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

Pull x86 microcode loading update from Peter Anvin:
 "This patchset lets us update the CPU microcode very, very early in
  initialization if the BIOS fails to do so (never happens, right?)

  This is handy for dealing with things like the Atom erratum where we
  have to run without PSE because microcode loading happens too late.

  As I mentioned in the x86/mm push request it depends on that
  infrastructure but it is otherwise a standalone feature."

* 'x86/microcode' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/Kconfig: Make early microcode loading a configuration feature
  x86/mm/init.c: Copy ucode from initrd image to kernel memory
  x86/head64.c: Early update ucode in 64-bit
  x86/head_32.S: Early update ucode in 32-bit
  x86/microcode_intel_early.c: Early update ucode on Intel's CPU
  x86/tlbflush.h: Define __native_flush_tlb_global_irq_disabled()
  x86/microcode_intel_lib.c: Early update ucode on Intel's CPU
  x86/microcode_core_early.c: Define interfaces for early loading ucode
  x86/common.c: load ucode in 64 bit or show loading ucode info in 32 bit on AP
  x86/common.c: Make have_cpuid_p() a global function
  x86/microcode_intel.h: Define functions and macros for early loading ucode
  x86, doc: Documentation for early microcode loading

Documentation/x86/early-microcode.txt

+Early load microcode
+====================
+By Fenghua Yu <fenghua.yu@intel.com>
+
+Kernel can update microcode in early phase of boot time. Loading microcode early
+can fix CPU issues before they are observed during kernel boot time.
+
+Microcode is stored in an initrd file. The microcode is read from the initrd
+file and loaded to CPUs during boot time.
+
+The format of the combined initrd image is microcode in cpio format followed by
+the initrd image (maybe compressed). Kernel parses the combined initrd image
+during boot time. The microcode file in cpio name space is:
+kernel/x86/microcode/GenuineIntel.bin
+
+During BSP boot (before SMP starts), if the kernel finds the microcode file in
+the initrd file, it parses the microcode and saves matching microcode in memory.
+If matching microcode is found, it will be uploaded in BSP and later on in all
+APs.
+
+The cached microcode patch is applied when CPUs resume from a sleep state.
+
+There are two legacy user space interfaces to load microcode, either through
+/dev/cpu/microcode or through /sys/devices/system/cpu/microcode/reload file
+in sysfs.
+
+In addition to these two legacy methods, the early loading method described
+here is the third method with which microcode can be uploaded to a system's
+CPUs.
+
+The following example script shows how to generate a new combined initrd file in
+/boot/initrd-3.5.0.ucode.img with original microcode microcode.bin and
+original initrd image /boot/initrd-3.5.0.img.
+
+mkdir initrd
+cd initrd
+mkdir kernel
+mkdir kernel/x86
+mkdir kernel/x86/microcode
+cp ../microcode.bin kernel/x86/microcode/GenuineIntel.bin
+find .|cpio -oc >../ucode.cpio
+cd ..
+cat ucode.cpio /boot/initrd-3.5.0.img >/boot/initrd-3.5.0.ucode.img

arch/x86/Kconfig

@@ -1054,6 +1054,24 @@ config MICROCODE_OLD_INTERFACE
 	def_bool y
 	depends on MICROCODE
 
+config MICROCODE_INTEL_LIB
+	def_bool y
+	depends on MICROCODE_INTEL
+
+config MICROCODE_INTEL_EARLY
+	bool "Early load microcode"
+	depends on MICROCODE_INTEL && BLK_DEV_INITRD
+	default y
+	help
+	  This option provides functionality to read additional microcode data
+	  at the beginning of initrd image. The data tells kernel to load
+	  microcode to CPU's as early as possible. No functional change if no
+	  microcode data is glued to the initrd, therefore it's safe to say Y.
+
+config MICROCODE_EARLY
+	def_bool y
+	depends on MICROCODE_INTEL_EARLY
+
 config X86_MSR
 	tristate "/dev/cpu/*/msr - Model-specific register support"
 	---help---

arch/x86/include/asm/microcode.h

@@ -57,4 +57,18 @@ static inline struct microcode_ops * __init init_amd_microcode(void)
 static inline void __exit exit_amd_microcode(void) {}
 #endif
 
