[mirror_ubuntu-jammy-kernel.git] / arch / x86 / include / asm / alternative.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_ALTERNATIVE_H
#define _ASM_X86_ALTERNATIVE_H

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

#define ALTINSTR_FLAG_INV	(1 << 15)
#define ALT_NOT(feat)		((feat) | ALTINSTR_FLAG_INV)

#ifndef __ASSEMBLY__

#include <linux/stddef.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_HERE \
		".pushsection .smp_locks,\"a\"\n"	\
		".balign 4\n"				\
		".long 671f - .\n" /* offset */		\
		".popsection\n"				\
		"671:"

#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "

#else /* ! CONFIG_SMP */
#define LOCK_PREFIX_HERE ""
#define LOCK_PREFIX ""
#endif

/*
 * objtool annotation to ignore the alternatives and only consider the original
 * instruction(s).
 */
#define ANNOTATE_IGNORE_ALTERNATIVE				\
	"999:\n\t"						\
	".pushsection .discard.ignore_alts\n\t"			\
	".long 999b - .\n\t"					\
	".popsection\n\t"

struct alt_instr {
	s32 instr_offset;	/* original instruction */
	s32 repl_offset;	/* offset to replacement instruction */
	u16 cpuid;		/* cpuid bit set for replacement */
	u8  instrlen;		/* length of original instruction */
	u8  replacementlen;	/* length of new instruction */
} __packed;

/*
 * Debug flag that can be tested to see whether alternative
 * instructions were patched in already:
 */
extern int alternatives_patched;

extern void alternative_instructions(void);
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
extern void apply_retpolines(s32 *start, s32 *end);
extern void apply_returns(s32 *start, s32 *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_enable_smp(void);
extern int alternatives_text_reserved(void *start, void *end);
extern bool skip_smp_alternatives;
#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_enable_smp(void) {}
static inline int alternatives_text_reserved(void *start, void *end)
{
	return 0;
}
#endif	/* CONFIG_SMP */

#define b_replacement(num)	"664"#num
#define e_replacement(num)	"665"#num

#define alt_end_marker		"663"
#define alt_slen		"662b-661b"
#define alt_total_slen		alt_end_marker"b-661b"
#define alt_rlen(num)		e_replacement(num)"f-"b_replacement(num)"f"

#define OLDINSTR(oldinstr, num)						\
	"# ALT: oldnstr\n"						\
	"661:\n\t" oldinstr "\n662:\n"					\
	"# ALT: padding\n"						\
	".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * "		\
		"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n"		\
	alt_end_marker ":\n"

/*
 * gas compatible max based on the idea from:
 * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
 *
 * The additional "-" is needed because gas uses a "true" value of -1.
 */
#define alt_max_short(a, b)	"((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"

/*
 * Pad the second replacement alternative with additional NOPs if it is
 * additionally longer than the first replacement alternative.
 */
#define OLDINSTR_2(oldinstr, num1, num2) \
	"# ALT: oldinstr2\n"									\
	"661:\n\t" oldinstr "\n662:\n"								\
	"# ALT: padding2\n"									\
	".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * "	\
		"(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n"	\
	alt_end_marker ":\n"

#define OLDINSTR_3(oldinsn, n1, n2, n3)								\
	"# ALT: oldinstr3\n"									\
	"661:\n\t" oldinsn "\n662:\n"								\
	"# ALT: padding3\n"									\
	".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3))	\
		" - (" alt_slen ")) > 0) * "							\
		"(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3))	\
		" - (" alt_slen ")), 0x90\n"							\
	alt_end_marker ":\n"

#define ALTINSTR_ENTRY(feature, num)					      \
	" .long 661b - .\n"				/* label           */ \
	" .long " b_replacement(num)"f - .\n"		/* new instruction */ \
	" .word " __stringify(feature) "\n"		/* feature bit     */ \
	" .byte " alt_total_slen "\n"			/* source len      */ \
	" .byte " alt_rlen(num) "\n"			/* replacement len */

#define ALTINSTR_REPLACEMENT(newinstr, num)		/* replacement */	\
	"# ALT: replacement " #num "\n"						\
	b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"

/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, newinstr, feature)			\
	OLDINSTR(oldinstr, 1)						\
	".pushsection .altinstructions,\"a\"\n"				\
	ALTINSTR_ENTRY(feature, 1)					\
	".popsection\n"							\
	".pushsection .altinstr_replacement, \"ax\"\n"			\
	ALTINSTR_REPLACEMENT(newinstr, 1)				\
	".popsection\n"

