| 1 |
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| 2 | |
| 3 | * arch/arm/include/asm/opcodes.h
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| 4 |
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| 5 |
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| 6 | #ifndef __ASM_ARM_OPCODES_H
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| 7 | #define __ASM_ARM_OPCODES_H
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| 8 |
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| 9 | #ifndef __ASSEMBLY__
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| 10 | #include <linux/linkage.h>
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| 11 | extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
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| 12 | #endif
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| 13 |
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| 14 | #define ARM_OPCODE_CONDTEST_FAIL 0
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| 15 | #define ARM_OPCODE_CONDTEST_PASS 1
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| 16 | #define ARM_OPCODE_CONDTEST_UNCOND 2
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| 17 |
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| 18 |
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| 19 | |
| 20 | * Assembler opcode byteswap helpers.
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| 21 | * These are only intended for use by this header: don't use them directly,
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| 22 | * because they will be suboptimal in most cases.
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| 23 |
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| 24 | #define ___asm_opcode_swab32(x) ( \
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| 25 | (((x) << 24) & 0xFF000000) \
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| 26 | | (((x) << 8) & 0x00FF0000) \
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| 27 | | (((x) >> 8) & 0x0000FF00) \
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| 28 | | (((x) >> 24) & 0x000000FF) \
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| 29 | )
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| 30 | #define ___asm_opcode_swab16(x) ( \
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| 31 | (((x) << 8) & 0xFF00) \
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| 32 | | (((x) >> 8) & 0x00FF) \
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| 33 | )
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| 34 | #define ___asm_opcode_swahb32(x) ( \
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| 35 | (((x) << 8) & 0xFF00FF00) \
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| 36 | | (((x) >> 8) & 0x00FF00FF) \
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| 37 | )
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| 38 | #define ___asm_opcode_swahw32(x) ( \
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| 39 | (((x) << 16) & 0xFFFF0000) \
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| 40 | | (((x) >> 16) & 0x0000FFFF) \
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| 41 | )
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| 42 | #define ___asm_opcode_identity32(x) ((x) & 0xFFFFFFFF)
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| 43 | #define ___asm_opcode_identity16(x) ((x) & 0xFFFF)
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| 44 |
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| 45 |
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| 46 | |
| 47 | * Opcode byteswap helpers
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| 48 | *
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| 49 | * These macros help with converting instructions between a canonical integer
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| 50 | * format and in-memory representation, in an endianness-agnostic manner.
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| 51 | *
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| 52 | * __mem_to_opcode_*() convert from in-memory representation to canonical form.
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| 53 | * __opcode_to_mem_*() convert from canonical form to in-memory representation.
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| 54 | *
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| 55 | *
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| 56 | * Canonical instruction representation:
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| 57 | *
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| 58 | * ARM: 0xKKLLMMNN
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| 59 | * Thumb 16-bit: 0x0000KKLL, where KK < 0xE8
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| 60 | * Thumb 32-bit: 0xKKLLMMNN, where KK >= 0xE8
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| 61 | *
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| 62 | * There is no way to distinguish an ARM instruction in canonical representation
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| 63 | * from a Thumb instruction (just as these cannot be distinguished in memory).
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| 64 | * Where this distinction is important, it needs to be tracked separately.
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| 65 | *
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| 66 | * Note that values in the range 0x0000E800..0xE7FFFFFF intentionally do not
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| 67 | * represent any valid Thumb-2 instruction. For this range,
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| 68 | * __opcode_is_thumb32() and __opcode_is_thumb16() will both be false.
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| 69 | *
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| 70 | * The ___asm variants are intended only for use by this header, in situations
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| 71 | * involving inline assembler. For .S files, the normal __opcode_*() macros
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| 72 | * should do the right thing.
