From f5f5195487affe53f90d99cba4aee73a20cae565 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Wed, 1 Feb 2012 10:42:22 +0100 Subject: ARM: 7311/1: Add generic instruction opcode manipulation helpers This patch adds some endianness-agnostic helpers to convert machine instructions between canonical integer form and in-memory representation. A canonical integer form for representing instructions is also formalised here. Signed-off-by: Dave Martin Acked-by: Nicolas Pitre Tested-by: Jon Medhurst Signed-off-by: Russell King --- arch/arm/include/asm/opcodes.h | 59 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'arch/arm/include/asm') 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 +#include + +#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 */ -- cgit v1.2.2