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ARM: 7311/1: Add generic instruction opcode manipulation helpers

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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 <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Dave Martin 2012-02-01 10:42:22 +01:00 committed by Russell King
parent a9d6d15131
commit f5f5195487
1 changed files with 59 additions and 0 deletions
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59
arch/arm/include/asm/opcodes.h
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@ -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 */