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508514ed25
For now, this patch just adds a definition for the HVC instruction. More can be added here later, as needed. Now that we have a real example of how to use the opcode injection macros properly, this patch also adds a cross-reference from the explanation in opcodes.h (since without an example, figuring out how to use the macros is not that easy). Signed-off-by: Dave Martin <dave.martin@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
231 lines
8.0 KiB
C
231 lines
8.0 KiB
C
/*
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* arch/arm/include/asm/opcodes.h
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __ASM_ARM_OPCODES_H
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#define __ASM_ARM_OPCODES_H
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#ifndef __ASSEMBLY__
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extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
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#endif
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#define ARM_OPCODE_CONDTEST_FAIL 0
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#define ARM_OPCODE_CONDTEST_PASS 1
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#define ARM_OPCODE_CONDTEST_UNCOND 2
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/*
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* Assembler opcode byteswap helpers.
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* These are only intended for use by this header: don't use them directly,
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* because they will be suboptimal in most cases.
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*/
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#define ___asm_opcode_swab32(x) ( \
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(((x) << 24) & 0xFF000000) \
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| (((x) << 8) & 0x00FF0000) \
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| (((x) >> 8) & 0x0000FF00) \
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| (((x) >> 24) & 0x000000FF) \
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)
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#define ___asm_opcode_swab16(x) ( \
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(((x) << 8) & 0xFF00) \
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| (((x) >> 8) & 0x00FF) \
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)
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#define ___asm_opcode_swahb32(x) ( \
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(((x) << 8) & 0xFF00FF00) \
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| (((x) >> 8) & 0x00FF00FF) \
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)
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#define ___asm_opcode_swahw32(x) ( \
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(((x) << 16) & 0xFFFF0000) \
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| (((x) >> 16) & 0x0000FFFF) \
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)
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#define ___asm_opcode_identity32(x) ((x) & 0xFFFFFFFF)
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#define ___asm_opcode_identity16(x) ((x) & 0xFFFF)
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/*
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* Opcode byteswap helpers
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*
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* These macros help with converting instructions between a canonical integer
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* format and in-memory representation, in an endianness-agnostic manner.
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*
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* __mem_to_opcode_*() convert from in-memory representation to canonical form.
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* __opcode_to_mem_*() convert from canonical form to in-memory representation.
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*
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*
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* Canonical instruction representation:
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*
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* ARM: 0xKKLLMMNN
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* Thumb 16-bit: 0x0000KKLL, where KK < 0xE8
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* Thumb 32-bit: 0xKKLLMMNN, where KK >= 0xE8
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*
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* There is no way to distinguish an ARM instruction in canonical representation
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* from a Thumb instruction (just as these cannot be distinguished in memory).
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* Where this distinction is important, it needs to be tracked separately.
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*
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* Note that values in the range 0x0000E800..0xE7FFFFFF intentionally do not
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* represent any valid Thumb-2 instruction. For this range,
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* __opcode_is_thumb32() and __opcode_is_thumb16() will both be false.
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*
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* The ___asm variants are intended only for use by this header, in situations
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* involving inline assembler. For .S files, the normal __opcode_*() macros
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* should do the right thing.
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*/
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#ifdef __ASSEMBLY__
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#define ___opcode_swab32(x) ___asm_opcode_swab32(x)
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#define ___opcode_swab16(x) ___asm_opcode_swab16(x)
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#define ___opcode_swahb32(x) ___asm_opcode_swahb32(x)
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#define ___opcode_swahw32(x) ___asm_opcode_swahw32(x)
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#define ___opcode_identity32(x) ___asm_opcode_identity32(x)
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#define ___opcode_identity16(x) ___asm_opcode_identity16(x)
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#else /* ! __ASSEMBLY__ */
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#include <linux/types.h>
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#include <linux/swab.h>
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#define ___opcode_swab32(x) swab32(x)
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#define ___opcode_swab16(x) swab16(x)
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#define ___opcode_swahb32(x) swahb32(x)
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#define ___opcode_swahw32(x) swahw32(x)
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#define ___opcode_identity32(x) ((u32)(x))
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#define ___opcode_identity16(x) ((u16)(x))
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#endif /* ! __ASSEMBLY__ */
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#ifdef CONFIG_CPU_ENDIAN_BE8
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#define __opcode_to_mem_arm(x) ___opcode_swab32(x)
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#define __opcode_to_mem_thumb16(x) ___opcode_swab16(x)
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#define __opcode_to_mem_thumb32(x) ___opcode_swahb32(x)
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#define ___asm_opcode_to_mem_arm(x) ___asm_opcode_swab32(x)
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#define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_swab16(x)
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#define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahb32(x)
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#else /* ! CONFIG_CPU_ENDIAN_BE8 */
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#define __opcode_to_mem_arm(x) ___opcode_identity32(x)
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#define __opcode_to_mem_thumb16(x) ___opcode_identity16(x)
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#define ___asm_opcode_to_mem_arm(x) ___asm_opcode_identity32(x)
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#define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_identity16(x)
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#ifndef CONFIG_CPU_ENDIAN_BE32
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/*
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* On BE32 systems, using 32-bit accesses to store Thumb instructions will not
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* work in all cases, due to alignment constraints. For now, a correct
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* version is not provided for BE32.
