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 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 } __packed; 17 18 void apply_alternative_instructions(void); 19 void 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 */ 121