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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 | /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_S390_ALTERNATIVE_H #define _ASM_S390_ALTERNATIVE_H #ifndef __ASSEMBLY__ #include <linux/types.h> #include <linux/stddef.h> #include <linux/stringify.h> struct alt_instr { s32 instr_offset; /* original instruction */ s32 repl_offset; /* offset to replacement instruction */ u16 facility; /* facility bit set for replacement */ u8 instrlen; /* length of original instruction */ } __packed; void apply_alternative_instructions(void); void apply_alternatives(struct alt_instr *start, struct alt_instr *end); /* * +---------------------------------+ * |661: |662: * | oldinstr | * +---------------------------------+ * * .altinstr_replacement section * +---------------------------------+ * |6641: |6651: * | alternative instr 1 | * +---------------------------------+ * |6642: |6652: * | alternative instr 2 | * +---------------------------------+ * * .altinstructions section * +---------------------------------+ * | alt_instr entries for each | * | alternative instr | * +---------------------------------+ */ #define b_altinstr(num) "664"#num #define e_altinstr(num) "665"#num #define oldinstr_len "662b-661b" #define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b" #define OLDINSTR(oldinstr) \ "661:\n\t" oldinstr "\n662:\n" #define ALTINSTR_ENTRY(facility, num) \ "\t.long 661b - .\n" /* old instruction */ \ "\t.long " b_altinstr(num)"b - .\n" /* alt instruction */ \ "\t.word " __stringify(facility) "\n" /* facility bit */ \ "\t.byte " oldinstr_len "\n" /* instruction len */ \ "\t.org . - (" oldinstr_len ") + (" altinstr_len(num) ")\n" \ "\t.org . - (" altinstr_len(num) ") + (" oldinstr_len ")\n" #define ALTINSTR_REPLACEMENT(altinstr, num) /* replacement */ \ b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n" /* alternative assembly primitive: */ #define ALTERNATIVE(oldinstr, altinstr, facility) \ ".pushsection .altinstr_replacement, \"ax\"\n" \ ALTINSTR_REPLACEMENT(altinstr, 1) \ ".popsection\n" \ OLDINSTR(oldinstr) \ ".pushsection .altinstructions,\"a\"\n" \ ALTINSTR_ENTRY(facility, 1) \ ".popsection\n" #define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\ ".pushsection .altinstr_replacement, \"ax\"\n" \ ALTINSTR_REPLACEMENT(altinstr1, 1) \ ALTINSTR_REPLACEMENT(altinstr2, 2) \ ".popsection\n" \ OLDINSTR(oldinstr) \ ".pushsection .altinstructions,\"a\"\n" \ ALTINSTR_ENTRY(facility1, 1) \ ALTINSTR_ENTRY(facility2, 2) \ ".popsection\n" /* * Alternative instructions for different CPU types or capabilities. * * This allows to use optimized instructions even on generic binary * kernels. * * oldinstr is padded with jump and nops at compile time if altinstr is * longer. altinstr is padded with jump and nops at run-time during patching. * * For non barrier like inlines please define new variants * without volatile and memory clobber. */ #define alternative(oldinstr, altinstr, facility) \ asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory") #define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \ asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1, \ altinstr2, facility2) ::: "memory") /* Alternative inline assembly with input. */ #define alternative_input(oldinstr, newinstr, feature, input...) \ asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ : : input) /* Like alternative_input, but with a single output argument */ #define alternative_io(oldinstr, altinstr, facility, output, input...) \ asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) \ : output : input) /* Use this macro if more than one output parameter is needed. */ #define ASM_OUTPUT2(a...) a /* Use this macro if clobbers are needed without inputs. */ #define ASM_NO_INPUT_CLOBBER(clobber...) : clobber #endif /* __ASSEMBLY__ */ #endif /* _ASM_S390_ALTERNATIVE_H */ |