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Commit f5f51954 authored by Dave Martin's avatar Dave Martin Committed by Russell King
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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: default avatarDave Martin <dave.martin@linaro.org>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Tested-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent a9d6d151

arch/arm/include/asm/opcodes.h

+59 −0
Original line number Diff line number Diff line
@@ -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 */