsigned int cpuid_1_eax;
@@ -392,101 +373,10 @@ static int apply_microcode_on_target(int cpu)
 	return ret;
 }
 
-#ifdef CONFIG_MICROCODE_OLD_INTERFACE
-static int do_microcode_update(const void __user *buf, size_t size)
-{
-	int error = 0;
-	int cpu;
-
-	for_each_online_cpu(cpu) {
-		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-		enum ucode_state ustate;
-
-		if (!uci->valid)
-			continue;
-
-		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
-		if (ustate == UCODE_ERROR) {
-			error = -1;
-			break;
-		} else if (ustate == UCODE_NEW) {
-			apply_microcode_on_target(cpu);
-		}
-	}
-
-	return error;
-}
-
-static int microcode_open(struct inode *inode, struct file *file)
-{
-	return capable(CAP_SYS_RAWIO) ? stream_open(inode, file) : -EPERM;
-}
-
-static ssize_t microcode_write(struct file *file, const char __user *buf,
-			       size_t len, loff_t *ppos)
-{
-	ssize_t ret = -EINVAL;
-	unsigned long nr_pages = totalram_pages();
-
-	if ((len >> PAGE_SHIFT) > nr_pages) {
-		pr_err("too much data (max %ld pages)\n", nr_pages);
-		return ret;
-	}
-
-	get_online_cpus();
-	mutex_lock(&microcode_mutex);
-
-	if (do_microcode_update(buf, len) == 0)
-		ret = (ssize_t)len;
-
-	if (ret > 0)
-		perf_check_microcode();
-
-	mutex_unlock(&microcode_mutex);
-	put_online_cpus();
-
-	return ret;
-}
-
-static const struct file_operations microcode_fops = {
-	.owner			= THIS_MODULE,
-	.write			= microcode_write,
-	.open			= microcode_open,
-	.llseek		= no_llseek,
-};
-
-static struct miscdevice microcode_dev = {
-	.minor			= MICROCODE_MINOR,
-	.name			= "microcode",
-	.nodename		= "cpu/microcode",
-	.fops			= &microcode_fops,
-};
-
-static int __init microcode_dev_init(void)
-{
-	int error;
-
-	error = misc_register(&microcode_dev);
-	if (error) {
-		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
-		return error;
-	}
-
-	return 0;
-}
-
-static void __exit microcode_dev_exit(void)
-{
-	misc_deregister(&microcode_dev);
-}
-#else
-#define microcode_dev_init()	0
-#define microcode_dev_exit()	do { } while (0)
-#endif
-
 /* fake device for request_firmware */
 static struct platform_device	*microcode_pdev;
 
+#ifdef CONFIG_MICROCODE_LATE_LOADING
 /*
  * Late loading dance. Why the heavy-handed stomp_machine effort?
  *
@@ -545,8 +435,7 @@ static int __wait_for_cpus(atomic_t *t, long long timeout)
 /*
  * Returns:
  * < 0 - on error
- *   0 - no update done
- *   1 - microcode was updated
+ *   0 - success (no update done or microcode was updated)
  */
 static int __reload_late(void *info)
 {
@@ -573,11 +462,11 @@ static int __reload_late(void *info)
 	else
 		goto wait_for_siblings;
 
-	if (err > UCODE_NFOUND) {
-		pr_warn("Error reloading microcode on CPU %d\n", cpu);
+	if (err >= UCODE_NFOUND) {
+		if (err == UCODE_ERROR)
+			pr_warn("Error reloading microcode on CPU %d\n", cpu);
+
 		ret = -1;
-	} else if (err == UCODE_UPDATED || err == UCODE_OK) {
-		ret = 1;
 	}
 
 wait_for_siblings:
@@ -602,16 +491,20 @@ wait_for_siblings:
  */
 static int microcode_reload_late(void)
 {
-	int ret;
+	int old = boot_cpu_data.microcode, ret;
+
+	pr_err("Attempting late microcode loading - it is dangerous and taints the kernel.\n");
+	pr_err("You should switch to early loading, if possible.\n");
 
 	atomic_set(&late_cpus_in,  0);
 	atomic_set(&late_cpus_out, 0);
 
 	ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
-	if (ret > 0)
+	if (ret == 0)
 		microcode_check();
 
