1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 *  arch/arm/include/asm/opcodes.h
4 */
5
6#ifndef __ASM_ARM_OPCODES_H
7#define __ASM_ARM_OPCODES_H
8
9#ifndef __ASSEMBLY__
10#include <linux/linkage.h>
11extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
12#endif
13
14#define ARM_OPCODE_CONDTEST_FAIL   0
15#define ARM_OPCODE_CONDTEST_PASS   1
16#define ARM_OPCODE_CONDTEST_UNCOND 2
17
18
19/*
20 * Assembler opcode byteswap helpers.
21 * These are only intended for use by this header: don't use them directly,
22 * because they will be suboptimal in most cases.
23 */
24#define ___asm_opcode_swab32(x) (	\
25	  (((x) << 24) & 0xFF000000)	\
26	| (((x) <<  8) & 0x00FF0000)	\
27	| (((x) >>  8) & 0x0000FF00)	\
28	| (((x) >> 24) & 0x000000FF)	\
29)
30#define ___asm_opcode_swab16(x) (	\
31	  (((x) << 8) & 0xFF00)		\
32	| (((x) >> 8) & 0x00FF)		\
33)
34#define ___asm_opcode_swahb32(x) (	\
35	  (((x) << 8) & 0xFF00FF00)	\
36	| (((x) >> 8) & 0x00FF00FF)	\
37)
38#define ___asm_opcode_swahw32(x) (	\
39	  (((x) << 16) & 0xFFFF0000)	\
40	| (((x) >> 16) & 0x0000FFFF)	\
41)
42#define ___asm_opcode_identity32(x) ((x) & 0xFFFFFFFF)
43#define ___asm_opcode_identity16(x) ((x) & 0xFFFF)
44
45
46/*
47 * Opcode byteswap helpers
48 *
49 * These macros help with converting instructions between a canonical integer
50 * format and in-memory representation, in an endianness-agnostic manner.
51 *
52 * __mem_to_opcode_*() convert from in-memory representation to canonical form.
53 * __opcode_to_mem_*() convert from canonical form to in-memory representation.
54 *
55 *
56 * Canonical instruction representation:
57 *
58 *	ARM:		0xKKLLMMNN
59 *	Thumb 16-bit:	0x0000KKLL, where KK < 0xE8
60 *	Thumb 32-bit:	0xKKLLMMNN, where KK >= 0xE8
61 *
62 * There is no way to distinguish an ARM instruction in canonical representation
63 * from a Thumb instruction (just as these cannot be distinguished in memory).
64 * Where this distinction is important, it needs to be tracked separately.
65 *
66 * Note that values in the range 0x0000E800..0xE7FFFFFF intentionally do not
67 * represent any valid Thumb-2 instruction.  For this range,
68 * __opcode_is_thumb32() and __opcode_is_thumb16() will both be false.
69 *
70 * The ___asm variants are intended only for use by this header, in situations
71 * involving inline assembler.  For .S files, the normal __opcode_*() macros
72 * should do the right thing.
73 */
74#ifdef __ASSEMBLY__
75
76#define ___opcode_swab32(x) ___asm_opcode_swab32(x)
77#define ___opcode_swab16(x) ___asm_opcode_swab16(x)
78#define ___opcode_swahb32(x) ___asm_opcode_swahb32(x)
79#define ___opcode_swahw32(x) ___asm_opcode_swahw32(x)
80#define ___opcode_identity32(x) ___asm_opcode_identity32(x)
81#define ___opcode_identity16(x) ___asm_opcode_identity16(x)
82
83#else /* ! __ASSEMBLY__ */
84
85#include <linux/types.h>
86#include <linux/swab.h>
87
88#define ___opcode_swab32(x) swab32(x)
89#define ___opcode_swab16(x) swab16(x)
90#define ___opcode_swahb32(x) swahb32(x)
91#define ___opcode_swahw32(x) swahw32(x)
92#define ___opcode_identity32(x) ((u32)(x))
93#define ___opcode_identity16(x) ((u16)(x))
94
95#endif /* ! __ASSEMBLY__ */
96
97
98#ifdef CONFIG_CPU_ENDIAN_BE8
99
100#define __opcode_to_mem_arm(x) ___opcode_swab32(x)
101#define __opcode_to_mem_thumb16(x) ___opcode_swab16(x)
102#define __opcode_to_mem_thumb32(x) ___opcode_swahb32(x)
103#define ___asm_opcode_to_mem_arm(x) ___asm_opcode_swab32(x)
104#define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_swab16(x)
105#define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahb32(x)
106
107#else /* ! CONFIG_CPU_ENDIAN_BE8 */
108
109#define __opcode_to_mem_arm(x) ___opcode_identity32(x)
110#define __opcode_to_mem_thumb16(x) ___opcode_identity16(x)
111#define ___asm_opcode_to_mem_arm(x) ___asm_opcode_identity32(x)
112#define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_identity16(x)
113#ifndef CONFIG_CPU_ENDIAN_BE32
114/*
115 * On BE32 systems, using 32-bit accesses to store Thumb instructions will not
116 * work in all cases, due to alignment constraints.  For now, a correct
117 * version is not provided for BE32.
