diff options
| -rw-r--r-- | arch/arm/include/asm/opcodes.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/arm/include/asm/opcodes.h b/arch/arm/include/asm/opcodes.h index c0efdd60966f..19c48deda70f 100644 --- a/arch/arm/include/asm/opcodes.h +++ b/arch/arm/include/asm/opcodes.h @@ -17,4 +17,63 @@ extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr); #define ARM_OPCODE_CONDTEST_PASS 1 #define ARM_OPCODE_CONDTEST_UNCOND 2 + +/* + * Opcode byteswap helpers + * + * These macros help with converting instructions between a canonical integer + * format and in-memory representation, in an endianness-agnostic manner. + * + * __mem_to_opcode_*() convert from in-memory representation to canonical form. + * __opcode_to_mem_*() convert from canonical form to in-memory representation. + * + * + * Canonical instruction representation: + * + * ARM: 0xKKLLMMNN + * Thumb 16-bit: 0x0000KKLL, where KK < 0xE8 + * Thumb 32-bit: 0xKKLLMMNN, where KK >= 0xE8 + * + * There is no way to distinguish an ARM instruction in canonical representation + * from a Thumb instruction (just as these cannot be distinguished in memory). + * Where this distinction is important, it needs to be tracked separately. + * + * Note that values in the range 0x0000E800..0xE7FFFFFF intentionally do not + * represent any valid Thumb-2 instruction. For this range, + * __opcode_is_thumb32() and __opcode_is_thumb16() will both be false. + */ + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <linux/swab.h> + +#ifdef CONFIG_CPU_ENDIAN_BE8 +#define __opcode_to_mem_arm(x) swab32(x) +#define __opcode_to_mem_thumb16(x) swab16(x) +#define __opcode_to_mem_thumb32(x) swahb32(x) +#else +#define __opcode_to_mem_arm(x) ((u32)(x)) +#define __opcode_to_mem_thumb16(x) ((u16)(x)) +#define __opcode_to_mem_thumb32(x) swahw32(x) +#endif + +#define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x) +#define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x) +#define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x) + +/* Operations specific to Thumb opcodes */ + +/* Instruction size checks: */ +#define __opcode_is_thumb32(x) ((u32)(x) >= 0xE8000000UL) +#define __opcode_is_thumb16(x) ((u32)(x) < 0xE800UL) + +/* Operations to construct or split 32-bit Thumb instructions: */ +#define __opcode_thumb32_first(x) ((u16)((x) >> 16)) +#define __opcode_thumb32_second(x) ((u16)(x)) +#define __opcode_thumb32_compose(first, second) \ + (((u32)(u16)(first) << 16) | (u32)(u16)(second)) + +#endif /* __ASSEMBLY__ */ + #endif /* __ASM_ARM_OPCODES_H */ |