Loading...
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 | /* 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 */ u8 replacementlen; /* length of new instruction */ } __packed; void apply_alternative_instructions(void); void apply_alternatives(struct alt_instr *start, struct alt_instr *end); /* * |661: |662: |6620 |663: * +-----------+---------------------+ * | oldinstr | oldinstr_padding | * | +----------+----------+ * | | | | * | | >6 bytes |6/4/2 nops| * | |6 bytes jg-----------> * +-----------+---------------------+ * ^^ static padding ^^ * * .altinstr_replacement section * +---------------------+-----------+ * |6641: |6651: * | alternative instr 1 | * +-----------+---------+- - - - - -+ * |6642: |6652: | * | alternative instr 2 | padding * +---------------------+- - - - - -+ * ^ runtime ^ * * .altinstructions section * +---------------------------------+ * | alt_instr entries for each | * | alternative instr | * +---------------------------------+ */ #define b_altinstr(num) "664"#num #define e_altinstr(num) "665"#num #define e_oldinstr_pad_end "663" #define oldinstr_len "662b-661b" #define oldinstr_total_len e_oldinstr_pad_end"b-661b" #define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b" #define oldinstr_pad_len(num) \ "-(((" altinstr_len(num) ")-(" oldinstr_len ")) > 0) * " \ "((" altinstr_len(num) ")-(" oldinstr_len "))" #define INSTR_LEN_SANITY_CHECK(len) \ ".if " len " > 254\n" \ "\t.error \"cpu alternatives does not support instructions " \ "blocks > 254 bytes\"\n" \ ".endif\n" \ ".if (" len ") %% 2\n" \ "\t.error \"cpu alternatives instructions length is odd\"\n" \ ".endif\n" #define OLDINSTR_PADDING(oldinstr, num) \ ".if " oldinstr_pad_len(num) " > 6\n" \ "\tjg " e_oldinstr_pad_end "f\n" \ "6620:\n" \ "\t.fill (" oldinstr_pad_len(num) " - (6620b-662b)) / 2, 2, 0x0700\n" \ ".else\n" \ "\t.fill " oldinstr_pad_len(num) " / 6, 6, 0xc0040000\n" \ "\t.fill " oldinstr_pad_len(num) " %% 6 / 4, 4, 0x47000000\n" \ "\t.fill " oldinstr_pad_len(num) " %% 6 %% 4 / 2, 2, 0x0700\n" \ ".endif\n" #define OLDINSTR(oldinstr, num) \ "661:\n\t" oldinstr "\n662:\n" \ OLDINSTR_PADDING(oldinstr, num) \ e_oldinstr_pad_end ":\n" \ INSTR_LEN_SANITY_CHECK(oldinstr_len) #define OLDINSTR_2(oldinstr, num1, num2) \ "661:\n\t" oldinstr "\n662:\n" \ ".if " altinstr_len(num1) " < " altinstr_len(num2) "\n" \ OLDINSTR_PADDING(oldinstr, num2) \ ".else\n" \ OLDINSTR_PADDING(oldinstr, num1) \ ".endif\n" \ e_oldinstr_pad_end ":\n" \ INSTR_LEN_SANITY_CHECK(oldinstr_len) #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_total_len "\n" /* source len */ \ "\t.byte " altinstr_len(num) "\n" /* alt instruction len */ #define ALTINSTR_REPLACEMENT(altinstr, num) /* replacement */ \ b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n" \ INSTR_LEN_SANITY_CHECK(altinstr_len(num)) /* alternative assembly primitive: */ #define ALTERNATIVE(oldinstr, altinstr, facility) \ ".pushsection .altinstr_replacement, \"ax\"\n" \ ALTINSTR_REPLACEMENT(altinstr, 1) \ ".popsection\n" \ OLDINSTR(oldinstr, 1) \ ".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_2(oldinstr, 1, 2) \ ".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") #endif /* __ASSEMBLY__ */ #endif /* _ASM_S390_ALTERNATIVE_H */ |