+#ifdef CONFIG_MICROCODE_EARLY
+#define MAX_UCODE_COUNT 128
+extern void __init load_ucode_bsp(void);
+extern __init void load_ucode_ap(void);
+extern int __init save_microcode_in_initrd(void);
+#else
+static inline void __init load_ucode_bsp(void) {}
+static inline __init void load_ucode_ap(void) {}
+static inline int __init save_microcode_in_initrd(void)
+{
+	return 0;
+}
+#endif
+
 #endif /* _ASM_X86_MICROCODE_H */

arch/x86/include/asm/microcode_intel.h

+#ifndef _ASM_X86_MICROCODE_INTEL_H
+#define _ASM_X86_MICROCODE_INTEL_H
+
+#include <asm/microcode.h>
+
+struct microcode_header_intel {
+	unsigned int            hdrver;
+	unsigned int            rev;
+	unsigned int            date;
+	unsigned int            sig;
+	unsigned int            cksum;
+	unsigned int            ldrver;
+	unsigned int            pf;
+	unsigned int            datasize;
+	unsigned int            totalsize;
+	unsigned int            reserved[3];
+};
+
+struct microcode_intel {
+	struct microcode_header_intel hdr;
+	unsigned int            bits[0];
+};
+
+/* microcode format is extended from prescott processors */
+struct extended_signature {
+	unsigned int            sig;
+	unsigned int            pf;
+	unsigned int            cksum;
+};
+
+struct extended_sigtable {
+	unsigned int            count;
+	unsigned int            cksum;
+	unsigned int            reserved[3];
+	struct extended_signature sigs[0];
+};
+
+#define DEFAULT_UCODE_DATASIZE	(2000)
+#define MC_HEADER_SIZE		(sizeof(struct microcode_header_intel))
+#define DEFAULT_UCODE_TOTALSIZE (DEFAULT_UCODE_DATASIZE + MC_HEADER_SIZE)
+#define EXT_HEADER_SIZE		(sizeof(struct extended_sigtable))
+#define EXT_SIGNATURE_SIZE	(sizeof(struct extended_signature))
+#define DWSIZE			(sizeof(u32))
+
+#define get_totalsize(mc) \
+	(((struct microcode_intel *)mc)->hdr.totalsize ? \
+	 ((struct microcode_intel *)mc)->hdr.totalsize : \
+	 DEFAULT_UCODE_TOTALSIZE)
+
+#define get_datasize(mc) \
+	(((struct microcode_intel *)mc)->hdr.datasize ? \
+	 ((struct microcode_intel *)mc)->hdr.datasize : DEFAULT_UCODE_DATASIZE)
+
+#define sigmatch(s1, s2, p1, p2) \
+	(((s1) == (s2)) && (((p1) & (p2)) || (((p1) == 0) && ((p2) == 0))))
+
+#define exttable_size(et) ((et)->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE)
+
+extern int
+get_matching_microcode(unsigned int csig, int cpf, void *mc, int rev);
+extern int microcode_sanity_check(void *mc, int print_err);
+extern int get_matching_sig(unsigned int csig, int cpf, void *mc, int rev);
+extern int
+update_match_revision(struct microcode_header_intel *mc_header, int rev);
+
+#ifdef CONFIG_MICROCODE_INTEL_EARLY
+extern void __init load_ucode_intel_bsp(void);
+extern void __cpuinit load_ucode_intel_ap(void);
+extern void show_ucode_info_early(void);
+#else
+static inline __init void load_ucode_intel_bsp(void) {}
+static inline __cpuinit void load_ucode_intel_ap(void) {}
+static inline void show_ucode_info_early(void) {}
+#endif
+
+#if defined(CONFIG_MICROCODE_INTEL_EARLY) && defined(CONFIG_HOTPLUG_CPU)
+extern int save_mc_for_early(u8 *mc);
+#else
+static inline int save_mc_for_early(u8 *mc)
+{
+	return 0;
+}
+#endif
+
+#endif /* _ASM_X86_MICROCODE_INTEL_H */

arch/x86/include/asm/processor.h

@@ -180,6 +180,14 @@ extern void init_amd_cacheinfo(struct cpuinfo_x86 *c);
 extern void detect_extended_topology(struct cpuinfo_x86 *c);
 extern void detect_ht(struct cpuinfo_x86 *c);
 