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| 73 |
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| 74 | #ifdef __ASSEMBLY__
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| 75 |
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| 76 | #define ___opcode_swab32(x) ___asm_opcode_swab32(x)
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| 77 | #define ___opcode_swab16(x) ___asm_opcode_swab16(x)
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| 78 | #define ___opcode_swahb32(x) ___asm_opcode_swahb32(x)
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| 79 | #define ___opcode_swahw32(x) ___asm_opcode_swahw32(x)
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| 80 | #define ___opcode_identity32(x) ___asm_opcode_identity32(x)
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| 81 | #define ___opcode_identity16(x) ___asm_opcode_identity16(x)
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| 82 |
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| 83 | #else
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| 84 |
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| 85 | #include <linux/types.h>
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| 86 | #include <linux/swab.h>
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| 87 |
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| 88 | #define ___opcode_swab32(x) swab32(x)
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| 89 | #define ___opcode_swab16(x) swab16(x)
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| 90 | #define ___opcode_swahb32(x) swahb32(x)
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| 91 | #define ___opcode_swahw32(x) swahw32(x)
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| 92 | #define ___opcode_identity32(x) ((u32)(x))
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| 93 | #define ___opcode_identity16(x) ((u16)(x))
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| 94 |
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| 95 | #endif
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| 96 |
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| 97 |
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| 98 | #ifdef CONFIG_CPU_ENDIAN_BE8
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| 99 |
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| 100 | #define __opcode_to_mem_arm(x) ___opcode_swab32(x)
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| 101 | #define __opcode_to_mem_thumb16(x) ___opcode_swab16(x)
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| 102 | #define __opcode_to_mem_thumb32(x) ___opcode_swahb32(x)
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| 103 | #define ___asm_opcode_to_mem_arm(x) ___asm_opcode_swab32(x)
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| 104 | #define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_swab16(x)
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| 105 | #define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahb32(x)
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| 106 |
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| 107 | #else
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| 108 |
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| 109 | #define __opcode_to_mem_arm(x) ___opcode_identity32(x)
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| 110 | #define __opcode_to_mem_thumb16(x) ___opcode_identity16(x)
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| 111 | #define ___asm_opcode_to_mem_arm(x) ___asm_opcode_identity32(x)
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| 112 | #define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_identity16(x)
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| 113 | #ifdef CONFIG_CPU_ENDIAN_BE32
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| 114 | #ifndef __ASSEMBLY__
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| 115 | |
| 116 | * On BE32 systems, using 32-bit accesses to store Thumb instructions will not
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| 117 | * work in all cases, due to alignment constraints. For now, a correct
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| 118 | * version is not provided for BE32, but the prototype needs to be there
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| 119 | * to compile patch.c.
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| 120 |
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| 121 | extern __u32 __opcode_to_mem_thumb32(__u32);
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| 122 | #endif
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| 123 | #else
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| 124 | #define __opcode_to_mem_thumb32(x) ___opcode_swahw32(x)
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| 125 | #define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahw32(x)
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| 126 | #endif
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| 127 |
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| 128 | #endif
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| 129 |
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| 130 | #define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x)
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| 131 | #define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x)
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| 132 | #ifndef CONFIG_CPU_ENDIAN_BE32
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| 133 | #define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x)
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| 134 | #endif
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| 135 |
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| 136 |
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| 137 |
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| 138 |
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| 139 | #define __opcode_is_thumb32(x) ( \
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| 140 | ((x) & 0xF8000000) == 0xE8000000 \
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| 141 | || ((x) & 0xF0000000) == 0xF0000000 \
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| 142 | )
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| 143 | #define __opcode_is_thumb16(x) ( \
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| 144 | ((x) & 0xFFFF0000) == 0 \
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| 145 | && !(((x) & 0xF800) == 0xE800 || ((x) & 0xF000) == 0xF000) \
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| 146 | )
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| 147 |
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| 148 |
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| 149 | #define __opcode_thumb32_first(x) (___opcode_identity16((x) >> 16))
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| 150 | #define __opcode_thumb32_second(x) (___opcode_identity16(x))
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| 151 | #define __opcode_thumb32_compose(first, second) ( \
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| 152 | (___opcode_identity32(___opcode_identity16(first)) << 16) \
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| 153 | | ___opcode_identity32(___opcode_identity16(second)) \
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| 154 | )
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| 155 | #define ___asm_opcode_thumb32_first(x) (___asm_opcode_identity16((x) >> 16))
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| 156 | #define ___asm_opcode_thumb32_second(x) (___asm_opcode_identity16(x))
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| 157 | #define ___asm_opcode_thumb32_compose(first, second) ( \
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| 158 | (___asm_opcode_identity32(___asm_opcode_identity16(first)) << 16) \
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| 159 | | ___asm_opcode_identity32(___asm_opcode_identity16(second)) \
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| 160 | )
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| 161 |
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| 162 | |
| 163 | * Opcode injection helpers
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| 164 | *
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| 165 | * In rare cases it is necessary to assemble an opcode which the
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| 166 | * assembler does not support directly, or which would normally be
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| 167 | * rejected because of the CFLAGS or AFLAGS used to build the affected
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| 168 | * file.
