1 #ifndef _ASM_S390_ALTERNATIVE_H 2 #define _ASM_S390_ALTERNATIVE_H 3 4 #ifndef __ASSEMBLY__ 5 6 #include <linux/types.h> 7 #include <linux/stddef.h> 8 #include <linux/stringify.h> 9 10 struct alt_instr { 11 s32 instr_offset; /* original instruction */ 12 s32 repl_offset; /* offset to replacement instruction */ 13 u16 facility; /* facility bit set for replacement */ 14 u8 instrlen; /* length of original instruction */ 15 u8 replacementlen; /* length of new instruction */ 16 } __packed; 17 18 #ifdef CONFIG_ALTERNATIVES 19 extern void apply_alternative_instructions(void); 20 extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); 21 #else 22 static inline void apply_alternative_instructions(void) {}; 23 static inline void apply_alternatives(struct alt_instr *start, 24 struct alt_instr *end) {}; 25 #endif 26 /* 27 * |661: |662: |6620 |663: 28 * +-----------+---------------------+ 29 * | oldinstr | oldinstr_padding | 30 * | +----------+----------+ 31 * | | | | 32 * | | >6 bytes |6/4/2 nops| 33 * | |6 bytes jg-----------> 34 * +-----------+---------------------+ 35 * ^^ static padding ^^ 36 * 37 * .altinstr_replacement section 38 * +---------------------+-----------+ 39 * |6641: |6651: 40 * | alternative instr 1 | 41 * +-----------+---------+- - - - - -+ 42 * |6642: |6652: | 43 * | alternative instr 2 | padding 44 * +---------------------+- - - - - -+ 45 * ^ runtime ^ 46 * 47 * .altinstructions section 48 * +---------------------------------+ 49 * | alt_instr entries for each | 50 * | alternative instr | 51 * +---------------------------------+ 52 */ 53 54 #define b_altinstr(num) "664"#num 55 #define e_altinstr(num) "665"#num 56 57 #define e_oldinstr_pad_end "663" 58 #define oldinstr_len "662b-661b" 59 #define oldinstr_total_len e_oldinstr_pad_end"b-661b" 60 #define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b" 61 #define oldinstr_pad_len(num) \ 62 "-(((" altinstr_len(num) ")-(" oldinstr_len ")) > 0) * " \ 63 "((" altinstr_len(num) ")-(" oldinstr_len "))" 64 65 #define INSTR_LEN_SANITY_CHECK(len) \ 66 ".if " len " > 254\n" \ 67 "\t.error \"cpu alternatives does not support instructions " \ 68 "blocks > 254 bytes\"\n" \ 69 ".endif\n" \ 70 ".if (" len ") %% 2\n" \ 71 "\t.error \"cpu alternatives instructions length is odd\"\n" \ 72 ".endif\n" 73 74 #define OLDINSTR_PADDING(oldinstr, num) \ 75 ".if " oldinstr_pad_len(num) " > 6\n" \ 76 "\tjg " e_oldinstr_pad_end "f\n" \ 77 "6620:\n" \ 78 "\t.fill (" oldinstr_pad_len(num) " - (6620b-662b)) / 2, 2, 0x0700\n" \ 79 ".else\n" \ 80 "\t.fill " oldinstr_pad_len(num) " / 6, 6, 0xc0040000\n" \ 81 "\t.fill " oldinstr_pad_len(num) " %% 6 / 4, 4, 0x47000000\n" \ 82 "\t.fill " oldinstr_pad_len(num) " %% 6 %% 4 / 2, 2, 0x0700\n" \ 83 ".endif\n" 84 85 #define OLDINSTR(oldinstr, num) \ 86 "661:\n\t" oldinstr "\n662:\n" \ 87 OLDINSTR_PADDING(oldinstr, num) \ 88 e_oldinstr_pad_end ":\n" \ 89 INSTR_LEN_SANITY_CHECK(oldinstr_len) 90 91 #define OLDINSTR_2(oldinstr, num1, num2) \ 92 "661:\n\t" oldinstr "\n662:\n" \ 93 ".if " altinstr_len(num1) " < " altinstr_len(num2) "\n" \ 94 OLDINSTR_PADDING(oldinstr, num2) \ 95 ".else\n" \ 96 OLDINSTR_PADDING(oldinstr, num1) \ 97 ".endif\n" \ 98 e_oldinstr_pad_end ":\n" \ 99 INSTR_LEN_SANITY_CHECK(oldinstr_len) 100 101 #define ALTINSTR_ENTRY(facility, num) \ 102 "\t.long 661b - .\n" /* old instruction */ \ 103 "\t.long " b_altinstr(num)"b - .\n" /* alt instruction */ \ 104 "\t.word " __stringify(facility) "\n" /* facility bit */ \ 105 "\t.byte " oldinstr_total_len "\n" /* source len */ \ 106 "\t.byte " altinstr_len(num) "\n" /* alt instruction len */ 107 108 #define ALTINSTR_REPLACEMENT(altinstr, num) /* replacement */ \ 109 b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n" \ 110 INSTR_LEN_SANITY_CHECK(altinstr_len(num)) 111 112 #ifdef CONFIG_ALTERNATIVES 113 /* alternative assembly primitive: */ 114 #define ALTERNATIVE(oldinstr, altinstr, facility) \ 115 ".pushsection .altinstr_replacement, \"ax\"\n" \ 116 ALTINSTR_REPLACEMENT(altinstr, 1) \ 117 ".popsection\n" \ 118 OLDINSTR(oldinstr, 1) \ 119 ".pushsection .altinstructions,\"a\"\n" \ 120 ALTINSTR_ENTRY(facility, 1) \ 121 ".popsection\n" 122 123 #define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\ 124 ".pushsection .altinstr_replacement, \"ax\"\n" \ 125 ALTINSTR_REPLACEMENT(altinstr1, 1) \ 126 ALTINSTR_REPLACEMENT(altinstr2, 2) \ 127 ".popsection\n" \ 128 OLDINSTR_2(oldinstr, 1, 2) \ 129 ".pushsection .altinstructions,\"a\"\n" \ 130 ALTINSTR_ENTRY(facility1, 1) \ 131 ALTINSTR_ENTRY(facility2, 2) \ 132 ".popsection\n" 133 #else 134 /* Alternative instructions are disabled, let's put just oldinstr in */ 135 #define ALTERNATIVE(oldinstr, altinstr, facility) \ 136 oldinstr "\n" 137 138 #define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \ 139 oldinstr "\n" 140 #endif 141 142 /* 143 * Alternative instructions for different CPU types or capabilities. 144 * 145 * This allows to use optimized instructions even on generic binary 146 * kernels. 147 * 148 * oldinstr is padded with jump and nops at compile time if altinstr is 149 * longer. altinstr is padded with jump and nops at run-time during patching. 150 * 151 * For non barrier like inlines please define new variants 152 * without volatile and memory clobber. 153 */ 154 #define alternative(oldinstr, altinstr, facility) \ 155 asm volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory") 156 157 #define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \ 158 asm volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1, \ 159 altinstr2, facility2) ::: "memory") 160 161 #endif /* __ASSEMBLY__ */ 162 163 #endif /* _ASM_S390_ALTERNATIVE_H */ 164