+#ifdef CONFIG_X86_32
+extern int have_cpuid_p(void);
+#else
+static inline int have_cpuid_p(void)
+{
+	return 1;
+}
+#endif
 static inline void native_cpuid(unsigned int *eax, unsigned int *ebx,
 				unsigned int *ecx, unsigned int *edx)
 {

arch/x86/include/asm/tlbflush.h

@@ -20,10 +20,20 @@ static inline void __native_flush_tlb(void)
 	native_write_cr3(native_read_cr3());
 }
 
+static inline void __native_flush_tlb_global_irq_disabled(void)
+{
+	unsigned long cr4;
+
+	cr4 = native_read_cr4();
+	/* clear PGE */
+	native_write_cr4(cr4 & ~X86_CR4_PGE);
+	/* write old PGE again and flush TLBs */
+	native_write_cr4(cr4);
+}
+
 static inline void __native_flush_tlb_global(void)
 {
 	unsigned long flags;
-	unsigned long cr4;
 
 	/*
 	 * Read-modify-write to CR4 - protect it from preemption and
@@ -32,11 +42,7 @@ static inline void __native_flush_tlb_global(void)
 	 */
 	raw_local_irq_save(flags);
 
-	cr4 = native_read_cr4();
-	/* clear PGE */
-	native_write_cr4(cr4 & ~X86_CR4_PGE);
-	/* write old PGE again and flush TLBs */
-	native_write_cr4(cr4);
+	__native_flush_tlb_global_irq_disabled();
 
 	raw_local_irq_restore(flags);
 }

arch/x86/kernel/Makefile

@@ -87,6 +87,9 @@ obj-$(CONFIG_PARAVIRT_CLOCK)	+= pvclock.o
 
 obj-$(CONFIG_PCSPKR_PLATFORM)	+= pcspeaker.o
 
+obj-$(CONFIG_MICROCODE_EARLY)		+= microcode_core_early.o
+obj-$(CONFIG_MICROCODE_INTEL_EARLY)	+= microcode_intel_early.o
+obj-$(CONFIG_MICROCODE_INTEL_LIB)	+= microcode_intel_lib.o
 microcode-y				:= microcode_core.o
 microcode-$(CONFIG_MICROCODE_INTEL)	+= microcode_intel.o
 microcode-$(CONFIG_MICROCODE_AMD)	+= microcode_amd.o

arch/x86/kernel/cpu/common.c

@@ -37,6 +37,8 @@
 #include <asm/mce.h>
 #include <asm/msr.h>
 #include <asm/pat.h>
+#include <asm/microcode.h>
+#include <asm/microcode_intel.h>
 
 #ifdef CONFIG_X86_LOCAL_APIC
 #include <asm/uv/uv.h>
@@ -213,7 +215,7 @@ static inline int flag_is_changeable_p(u32 flag)
 }
 
 /* Probe for the CPUID instruction */
-static int __cpuinit have_cpuid_p(void)
+int __cpuinit have_cpuid_p(void)
 {
 	return flag_is_changeable_p(X86_EFLAGS_ID);
 }
@@ -249,11 +251,6 @@ static inline int flag_is_changeable_p(u32 flag)
 {
 	return 1;
 }
-/* Probe for the CPUID instruction */
-static inline int have_cpuid_p(void)
-{
-	return 1;
-}
 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
 {
 }
@@ -1223,6 +1220,12 @@ void __cpuinit cpu_init(void)
 	int cpu;
 	int i;
 
+	/*
+	 * Load microcode on this cpu if a valid microcode is available.
+	 * This is early microcode loading procedure.
+	 */
+	load_ucode_ap();
+
 	cpu = stack_smp_processor_id();
 	t = &per_cpu(init_tss, cpu);
 	oist = &per_cpu(orig_ist, cpu);
@@ -1314,6 +1317,8 @@ void __cpuinit cpu_init(void)
 	struct tss_struct *t = &per_cpu(init_tss, cpu);
 	struct thread_struct *thread = &curr->thread;
 
