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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 | /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_S390_ALTERNATIVE_ASM_H #define _ASM_S390_ALTERNATIVE_ASM_H #ifdef __ASSEMBLY__ /* * Check the length of an instruction sequence. The length may not be larger * than 254 bytes and it has to be divisible by 2. */ .macro alt_len_check start,end .if ( \end - \start ) > 254 .error "cpu alternatives does not support instructions blocks > 254 bytes\n" .endif .if ( \end - \start ) % 2 .error "cpu alternatives instructions length is odd\n" .endif .endm /* * Issue one struct alt_instr descriptor entry (need to put it into * the section .altinstructions, see below). This entry contains * enough information for the alternatives patching code to patch an * instruction. See apply_alternatives(). */ .macro alt_entry orig_start, orig_end, alt_start, alt_end, feature .long \orig_start - . .long \alt_start - . .word \feature .byte \orig_end - \orig_start .byte \alt_end - \alt_start .endm /* * Fill up @bytes with nops. The macro emits 6-byte nop instructions * for the bulk of the area, possibly followed by a 4-byte and/or * a 2-byte nop if the size of the area is not divisible by 6. */ .macro alt_pad_fill bytes .fill ( \bytes ) / 6, 6, 0xc0040000 .fill ( \bytes ) % 6 / 4, 4, 0x47000000 .fill ( \bytes ) % 6 % 4 / 2, 2, 0x0700 .endm /* * Fill up @bytes with nops. If the number of bytes is larger * than 6, emit a jg instruction to branch over all nops, then * fill an area of size (@bytes - 6) with nop instructions. */ .macro alt_pad bytes .if ( \bytes > 0 ) .if ( \bytes > 6 ) jg . + \bytes alt_pad_fill \bytes - 6 .else alt_pad_fill \bytes .endif .endif .endm /* * Define an alternative between two instructions. If @feature is * present, early code in apply_alternatives() replaces @oldinstr with * @newinstr. ".skip" directive takes care of proper instruction padding * in case @newinstr is longer than @oldinstr. */ .macro ALTERNATIVE oldinstr, newinstr, feature .pushsection .altinstr_replacement,"ax" 770: \newinstr 771: .popsection 772: \oldinstr 773: alt_len_check 770b, 771b alt_len_check 772b, 773b alt_pad ( ( 771b - 770b ) - ( 773b - 772b ) ) 774: .pushsection .altinstructions,"a" alt_entry 772b, 774b, 770b, 771b, \feature .popsection .endm /* * Define an alternative between two instructions. If @feature is * present, early code in apply_alternatives() replaces @oldinstr with * @newinstr. ".skip" directive takes care of proper instruction padding * in case @newinstr is longer than @oldinstr. */ .macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2 .pushsection .altinstr_replacement,"ax" 770: \newinstr1 771: \newinstr2 772: .popsection 773: \oldinstr 774: alt_len_check 770b, 771b alt_len_check 771b, 772b alt_len_check 773b, 774b .if ( 771b - 770b > 772b - 771b ) alt_pad ( ( 771b - 770b ) - ( 774b - 773b ) ) .else alt_pad ( ( 772b - 771b ) - ( 774b - 773b ) ) .endif 775: .pushsection .altinstructions,"a" alt_entry 773b, 775b, 770b, 771b,\feature1 alt_entry 773b, 775b, 771b, 772b,\feature2 .popsection .endm #endif /* __ASSEMBLY__ */ #endif /* _ASM_S390_ALTERNATIVE_ASM_H */ |