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*/
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#define __opcode_to_mem_thumb32(x) ___opcode_swahw32(x)
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#define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahw32(x)
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#endif
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#endif /* ! CONFIG_CPU_ENDIAN_BE8 */
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#define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x)
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#define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x)
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#ifndef CONFIG_CPU_ENDIAN_BE32
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#define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x)
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#endif
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/* Operations specific to Thumb opcodes */
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/* Instruction size checks: */
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#define __opcode_is_thumb32(x) ( \
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((x) & 0xF8000000) == 0xE8000000 \
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|| ((x) & 0xF0000000) == 0xF0000000 \
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)
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#define __opcode_is_thumb16(x) ( \
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((x) & 0xFFFF0000) == 0 \
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&& !(((x) & 0xF800) == 0xE800 || ((x) & 0xF000) == 0xF000) \
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)
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/* Operations to construct or split 32-bit Thumb instructions: */
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#define __opcode_thumb32_first(x) (___opcode_identity16((x) >> 16))
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#define __opcode_thumb32_second(x) (___opcode_identity16(x))
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#define __opcode_thumb32_compose(first, second) ( \
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(___opcode_identity32(___opcode_identity16(first)) << 16) \
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| ___opcode_identity32(___opcode_identity16(second)) \
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)
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#define ___asm_opcode_thumb32_first(x) (___asm_opcode_identity16((x) >> 16))
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#define ___asm_opcode_thumb32_second(x) (___asm_opcode_identity16(x))
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#define ___asm_opcode_thumb32_compose(first, second) ( \
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(___asm_opcode_identity32(___asm_opcode_identity16(first)) << 16) \
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| ___asm_opcode_identity32(___asm_opcode_identity16(second)) \
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)
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/*
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* Opcode injection helpers
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*
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* In rare cases it is necessary to assemble an opcode which the
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* assembler does not support directly, or which would normally be
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* rejected because of the CFLAGS or AFLAGS used to build the affected
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* file.
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*
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* Before using these macros, consider carefully whether it is feasible
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* instead to change the build flags for your file, or whether it really
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* makes sense to support old assembler versions when building that
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* particular kernel feature.
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*
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* The macros defined here should only be used where there is no viable
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* alternative.
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*
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*
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* __inst_arm(x): emit the specified ARM opcode
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* __inst_thumb16(x): emit the specified 16-bit Thumb opcode
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* __inst_thumb32(x): emit the specified 32-bit Thumb opcode
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*
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* __inst_arm_thumb16(arm, thumb): emit either the specified arm or
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* 16-bit Thumb opcode, depending on whether an ARM or Thumb-2
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* kernel is being built
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*
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* __inst_arm_thumb32(arm, thumb): emit either the specified arm or
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* 32-bit Thumb opcode, depending on whether an ARM or Thumb-2
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* kernel is being built
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*
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*
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* Note that using these macros directly is poor practice. Instead, you
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* should use them to define human-readable wrapper macros to encode the
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* instructions that you care about. In code which might run on ARMv7 or
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* above, you can usually use the __inst_arm_thumb{16,32} macros to
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* specify the ARM and Thumb alternatives at the same time. This ensures
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* that the correct opcode gets emitted depending on the instruction set
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* used for the kernel build.
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*
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* Look at opcodes-virt.h for an example of how to use these macros.
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*/
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#include <linux/stringify.h>
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#define __inst_arm(x) ___inst_arm(___asm_opcode_to_mem_arm(x))
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#define __inst_thumb32(x) ___inst_thumb32( \
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___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_first(x)), \
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___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_second(x)) \
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)
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#define __inst_thumb16(x) ___inst_thumb16(___asm_opcode_to_mem_thumb16(x))
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#ifdef CONFIG_THUMB2_KERNEL
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#define __inst_arm_thumb16(arm_opcode, thumb_opcode) \
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__inst_thumb16(thumb_opcode)
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#define __inst_arm_thumb32(arm_opcode, thumb_opcode) \
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__inst_thumb32(thumb_opcode)
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#else
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#define __inst_arm_thumb16(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
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#define __inst_arm_thumb32(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
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#endif
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/* Helpers for the helpers. Don't use these directly. */
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#ifdef __ASSEMBLY__
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#define ___inst_arm(x) .long x
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#define ___inst_thumb16(x) .short x
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#define ___inst_thumb32(first, second) .short first, second
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#else
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#define ___inst_arm(x) ".long " __stringify(x) "\n\t"
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#define ___inst_thumb16(x) ".short " __stringify(x) "\n\t"
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#define ___inst_thumb32(first, second) \
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".short " __stringify(first) ", " __stringify(second) "\n\t"
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#endif
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#endif /* __ASM_ARM_OPCODES_H */
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