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| 169 | *
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| 170 | * Before using these macros, consider carefully whether it is feasible
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| 171 | * instead to change the build flags for your file, or whether it really
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| 172 | * makes sense to support old assembler versions when building that
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| 173 | * particular kernel feature.
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| 174 | *
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| 175 | * The macros defined here should only be used where there is no viable
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| 176 | * alternative.
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| 177 | *
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| 178 | *
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| 179 | * __inst_arm(x): emit the specified ARM opcode
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| 180 | * __inst_thumb16(x): emit the specified 16-bit Thumb opcode
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| 181 | * __inst_thumb32(x): emit the specified 32-bit Thumb opcode
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| 182 | *
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| 183 | * __inst_arm_thumb16(arm, thumb): emit either the specified arm or
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| 184 | * 16-bit Thumb opcode, depending on whether an ARM or Thumb-2
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| 185 | * kernel is being built
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| 186 | *
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| 187 | * __inst_arm_thumb32(arm, thumb): emit either the specified arm or
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| 188 | * 32-bit Thumb opcode, depending on whether an ARM or Thumb-2
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| 189 | * kernel is being built
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| 190 | *
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| 191 | *
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| 192 | * Note that using these macros directly is poor practice. Instead, you
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| 193 | * should use them to define human-readable wrapper macros to encode the
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| 194 | * instructions that you care about. In code which might run on ARMv7 or
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| 195 | * above, you can usually use the __inst_arm_thumb{16,32} macros to
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| 196 | * specify the ARM and Thumb alternatives at the same time. This ensures
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| 197 | * that the correct opcode gets emitted depending on the instruction set
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| 198 | * used for the kernel build.
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| 199 | *
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| 200 | * Look at opcodes-virt.h for an example of how to use these macros.
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| 201 |
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| 202 | #include <linux/stringify.h>
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| 203 |
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| 204 | #define __inst_arm(x) ___inst_arm(___asm_opcode_to_mem_arm(x))
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| 205 | #define __inst_thumb32(x) ___inst_thumb32( \
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| 206 | ___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_first(x)), \
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| 207 | ___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_second(x)) \
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| 208 | )
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| 209 | #define __inst_thumb16(x) ___inst_thumb16(___asm_opcode_to_mem_thumb16(x))
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| 210 |
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| 211 | #ifdef CONFIG_THUMB2_KERNEL
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| 212 | #define __inst_arm_thumb16(arm_opcode, thumb_opcode) \
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| 213 | __inst_thumb16(thumb_opcode)
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| 214 | #define __inst_arm_thumb32(arm_opcode, thumb_opcode) \
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| 215 | __inst_thumb32(thumb_opcode)
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| 216 | #else
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| 217 | #define __inst_arm_thumb16(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
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| 218 | #define __inst_arm_thumb32(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
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| 219 | #endif
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| 220 |
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| 221 |
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| 222 | #ifdef __ASSEMBLY__
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| 223 | #define ___inst_arm(x) .long x
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| 224 | #define ___inst_thumb16(x) .short x
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| 225 | #define ___inst_thumb32(first, second) .short first, second
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| 226 | #else
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| 227 | #define ___inst_arm(x) ".long " __stringify(x) "\n\t"
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| 228 | #define ___inst_thumb16(x) ".short " __stringify(x) "\n\t"
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| 229 | #define ___inst_thumb32(first, second) \
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| 230 | ".short " __stringify(first) ", " __stringify(second) "\n\t"
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| 231 | #endif
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| 232 |
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| 233 | #endif
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