Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 microcode updates from Ingo Molnar:
 "The main changes are a fix early microcode application for
  resume-from-RAM, plus a 32-bit initrd placement fix - by Borislav
  Petkov"

* 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode: Make a couple of symbols static
  x86/microcode/intel: Save pointer to ucode patch for early AP loading
  x86/microcode: Look for the initrd at the correct address on 32-bit

3 files changed, 34 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index e9f4d762aa5b..21b185793c80 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -251,7 +251,7 @@ static bool get_builtin_microcode(struct cpio_data *cp, unsigned int family)
 #endif
 }
 
-void __load_ucode_amd(unsigned int cpuid_1_eax, struct cpio_data *ret)
+static void __load_ucode_amd(unsigned int cpuid_1_eax, struct cpio_data *ret)
 {
 	struct ucode_cpu_info *uci;
 	struct cpio_data cp;
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index e53d3c909840..9cb98ee103db 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -290,6 +290,17 @@ struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
 			return (struct cpio_data){ NULL, 0, "" };
 		if (initrd_start)
 			start = initrd_start;
+	} else {
+		/*
+		 * The picture with physical addresses is a bit different: we
+		 * need to get the *physical* address to which the ramdisk was
+		 * relocated, i.e., relocated_ramdisk (not initrd_start) and
+		 * since we're running from physical addresses, we need to access
+		 * relocated_ramdisk through its *physical* address too.
+		 */
+		u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
+		if (*rr)
+			start = *rr;
 	}
 
 	return find_cpio_data(path, (void *)start, size, NULL);
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index f522415bf9e5..59edbe9d4ccb 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -42,7 +42,7 @@
 static const char ucode_path[] = "kernel/x86/microcode/GenuineIntel.bin";
 
 /* Current microcode patch used in early patching on the APs. */
-struct microcode_intel *intel_ucode_patch;
+static struct microcode_intel *intel_ucode_patch;
 
 static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
 					unsigned int s2, unsigned int p2)
@@ -166,7 +166,7 @@ static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
 static void save_microcode_patch(void *data, unsigned int size)
 {
 	struct microcode_header_intel *mc_hdr, *mc_saved_hdr;
-	struct ucode_patch *iter, *tmp, *p;
+	struct ucode_patch *iter, *tmp, *p = NULL;
 	bool prev_found = false;
 	unsigned int sig, pf;
 
@@ -202,6 +202,18 @@ static void save_microcode_patch(void *data, unsigned int size)
 		else
 			list_add_tail(&p->plist, &microcode_cache);
 	}
+
+	/*
+	 * Save for early loading. On 32-bit, that needs to be a physical
+	 * address as the APs are running from physical addresses, before
+	 * paging has been enabled.
+	 */
+	if (p) {
+		if (IS_ENABLED(CONFIG_X86_32))
+			intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
+		else
+			intel_ucode_patch = p->data;
+	}
 }
 
 static int microcode_sanity_check(void *mc, int print_err)
@@ -607,6 +619,14 @@ int __init save_microcode_in_initrd_intel(void)
 	struct ucode_cpu_info uci;
 	struct cpio_data cp;
 
+	/*
+	 * initrd is going away, clear patch ptr. We will scan the microcode one
+	 * last time before jettisoning and save a patch, if found. Then we will
+	 * update that pointer too, with a stable patch address to use when
+	 * resuming the cores.
+	 */
+	intel_ucode_patch = NULL;
+
 	if (!load_builtin_intel_microcode(&cp))
 		cp = find_microcode_in_initrd(ucode_path, false);
 
@@ -619,9 +639,6 @@ int __init save_microcode_in_initrd_intel(void)
 
 	show_saved_mc();
 
-	/* initrd is going away, clear patch ptr. */
-	intel_ucode_patch = NULL;
-
 	return 0;
 }