x86/microcode/amd: Cache builtin/initrd microcode early

There is no reason to scan builtin/initrd microcode on each AP.

Cache the builtin/initrd microcode in an early initcall so that the
early AP loader can utilize the cache.

The existing fs initcall which invoked save_microcode_in_initrd_amd() is
still required to maintain the initrd_gone flag. Rename it accordingly.
This will be removed once the AP loader code is converted to use the
cache.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211723.187566507@linutronix.de

Author: KAGA-KOKO

arch/x86/kernel/cpu/microcode/amd.c

@@ -527,12 +527,17 @@ void load_ucode_amd_early(unsigned int cpuid_1_eax)
 
 static enum ucode_state load_microcode_amd(u8 family, const u8 *data, size_t size);
 
-int __init save_microcode_in_initrd_amd(unsigned int cpuid_1_eax)
+static int __init save_microcode_in_initrd(void)
 {
+	unsigned int cpuid_1_eax = native_cpuid_eax(1);
+	struct cpuinfo_x86 *c = &boot_cpu_data;
 	struct cont_desc desc = { 0 };
 	enum ucode_state ret;
 	struct cpio_data cp;
 
+	if (dis_ucode_ldr || c->x86_vendor != X86_VENDOR_AMD || c->x86 < 0x10)
+		return 0;
+
 	find_blobs_in_containers(cpuid_1_eax, &cp);
 	if (!(cp.data && cp.size))
 		return -EINVAL;
@@ -549,6 +554,7 @@ int __init save_microcode_in_initrd_amd(unsigned int cpuid_1_eax)
 
 	return 0;
 }
+early_initcall(save_microcode_in_initrd);
 
 /*
  * a small, trivial cache of per-family ucode patches

arch/x86/kernel/cpu/microcode/core.c

@@ -180,24 +180,13 @@ void load_ucode_ap(void)
 	}
 }
 
-static int __init save_microcode_in_initrd(void)
+/* Temporary workaround until find_microcode_in_initrd() is __init */
+static int __init mark_initrd_gone(void)
 {
-	struct cpuinfo_x86 *c = &boot_cpu_data;
-	int ret = -EINVAL;
-
-	switch (c->x86_vendor) {
-	case X86_VENDOR_AMD:
-		if (c->x86 >= 0x10)
-			ret = save_microcode_in_initrd_amd(cpuid_eax(1));
-		break;
-	default:
-		break;
-	}
-
 	initrd_gone = true;
-
-	return ret;
+	return 0;
 }
+fs_initcall(mark_initrd_gone);
 
 struct cpio_data find_microcode_in_initrd(const char *path)
 {
@@ -615,5 +604,4 @@ static int __init microcode_init(void)
 	return error;
 
 }
-fs_initcall(save_microcode_in_initrd);
 late_initcall(microcode_init);