1 files changed, 24 insertions, 109 deletions

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 24a5c8b594c6..03a55bfa88c5 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -33,10 +33,10 @@
 static const char ucode_path[] = "kernel/x86/microcode/GenuineIntel.bin";
 
 /* Current microcode patch used in early patching on the APs. */
-static struct microcode_intel *intel_ucode_patch;
+static struct microcode_intel *intel_ucode_patch __read_mostly;
 
 /* last level cache size per core */
-static int llc_size_per_core;
+static int llc_size_per_core __ro_after_init;
 
 /* microcode format is extended from prescott processors */
 struct extended_signature {
@@ -253,74 +253,17 @@ static int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev
 	return intel_find_matching_signature(mc, csig, cpf);
 }
 
-static struct ucode_patch *memdup_patch(void *data, unsigned int size)
+static void save_microcode_patch(void *data, unsigned int size)
 {
-	struct ucode_patch *p;
-
-	p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL);
-	if (!p)
-		return NULL;
-
-	p->data = kmemdup(data, size, GFP_KERNEL);
-	if (!p->data) {
-		kfree(p);
-		return NULL;
-	}
-
-	return p;
-}
-
-static void save_microcode_patch(struct ucode_cpu_info *uci, void *data, unsigned int size)
-{
-	struct microcode_header_intel *mc_hdr, *mc_saved_hdr;
-	struct ucode_patch *iter, *tmp, *p = NULL;
-	bool prev_found = false;
-	unsigned int sig, pf;
-
-	mc_hdr = (struct microcode_header_intel *)data;
-
-	list_for_each_entry_safe(iter, tmp, &microcode_cache, plist) {
-		mc_saved_hdr = (struct microcode_header_intel *)iter->data;
-		sig	     = mc_saved_hdr->sig;
-		pf	     = mc_saved_hdr->pf;
-
-		if (intel_find_matching_signature(data, sig, pf)) {
-			prev_found = true;
-
-			if (mc_hdr->rev <= mc_saved_hdr->rev)
-				continue;
-
-			p = memdup_patch(data, size);
-			if (!p)
-				pr_err("Error allocating buffer %p\n", data);
-			else {
-				list_replace(&iter->plist, &p->plist);
-				kfree(iter->data);
-				kfree(iter);
-			}
-		}
-	}
-
-	/*
-	 * There weren't any previous patches found in the list cache; save the
-	 * newly found.
-	 */
-	if (!prev_found) {
-		p = memdup_patch(data, size);
-		if (!p)
-			pr_err("Error allocating buffer for %p\n", data);
-		else
-			list_add_tail(&p->plist, &microcode_cache);
-	}
+	struct microcode_header_intel *p;
 
+	p = kmemdup(data, size, GFP_KERNEL);
 	if (!p)
 		return;
 
-	if (!intel_find_matching_signature(p->data, uci->cpu_sig.sig, uci->cpu_sig.pf))
-		return;
-
+	kfree(intel_ucode_patch);
 	/* Save for early loading */
-	intel_ucode_patch = p->data;
+	intel_ucode_patch = (struct microcode_intel *)p;
 }
 
 /*
@@ -332,6 +275,7 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
 {
 	struct microcode_header_intel *mc_header;
 	struct microcode_intel *patch = NULL;
+	u32 cur_rev = uci->cpu_sig.rev;
 	unsigned int mc_size;
 
 	while (size) {
@@ -341,8 +285,7 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
 		mc_header = (struct microcode_header_intel *)data;
 
 		mc_size = get_totalsize(mc_header);
-		if (!mc_size ||
-		    mc_size > size ||
+		if (!mc_size || mc_size > size ||
 		    intel_microcode_sanity_check(data, false, MC_HEADER_TYPE_MICROCODE) < 0)
 			break;
 
@@ -354,31 +297,16 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
 			continue;
 		}
 
-		if (save) {
-			save_microcode_patch(uci, data, mc_size);
+		/* BSP scan: Check whether there is newer microcode */
+		if (!save && cur_rev >= mc_header->rev)
 			goto next;
-		}
-
-
-		if (!patch) {
-			if (!has_newer_microcode(data,
-						 uci->cpu_sig.sig,
-						 uci->cpu_sig.pf,
-						 uci->cpu_sig.rev))
-				goto next;
 
-		} else {
-			struct microcode_header_intel *phdr = &patch->hdr;
-
-			if (!has_newer_microcode(data,
-						 phdr->sig,
-						 phdr->pf,
-						 phdr->rev))
-				goto next;
-		}
+		/* Save scan: Check whether there is newer or matching microcode */
+		if (save && cur_rev != mc_header->rev)
+			goto next;
 
-		/* We have a newer patch, save it. */
 		patch = data;
+		cur_rev = mc_header->rev;
 
 next:
 		data += mc_size;
@@ -387,6 +315,9 @@ next:
 	if (size)
 		return NULL;
 
+	if (save && patch)
+		save_microcode_patch(patch, mc_size);
+
 	return patch;
 }
 
@@ -528,26 +459,10 @@ void load_ucode_intel_ap(void)
 	apply_microcode_early(&uci);
 }
 
-static struct microcode_intel *find_patch(struct ucode_cpu_info *uci)
+/* Accessor for microcode pointer */
+static struct microcode_intel *ucode_get_patch(void)
 {
-	struct microcode_header_intel *phdr;
-	struct ucode_patch *iter, *tmp;
-
-	list_for_each_entry_safe(iter, tmp, &microcode_cache, plist) {
-
-		phdr = (struct microcode_header_intel *)iter->data;
-
-		if (phdr->rev <= uci->cpu_sig.rev)
-			continue;
-
-		if (!intel_find_matching_signature(phdr,
-						   uci->cpu_sig.sig,
-						   uci->cpu_sig.pf))
-			continue;
-
-		return iter->data;
-	}
-	return NULL;
+	return intel_ucode_patch;
 }
 
 void reload_ucode_intel(void)
@@ -557,7 +472,7 @@ void reload_ucode_intel(void)
 
 	intel_cpu_collect_info(&uci);
 
-	p = find_patch(&uci);
+	p = ucode_get_patch();
 	if (!p)
 		return;
 
@@ -601,7 +516,7 @@ static enum ucode_state apply_microcode_intel(int cpu)
 		return UCODE_ERROR;
 
 	/* Look for a newer patch in our cache: */
-	mc = find_patch(uci);
+	mc = ucode_get_patch();
 	if (!mc) {
 		mc = uci->mc;
 		if (!mc)
@@ -730,7 +645,7 @@ static enum ucode_state generic_load_microcode(int cpu, struct iov_iter *iter)
 	uci->mc = (struct microcode_intel *)new_mc;
 
 	/* Save for CPU hotplug */
-	save_microcode_patch(uci, new_mc, new_mc_size);
+	save_microcode_patch(new_mc, new_mc_size);
 
 	pr_debug("CPU%d found a matching microcode update with version 0x%x (current=0x%x)\n",
 		 cpu, new_rev, uci->cpu_sig.rev);