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#ifndef _ASM_X86_ALTERNATIVE_H

#define _ASM_X86_ALTERNATIVE_H

#include 

#include 

#include 

#include 

/*

 * Alternative inline assembly for SMP.

 *

 * The LOCK_PREFIX macro defined here replaces the LOCK and

 * LOCK_PREFIX macros used everywhere in the source tree.

 *

 * SMP alternatives use the same data structures as the other

 * alternatives and the X86_FEATURE_UP flag to indicate the case of a

 * UP system running a SMP kernel.  The existing apply_alternatives()

 * works fine for patching a SMP kernel for UP.

 *

 * The SMP alternative tables can be kept after boot and contain both

 * UP and SMP versions of the instructions to allow switching back to

 * SMP at runtime, when hotplugging in a new CPU, which is especially

 * useful in virtualized environments.

 *

 * The very common lock prefix is handled as special case in a

 * separate table which is a pure address list without replacement ptr

 * and size information.  That keeps the table sizes small.

 */

#ifdef CONFIG_SMP

#define LOCK_PREFIX \

		".section .smp_locks,\"a\"\n"	\

		_ASM_ALIGN "\n"			\

		_ASM_PTR "661f\n" /* address */	\

		".previous\n"			\

		"661:\n\tlock; "

#else /* ! CONFIG_SMP */

#define LOCK_PREFIX ""

#endif

/* This must be included *after* the definition of LOCK_PREFIX */

#include 

struct alt_instr {

	u8 *instr;		/* original instruction */

	u8 *replacement;

	u8  cpuid;		/* cpuid bit set for replacement */

	u8  instrlen;		/* length of original instruction */

	u8  replacementlen;	/* length of new instruction, <= instrlen */

	u8  pad1;

#ifdef CONFIG_X86_64

	u32 pad2;

#endif

};

extern void alternative_instructions(void);

extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);

struct module;

#ifdef CONFIG_SMP

extern void alternatives_smp_module_add(struct module *mod, char *name,

					void *locks, void *locks_end,

					void *text, void *text_end);

extern void alternatives_smp_module_del(struct module *mod);

extern void alternatives_smp_switch(int smp);

#else

static inline void alternatives_smp_module_add(struct module *mod, char *name,

					       void *locks, void *locks_end,

					       void *text, void *text_end) {}

static inline void alternatives_smp_module_del(struct module *mod) {}

static inline void alternatives_smp_switch(int smp) {}

#endif	/* CONFIG_SMP */

/* alternative assembly primitive: */

#define ALTERNATIVE(oldinstr, newinstr, feature)			\

									\

      "661:\n\t" oldinstr "\n662:\n"					\

      ".section .altinstructions,\"a\"\n"				\

      _ASM_ALIGN "\n"							\

      _ASM_PTR "661b\n"				/* label           */	\

      _ASM_PTR "663f\n"				/* new instruction */	\

      "	 .byte " __stringify(feature) "\n"	/* feature bit     */	\

      "	 .byte 662b-661b\n"			/* sourcelen       */	\

      "	 .byte 664f-663f\n"			/* replacementlen  */	\

      "	 .byte 0xff + (664f-663f) - (662b-661b)\n" /* rlen <= slen */	\

      ".previous\n"							\

      ".section .altinstr_replacement, \"ax\"\n"			\

      "663:\n\t" newinstr "\n664:\n"		/* replacement     */	\

      ".previous"

/*

 * Alternative instructions for different CPU types or capabilities.

 *

 * This allows to use optimized instructions even on generic binary

 * kernels.

 *

 * length of oldinstr must be longer or equal the length of newinstr

 * It can be padded with nops as needed.

 *

 * For non barrier like inlines please define new variants

 * without volatile and memory clobber.

 */

#define alternative(oldinstr, newinstr, feature)			\

	asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")

/*

 * Alternative inline assembly with input.

 *

 * Pecularities:

 * No memory clobber here.

 * Argument numbers start with 1.

 * Best is to use constraints that are fixed size (like (%1) ... "r")

 * If you use variable sized constraints like "m" or "g" in the

 * replacement make sure to pad to the worst case length.

 * Leaving an unused argument 0 to keep API compatibility.

 */

#define alternative_input(oldinstr, newinstr, feature, input...)	\

	asm volatile (ALTERNATIVE(oldinstr, newinstr, feature)		\

		: : "i" (0), ## input)

/* Like alternative_input, but with a single output argument */

#define alternative_io(oldinstr, newinstr, feature, output, input...)	\

	asm volatile (ALTERNATIVE(oldinstr, newinstr, feature)		\

		: output : "i" (0), ## input)

/*

 * use this macro(s) if you need more than one output parameter

 * in alternative_io

 */

#define ASM_OUTPUT2(a) a

struct paravirt_patch_site;

#ifdef CONFIG_PARAVIRT

void apply_paravirt(struct paravirt_patch_site *start,

		    struct paravirt_patch_site *end);

#else

static inline void apply_paravirt(struct paravirt_patch_site *start,

				  struct paravirt_patch_site *end)

{}

#define __parainstructions	NULL

#define __parainstructions_end	NULL

#endif

/*

 * Clear and restore the kernel write-protection flag on the local CPU.

 * Allows the kernel to edit read-only pages.

 * Side-effect: any interrupt handler running between save and restore will have

 * the ability to write to read-only pages.

 *

 * Warning:

 * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and

 * no thread can be preempted in the instructions being modified (no iret to an

 * invalid instruction possible) or if the instructions are changed from a

 * consistent state to another consistent state atomically.

 * More care must be taken when modifying code in the SMP case because of

 * Intel's errata.

 * On the local CPU you need to be protected again NMI or MCE handlers seeing an

 * inconsistent instruction while you patch.

 */

extern void *text_poke(void *addr, const void *opcode, size_t len);

#endif /* _ASM_X86_ALTERNATIVE_H */