x86/microcode/intel: Unify microcode apply() functions

Deduplicate the early and late apply() functions.

  [ bp: Rename the function which does the actual application to
      __apply_microcode() to differentiate it from
      microcode_ops.apply_microcode(). ]

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20231017211722.795508212@linutronix.de

Author: KAGA-KOKO

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

@@ -307,12 +307,12 @@ static __init struct microcode_intel *scan_microcode(void *data, size_t size,
 	return size ? NULL : patch;
 }
 
-static enum ucode_state apply_microcode_early(struct ucode_cpu_info *uci)
+static enum ucode_state __apply_microcode(struct ucode_cpu_info *uci,
+					  struct microcode_intel *mc,
+					  u32 *cur_rev)
 {
-	struct microcode_intel *mc;
-	u32 rev, old_rev, date;
+	u32 rev;
 
-	mc = uci->mc;
 	if (!mc)
 		return UCODE_NFOUND;
 
@@ -321,14 +321,12 @@ static enum ucode_state apply_microcode_early(struct ucode_cpu_info *uci)
 	 * operation - when the other hyperthread has updated the microcode
 	 * already.
 	 */
-	rev = intel_get_microcode_revision();
-	if (rev >= mc->hdr.rev) {
-		uci->cpu_sig.rev = rev;
+	*cur_rev = intel_get_microcode_revision();
+	if (*cur_rev >= mc->hdr.rev) {
+		uci->cpu_sig.rev = *cur_rev;
 		return UCODE_OK;
 	}
 
-	old_rev = rev;
-
 	/*
 	 * Writeback and invalidate caches before updating microcode to avoid
 	 * internal issues depending on what the microcode is updating.
@@ -343,13 +341,24 @@ static enum ucode_state apply_microcode_early(struct ucode_cpu_info *uci)
 		return UCODE_ERROR;
 
 	uci->cpu_sig.rev = rev;
-
-	date = mc->hdr.date;
-	pr_info_once("updated early: 0x%x -> 0x%x, date = %04x-%02x-%02x\n",
-		     old_rev, rev, date & 0xffff, date >> 24, (date >> 16) & 0xff);
 	return UCODE_UPDATED;
 }
 
+static enum ucode_state apply_microcode_early(struct ucode_cpu_info *uci)
+{
+	struct microcode_intel *mc = uci->mc;
+	enum ucode_state ret;
+	u32 cur_rev, date;
+
+	ret = __apply_microcode(uci, mc, &cur_rev);
+	if (ret == UCODE_UPDATED) {
+		date = mc->hdr.date;
+		pr_info_once("updated early: 0x%x -> 0x%x, date = %04x-%02x-%02x\n",
+			     cur_rev, mc->hdr.rev, date & 0xffff, date >> 24, (date >> 16) & 0xff);
+	}
+	return ret;
+}
+
 static __init bool load_builtin_intel_microcode(struct cpio_data *cp)
 {
 	unsigned int eax = 1, ebx, ecx = 0, edx;
@@ -459,70 +468,29 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
 	return 0;
 }
 
-static enum ucode_state apply_microcode_intel(int cpu)
+static enum ucode_state apply_microcode_late(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-	struct cpuinfo_x86 *c = &cpu_data(cpu);
-	bool bsp = c->cpu_index == boot_cpu_data.cpu_index;
-	struct microcode_intel *mc;
+	struct microcode_intel *mc = ucode_patch_late;
 	enum ucode_state ret;
-	static int prev_rev;
-	u32 rev;
+	u32 cur_rev;
 
-	/* We should bind the task to the CPU */
-	if (WARN_ON(raw_smp_processor_id() != cpu))
+	if (WARN_ON_ONCE(smp_processor_id() != cpu))
 		return UCODE_ERROR;
 
-	mc = ucode_patch_late;
-	if (!mc)
-		return UCODE_NFOUND;
+	ret = __apply_microcode(uci, mc, &cur_rev);
+	if (ret != UCODE_UPDATED && ret != UCODE_OK)
+		return ret;
 
-	/*
-	 * Save us the MSR write below - which is a particular expensive
-	 * operation - when the other hyperthread has updated the microcode
-	 * already.
-	 */
-	rev = intel_get_microcode_revision();
-	if (rev >= mc->hdr.rev) {
-		ret = UCODE_OK;
-		goto out;
-	}
-
-	/*
-	 * Writeback and invalidate caches before updating microcode to avoid
-	 * internal issues depending on what the microcode is updating.
-	 */
-	native_wbinvd();
-
-	/* write microcode via MSR 0x79 */
-	wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
-
-	rev = intel_get_microcode_revision();
-
-	if (rev != mc->hdr.rev) {
-		pr_err("CPU%d update to revision 0x%x failed\n",
-		       cpu, mc->hdr.rev);
-		return UCODE_ERROR;
-	}
-
-	if (bsp && rev != prev_rev) {
-		pr_info("updated to revision 0x%x, date = %04x-%02x-%02x\n",
-			rev,
-			mc->hdr.date & 0xffff,
-			mc->hdr.date >> 24,
+	if (!cpu && uci->cpu_sig.rev != cur_rev) {
+		pr_info("Updated to revision 0x%x, date = %04x-%02x-%02x\n",
+			uci->cpu_sig.rev, mc->hdr.date & 0xffff, mc->hdr.date >> 24,
 			(mc->hdr.date >> 16) & 0xff);
-		prev_rev = rev;
 	}
 
-	ret = UCODE_UPDATED;
-
-out:
-	uci->cpu_sig.rev = rev;
-	c->microcode	 = rev;
-
-	/* Update boot_cpu_data's revision too, if we're on the BSP: */
-	if (bsp)
-		boot_cpu_data.microcode = rev;
+	cpu_data(cpu).microcode	 = uci->cpu_sig.rev;
+	if (!cpu)
+		boot_cpu_data.microcode = uci->cpu_sig.rev;
 
 	return ret;
 }
@@ -663,7 +631,7 @@ static void finalize_late_load(int result)
 static struct microcode_ops microcode_intel_ops = {
 	.request_microcode_fw	= request_microcode_fw,
 	.collect_cpu_info	= collect_cpu_info,
-	.apply_microcode	= apply_microcode_intel,
+	.apply_microcode	= apply_microcode_late,
 	.finalize_late_load	= finalize_late_load,
 };