[deliverable/linux.git] / include / asm-x86 / alternative.h

#ifndef _ASM_X86_ALTERNATIVE_H
#define _ASM_X86_ALTERNATIVE_H

#include <linux/types.h>
#include <linux/stddef.h>
#include <asm/asm.h>

/*
 * 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 <asm/cpufeature.h>

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 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 ("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 %c0\n"		/* feature bit */	\
		      "	 .byte 662b-661b\n"	/* sourcelen */		\
		      "	 .byte 664f-663f\n"	/* replacementlen */	\
		      ".previous\n"					\
		      ".section .altinstr_replacement,\"ax\"\n"		\
		      "663:\n\t" newinstr "\n664:\n"  /* replacement */	\
		      ".previous" :: "i" (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.
 */
#define alternative_input(oldinstr, newinstr, feature, input...)	\
	asm volatile ("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 %c0\n"		/* feature bit */	\
		      "	 .byte 662b-661b\n"	/* sourcelen */		\
		      "	 .byte 664f-663f\n"	/* replacementlen */	\
		      ".previous\n"					\
		      ".section .altinstr_replacement,\"ax\"\n"		\
		      "663:\n\t" newinstr "\n664:\n"  /* replacement */	\
		      ".previous" :: "i" (feature), ##input)

/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, feature, output, input...)	\
	asm volatile ("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 %c[feat]\n"	/* feature bit */	\
		      "	 .byte 662b-661b\n"	/* sourcelen */		\
		      "	 .byte 664f-663f\n"	/* replacementlen */	\
		      ".previous\n"					\
		      ".section .altinstr_replacement,\"ax\"\n"		\
		      "663:\n\t" newinstr "\n664:\n"  /* replacement */ \
		      ".previous" : output : [feat] "i" (feature), ##input)

/*
 * use this macro(s) if you need more than one output parameter
 * in alternative_io
 */
#define ASM_OUTPUT2(a, b) a, b

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

extern void text_poke(void *addr, unsigned char *opcode, int len);

