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9fa1db4c | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
686140a1 VG |
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 | ||
11 | struct 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 | ||
049a2c2d HC |
19 | void apply_alternative_instructions(void); |
20 | void apply_alternatives(struct alt_instr *start, struct alt_instr *end); | |
21 | ||
686140a1 VG |
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 | ||
686140a1 VG |
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" | |
686140a1 VG |
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 */ |