1 files changed, 129 insertions, 0 deletions
diff --git a/include/asm-i386/alternative.h b/include/asm-i386/alternative.h
new file mode 100644
index 00000000000..e201decea0c
--- /dev/null
+++ b/include/asm-i386/alternative.h
@@ -0,0 +1,129 @@
+#ifndef _I386_ALTERNATIVE_H
+#define _I386_ALTERNATIVE_H
+#ifdef __KERNEL__
+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  pad;
+};
+extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
+struct module;
+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);
+#endif
+/*
+ * 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"               \
+                      "  .align 4\n"                                    \
+                      "  .long 661b\n"            /* label */           \
+                      "  .long 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 maake 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"               \
+                      "  .align 4\n"                                    \
+                      "  .long 661b\n"            /* label */           \
+                      "  .long 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)
+/*
+ * Alternative inline assembly for SMP.
+ *
+ * alternative_smp() takes two versions (SMP first, UP second) and is
+ * for more complex stuff such as spinlocks.
+ *
+ * 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 alternative_smp(smpinstr, upinstr, args...)                     \
+        asm volatile ("661:\n\t" smpinstr "\n662:\n"                    \
+                      ".section .smp_altinstructions,\"a\"\n"           \
+                      "  .align 4\n"                                    \
+                      "  .long 661b\n"            /* label */           \
+                      "  .long 663f\n"            /* new instruction */ \
+                      "  .byte 0x68\n"            /* X86_FEATURE_UP */  \
+                      "  .byte 662b-661b\n"       /* sourcelen */       \
+                      "  .byte 664f-663f\n"       /* replacementlen */  \
+                      ".previous\n"                                     \
+                      ".section .smp_altinstr_replacement,\"awx\"\n"    \
+                      "663:\n\t" upinstr "\n"     /* replacement */     \
+                      "664:\n\t.fill 662b-661b,1,0x42\n" /* space for original */ \
+                      ".previous" : args)
+#define LOCK_PREFIX \
+                ".section .smp_locks,\"a\"\n"   \
+                "  .align 4\n"                  \
+                "  .long 661f\n" /* address */  \
+                ".previous\n"                   \
+                "661:\n\tlock; "
+#else /* ! CONFIG_SMP */
+#define alternative_smp(smpinstr, upinstr, args...) \
+        asm volatile (upinstr : args)
+#define LOCK_PREFIX ""
+#endif
+#endif /* _I386_ALTERNATIVE_H */

diff --git a/include/asm-i386/alternative.h b/include/asm-i386/alternative.h new file mode 100644 index 00000000000..e201decea0c --- /dev/null +++ b/include/asm-i386/alternative.h
@@ -0,0 +1,129 @@
	1	#ifndef _I386_ALTERNATIVE_H
	2	#define _I386_ALTERNATIVE_H
	3
	4	#ifdef __KERNEL__
	5
	6	struct alt_instr {
	7	u8 instr; / original instruction */
	8	u8 *replacement;
	9	u8 cpuid; /* cpuid bit set for replacement */
	10	u8 instrlen; /* length of original instruction */
	11	u8 replacementlen; /* length of new instruction, <= instrlen */
	12	u8 pad;
	13	};
	14
	15	extern void apply_alternatives(struct alt_instr start, struct alt_instr end);
	16
	17	struct module;
	18	extern void alternatives_smp_module_add(struct module mod, char name,
	19	void locks, void locks_end,
	20	void text, void text_end);
	21	extern void alternatives_smp_module_del(struct module *mod);
	22	extern void alternatives_smp_switch(int smp);
	23
	24	#endif
	25
	26	/*
	27	* Alternative instructions for different CPU types or capabilities.
	28	*
	29	* This allows to use optimized instructions even on generic binary
	30	* kernels.
	31	*
	32	* length of oldinstr must be longer or equal the length of newinstr
	33	* It can be padded with nops as needed.
	34	*
	35	* For non barrier like inlines please define new variants
	36	* without volatile and memory clobber.