+	show_ucode_info_early();
+
 	if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask)) {
 		printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
 		for (;;)

arch/x86/kernel/head64.c

@@ -26,6 +26,7 @@
 #include <asm/e820.h>
 #include <asm/bios_ebda.h>
 #include <asm/bootparam_utils.h>
+#include <asm/microcode.h>
 
 /*
  * Manage page tables very early on.
@@ -165,6 +166,11 @@ void __init x86_64_start_kernel(char * real_mode_data)
 
 	copy_bootdata(__va(real_mode_data));
 
+	/*
+	 * Load microcode early on BSP.
+	 */
+	load_ucode_bsp();
+
 	if (console_loglevel == 10)
 		early_printk("Kernel alive\n");
 

arch/x86/kernel/head_32.S

@@ -144,6 +144,11 @@ ENTRY(startup_32)
 	movl %eax, pa(olpc_ofw_pgd)
 #endif
 
+#ifdef CONFIG_MICROCODE_EARLY
+	/* Early load ucode on BSP. */
+	call load_ucode_bsp
+#endif
+
 /*
  * Initialize page tables.  This creates a PDE and a set of page
  * tables, which are located immediately beyond __brk_base.  The variable
@@ -299,6 +304,12 @@ ENTRY(startup_32_smp)
 	movl %eax,%ss
 	leal -__PAGE_OFFSET(%ecx),%esp
 
+#ifdef CONFIG_MICROCODE_EARLY
+	/* Early load ucode on AP. */
+	call load_ucode_ap
+#endif
+
+
 default_entry:
 #define CR0_STATE	(X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
 			 X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \

arch/x86/kernel/microcode_core.c

@@ -364,10 +364,7 @@ static struct attribute_group mc_attr_group = {
 
 static void microcode_fini_cpu(int cpu)
 {
-	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-
 	microcode_ops->microcode_fini_cpu(cpu);
-	uci->valid = 0;
 }
 
 static enum ucode_state microcode_resume_cpu(int cpu)
@@ -383,6 +380,10 @@ static enum ucode_state microcode_resume_cpu(int cpu)
 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
 {
 	enum ucode_state ustate;
+	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+	if (uci && uci->valid)
+		return UCODE_OK;
 
 	if (collect_cpu_info(cpu))
 		return UCODE_ERROR;

arch/x86/kernel/microcode_core_early.c

+/*
+ *	X86 CPU microcode early update for Linux
+ *
+ *	Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
+ *			   H Peter Anvin" <hpa@zytor.com>
+ *
+ *	This driver allows to early upgrade microcode on Intel processors
+ *	belonging to IA-32 family - PentiumPro, Pentium II,
+ *	Pentium III, Xeon, Pentium 4, etc.
+ *
+ *	Reference: Section 9.11 of Volume 3, IA-32 Intel Architecture
+ *	Software Developer's Manual.
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+#include <linux/module.h>
+#include <asm/microcode_intel.h>
+#include <asm/processor.h>
+
+#define QCHAR(a, b, c, d) ((a) + ((b) << 8) + ((c) << 16) + ((d) << 24))
+#define CPUID_INTEL1 QCHAR('G', 'e', 'n', 'u')
+#define CPUID_INTEL2 QCHAR('i', 'n', 'e', 'I')
+#define CPUID_INTEL3 QCHAR('n', 't', 'e', 'l')
+#define CPUID_AMD1 QCHAR('A', 'u', 't', 'h')
+#define CPUID_AMD2 QCHAR('e', 'n', 't', 'i')
+#define CPUID_AMD3 QCHAR('c', 'A', 'M', 'D')
+
+#define CPUID_IS(a, b, c, ebx, ecx, edx)	\
+		(!((ebx ^ (a))|(edx ^ (b))|(ecx ^ (c))))
+
+/*
+ * In early loading microcode phase on BSP, boot_cpu_data is not set up yet.
+ * x86_vendor() gets vendor id for BSP.
+ *
+ * In 32 bit AP case, accessing boot_cpu_data needs linear address. To simplify
+ * coding, we still use x86_vendor() to get vendor id for AP.
+ *
+ * x86_vendor() gets vendor information directly through cpuid.
+ */
+static int __cpuinit x86_vendor(void)
+{
+	u32 eax = 0x00000000;
+	u32 ebx, ecx = 0, edx;
+
+	if (!have_cpuid_p())
+		return X86_VENDOR_UNKNOWN;
+
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+
+	if (CPUID_IS(CPUID_INTEL1, CPUID_INTEL2, CPUID_INTEL3, ebx, ecx, edx))
+		return X86_VENDOR_INTEL;
+
+	if (CPUID_IS(CPUID_AMD1, CPUID_AMD2, CPUID_AMD3, ebx, ecx, edx))
+		return X86_VENDOR_AMD;
+
+	return X86_VENDOR_UNKNOWN;
+}
+
+void __init load_ucode_bsp(void)
+{
+	int vendor = x86_vendor();
+
+	if (vendor == X86_VENDOR_INTEL)
+		load_ucode_intel_bsp();
+}
+
+void __cpuinit load_ucode_ap(void)
+{
+	int vendor = x86_vendor();
+
+	if (vendor == X86_VENDOR_INTEL)
+		load_ucode_intel_ap();
+}

