arch/arm/include/asm/opcodes.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  arch/arm/include/asm/opcodes.h
   4  */
   5
   6 #ifndef __ASM_ARM_OPCODES_H
   7 #define __ASM_ARM_OPCODES_H
   8
   9 #ifndef __ASSEMBLY__
  10 #include <linux/linkage.h>
  11 extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
  12 #endif
  13
  14 #define ARM_OPCODE_CONDTEST_FAIL   0
  15 #define ARM_OPCODE_CONDTEST_PASS   1
  16 #define ARM_OPCODE_CONDTEST_UNCOND 2
  17
  18
  19 /*
  20  * Assembler opcode byteswap helpers.
  21  * These are only intended for use by this header: don't use them directly,
  22  * because they will be suboptimal in most cases.
  23  */
  24 #define ___asm_opcode_swab32(x) (       \
  25           (((x) << 24) & 0xFF000000)    \
  26         | (((x) <<  8) & 0x00FF0000)    \
  27         | (((x) >>  8) & 0x0000FF00)    \
  28         | (((x) >> 24) & 0x000000FF)    \
  29 )
  30 #define ___asm_opcode_swab16(x) (       \
  31           (((x) << 8) & 0xFF00)         \
  32         | (((x) >> 8) & 0x00FF)         \
  33 )
  34 #define ___asm_opcode_swahb32(x) (      \
  35           (((x) << 8) & 0xFF00FF00)     \
  36         | (((x) >> 8) & 0x00FF00FF)     \
  37 )
  38 #define ___asm_opcode_swahw32(x) (      \
  39           (((x) << 16) & 0xFFFF0000)    \
  40         | (((x) >> 16) & 0x0000FFFF)    \
  41 )
  42 #define ___asm_opcode_identity32(x) ((x) & 0xFFFFFFFF)
  43 #define ___asm_opcode_identity16(x) ((x) & 0xFFFF)
  44
  45
  46 /*
  47  * Opcode byteswap helpers
  48  *
  49  * These macros help with converting instructions between a canonical integer
  50  * format and in-memory representation, in an endianness-agnostic manner.
  51  *
  52  * __mem_to_opcode_*() convert from in-memory representation to canonical form.
  53  * __opcode_to_mem_*() convert from canonical form to in-memory representation.
  54  *
  55  *
  56  * Canonical instruction representation:
  57  *
  58  *      ARM:            0xKKLLMMNN
  59  *      Thumb 16-bit:   0x0000KKLL, where KK < 0xE8
  60  *      Thumb 32-bit:   0xKKLLMMNN, where KK >= 0xE8
  61  *
  62  * There is no way to distinguish an ARM instruction in canonical representation
  63  * from a Thumb instruction (just as these cannot be distinguished in memory).
  64  * Where this distinction is important, it needs to be tracked separately.
  65  *
  66  * Note that values in the range 0x0000E800..0xE7FFFFFF intentionally do not
  67  * represent any valid Thumb-2 instruction.  For this range,
  68  * __opcode_is_thumb32() and __opcode_is_thumb16() will both be false.
  69  *
  70  * The ___asm variants are intended only for use by this header, in situations
  71  * involving inline assembler.  For .S files, the normal __opcode_*() macros
  72  * should do the right thing.
  73  */
  74 #ifdef __ASSEMBLY__
  75
  76 #define ___opcode_swab32(x) ___asm_opcode_swab32(x)
  77 #define ___opcode_swab16(x) ___asm_opcode_swab16(x)
  78 #define ___opcode_swahb32(x) ___asm_opcode_swahb32(x)
  79 #define ___opcode_swahw32(x) ___asm_opcode_swahw32(x)
  80 #define ___opcode_identity32(x) ___asm_opcode_identity32(x)
  81 #define ___opcode_identity16(x) ___asm_opcode_identity16(x)
  82
  83 #else /* ! __ASSEMBLY__ */
  84
  85 #include <linux/types.h>
  86 #include <linux/swab.h>
  87
  88 #define ___opcode_swab32(x) swab32(x)
  89 #define ___opcode_swab16(x) swab16(x)
  90 #define ___opcode_swahb32(x) swahb32(x)
  91 #define ___opcode_swahw32(x) swahw32(x)
  92 #define ___opcode_identity32(x) ((u32)(x))
  93 #define ___opcode_identity16(x) ((u16)(x))
  94
  95 #endif /* ! __ASSEMBLY__ */
  96
  97
  98 #ifdef CONFIG_CPU_ENDIAN_BE8
  99
 100 #define __opcode_to_mem_arm(x) ___opcode_swab32(x)
 101 #define __opcode_to_mem_thumb16(x) ___opcode_swab16(x)
 102 #define __opcode_to_mem_thumb32(x) ___opcode_swahb32(x)
 103 #define ___asm_opcode_to_mem_arm(x) ___asm_opcode_swab32(x)
 104 #define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_swab16(x)
 105 #define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahb32(x)
 106
 107 #else /* ! CONFIG_CPU_ENDIAN_BE8 */
 108
 109 #define __opcode_to_mem_arm(x) ___opcode_identity32(x)
 110 #define __opcode_to_mem_thumb16(x) ___opcode_identity16(x)
 111 #define ___asm_opcode_to_mem_arm(x) ___asm_opcode_identity32(x)
 112 #define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_identity16(x)
 113 #ifndef CONFIG_CPU_ENDIAN_BE32
 114 /*
 115  * On BE32 systems, using 32-bit accesses to store Thumb instructions will not
 116  * work in all cases, due to alignment constraints.  For now, a correct
 117  * version is not provided for BE32.
