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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_S390_ALTERNATIVE_H
3#define _ASM_S390_ALTERNATIVE_H
4
5#ifndef __ASSEMBLY__
6
7#include <linux/types.h>
8#include <linux/stddef.h>
9#include <linux/stringify.h>
10
11struct alt_instr {
12 s32 instr_offset; /* original instruction */
13 s32 repl_offset; /* offset to replacement instruction */
14 u16 facility; /* facility bit set for replacement */
15 u8 instrlen; /* length of original instruction */
16} __packed;
17
18void apply_alternative_instructions(void);
19void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
20
21/*
22 * +---------------------------------+
23 * |661: |662:
24 * | oldinstr |
25 * +---------------------------------+
26 *
27 * .altinstr_replacement section
28 * +---------------------------------+
29 * |6641: |6651:
30 * | alternative instr 1 |
31 * +---------------------------------+
32 * |6642: |6652:
33 * | alternative instr 2 |
34 * +---------------------------------+
35 *
36 * .altinstructions section
37 * +---------------------------------+
38 * | alt_instr entries for each |
39 * | alternative instr |
40 * +---------------------------------+
41 */
42
43#define b_altinstr(num) "664"#num
44#define e_altinstr(num) "665"#num
45#define oldinstr_len "662b-661b"
46#define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b"
47
48#define OLDINSTR(oldinstr) \
49 "661:\n\t" oldinstr "\n662:\n"
50
51#define ALTINSTR_ENTRY(facility, num) \
52 "\t.long 661b - .\n" /* old instruction */ \
53 "\t.long " b_altinstr(num)"b - .\n" /* alt instruction */ \
54 "\t.word " __stringify(facility) "\n" /* facility bit */ \
55 "\t.byte " oldinstr_len "\n" /* instruction len */ \
56 "\t.org . - (" oldinstr_len ") + (" altinstr_len(num) ")\n" \
57 "\t.org . - (" altinstr_len(num) ") + (" oldinstr_len ")\n"
58
59#define ALTINSTR_REPLACEMENT(altinstr, num) /* replacement */ \
60 b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n"
61
62/* alternative assembly primitive: */
63#define ALTERNATIVE(oldinstr, altinstr, facility) \
64 ".pushsection .altinstr_replacement, \"ax\"\n" \
65 ALTINSTR_REPLACEMENT(altinstr, 1) \
66 ".popsection\n" \
67 OLDINSTR(oldinstr) \
68 ".pushsection .altinstructions,\"a\"\n" \
69 ALTINSTR_ENTRY(facility, 1) \
70 ".popsection\n"
71
72#define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\
73 ".pushsection .altinstr_replacement, \"ax\"\n" \
74 ALTINSTR_REPLACEMENT(altinstr1, 1) \
75 ALTINSTR_REPLACEMENT(altinstr2, 2) \
76 ".popsection\n" \
77 OLDINSTR(oldinstr) \
78 ".pushsection .altinstructions,\"a\"\n" \
79 ALTINSTR_ENTRY(facility1, 1) \
80 ALTINSTR_ENTRY(facility2, 2) \
81 ".popsection\n"
82
83/*
84 * Alternative instructions for different CPU types or capabilities.
85 *
86 * This allows to use optimized instructions even on generic binary
87 * kernels.
88 *
89 * oldinstr is padded with jump and nops at compile time if altinstr is
90 * longer. altinstr is padded with jump and nops at run-time during patching.
91 *
92 * For non barrier like inlines please define new variants
93 * without volatile and memory clobber.
94 */
95#define alternative(oldinstr, altinstr, facility) \
96 asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory")
97
98#define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \
99 asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1, \
100 altinstr2, facility2) ::: "memory")
101
102/* Alternative inline assembly with input. */
103#define alternative_input(oldinstr, newinstr, feature, input...) \
104 asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
105 : : input)
106
107/* Like alternative_input, but with a single output argument */
108#define alternative_io(oldinstr, altinstr, facility, output, input...) \
109 asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) \
110 : output : input)
111
112/* Use this macro if more than one output parameter is needed. */
113#define ASM_OUTPUT2(a...) a
114
115/* Use this macro if clobbers are needed without inputs. */
116#define ASM_NO_INPUT_CLOBBER(clobber...) : clobber
117
118#endif /* __ASSEMBLY__ */
119
120#endif /* _ASM_S390_ALTERNATIVE_H */
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_S390_ALTERNATIVE_H
3#define _ASM_S390_ALTERNATIVE_H
4
5#ifndef __ASSEMBLY__
6
7#include <linux/types.h>
8#include <linux/stddef.h>
9#include <linux/stringify.h>
10
11struct alt_instr {
12 s32 instr_offset; /* original instruction */
13 s32 repl_offset; /* offset to replacement instruction */
14 u16 facility; /* facility bit set for replacement */
15 u8 instrlen; /* length of original instruction */
16 u8 replacementlen; /* length of new instruction */