arch/x86/kernel/microcode_intel.c

@@ -79,7 +79,7 @@
 #include <linux/module.h>
 #include <linux/vmalloc.h>
 
-#include <asm/microcode.h>
+#include <asm/microcode_intel.h>
 #include <asm/processor.h>
 #include <asm/msr.h>
 
@@ -87,59 +87,6 @@ MODULE_DESCRIPTION("Microcode Update Driver");
 MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
 MODULE_LICENSE("GPL");
 
-struct microcode_header_intel {
-	unsigned int            hdrver;
-	unsigned int            rev;
-	unsigned int            date;
-	unsigned int            sig;
-	unsigned int            cksum;
-	unsigned int            ldrver;
-	unsigned int            pf;
-	unsigned int            datasize;
-	unsigned int            totalsize;
-	unsigned int            reserved[3];
-};
-
-struct microcode_intel {
-	struct microcode_header_intel hdr;
-	unsigned int            bits[0];
-};
-
-/* microcode format is extended from prescott processors */
-struct extended_signature {
-	unsigned int            sig;
-	unsigned int            pf;
-	unsigned int            cksum;
-};
-
-struct extended_sigtable {
-	unsigned int            count;
-	unsigned int            cksum;
-	unsigned int            reserved[3];
-	struct extended_signature sigs[0];
-};
-
-#define DEFAULT_UCODE_DATASIZE	(2000)
-#define MC_HEADER_SIZE		(sizeof(struct microcode_header_intel))
-#define DEFAULT_UCODE_TOTALSIZE (DEFAULT_UCODE_DATASIZE + MC_HEADER_SIZE)
-#define EXT_HEADER_SIZE		(sizeof(struct extended_sigtable))
-#define EXT_SIGNATURE_SIZE	(sizeof(struct extended_signature))
-#define DWSIZE			(sizeof(u32))
-
-#define get_totalsize(mc) \
-	(((struct microcode_intel *)mc)->hdr.totalsize ? \
-	 ((struct microcode_intel *)mc)->hdr.totalsize : \
-	 DEFAULT_UCODE_TOTALSIZE)
-
-#define get_datasize(mc) \
-	(((struct microcode_intel *)mc)->hdr.datasize ? \
-	 ((struct microcode_intel *)mc)->hdr.datasize : DEFAULT_UCODE_DATASIZE)
-
-#define sigmatch(s1, s2, p1, p2) \
-	(((s1) == (s2)) && (((p1) & (p2)) || (((p1) == 0) && ((p2) == 0))))
-
-#define exttable_size(et) ((et)->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE)
-
 static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu_num);
@@ -162,128 +109,25 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
 	return 0;
 }
 
