1 files changed, 42 insertions, 5 deletions

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index b92e09a87c69..f75c140906d0 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -43,10 +43,19 @@
 #include "internal.h"
 
 static struct microcode_ops *microcode_ops;
-static bool dis_ucode_ldr = false;
+static bool dis_ucode_ldr;
 
 bool force_minrev = IS_ENABLED(CONFIG_MICROCODE_LATE_FORCE_MINREV);
-module_param(force_minrev, bool, S_IRUSR | S_IWUSR);
+
+/*
+ * Those below should be behind CONFIG_MICROCODE_DBG ifdeffery but in
+ * order to not uglify the code with ifdeffery and use IS_ENABLED()
+ * instead, leave them in. When microcode debugging is not enabled,
+ * those are meaningless anyway.
+ */
+/* base microcode revision for debugging */
+u32 base_rev;
+u32 microcode_rev[NR_CPUS] = {};
 
 /*
  * Synchronization.
@@ -119,20 +128,48 @@ bool __init microcode_loader_disabled(void)
 	 *    overwritten.
 	 */
 	if (!cpuid_feature() ||
-	    native_cpuid_ecx(1) & BIT(31) ||
+	    ((native_cpuid_ecx(1) & BIT(31)) &&
+	      !IS_ENABLED(CONFIG_MICROCODE_DBG)) ||
 	    amd_check_current_patch_level())
 		dis_ucode_ldr = true;
 
 	return dis_ucode_ldr;
 }
 
+static void early_parse_cmdline(void)
+{
+	char cmd_buf[64] = {};
+	char *s, *p = cmd_buf;
+
+	if (cmdline_find_option(boot_command_line, "microcode", cmd_buf, sizeof(cmd_buf)) > 0) {
+		while ((s = strsep(&p, ","))) {
+			if (IS_ENABLED(CONFIG_MICROCODE_DBG)) {
+				if (strstr(s, "base_rev=")) {
+					/* advance to the option arg */
+					strsep(&s, "=");
+					if (kstrtouint(s, 16, &base_rev)) { ; }
+				}
+			}
+
+			if (!strcmp("force_minrev", s))
+				force_minrev = true;
+
+			if (!strcmp(s, "dis_ucode_ldr"))
+				dis_ucode_ldr = true;
+		}
+	}
+
+	/* old, compat option */
+	if (cmdline_find_option_bool(boot_command_line, "dis_ucode_ldr") > 0)
+		dis_ucode_ldr = true;
+}
+
 void __init load_ucode_bsp(void)
 {
 	unsigned int cpuid_1_eax;
 	bool intel = true;
 
-	if (cmdline_find_option_bool(boot_command_line, "dis_ucode_ldr") > 0)
-		dis_ucode_ldr = true;
+	early_parse_cmdline();
 
 	if (microcode_loader_disabled())
 		return;