17} __packed;
18
19void apply_alternative_instructions(void);
20void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
21
22/*
23 * |661: |662: |6620 |663:
24 * +-----------+---------------------+
25 * | oldinstr | oldinstr_padding |
26 * | +----------+----------+
27 * | | | |
28 * | | >6 bytes |6/4/2 nops|
29 * | |6 bytes jg----------->
30 * +-----------+---------------------+
31 * ^^ static padding ^^
32 *
33 * .altinstr_replacement section
34 * +---------------------+-----------+
35 * |6641: |6651:
36 * | alternative instr 1 |
37 * +-----------+---------+- - - - - -+
38 * |6642: |6652: |
39 * | alternative instr 2 | padding
40 * +---------------------+- - - - - -+
41 * ^ runtime ^
42 *
43 * .altinstructions section
44 * +---------------------------------+
45 * | alt_instr entries for each |
46 * | alternative instr |
47 * +---------------------------------+
48 */
49
50#define b_altinstr(num) "664"#num
51#define e_altinstr(num) "665"#num
52
53#define e_oldinstr_pad_end "663"
54#define oldinstr_len "662b-661b"
55#define oldinstr_total_len e_oldinstr_pad_end"b-661b"
56#define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b"
57#define oldinstr_pad_len(num) \
58 "-(((" altinstr_len(num) ")-(" oldinstr_len ")) > 0) * " \
59 "((" altinstr_len(num) ")-(" oldinstr_len "))"
60
61#define INSTR_LEN_SANITY_CHECK(len) \
62 ".if " len " > 254\n" \
63 "\t.error \"cpu alternatives does not support instructions " \
64 "blocks > 254 bytes\"\n" \
65 ".endif\n" \
66 ".if (" len ") %% 2\n" \
67 "\t.error \"cpu alternatives instructions length is odd\"\n" \
68 ".endif\n"
69
70#define OLDINSTR_PADDING(oldinstr, num) \
71 ".if " oldinstr_pad_len(num) " > 6\n" \
72 "\tjg " e_oldinstr_pad_end "f\n" \
73 "6620:\n" \
74 "\t.fill (" oldinstr_pad_len(num) " - (6620b-662b)) / 2, 2, 0x0700\n" \
75 ".else\n" \
76 "\t.fill " oldinstr_pad_len(num) " / 6, 6, 0xc0040000\n" \
77 "\t.fill " oldinstr_pad_len(num) " %% 6 / 4, 4, 0x47000000\n" \
78 "\t.fill " oldinstr_pad_len(num) " %% 6 %% 4 / 2, 2, 0x0700\n" \
79 ".endif\n"
80
81#define OLDINSTR(oldinstr, num) \
82 "661:\n\t" oldinstr "\n662:\n" \
83 OLDINSTR_PADDING(oldinstr, num) \
84 e_oldinstr_pad_end ":\n" \
85 INSTR_LEN_SANITY_CHECK(oldinstr_len)
86
87#define OLDINSTR_2(oldinstr, num1, num2) \
88 "661:\n\t" oldinstr "\n662:\n" \
89 ".if " altinstr_len(num1) " < " altinstr_len(num2) "\n" \
90 OLDINSTR_PADDING(oldinstr, num2) \
91 ".else\n" \
92 OLDINSTR_PADDING(oldinstr, num1) \
93 ".endif\n" \
94 e_oldinstr_pad_end ":\n" \
95 INSTR_LEN_SANITY_CHECK(oldinstr_len)
96
97#define ALTINSTR_ENTRY(facility, num) \
98 "\t.long 661b - .\n" /* old instruction */ \
99 "\t.long " b_altinstr(num)"b - .\n" /* alt instruction */ \
100 "\t.word " __stringify(facility) "\n" /* facility bit */ \
101 "\t.byte " oldinstr_total_len "\n" /* source len */ \
102 "\t.byte " altinstr_len(num) "\n" /* alt instruction len */
103
104#define ALTINSTR_REPLACEMENT(altinstr, num) /* replacement */ \
105 b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n" \
106 INSTR_LEN_SANITY_CHECK(altinstr_len(num))
107
108/* alternative assembly primitive: */
109#define ALTERNATIVE(oldinstr, altinstr, facility) \
110 ".pushsection .altinstr_replacement, \"ax\"\n" \
111 ALTINSTR_REPLACEMENT(altinstr, 1) \
112 ".popsection\n" \
113 OLDINSTR(oldinstr, 1) \
114 ".pushsection .altinstructions,\"a\"\n" \
115 ALTINSTR_ENTRY(facility, 1) \
116 ".popsection\n"
117
118#define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\
119 ".pushsection .altinstr_replacement, \"ax\"\n" \
120 ALTINSTR_REPLACEMENT(altinstr1, 1) \
121 ALTINSTR_REPLACEMENT(altinstr2, 2) \
122 ".popsection\n" \
123 OLDINSTR_2(oldinstr, 1, 2) \
124 ".pushsection .altinstructions,\"a\"\n" \
125 ALTINSTR_ENTRY(facility1, 1) \
126 ALTINSTR_ENTRY(facility2, 2) \
127 ".popsection\n"
128
129/*
130 * Alternative instructions for different CPU types or capabilities.
131 *
132 * This allows to use optimized instructions even on generic binary
133 * kernels.
134 *
135 * oldinstr is padded with jump and nops at compile time if altinstr is
136 * longer. altinstr is padded with jump and nops at run-time during patching.
137 *
138 * For non barrier like inlines please define new variants
139 * without volatile and memory clobber.
140 */
141#define alternative(oldinstr, altinstr, facility) \
142 asm volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory")
143
144#define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \
145 asm volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1, \
146 altinstr2, facility2) ::: "memory")
147
148#endif /* __ASSEMBLY__ */
149
150#endif /* _ASM_S390_ALTERNATIVE_H */