 118  */
 119 #define __opcode_to_mem_thumb32(x) ___opcode_swahw32(x)
 120 #define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahw32(x)
 121 #endif
 122
 123 #endif /* ! CONFIG_CPU_ENDIAN_BE8 */
 124
 125 #define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x)
 126 #define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x)
 127 #ifndef CONFIG_CPU_ENDIAN_BE32
 128 #define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x)
 129 #endif
 130
 131 /* Operations specific to Thumb opcodes */
 132
 133 /* Instruction size checks: */
 134 #define __opcode_is_thumb32(x) (                \
 135            ((x) & 0xF8000000) == 0xE8000000     \
 136         || ((x) & 0xF0000000) == 0xF0000000     \
 137 )
 138 #define __opcode_is_thumb16(x) (                                        \
 139            ((x) & 0xFFFF0000) == 0                                      \
 140         && !(((x) & 0xF800) == 0xE800 || ((x) & 0xF000) == 0xF000)      \
 141 )
 142
 143 /* Operations to construct or split 32-bit Thumb instructions: */
 144 #define __opcode_thumb32_first(x) (___opcode_identity16((x) >> 16))
 145 #define __opcode_thumb32_second(x) (___opcode_identity16(x))
 146 #define __opcode_thumb32_compose(first, second) (                       \
 147           (___opcode_identity32(___opcode_identity16(first)) << 16)     \
 148         | ___opcode_identity32(___opcode_identity16(second))            \
 149 )
 150 #define ___asm_opcode_thumb32_first(x) (___asm_opcode_identity16((x) >> 16))
 151 #define ___asm_opcode_thumb32_second(x) (___asm_opcode_identity16(x))
 152 #define ___asm_opcode_thumb32_compose(first, second) (                      \
 153           (___asm_opcode_identity32(___asm_opcode_identity16(first)) << 16) \
 154         | ___asm_opcode_identity32(___asm_opcode_identity16(second))        \
 155 )
 156
 157 /*
 158  * Opcode injection helpers
 159  *
 160  * In rare cases it is necessary to assemble an opcode which the
 161  * assembler does not support directly, or which would normally be
 162  * rejected because of the CFLAGS or AFLAGS used to build the affected
 163  * file.
 164  *
 165  * Before using these macros, consider carefully whether it is feasible
 166  * instead to change the build flags for your file, or whether it really
 167  * makes sense to support old assembler versions when building that
 168  * particular kernel feature.
 169  *
 170  * The macros defined here should only be used where there is no viable
 171  * alternative.
 172  *
 173  *
 174  * __inst_arm(x): emit the specified ARM opcode
 175  * __inst_thumb16(x): emit the specified 16-bit Thumb opcode
 176  * __inst_thumb32(x): emit the specified 32-bit Thumb opcode
 177  *
 178  * __inst_arm_thumb16(arm, thumb): emit either the specified arm or
 179  *      16-bit Thumb opcode, depending on whether an ARM or Thumb-2
 180  *      kernel is being built
 181  *
 182  * __inst_arm_thumb32(arm, thumb): emit either the specified arm or
 183  *      32-bit Thumb opcode, depending on whether an ARM or Thumb-2
 184  *      kernel is being built
 185  *
 186  *
 187  * Note that using these macros directly is poor practice.  Instead, you
 188  * should use them to define human-readable wrapper macros to encode the
 189  * instructions that you care about.  In code which might run on ARMv7 or
 190  * above, you can usually use the __inst_arm_thumb{16,32} macros to
 191  * specify the ARM and Thumb alternatives at the same time.  This ensures
 192  * that the correct opcode gets emitted depending on the instruction set
 193  * used for the kernel build.
 194  *
 195  * Look at opcodes-virt.h for an example of how to use these macros.
 196  */
 197 #include <linux/stringify.h>
 198
 199 #define __inst_arm(x) ___inst_arm(___asm_opcode_to_mem_arm(x))
 200 #define __inst_thumb32(x) ___inst_thumb32(                              \
 201         ___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_first(x)),   \
 202         ___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_second(x))   \
 203 )
 204 #define __inst_thumb16(x) ___inst_thumb16(___asm_opcode_to_mem_thumb16(x))
 205
 206 #ifdef CONFIG_THUMB2_KERNEL
 207 #define __inst_arm_thumb16(arm_opcode, thumb_opcode) \
 208         __inst_thumb16(thumb_opcode)
 209 #define __inst_arm_thumb32(arm_opcode, thumb_opcode) \
 210         __inst_thumb32(thumb_opcode)
 211 #else
 212 #define __inst_arm_thumb16(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
 213 #define __inst_arm_thumb32(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
 214 #endif
 215
 216 /* Helpers for the helpers.  Don't use these directly. */
 217 #ifdef __ASSEMBLY__
 218 #define ___inst_arm(x) .long x
 219 #define ___inst_thumb16(x) .short x
 220 #define ___inst_thumb32(first, second) .short first, second
 221 #else
 222 #define ___inst_arm(x) ".long " __stringify(x) "\n\t"
 223 #define ___inst_thumb16(x) ".short " __stringify(x) "\n\t"
 224 #define ___inst_thumb32(first, second) \
 225         ".short " __stringify(first) ", " __stringify(second) "\n\t"
 226 #endif
 227
 228 #endif /* __ASM_ARM_OPCODES_H */