#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\
	OLDINSTR_2(oldinstr, 1, 2)					\
	".pushsection .altinstructions,\"a\"\n"				\
	ALTINSTR_ENTRY(feature1, 1)					\
	ALTINSTR_ENTRY(feature2, 2)					\
	".popsection\n"							\
	".pushsection .altinstr_replacement, \"ax\"\n"			\
	ALTINSTR_REPLACEMENT(newinstr1, 1)				\
	ALTINSTR_REPLACEMENT(newinstr2, 2)				\
	".popsection\n"

/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
		      newinstr_yes, feature)

#define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \
	OLDINSTR_3(oldinsn, 1, 2, 3)						\
	".pushsection .altinstructions,\"a\"\n"					\
	ALTINSTR_ENTRY(feat1, 1)						\
	ALTINSTR_ENTRY(feat2, 2)						\
	ALTINSTR_ENTRY(feat3, 3)						\
	".popsection\n"								\
	".pushsection .altinstr_replacement, \"ax\"\n"				\
	ALTINSTR_REPLACEMENT(newinsn1, 1)					\
	ALTINSTR_REPLACEMENT(newinsn2, 2)					\
	ALTINSTR_REPLACEMENT(newinsn3, 3)					\
	".popsection\n"

/*
 * 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_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")

#define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \
	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory")

#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \
	asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory")

/*
 * Alternative inline assembly with input.
 *
 * Peculiarities:
 * No memory clobber here.
 * Argument numbers start with 1.
 * Leaving an unused argument 0 to keep API compatibility.
 */
#define alternative_input(oldinstr, newinstr, feature, input...)	\
	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature)	\
		: : "i" (0), ## input)

/*
 * This is similar to alternative_input. But it has two features and
 * respective instructions.
 *
 * If CPU has feature2, newinstr2 is used.
 * Otherwise, if CPU has feature1, newinstr1 is used.
 * Otherwise, oldinstr is used.
 */
#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2,	     \
			   feature2, input...)				     \
	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1,     \
		newinstr2, feature2)					     \
		: : "i" (0), ## input)

/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, feature, output, input...)	\
	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature)	\
		: output : "i" (0), ## input)

/* Like alternative_io, but for replacing a direct call with another one. */
#define alternative_call(oldfunc, newfunc, feature, output, input...)	\
	asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \
		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

/*
 * Like alternative_call, but there are two features and respective functions.
 * If CPU has feature2, function2 is used.
 * Otherwise, if CPU has feature1, function1 is used.
 * Otherwise, old function is used.
 */
#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2,   \
			   output, input...)				      \
	asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
		"call %P[new2]", feature2)				      \
		: output, ASM_CALL_CONSTRAINT				      \
		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		      \
		  [new2] "i" (newfunc2), ## input)

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

/*
 * use this macro if you need clobbers but no inputs in
 * alternative_{input,io,call}()
 */
#define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr

#else /* __ASSEMBLY__ */

#ifdef CONFIG_SMP
	.macro LOCK_PREFIX
672:	lock
	.pushsection .smp_locks,"a"
	.balign 4
	.long 672b - .
	.popsection
	.endm
#else
	.macro LOCK_PREFIX
	.endm
#endif

/*
 * objtool annotation to ignore the alternatives and only consider the original
 * instruction(s).
 */
.macro ANNOTATE_IGNORE_ALTERNATIVE
	.Lannotate_\@:
	.pushsection .discard.ignore_alts
	.long .Lannotate_\@ - .
	.popsection
.endm

/*
 * Issue one struct alt_instr descriptor entry (need to put it into
 * the section .altinstructions, see below). This entry contains
 * enough information for the alternatives patching code to patch an
 * instruction. See apply_alternatives().
 */
.macro altinstruction_entry orig alt feature orig_len alt_len
	.long \orig - .
	.long \alt - .
	.word \feature
	.byte \orig_len
	.byte \alt_len
.endm

/*
 * Define an alternative between two instructions. If @feature is
 * present, early code in apply_alternatives() replaces @oldinstr with
 * @newinstr. ".skip" directive takes care of proper instruction padding
 * in case @newinstr is longer than @oldinstr.
 */
.macro ALTERNATIVE oldinstr, newinstr, feature
140:
	\oldinstr
141:
	.skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
142:

	.pushsection .altinstructions,"a"
	altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f
	.popsection