#endif /* _ASM_X86_ALTERNATIVE_H */
Commit	Line	Data
6b592570 PA	1	#ifndef _ASM_X86_ALTERNATIVE_H
	2	#define _ASM_X86_ALTERNATIVE_H
	3
	4	#include <linux/types.h>
	5	#include <linux/stddef.h>
	6	#include <asm/asm.h>
	7
	8	/*
	9	* Alternative inline assembly for SMP.
	10	*
	11	* The LOCK_PREFIX macro defined here replaces the LOCK and
	12	* LOCK_PREFIX macros used everywhere in the source tree.
	13	*
	14	* SMP alternatives use the same data structures as the other
	15	* alternatives and the X86_FEATURE_UP flag to indicate the case of a
	16	* UP system running a SMP kernel. The existing apply_alternatives()
	17	* works fine for patching a SMP kernel for UP.
	18	*
	19	* The SMP alternative tables can be kept after boot and contain both
	20	* UP and SMP versions of the instructions to allow switching back to
	21	* SMP at runtime, when hotplugging in a new CPU, which is especially
	22	* useful in virtualized environments.
	23	*
	24	* The very common lock prefix is handled as special case in a
	25	* separate table which is a pure address list without replacement ptr
	26	* and size information. That keeps the table sizes small.
	27	*/
	28
	29	#ifdef CONFIG_SMP
	30	#define LOCK_PREFIX \
	31	".section .smp_locks,\"a\"\n" \
	32	_ASM_ALIGN "\n" \
	33	_ASM_PTR "661f\n" /* address */ \
	34	".previous\n" \
	35	"661:\n\tlock; "
	36
	37	#else /* ! CONFIG_SMP */
	38	#define LOCK_PREFIX ""
	39	#endif
	40
	41	/* This must be included after the definition of LOCK_PREFIX */
	42	#include <asm/cpufeature.h>
	43
	44	struct alt_instr {
	45	u8 instr; / original instruction */
	46	u8 *replacement;
	47	u8 cpuid; /* cpuid bit set for replacement */
	48	u8 instrlen; /* length of original instruction */
	49	u8 replacementlen; /* length of new instruction, <= instrlen */
	50	u8 pad1;
	51	#ifdef CONFIG_X86_64
	52	u32 pad2;
	53	#endif
	54	};
	55
	56	extern void alternative_instructions(void);
	57	extern void apply_alternatives(struct alt_instr start, struct alt_instr end);
	58
	59	struct module;
	60
	61	#ifdef CONFIG_SMP
	62	extern void alternatives_smp_module_add(struct module mod, char name,
	63	void locks, void locks_end,
	64	void text, void text_end);
65	extern void alternatives_smp_module_del(struct module *mod);
66	extern void alternatives_smp_switch(int smp);
67	#else
68	static inline void alternatives_smp_module_add(struct module mod, char name,
69	void locks, void locks_end,
70	void text, void text_end) {}
71	static inline void alternatives_smp_module_del(struct module *mod) {}
72	static inline void alternatives_smp_switch(int smp) {}
73	#endif /* CONFIG_SMP */
74
75	/*
76	* Alternative instructions for different CPU types or capabilities.
77	*
78	* This allows to use optimized instructions even on generic binary
79	* kernels.
80	*
81	* length of oldinstr must be longer or equal the length of newinstr
82	* It can be padded with nops as needed.
83	*
84	* For non barrier like inlines please define new variants
85	* without volatile and memory clobber.
86	*/
87	#define alternative(oldinstr, newinstr, feature) \
88	asm volatile ("661:\n\t" oldinstr "\n662:\n" \
89	".section .altinstructions,\"a\"\n" \
90	_ASM_ALIGN "\n" \
91	_ASM_PTR "661b\n" /* label */ \
92	_ASM_PTR "663f\n" /* new instruction */ \
93	" .byte %c0\n" /* feature bit */ \
94	" .byte 662b-661b\n" /* sourcelen */ \
95	" .byte 664f-663f\n" /* replacementlen */ \
96	".previous\n" \
97	".section .altinstr_replacement,\"ax\"\n" \
98	"663:\n\t" newinstr "\n664:\n" /* replacement */ \
99	".previous" :: "i" (feature) : "memory")
100
101	/*
102	* Alternative inline assembly with input.
103	*
104	* Pecularities:
105	* No memory clobber here.
106	* Argument numbers start with 1.
107	* Best is to use constraints that are fixed size (like (%1) ... "r")
108	* If you use variable sized constraints like "m" or "g" in the
109	* replacement make sure to pad to the worst case length.
110	*/
111	#define alternative_input(oldinstr, newinstr, feature, input...) \
112	asm volatile ("661:\n\t" oldinstr "\n662:\n" \
113	".section .altinstructions,\"a\"\n" \
114	_ASM_ALIGN "\n" \
115	_ASM_PTR "661b\n" /* label */ \
116	_ASM_PTR "663f\n" /* new instruction */ \
117	" .byte %c0\n" /* feature bit */ \
118	" .byte 662b-661b\n" /* sourcelen */ \
119	" .byte 664f-663f\n" /* replacementlen */ \
120	".previous\n" \
121	".section .altinstr_replacement,\"ax\"\n" \
122	"663:\n\t" newinstr "\n664:\n" /* replacement */ \
123	".previous" :: "i" (feature), ##input)
124
125	/* Like alternative_input, but with a single output argument */
126	#define alternative_io(oldinstr, newinstr, feature, output, input...) \
127	asm volatile ("661:\n\t" oldinstr "\n662:\n" \
128	".section .altinstructions,\"a\"\n" \
129	_ASM_ALIGN "\n" \
130	_ASM_PTR "661b\n" /* label */ \
131	_ASM_PTR "663f\n" /* new instruction */ \
132	" .byte %c[feat]\n" /* feature bit */ \
133	" .byte 662b-661b\n" /* sourcelen */ \
134	" .byte 664f-663f\n" /* replacementlen */ \
135	".previous\n" \
136	".section .altinstr_replacement,\"ax\"\n" \
137	"663:\n\t" newinstr "\n664:\n" /* replacement */ \
138	".previous" : output : [feat] "i" (feature), ##input)
139
140	/*
141	* use this macro(s) if you need more than one output parameter
142	* in alternative_io
143	*/
144	#define ASM_OUTPUT2(a, b) a, b
145
146	struct paravirt_patch_site;
147	#ifdef CONFIG_PARAVIRT
148	void apply_paravirt(struct paravirt_patch_site *start,
149	struct paravirt_patch_site *end);
96a388de	150	#else
6b592570 PA	151	static inline void
	152	apply_paravirt(struct paravirt_patch_site *start,
	153	struct paravirt_patch_site *end)
	154	{}
	155	#define __parainstructions NULL
	156	#define __parainstructions_end NULL
96a388de	157	#endif
6b592570 PA	158
	159	extern void text_poke(void addr, unsigned char opcode, int len);
	160
	161	#endif /* _ASM_X86_ALTERNATIVE_H */