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Gerd Hoffmann9a0b5812006-03-23 02:59:32 -08001#ifndef _I386_ALTERNATIVE_H
2#define _I386_ALTERNATIVE_H
3
Kirill Smelkov30343d62006-06-23 02:04:33 -07004#include <asm/types.h>
Rusty Russell139ec7c2006-12-07 02:14:08 +01005#include <linux/stddef.h>
Gerd Hoffmannd167a512006-06-26 13:56:16 +02006#include <linux/types.h>
7
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -08008struct alt_instr {
9 u8 *instr; /* original instruction */
10 u8 *replacement;
11 u8 cpuid; /* cpuid bit set for replacement */
12 u8 instrlen; /* length of original instruction */
13 u8 replacementlen; /* length of new instruction, <= instrlen */
14 u8 pad;
15};
16
Jeremy Fitzhardinge1353ebb2007-05-02 19:27:12 +020017extern void alternative_instructions(void);
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -080018extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
19
20struct module;
Gerd Hoffmann8ec4d412006-07-01 04:36:18 -070021#ifdef CONFIG_SMP
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -080022extern void alternatives_smp_module_add(struct module *mod, char *name,
23 void *locks, void *locks_end,
24 void *text, void *text_end);
25extern void alternatives_smp_module_del(struct module *mod);
26extern void alternatives_smp_switch(int smp);
Gerd Hoffmann8ec4d412006-07-01 04:36:18 -070027#else
28static inline void alternatives_smp_module_add(struct module *mod, char *name,
29 void *locks, void *locks_end,
30 void *text, void *text_end) {}
31static inline void alternatives_smp_module_del(struct module *mod) {}
32static inline void alternatives_smp_switch(int smp) {}
Jeremy Fitzhardinged0175ab2007-05-02 19:27:13 +020033#endif /* CONFIG_SMP */
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -080034
35/*
36 * Alternative instructions for different CPU types or capabilities.
37 *
38 * This allows to use optimized instructions even on generic binary
39 * kernels.
40 *
41 * length of oldinstr must be longer or equal the length of newinstr
42 * It can be padded with nops as needed.
43 *
44 * For non barrier like inlines please define new variants
45 * without volatile and memory clobber.
46 */
47#define alternative(oldinstr, newinstr, feature) \
48 asm volatile ("661:\n\t" oldinstr "\n662:\n" \
49 ".section .altinstructions,\"a\"\n" \
50 " .align 4\n" \
51 " .long 661b\n" /* label */ \
52 " .long 663f\n" /* new instruction */ \
53 " .byte %c0\n" /* feature bit */ \
54 " .byte 662b-661b\n" /* sourcelen */ \
55 " .byte 664f-663f\n" /* replacementlen */ \
56 ".previous\n" \
57 ".section .altinstr_replacement,\"ax\"\n" \
58 "663:\n\t" newinstr "\n664:\n" /* replacement */\
59 ".previous" :: "i" (feature) : "memory")
60
61/*
62 * Alternative inline assembly with input.
63 *
64 * Pecularities:
65 * No memory clobber here.
66 * Argument numbers start with 1.
67 * Best is to use constraints that are fixed size (like (%1) ... "r")
68 * If you use variable sized constraints like "m" or "g" in the
69 * replacement maake sure to pad to the worst case length.
70 */
71#define alternative_input(oldinstr, newinstr, feature, input...) \
72 asm volatile ("661:\n\t" oldinstr "\n662:\n" \
73 ".section .altinstructions,\"a\"\n" \
74 " .align 4\n" \
75 " .long 661b\n" /* label */ \
76 " .long 663f\n" /* new instruction */ \
77 " .byte %c0\n" /* feature bit */ \
78 " .byte 662b-661b\n" /* sourcelen */ \
79 " .byte 664f-663f\n" /* replacementlen */ \
80 ".previous\n" \
81 ".section .altinstr_replacement,\"ax\"\n" \
82 "663:\n\t" newinstr "\n664:\n" /* replacement */\
83 ".previous" :: "i" (feature), ##input)
84
85/*
86 * Alternative inline assembly for SMP.
87 *
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -080088 * The LOCK_PREFIX macro defined here replaces the LOCK and
89 * LOCK_PREFIX macros used everywhere in the source tree.
90 *
91 * SMP alternatives use the same data structures as the other
92 * alternatives and the X86_FEATURE_UP flag to indicate the case of a
93 * UP system running a SMP kernel. The existing apply_alternatives()
94 * works fine for patching a SMP kernel for UP.
95 *
96 * The SMP alternative tables can be kept after boot and contain both
97 * UP and SMP versions of the instructions to allow switching back to
98 * SMP at runtime, when hotplugging in a new CPU, which is especially
99 * useful in virtualized environments.
100 *
101 * The very common lock prefix is handled as special case in a
102 * separate table which is a pure address list without replacement ptr
103 * and size information. That keeps the table sizes small.
104 */
105
106#ifdef CONFIG_SMP
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -0800107#define LOCK_PREFIX \
108 ".section .smp_locks,\"a\"\n" \
109 " .align 4\n" \
110 " .long 661f\n" /* address */ \
111 ".previous\n" \
112 "661:\n\tlock; "
113
114#else /* ! CONFIG_SMP */
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -0800115#define LOCK_PREFIX ""
116#endif
117
Jeremy Fitzhardinge98de0322007-05-02 19:27:14 +0200118struct paravirt_patch_site;
Rusty Russell139ec7c2006-12-07 02:14:08 +0100119#ifdef CONFIG_PARAVIRT
Jeremy Fitzhardinge98de0322007-05-02 19:27:14 +0200120void apply_paravirt(struct paravirt_patch_site *start,
121 struct paravirt_patch_site *end);
Rusty Russell139ec7c2006-12-07 02:14:08 +0100122#else
123static inline void
Jeremy Fitzhardinge98de0322007-05-02 19:27:14 +0200124apply_paravirt(struct paravirt_patch_site *start,
125 struct paravirt_patch_site *end)
Rusty Russell139ec7c2006-12-07 02:14:08 +0100126{}
Jeremy Fitzhardinge441d40d2007-05-02 19:27:16 +0200127#define __parainstructions NULL
128#define __parainstructions_end NULL
Rusty Russell139ec7c2006-12-07 02:14:08 +0100129#endif
130
Gerd Hoffmann9a0b5812006-03-23 02:59:32 -0800131#endif /* _I386_ALTERNATIVE_H */