	.pushsection .altinstr_replacement,"ax"
143:
	\newinstr
144:
	.popsection
.endm

#define old_len			141b-140b
#define new_len1		144f-143f
#define new_len2		145f-144f

/*
 * gas compatible max based on the idea from:
 * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
 *
 * The additional "-" is needed because gas uses a "true" value of -1.
 */
#define alt_max_short(a, b)	((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))


/*
 * Same as ALTERNATIVE macro above but for two alternatives. If CPU
 * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
 * @feature2, it replaces @oldinstr with @feature2.
 */
.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
140:
	\oldinstr
141:
	.skip -((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \
		(alt_max_short(new_len1, new_len2) - (old_len)),0x90
142:

	.pushsection .altinstructions,"a"
	altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f
	altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f
	.popsection

	.pushsection .altinstr_replacement,"ax"
143:
	\newinstr1
144:
	\newinstr2
145:
	.popsection
.endm

/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
	ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
	newinstr_yes, feature

#endif /* __ASSEMBLY__ */

#endif /* _ASM_X86_ALTERNATIVE_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1965aae3 PA	2	#ifndef _ASM_X86_ALTERNATIVE_H
1965aae3 PA	3	#define _ASM_X86_ALTERNATIVE_H
6b592570 PA	4
6b592570 PA	5	#include <linux/types.h>
edc953fa	6	#include <linux/stringify.h>
6b592570 PA	7	#include <asm/asm.h>
6b592570 PA	8
dda7bb76 JG	9	#define ALTINSTR_FLAG_INV (1 << 15)
	10	#define ALT_NOT(feat) ((feat) \| ALTINSTR_FLAG_INV)
	11
5e21a3ec JG	12	#ifndef __ASSEMBLY__
	13
	14	#include <linux/stddef.h>
	15
6b592570 PA	16	/*
	17	* Alternative inline assembly for SMP.
	18	*
	19	* The LOCK_PREFIX macro defined here replaces the LOCK and
	20	* LOCK_PREFIX macros used everywhere in the source tree.
	21	*
	22	* SMP alternatives use the same data structures as the other
	23	* alternatives and the X86_FEATURE_UP flag to indicate the case of a
	24	* UP system running a SMP kernel. The existing apply_alternatives()
	25	* works fine for patching a SMP kernel for UP.
	26	*
	27	* The SMP alternative tables can be kept after boot and contain both
	28	* UP and SMP versions of the instructions to allow switching back to
	29	* SMP at runtime, when hotplugging in a new CPU, which is especially
	30	* useful in virtualized environments.
	31	*
	32	* The very common lock prefix is handled as special case in a
	33	* separate table which is a pure address list without replacement ptr
	34	* and size information. That keeps the table sizes small.
	35	*/
	36
	37	#ifdef CONFIG_SMP
851a4cd7 IM	38	#define LOCK_PREFIX_HERE \
	39	".pushsection .smp_locks,\"a\"\n" \
	40	".balign 4\n" \
	41	".long 671f - .\n" /* offset */ \
	42	".popsection\n" \
	43	"671:"
	44
	45	#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
	46
6b592570	47	#else /* ! CONFIG_SMP */
b701a47b	48	#define LOCK_PREFIX_HERE ""
6b592570 PA	49	#define LOCK_PREFIX ""
	50	#endif
	51
ff05ab23 PZ	52	/*
	53	* objtool annotation to ignore the alternatives and only consider the original
	54	* instruction(s).
	55	*/
	56	#define ANNOTATE_IGNORE_ALTERNATIVE \
	57	"999:\n\t" \
	58	".pushsection .discard.ignore_alts\n\t" \
	59	".long 999b - .\n\t" \
	60	".popsection\n\t"
	61
6b592570	62	struct alt_instr {
59e97e4d AL	63	s32 instr_offset; /* original instruction */
59e97e4d AL	64	s32 repl_offset; /* offset to replacement instruction */
83a7a2ad	65	u16 cpuid; /* cpuid bit set for replacement */
6b592570	66	u8 instrlen; /* length of original instruction */
4332195c	67	u8 replacementlen; /* length of new instruction */
4332195c	68	} __packed;
6b592570	69
5e907bb0 IM	70	/*
	71	* Debug flag that can be tested to see whether alternative
	72	* instructions were patched in already:
	73	*/
	74	extern int alternatives_patched;
	75
6b592570 PA	76	extern void alternative_instructions(void);
6b592570 PA	77	extern void apply_alternatives(struct alt_instr start, struct alt_instr end);
