LXR linux/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>
  14extern 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 */
 232