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, 30 insertions, 15 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index f3cc7699e1e1..6a25e93f2a87 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2302,30 +2302,45 @@ void cpu_init_secondary(void)
 #endif
 
 #ifdef CONFIG_MICROCODE_LATE_LOADING
-/*
+/**
+ * store_cpu_caps() - Store a snapshot of CPU capabilities
+ * @curr_info: Pointer where to store it
+ *
+ * Returns: None
+ */
+void store_cpu_caps(struct cpuinfo_x86 *curr_info)
+{
+	/* Reload CPUID max function as it might've changed. */
+	curr_info->cpuid_level = cpuid_eax(0);
+
+	/* Copy all capability leafs and pick up the synthetic ones. */
+	memcpy(&curr_info->x86_capability, &boot_cpu_data.x86_capability,
+	       sizeof(curr_info->x86_capability));
+
+	/* Get the hardware CPUID leafs */
+	get_cpu_cap(curr_info);
+}
+
+/**
+ * microcode_check() - Check if any CPU capabilities changed after an update.
+ * @prev_info:	CPU capabilities stored before an update.
+ *
  * The microcode loader calls this upon late microcode load to recheck features,
  * only when microcode has been updated. Caller holds microcode_mutex and CPU
  * hotplug lock.
+ *
+ * Return: None
  */
-void microcode_check(void)
+void microcode_check(struct cpuinfo_x86 *prev_info)
 {
-	struct cpuinfo_x86 info;
+	struct cpuinfo_x86 curr_info;
 
 	perf_check_microcode();
 
-	/* Reload CPUID max function as it might've changed. */
-	info.cpuid_level = cpuid_eax(0);
-
-	/*
-	 * Copy all capability leafs to pick up the synthetic ones so that
-	 * memcmp() below doesn't fail on that. The ones coming from CPUID will
-	 * get overwritten in get_cpu_cap().
-	 */
-	memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability));
-
-	get_cpu_cap(&info);
+	store_cpu_caps(&curr_info);
 
-	if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)))
+	if (!memcmp(&prev_info->x86_capability, &curr_info.x86_capability,
+		    sizeof(prev_info->x86_capability)))
 		return;
 
 	pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");