81211f23	78	extern void apply_retpolines(s32 start, s32 end);
196de01a	79	extern void apply_returns(s32 start, s32 end);
6b592570 PA	80
	81	struct module;
	82
	83	#ifdef CONFIG_SMP
	84	extern void alternatives_smp_module_add(struct module mod, char name,
	85	void locks, void locks_end,
	86	void text, void text_end);
	87	extern void alternatives_smp_module_del(struct module *mod);
816afe4f	88	extern void alternatives_enable_smp(void);
2cfa1978	89	extern int alternatives_text_reserved(void start, void end);
3fb82d56	90	extern bool skip_smp_alternatives;
6b592570 PA	91	#else
6b592570 PA	92	static inline void alternatives_smp_module_add(struct module mod, char name,
2ac1ea7c JP	93	void locks, void locks_end,
2ac1ea7c JP	94	void text, void text_end) {}
6b592570	95	static inline void alternatives_smp_module_del(struct module *mod) {}
816afe4f	96	static inline void alternatives_enable_smp(void) {}
2cfa1978 MH	97	static inline int alternatives_text_reserved(void start, void end)
	98	{
	99	return 0;
	100	}
6b592570 PA	101	#endif /* CONFIG_SMP */
6b592570 PA	102
4332195c BP	103	#define b_replacement(num) "664"#num
4332195c BP	104	#define e_replacement(num) "665"#num
954e482b	105
4332195c BP	106	#define alt_end_marker "663"
4332195c BP	107	#define alt_slen "662b-661b"
4332195c BP	108	#define alt_total_slen alt_end_marker"b-661b"
4332195c BP	109	#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f"
954e482b	110
1c1ed473 BP	111	#define OLDINSTR(oldinstr, num) \
1c1ed473 BP	112	"# ALT: oldnstr\n" \
4332195c	113	"661:\n\t" oldinstr "\n662:\n" \
1c1ed473	114	"# ALT: padding\n" \
4332195c	115	".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \
1c1ed473	116	"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \
4332195c BP	117	alt_end_marker ":\n"
4332195c BP	118
dbe4058a	119	/*
6b32c126	120	* gas compatible max based on the idea from:
dbe4058a BP	121	* http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
dbe4058a BP	122	*
6b32c126	123	* The additional "-" is needed because gas uses a "true" value of -1.
dbe4058a	124	*/
6b32c126	125	#define alt_max_short(a, b) "((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"
dbe4058a	126
4332195c BP	127	/*
	128	* Pad the second replacement alternative with additional NOPs if it is
	129	* additionally longer than the first replacement alternative.
	130	*/
dbe4058a	131	#define OLDINSTR_2(oldinstr, num1, num2) \
1c1ed473	132	"# ALT: oldinstr2\n" \
dbe4058a	133	"661:\n\t" oldinstr "\n662:\n" \
1c1ed473	134	"# ALT: padding2\n" \
dbe4058a BP	135	".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \
dbe4058a BP	136	"(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \
4332195c BP	137	alt_end_marker ":\n"
4332195c BP	138
71a93c26 BP	139	#define OLDINSTR_3(oldinsn, n1, n2, n3) \
	140	"# ALT: oldinstr3\n" \
	141	"661:\n\t" oldinsn "\n662:\n" \
	142	"# ALT: padding3\n" \
	143	".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
	144	" - (" alt_slen ")) > 0) * " \
	145	"(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
	146	" - (" alt_slen ")), 0x90\n" \
	147	alt_end_marker ":\n"
	148
4332195c	149	#define ALTINSTR_ENTRY(feature, num) \
954e482b	150	" .long 661b - .\n" /* label */ \
4332195c	151	" .long " b_replacement(num)"f - .\n" /* new instruction */ \
954e482b	152	" .word " __stringify(feature) "\n" /* feature bit */ \
4332195c	153	" .byte " alt_total_slen "\n" /* source len */ \
23c1ad53	154	" .byte " alt_rlen(num) "\n" /* replacement len */
954e482b	155
db16e072	156	#define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \
1c1ed473 BP	157	"# ALT: replacement " #num "\n" \
1c1ed473 BP	158	b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
954e482b	159
edc953fa MD	160	/* alternative assembly primitive: */
edc953fa MD	161	#define ALTERNATIVE(oldinstr, newinstr, feature) \
4332195c	162	OLDINSTR(oldinstr, 1) \
9cebed42	163	".pushsection .altinstructions,\"a\"\n" \
954e482b	164	ALTINSTR_ENTRY(feature, 1) \
9cebed42	165	".popsection\n" \
9cebed42	166	".pushsection .altinstr_replacement, \"ax\"\n" \
