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Commit c47f39e3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 0cc9129d da76f64e

Documentation/x86/early-microcode.txt

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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

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@@ -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

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@@ -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

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#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

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@@ -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)

{