-static inline int update_match_cpu(struct cpu_signature *csig, int sig, int pf)
-{
-	return (!sigmatch(sig, csig->sig, pf, csig->pf)) ? 0 : 1;
-}
-
-static inline int
-update_match_revision(struct microcode_header_intel *mc_header, int rev)
-{
-	return (mc_header->rev <= rev) ? 0 : 1;
-}
-
-static int microcode_sanity_check(void *mc)
-{
-	unsigned long total_size, data_size, ext_table_size;
-	struct microcode_header_intel *mc_header = mc;
-	struct extended_sigtable *ext_header = NULL;
-	int sum, orig_sum, ext_sigcount = 0, i;
-	struct extended_signature *ext_sig;
-
-	total_size = get_totalsize(mc_header);
-	data_size = get_datasize(mc_header);
-
-	if (data_size + MC_HEADER_SIZE > total_size) {
-		pr_err("error! Bad data size in microcode data file\n");
-		return -EINVAL;
-	}
-
-	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
-		pr_err("error! Unknown microcode update format\n");
-		return -EINVAL;
-	}
-	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
-	if (ext_table_size) {
-		if ((ext_table_size < EXT_HEADER_SIZE)
-		 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
-			pr_err("error! Small exttable size in microcode data file\n");
-			return -EINVAL;
-		}
-		ext_header = mc + MC_HEADER_SIZE + data_size;
-		if (ext_table_size != exttable_size(ext_header)) {
-			pr_err("error! Bad exttable size in microcode data file\n");
-			return -EFAULT;
-		}
-		ext_sigcount = ext_header->count;
-	}
-
-	/* check extended table checksum */
-	if (ext_table_size) {
-		int ext_table_sum = 0;
-		int *ext_tablep = (int *)ext_header;
-
-		i = ext_table_size / DWSIZE;
-		while (i--)
-			ext_table_sum += ext_tablep[i];
-		if (ext_table_sum) {
-			pr_warning("aborting, bad extended signature table checksum\n");
-			return -EINVAL;
-		}
-	}
-
-	/* calculate the checksum */
-	orig_sum = 0;
-	i = (MC_HEADER_SIZE + data_size) / DWSIZE;
-	while (i--)
-		orig_sum += ((int *)mc)[i];
-	if (orig_sum) {
-		pr_err("aborting, bad checksum\n");
-		return -EINVAL;
-	}
-	if (!ext_table_size)
-		return 0;
-	/* check extended signature checksum */
-	for (i = 0; i < ext_sigcount; i++) {
-		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
-			  EXT_SIGNATURE_SIZE * i;
-		sum = orig_sum
-			- (mc_header->sig + mc_header->pf + mc_header->cksum)
-			+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
-		if (sum) {
-			pr_err("aborting, bad checksum\n");
-			return -EINVAL;
-		}
-	}
-	return 0;
-}
-
 /*
  * return 0 - no update found
  * return 1 - found update
  */
-static int
-get_matching_microcode(struct cpu_signature *cpu_sig, void *mc, int rev)
+static int get_matching_mc(struct microcode_intel *mc_intel, int cpu)
 {
-	struct microcode_header_intel *mc_header = mc;
-	struct extended_sigtable *ext_header;
-	unsigned long total_size = get_totalsize(mc_header);
-	int ext_sigcount, i;
-	struct extended_signature *ext_sig;
-
-	if (!update_match_revision(mc_header, rev))
-		return 0;
-
-	if (update_match_cpu(cpu_sig, mc_header->sig, mc_header->pf))
-		return 1;
+	struct cpu_signature cpu_sig;
+	unsigned int csig, cpf, crev;
 
-	/* Look for ext. headers: */
-	if (total_size <= get_datasize(mc_header) + MC_HEADER_SIZE)
-		return 0;
+	collect_cpu_info(cpu, &cpu_sig);
 
-	ext_header = mc + get_datasize(mc_header) + MC_HEADER_SIZE;
-	ext_sigcount = ext_header->count;
-	ext_sig = (void *)ext_header + EXT_HEADER_SIZE;
+	csig = cpu_sig.sig;
+	cpf = cpu_sig.pf;
+	crev = cpu_sig.rev;
 
-	for (i = 0; i < ext_sigcount; i++) {
-		if (update_match_cpu(cpu_sig, ext_sig->sig, ext_sig->pf))
-			return 1;
-		ext_sig++;
-	}
-	return 0;
+	return get_matching_microcode(csig, cpf, mc_intel, crev);
 }
 
-static int apply_microcode(int cpu)
+int apply_microcode(int cpu)
 {
 	struct microcode_intel *mc_intel;
 	struct ucode_cpu_info *uci;
@@ -300,6 +144,14 @@ static int apply_microcode(int cpu)
 	if (mc_intel == NULL)
 		return 0;
 
