Merge tag 'x86_microcode_for_v6.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 microcode loader updates from Borislav Petkov:

 - Fix mixed steppings support on AMD which got broken somewhere along
   the way

 - Improve revision reporting

 - Properly check CPUID capabilities after late microcode upgrade to
   avoid false positives

 - A garden variety of other small fixes

* tag 'x86_microcode_for_v6.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode/core: Return an error only when necessary
  x86/microcode/AMD: Fix mixed steppings support
  x86/microcode/AMD: Add a @cpu parameter to the reloading functions
  x86/microcode/amd: Remove load_microcode_amd()'s bsp parameter
  x86/microcode: Allow only "1" as a late reload trigger value
  x86/microcode/intel: Print old and new revision during early boot
  x86/microcode/intel: Pass the microcode revision to print_ucode_info() directly
  x86/microcode: Adjust late loading result reporting message
  x86/microcode: Check CPU capabilities after late microcode update correctly
  x86/microcode: Add a parameter to microcode_check() to store CPU capabilities
  x86/microcode: Use the DEVICE_ATTR_RO() macro
  x86/microcode/AMD: Handle multiple glued containers properly
  x86/microcode/AMD: Rename a couple of functions

1 files changed, 26 insertions, 19 deletions

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 712aafff96e0..7a329e561354 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -298,7 +298,7 @@ struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
 #endif
 }
 
-void reload_early_microcode(void)
+void reload_early_microcode(unsigned int cpu)
 {
 	int vendor, family;
 
@@ -312,7 +312,7 @@ void reload_early_microcode(void)
 		break;
 	case X86_VENDOR_AMD:
 		if (family >= 0x10)
-			reload_ucode_amd();
+			reload_ucode_amd(cpu);
 		break;
 	default:
 		break;
@@ -409,10 +409,10 @@ static int __reload_late(void *info)
 		goto wait_for_siblings;
 
 	if (err >= UCODE_NFOUND) {
-		if (err == UCODE_ERROR)
+		if (err == UCODE_ERROR) {
 			pr_warn("Error reloading microcode on CPU %d\n", cpu);
-
-		ret = -1;
+			ret = -1;
+		}
 	}
 
 wait_for_siblings:
@@ -438,6 +438,7 @@ wait_for_siblings:
 static int microcode_reload_late(void)
 {
 	int old = boot_cpu_data.microcode, ret;
+	struct cpuinfo_x86 prev_info;
 
 	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");
@@ -445,12 +446,21 @@ static int microcode_reload_late(void)
 	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)
-		microcode_check();
+	/*
+	 * Take a snapshot before the microcode update in order to compare and
+	 * check whether any bits changed after an update.
+	 */
+	store_cpu_caps(&prev_info);
 
-	pr_info("Reload completed, microcode revision: 0x%x -> 0x%x\n",
-		old, boot_cpu_data.microcode);
+	ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
+	if (!ret) {
+		pr_info("Reload succeeded, microcode revision: 0x%x -> 0x%x\n",
+			old, boot_cpu_data.microcode);
+		microcode_check(&prev_info);
+	} else {
+		pr_info("Reload failed, current microcode revision: 0x%x\n",
+			boot_cpu_data.microcode);
+	}
 
 	return ret;
 }
@@ -465,11 +475,8 @@ static ssize_t reload_store(struct device *dev,
 	ssize_t ret = 0;
 
 	ret = kstrtoul(buf, 0, &val);
-	if (ret)
-		return ret;
-
-	if (val != 1)
-		return size;
+	if (ret || val != 1)
+		return -EINVAL;
 
 	cpus_read_lock();
 
@@ -507,7 +514,7 @@ static ssize_t version_show(struct device *dev,
 	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
 }
 
-static ssize_t pf_show(struct device *dev,
+static ssize_t processor_flags_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
@@ -515,8 +522,8 @@ static ssize_t pf_show(struct device *dev,
 	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
 }
 
-static DEVICE_ATTR(version, 0444, version_show, NULL);
-static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
+static DEVICE_ATTR_RO(version);
+static DEVICE_ATTR_RO(processor_flags);
 
 static struct attribute *mc_default_attrs[] = {
 	&dev_attr_version.attr,
@@ -557,7 +564,7 @@ void microcode_bsp_resume(void)
 	if (uci->mc)
 		microcode_ops->apply_microcode(cpu);
 	else
-		reload_early_microcode();
+		reload_early_microcode(cpu);
 }
 
 static struct syscore_ops mc_syscore_ops = {