-	pr_info("Reload completed, microcode revision: 0x%x\n", boot_cpu_data.microcode);
+	pr_info("Reload completed, microcode revision: 0x%x -> 0x%x\n",
+		old, boot_cpu_data.microcode);
 
 	return ret;
 }
@@ -632,29 +525,34 @@ static ssize_t reload_store(struct device *dev,
 	if (val != 1)
 		return size;
 
-	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
-	if (tmp_ret != UCODE_NEW)
-		return size;
-
-	get_online_cpus();
+	cpus_read_lock();
 
 	ret = check_online_cpus();
 	if (ret)
 		goto put;
 
+	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
+	if (tmp_ret != UCODE_NEW)
+		goto put;
+
 	mutex_lock(&microcode_mutex);
 	ret = microcode_reload_late();
 	mutex_unlock(&microcode_mutex);
 
 put:
-	put_online_cpus();
+	cpus_read_unlock();
 
-	if (ret >= 0)
+	if (ret == 0)
 		ret = size;
 
+	add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
+
 	return ret;
 }
 
+static DEVICE_ATTR_WO(reload);
+#endif
+
 static ssize_t version_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
@@ -671,7 +569,6 @@ static ssize_t pf_show(struct device *dev,
 	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
 }
 
-static DEVICE_ATTR_WO(reload);
 static DEVICE_ATTR(version, 0444, version_show, NULL);
 static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
 
@@ -778,9 +675,9 @@ static struct subsys_interface mc_cpu_interface = {
 };
 
 /**
- * mc_bp_resume - Update boot CPU microcode during resume.
+ * microcode_bsp_resume - Update boot CPU microcode during resume.
  */
-static void mc_bp_resume(void)
+void microcode_bsp_resume(void)
 {
 	int cpu = smp_processor_id();
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -792,7 +689,7 @@ static void mc_bp_resume(void)
 }
 
 static struct syscore_ops mc_syscore_ops = {
-	.resume			= mc_bp_resume,
+	.resume			= microcode_bsp_resume,
 };
 
 static int mc_cpu_starting(unsigned int cpu)
@@ -824,7 +721,9 @@ static int mc_cpu_down_prep(unsigned int cpu)
 }
 
 static struct attribute *cpu_root_microcode_attrs[] = {
+#ifdef CONFIG_MICROCODE_LATE_LOADING
 	&dev_attr_reload.attr,
+#endif
 	NULL
 };
 
@@ -833,7 +732,7 @@ static const struct attribute_group cpu_root_microcode_group = {
 	.attrs = cpu_root_microcode_attrs,
 };
 
-int __init microcode_init(void)
+static int __init microcode_init(void)
 {
 	struct cpuinfo_x86 *c = &boot_cpu_data;
 	int error;
@@ -856,14 +755,11 @@ int __init microcode_init(void)
 	if (IS_ERR(microcode_pdev))
 		return PTR_ERR(microcode_pdev);
 
-	get_online_cpus();
+	cpus_read_lock();
 	mutex_lock(&microcode_mutex);
-
 	error = subsys_interface_register(&mc_cpu_interface);
-	if (!error)
-		perf_check_microcode();
 	mutex_unlock(&microcode_mutex);
-	put_online_cpus();
+	cpus_read_unlock();
 
 	if (error)
 		goto out_pdev;
@@ -876,10 +772,6 @@ int __init microcode_init(void)
 		goto out_driver;
 	}
 
-	error = microcode_dev_init();
-	if (error)
-		goto out_ucode_group;
-
 	register_syscore_ops(&mc_syscore_ops);
 	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
 				  mc_cpu_starting, NULL);
@@ -890,18 +782,14 @@ int __init microcode_init(void)
 
 	return 0;
 
- out_ucode_group:
-	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
-			   &cpu_root_microcode_group);
-
  out_driver:
-	get_online_cpus();
+	cpus_read_lock();
 	mutex_lock(&microcode_mutex);
 
 	subsys_interface_unregister(&mc_cpu_interface);
 
 	mutex_unlock(&microcode_mutex);
-	put_online_cpus();
+	cpus_read_unlock();
 
  out_pdev:
 	platform_device_unregister(microcode_pdev);