+	/*
+	 * Microcode on this CPU could be updated earlier. Only apply the
+	 * microcode patch in mc_intel when it is newer than the one on this
+	 * CPU.
+	 */
+	if (get_matching_mc(mc_intel, cpu) == 0)
+		return 0;
+
 	/* write microcode via MSR 0x79 */
 	wrmsr(MSR_IA32_UCODE_WRITE,
 	      (unsigned long) mc_intel->bits,
@@ -338,6 +190,7 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
 	unsigned int leftover = size;
 	enum ucode_state state = UCODE_OK;
 	unsigned int curr_mc_size = 0;
+	unsigned int csig, cpf;
 
 	while (leftover) {
 		struct microcode_header_intel mc_header;
@@ -362,11 +215,13 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
 		}
 
 		if (get_ucode_data(mc, ucode_ptr, mc_size) ||
-		    microcode_sanity_check(mc) < 0) {
+		    microcode_sanity_check(mc, 1) < 0) {
 			break;
 		}
 
-		if (get_matching_microcode(&uci->cpu_sig, mc, new_rev)) {
+		csig = uci->cpu_sig.sig;
+		cpf = uci->cpu_sig.pf;
+		if (get_matching_microcode(csig, cpf, mc, new_rev)) {
 			vfree(new_mc);
 			new_rev = mc_header.rev;
 			new_mc  = mc;
@@ -393,6 +248,13 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
 	vfree(uci->mc);
 	uci->mc = (struct microcode_intel *)new_mc;
 
+	/*
+	 * If early loading microcode is supported, save this mc into
+	 * permanent memory. So it will be loaded early when a CPU is hot added
+	 * or resumes.
+	 */
+	save_mc_for_early(new_mc);
+
 	pr_debug("CPU%d found a matching microcode update with version 0x%x (current=0x%x)\n",
 		 cpu, new_rev, uci->cpu_sig.rev);
 out:

arch/x86/kernel/microcode_intel_lib.c

+/*
+ *	Intel CPU Microcode Update Driver for Linux
+ *
+ *	Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
+ *			   H Peter Anvin" <hpa@zytor.com>
+ *
+ *	This driver allows to upgrade microcode on Intel processors
+ *	belonging to IA-32 family - PentiumPro, Pentium II,
+ *	Pentium III, Xeon, Pentium 4, etc.
+ *
+ *	Reference: Section 8.11 of Volume 3a, IA-32 Intel? Architecture
+ *	Software Developer's Manual
+ *	Order Number 253668 or free download from:
+ *
+ *	http://developer.intel.com/Assets/PDF/manual/253668.pdf
+ *
+ *	For more information, go to http://www.urbanmyth.org/microcode
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ */
+#include <linux/firmware.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <asm/microcode_intel.h>
+#include <asm/processor.h>
+#include <asm/msr.h>
+
+static inline int
+update_match_cpu(unsigned int csig, unsigned int cpf,
+		 unsigned int sig, unsigned int pf)
+{
+	return (!sigmatch(sig, csig, pf, cpf)) ? 0 : 1;
+}
+
+int
+update_match_revision(struct microcode_header_intel *mc_header, int rev)
+{
+	return (mc_header->rev <= rev) ? 0 : 1;
+}
+
+int microcode_sanity_check(void *mc, int print_err)
+{
+	unsigned long total_size, data_size, ext_table_size;
+	struct microcode_header_intel *mc_header = mc;
+	struct extended_sigtable *ext_header = NULL;
+	int sum, orig_sum, ext_sigcount = 0, i;
+	struct extended_signature *ext_sig;
+
+	total_size = get_totalsize(mc_header);
+	data_size = get_datasize(mc_header);
+
+	if (data_size + MC_HEADER_SIZE > total_size) {
+		if (print_err)
+			pr_err("error! Bad data size in microcode data file\n");
+		return -EINVAL;
+	}
+
+	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
+		if (print_err)
+			pr_err("error! Unknown microcode update format\n");
+		return -EINVAL;
+	}
+	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
+	if (ext_table_size) {
+		if ((ext_table_size < EXT_HEADER_SIZE)
+		 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
+			if (print_err)
+				pr_err("error! Small exttable size in microcode data file\n");
+			return -EINVAL;
+		}
+		ext_header = mc + MC_HEADER_SIZE + data_size;
+		if (ext_table_size != exttable_size(ext_header)) {
+			if (print_err)
+				pr_err("error! Bad exttable size in microcode data file\n");
+			return -EFAULT;
+		}
+		ext_sigcount = ext_header->count;
+	}
+
+	/* check extended table checksum */
+	if (ext_table_size) {
+		int ext_table_sum = 0;
+		int *ext_tablep = (int *)ext_header;
+
+		i = ext_table_size / DWSIZE;
+		while (i--)
+			ext_table_sum += ext_tablep[i];
+		if (ext_table_sum) {
+			if (print_err)
+				pr_warn("aborting, bad extended signature table checksum\n");
+			return -EINVAL;
+		}
+	}
+
+	/* calculate the checksum */
+	orig_sum = 0;
+	i = (MC_HEADER_SIZE + data_size) / DWSIZE;
+	while (i--)
+		orig_sum += ((int *)mc)[i];
+	if (orig_sum) {
+		if (print_err)
+			pr_err("aborting, bad checksum\n");
+		return -EINVAL;
+	}
+	if (!ext_table_size)
+		return 0;
+	/* check extended signature checksum */
+	for (i = 0; i < ext_sigcount; i++) {
+		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
+			  EXT_SIGNATURE_SIZE * i;
+		sum = orig_sum
+			- (mc_header->sig + mc_header->pf + mc_header->cksum)
+			+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
+		if (sum) {
+			if (print_err)
+				pr_err("aborting, bad checksum\n");
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(microcode_sanity_check);
+
+/*
+ * return 0 - no update found
+ * return 1 - found update
+ */
+int get_matching_sig(unsigned int csig, int cpf, void *mc, int rev)
+{
+	struct microcode_header_intel *mc_header = mc;
+	struct extended_sigtable *ext_header;
+	unsigned long total_size = get_totalsize(mc_header);
+	int ext_sigcount, i;
+	struct extended_signature *ext_sig;
+
+	if (update_match_cpu(csig, cpf, mc_header->sig, mc_header->pf))
+		return 1;
+
+	/* Look for ext. headers: */
+	if (total_size <= get_datasize(mc_header) + MC_HEADER_SIZE)
+		return 0;
+
+	ext_header = mc + get_datasize(mc_header) + MC_HEADER_SIZE;
+	ext_sigcount = ext_header->count;
+	ext_sig = (void *)ext_header + EXT_HEADER_SIZE;
+
+	for (i = 0; i < ext_sigcount; i++) {
+		if (update_match_cpu(csig, cpf, ext_sig->sig, ext_sig->pf))
+			return 1;
+		ext_sig++;
+	}
+	return 0;
+}
+
+/*
+ * return 0 - no update found
+ * return 1 - found update
+ */
+int get_matching_microcode(unsigned int csig, int cpf, void *mc, int rev)
+{
+	struct microcode_header_intel *mc_header = mc;
+
+	if (!update_match_revision(mc_header, rev))
+		return 0;
+
+	return get_matching_sig(csig, cpf, mc, rev);
+}
+EXPORT_SYMBOL_GPL(get_matching_microcode);

arch/x86/mm/init.c

@@ -16,6 +16,7 @@
 #include <asm/tlb.h>
 #include <asm/proto.h>
 #include <asm/dma.h>		/* for MAX_DMA_PFN */
+#include <asm/microcode.h>
 
 #include "mm_internal.h"
 
@@ -534,6 +535,15 @@ void free_initmem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 void __init free_initrd_mem(unsigned long start, unsigned long end)
 {
+#ifdef CONFIG_MICROCODE_EARLY
+	/*
+	 * Remember, initrd memory may contain microcode or other useful things.
+	 * Before we lose initrd mem, we need to find a place to hold them
+	 * now that normal virtual memory is enabled.
+	 */
+	save_microcode_in_initrd();
+#endif
+
 	/*
 	 * end could be not aligned, and We can not align that,
 	 * decompresser could be confused by aligned initrd_end