db16e072	167	ALTINSTR_REPLACEMENT(newinstr, 1) \
b9e705ef	168	".popsection\n"
954e482b FY	169
954e482b FY	170	#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\
4332195c	171	OLDINSTR_2(oldinstr, 1, 2) \
9cebed42	172	".pushsection .altinstructions,\"a\"\n" \
954e482b FY	173	ALTINSTR_ENTRY(feature1, 1) \
954e482b FY	174	ALTINSTR_ENTRY(feature2, 2) \
9cebed42	175	".popsection\n" \
9cebed42	176	".pushsection .altinstr_replacement, \"ax\"\n" \
db16e072 JG	177	ALTINSTR_REPLACEMENT(newinstr1, 1) \
db16e072 JG	178	ALTINSTR_REPLACEMENT(newinstr2, 2) \
b9e705ef	179	".popsection\n"
edc953fa	180
e208b3c4 JG	181	/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
	182	#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
	183	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
	184	newinstr_yes, feature)
	185
71a93c26 BP	186	#define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \
	187	OLDINSTR_3(oldinsn, 1, 2, 3) \
	188	".pushsection .altinstructions,\"a\"\n" \
	189	ALTINSTR_ENTRY(feat1, 1) \
	190	ALTINSTR_ENTRY(feat2, 2) \
	191	ALTINSTR_ENTRY(feat3, 3) \
	192	".popsection\n" \
	193	".pushsection .altinstr_replacement, \"ax\"\n" \
db16e072 JG	194	ALTINSTR_REPLACEMENT(newinsn1, 1) \
	195	ALTINSTR_REPLACEMENT(newinsn2, 2) \
	196	ALTINSTR_REPLACEMENT(newinsn3, 3) \
71a93c26 BP	197	".popsection\n"
71a93c26 BP	198
6b592570 PA	199	/*
	200	* Alternative instructions for different CPU types or capabilities.
	201	*
	202	* This allows to use optimized instructions even on generic binary
	203	* kernels.
	204	*
	205	* length of oldinstr must be longer or equal the length of newinstr
	206	* It can be padded with nops as needed.
	207	*
	208	* For non barrier like inlines please define new variants
	209	* without volatile and memory clobber.
	210	*/
	211	#define alternative(oldinstr, newinstr, feature) \
40576e5e	212	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")
6b592570	213
4332195c	214	#define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \
40576e5e	215	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory")
4332195c	216
e208b3c4 JG	217	#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \
	218	asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory")
	219
6b592570 PA	220	/*
	221	* Alternative inline assembly with input.
	222	*
a97673a1	223	* Peculiarities:
6b592570 PA	224	* No memory clobber here.
6b592570 PA	225	* Argument numbers start with 1.
edc953fa	226	* Leaving an unused argument 0 to keep API compatibility.
6b592570 PA	227	*/
6b592570 PA	228	#define alternative_input(oldinstr, newinstr, feature, input...) \
40576e5e	229	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
edc953fa	230	: : "i" (0), ## input)
6b592570	231
5b3e83f4 FY	232	/*
	233	* This is similar to alternative_input. But it has two features and
	234	* respective instructions.
	235	*
	236	* If CPU has feature2, newinstr2 is used.
	237	* Otherwise, if CPU has feature1, newinstr1 is used.
	238	* Otherwise, oldinstr is used.
	239	*/
	240	#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \
	241	feature2, input...) \
40576e5e	242	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \
5b3e83f4 FY	243	newinstr2, feature2) \
	244	: : "i" (0), ## input)
	245
6b592570 PA	246	/* Like alternative_input, but with a single output argument */
6b592570 PA	247	#define alternative_io(oldinstr, newinstr, feature, output, input...) \
40576e5e	248	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
edc953fa	249	: output : "i" (0), ## input)
6b592570	250
1b1d9258 JB	251	/* Like alternative_io, but for replacing a direct call with another one. */
1b1d9258 JB	252	#define alternative_call(oldfunc, newfunc, feature, output, input...) \
40576e5e	253	asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \
1b1d9258 JB	254	: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
1b1d9258 JB	255
954e482b FY	256	/*
	257	* Like alternative_call, but there are two features and respective functions.
	258	* If CPU has feature2, function2 is used.
	259	* Otherwise, if CPU has feature1, function1 is used.
