arch/arm/include/asm/opcodes.h

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