118 */
119#define __opcode_to_mem_thumb32(x) ___opcode_swahw32(x)
120#define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahw32(x)
121#endif
122
123#endif /* ! CONFIG_CPU_ENDIAN_BE8 */
124
125#define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x)
126#define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x)
127#ifndef CONFIG_CPU_ENDIAN_BE32
128#define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x)
129#endif
130
131/* Operations specific to Thumb opcodes */
132
133/* Instruction size checks: */
134#define __opcode_is_thumb32(x) (		\
135	   ((x) & 0xF8000000) == 0xE8000000	\
136	|| ((x) & 0xF0000000) == 0xF0000000	\
137)
138#define __opcode_is_thumb16(x) (					\
139	   ((x) & 0xFFFF0000) == 0					\
140	&& !(((x) & 0xF800) == 0xE800 || ((x) & 0xF000) == 0xF000)	\
141)
142
143/* Operations to construct or split 32-bit Thumb instructions: */
144#define __opcode_thumb32_first(x) (___opcode_identity16((x) >> 16))
145#define __opcode_thumb32_second(x) (___opcode_identity16(x))
146#define __opcode_thumb32_compose(first, second) (			\
147	  (___opcode_identity32(___opcode_identity16(first)) << 16)	\
148	| ___opcode_identity32(___opcode_identity16(second))		\
149)
150#define ___asm_opcode_thumb32_first(x) (___asm_opcode_identity16((x) >> 16))
151#define ___asm_opcode_thumb32_second(x) (___asm_opcode_identity16(x))
152#define ___asm_opcode_thumb32_compose(first, second) (			    \
153	  (___asm_opcode_identity32(___asm_opcode_identity16(first)) << 16) \
154	| ___asm_opcode_identity32(___asm_opcode_identity16(second))	    \
155)
156
157/*
158 * Opcode injection helpers
159 *
160 * In rare cases it is necessary to assemble an opcode which the
161 * assembler does not support directly, or which would normally be
162 * rejected because of the CFLAGS or AFLAGS used to build the affected
163 * file.
164 *
165 * Before using these macros, consider carefully whether it is feasible
166 * instead to change the build flags for your file, or whether it really
167 * makes sense to support old assembler versions when building that
168 * particular kernel feature.
169 *
170 * The macros defined here should only be used where there is no viable
171 * alternative.
172 *
173 *
174 * __inst_arm(x): emit the specified ARM opcode
175 * __inst_thumb16(x): emit the specified 16-bit Thumb opcode
176 * __inst_thumb32(x): emit the specified 32-bit Thumb opcode
177 *
178 * __inst_arm_thumb16(arm, thumb): emit either the specified arm or
179 *	16-bit Thumb opcode, depending on whether an ARM or Thumb-2
180 *	kernel is being built
181 *
182 * __inst_arm_thumb32(arm, thumb): emit either the specified arm or
183 *	32-bit Thumb opcode, depending on whether an ARM or Thumb-2
184 *	kernel is being built
185 *
186 *
187 * Note that using these macros directly is poor practice.  Instead, you
188 * should use them to define human-readable wrapper macros to encode the
189 * instructions that you care about.  In code which might run on ARMv7 or
190 * above, you can usually use the __inst_arm_thumb{16,32} macros to
191 * specify the ARM and Thumb alternatives at the same time.  This ensures
192 * that the correct opcode gets emitted depending on the instruction set
193 * used for the kernel build.
194 *
195 * Look at opcodes-virt.h for an example of how to use these macros.
196 */
197#include <linux/stringify.h>
198
199#define __inst_arm(x) ___inst_arm(___asm_opcode_to_mem_arm(x))
200#define __inst_thumb32(x) ___inst_thumb32(				\
201	___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_first(x)),	\
202	___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_second(x))	\
203)
204#define __inst_thumb16(x) ___inst_thumb16(___asm_opcode_to_mem_thumb16(x))
205
206#ifdef CONFIG_THUMB2_KERNEL
207#define __inst_arm_thumb16(arm_opcode, thumb_opcode) \
208	__inst_thumb16(thumb_opcode)
209#define __inst_arm_thumb32(arm_opcode, thumb_opcode) \
210	__inst_thumb32(thumb_opcode)
211#else
212#define __inst_arm_thumb16(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
213#define __inst_arm_thumb32(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
214#endif
215
216/* Helpers for the helpers.  Don't use these directly. */
217#ifdef __ASSEMBLY__
218#define ___inst_arm(x) .long x
219#define ___inst_thumb16(x) .short x
220#define ___inst_thumb32(first, second) .short first, second
221#else
222#define ___inst_arm(x) ".long " __stringify(x) "\n\t"
223#define ___inst_thumb16(x) ".short " __stringify(x) "\n\t"
224#define ___inst_thumb32(first, second) \
225	".short " __stringify(first) ", " __stringify(second) "\n\t"
226#endif
227
228#endif /* __ASM_ARM_OPCODES_H */
229