	260	* Otherwise, old function is used.
	261	*/
	262	#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2, \
	263	output, input...) \
40576e5e	264	asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
954e482b	265	"call %P[new2]", feature2) \
f5caf621	266	: output, ASM_CALL_CONSTRAINT \
317c2ce7	267	: [old] "i" (oldfunc), [new1] "i" (newfunc1), \
bd627103	268	[new2] "i" (newfunc2), ## input)
954e482b	269
6b592570 PA	270	/*
	271	* use this macro(s) if you need more than one output parameter
	272	* in alternative_io
	273	*/
1b1d9258	274	#define ASM_OUTPUT2(a...) a
6b592570	275
819165fb JB	276	/*
	277	* use this macro if you need clobbers but no inputs in
	278	* alternative_{input,io,call}()
	279	*/
	280	#define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr
	281
5e21a3ec JG	282	#else /* __ASSEMBLY__ */
	283
	284	#ifdef CONFIG_SMP
	285	.macro LOCK_PREFIX
	286	672: lock
	287	.pushsection .smp_locks,"a"
	288	.balign 4
	289	.long 672b - .
	290	.popsection
	291	.endm
	292	#else
	293	.macro LOCK_PREFIX
	294	.endm
	295	#endif
	296
	297	/*
	298	* objtool annotation to ignore the alternatives and only consider the original
	299	* instruction(s).
	300	*/
	301	.macro ANNOTATE_IGNORE_ALTERNATIVE
	302	.Lannotate_\@:
	303	.pushsection .discard.ignore_alts
	304	.long .Lannotate_\@ - .
	305	.popsection
	306	.endm
	307
	308	/*
	309	* Issue one struct alt_instr descriptor entry (need to put it into
	310	* the section .altinstructions, see below). This entry contains
	311	* enough information for the alternatives patching code to patch an
	312	* instruction. See apply_alternatives().
	313	*/
23c1ad53	314	.macro altinstruction_entry orig alt feature orig_len alt_len
5e21a3ec JG	315	.long \orig - .
	316	.long \alt - .
	317	.word \feature
	318	.byte \orig_len
	319	.byte \alt_len
5e21a3ec JG	320	.endm
	321
	322	/*
	323	* Define an alternative between two instructions. If @feature is
	324	* present, early code in apply_alternatives() replaces @oldinstr with
	325	* @newinstr. ".skip" directive takes care of proper instruction padding
	326	* in case @newinstr is longer than @oldinstr.
	327	*/
	328	.macro ALTERNATIVE oldinstr, newinstr, feature
	329	140:
	330	\oldinstr
	331	141:
	332	.skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
	333	142:
	334
	335	.pushsection .altinstructions,"a"
23c1ad53	336	altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f
5e21a3ec JG	337	.popsection
	338
	339	.pushsection .altinstr_replacement,"ax"
	340	143:
	341	\newinstr
	342	144:
	343	.popsection
	344	.endm
	345
	346	#define old_len 141b-140b
	347	#define new_len1 144f-143f
	348	#define new_len2 145f-144f
	349
	350	/*
	351	* gas compatible max based on the idea from:
	352	* http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
	353	*
	354	* The additional "-" is needed because gas uses a "true" value of -1.
	355	*/
	356	#define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
	357
	358
	359	/*
	360	* Same as ALTERNATIVE macro above but for two alternatives. If CPU
	361	* has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
	362	* @feature2, it replaces @oldinstr with @feature2.
	363	*/
	364	.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
	365	140:
	366	\oldinstr
	367	141:
	368	.skip -((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \
	369	(alt_max_short(new_len1, new_len2) - (old_len)),0x90
	370	142:
	371
	372	.pushsection .altinstructions,"a"
23c1ad53 PZ	373	altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f
23c1ad53 PZ	374	altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f
5e21a3ec JG	375	.popsection
	376
	377	.pushsection .altinstr_replacement,"ax"
	378	143:
	379	\newinstr1
	380	144:
	381	\newinstr2
	382	145:
	383	.popsection
	384	.endm
	385
e208b3c4 JG	386	/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
	387	#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
	388	ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
	389	newinstr_yes, feature
	390
f005f5d8 AL	391	#endif /* __ASSEMBLY__ */
f005f5d8 AL	392
1965aae3	393	#endif /* _ASM_X86_ALTERNATIVE_H */