	37	*/
	38	#define alternative(oldinstr, newinstr, feature) \
	39	asm volatile ("661:\n\t" oldinstr "\n662:\n" \
	40	".section .altinstructions,\"a\"\n" \
	41	" .align 4\n" \
	42	" .long 661b\n" /* label */ \
	43	" .long 663f\n" /* new instruction */ \
	44	" .byte %c0\n" /* feature bit */ \
	45	" .byte 662b-661b\n" /* sourcelen */ \
	46	" .byte 664f-663f\n" /* replacementlen */ \
	47	".previous\n" \
	48	".section .altinstr_replacement,\"ax\"\n" \
	49	"663:\n\t" newinstr "\n664:\n" /* replacement */\
	50	".previous" :: "i" (feature) : "memory")
	51
	52	/*
	53	* Alternative inline assembly with input.
	54	*
	55	* Pecularities:
	56	* No memory clobber here.
	57	* Argument numbers start with 1.
	58	* Best is to use constraints that are fixed size (like (%1) ... "r")
	59	* If you use variable sized constraints like "m" or "g" in the
	60	* replacement maake sure to pad to the worst case length.
	61	*/
	62	#define alternative_input(oldinstr, newinstr, feature, input...) \
	63	asm volatile ("661:\n\t" oldinstr "\n662:\n" \
	64	".section .altinstructions,\"a\"\n" \
	65	" .align 4\n" \
	66	" .long 661b\n" /* label */ \
	67	" .long 663f\n" /* new instruction */ \
	68	" .byte %c0\n" /* feature bit */ \
	69	" .byte 662b-661b\n" /* sourcelen */ \
	70	" .byte 664f-663f\n" /* replacementlen */ \
	71	".previous\n" \
	72	".section .altinstr_replacement,\"ax\"\n" \
	73	"663:\n\t" newinstr "\n664:\n" /* replacement */\
	74	".previous" :: "i" (feature), ##input)
	75
	76	/*
	77	* Alternative inline assembly for SMP.
	78	*
	79	* alternative_smp() takes two versions (SMP first, UP second) and is
	80	* for more complex stuff such as spinlocks.
	81	*
	82	* The LOCK_PREFIX macro defined here replaces the LOCK and
	83	* LOCK_PREFIX macros used everywhere in the source tree.
	84	*
	85	* SMP alternatives use the same data structures as the other
	86	* alternatives and the X86_FEATURE_UP flag to indicate the case of a
	87	* UP system running a SMP kernel. The existing apply_alternatives()
	88	* works fine for patching a SMP kernel for UP.
	89	*
	90	* The SMP alternative tables can be kept after boot and contain both
	91	* UP and SMP versions of the instructions to allow switching back to
	92	* SMP at runtime, when hotplugging in a new CPU, which is especially
	93	* useful in virtualized environments.
	94	*
	95	* The very common lock prefix is handled as special case in a
	96	* separate table which is a pure address list without replacement ptr
	97	* and size information. That keeps the table sizes small.
	98	*/
	99
	100	#ifdef CONFIG_SMP
	101	#define alternative_smp(smpinstr, upinstr, args...) \
	102	asm volatile ("661:\n\t" smpinstr "\n662:\n" \
	103	".section .smp_altinstructions,\"a\"\n" \
	104	" .align 4\n" \
	105	" .long 661b\n" /* label */ \
	106	" .long 663f\n" /* new instruction */ \
	107	" .byte 0x68\n" /* X86_FEATURE_UP */ \
	108	" .byte 662b-661b\n" /* sourcelen */ \
	109	" .byte 664f-663f\n" /* replacementlen */ \
	110	".previous\n" \
	111	".section .smp_altinstr_replacement,\"awx\"\n" \
	112	"663:\n\t" upinstr "\n" /* replacement */ \
	113	"664:\n\t.fill 662b-661b,1,0x42\n" /* space for original */ \
	114	".previous" : args)
	115
	116	#define LOCK_PREFIX \
	117	".section .smp_locks,\"a\"\n" \
	118	" .align 4\n" \
	119	" .long 661f\n" /* address */ \
	120	".previous\n" \
	121	"661:\n\tlock; "
	122
	123	#else /* ! CONFIG_SMP */
	124	#define alternative_smp(smpinstr, upinstr, args...) \
	125	asm volatile (upinstr : args)
	126	#define LOCK_PREFIX ""
	127	#endif
	128
	129	#endif /* _I386_ALTERNATIVE_H */