1 /* SPDX-License-Identifier: GPL-2.0-only */
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>
11 extern 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 #ifdef CONFIG_CPU_ENDIAN_BE32
114 #ifndef __ASSEMBLY__
115 /*
116  * On BE32 systems, using 32-bit accesses to store Thumb instructions will not
117  * work in all cases, due to alignment constraints.  For now, a correct
118  * version is not provided for BE32, but the prototype needs to be there
119  * to compile patch.c.
120  */
121 extern __u32 __opcode_to_mem_thumb32(__u32);
122 #endif
123 #else
124 #define __opcode_to_mem_thumb32(x) ___opcode_swahw32(x)
125 #define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahw32(x)
126 #endif
127 
128 #endif /* ! CONFIG_CPU_ENDIAN_BE8 */
129 
130 #define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x)
131 #define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x)
132 #ifndef CONFIG_CPU_ENDIAN_BE32
133 #define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x)
134 #endif
135 
136 /* Operations specific to Thumb opcodes */
137 
138 /* Instruction size checks: */
139 #define __opcode_is_thumb32(x) (		\
140 	   ((x) & 0xF8000000) == 0xE8000000	\
141 	|| ((x) & 0xF0000000) == 0xF0000000	\
142 )
143 #define __opcode_is_thumb16(x) (					\
144 	   ((x) & 0xFFFF0000) == 0					\
145 	&& !(((x) & 0xF800) == 0xE800 || ((x) & 0xF000) == 0xF000)	\
146 )
147 
148 /* Operations to construct or split 32-bit Thumb instructions: */
149 #define __opcode_thumb32_first(x) (___opcode_identity16((x) >> 16))
150 #define __opcode_thumb32_second(x) (___opcode_identity16(x))
151 #define __opcode_thumb32_compose(first, second) (			\
152 	  (___opcode_identity32(___opcode_identity16(first)) << 16)	\
153 	| ___opcode_identity32(___opcode_identity16(second))		\
154 )
155 #define ___asm_opcode_thumb32_first(x) (___asm_opcode_identity16((x) >> 16))
156 #define ___asm_opcode_thumb32_second(x) (___asm_opcode_identity16(x))
157 #define ___asm_opcode_thumb32_compose(first, second) (			    \
158 	  (___asm_opcode_identity32(___asm_opcode_identity16(first)) << 16) \
159 	| ___asm_opcode_identity32(___asm_opcode_identity16(second))	    \
160 )
161 
162 /*
163  * Opcode injection helpers
164  *
165  * In rare cases it is necessary to assemble an opcode which the
166  * assembler does not support directly, or which would normally be
167  * rejected because of the CFLAGS or AFLAGS used to build the affected
168  * file.
169  *
170  * Before using these macros, consider carefully whether it is feasible
171  * instead to change the build flags for your file, or whether it really
172  * makes sense to support old assembler versions when building that
173  * particular kernel feature.
174  *
175  * The macros defined here should only be used where there is no viable
176  * alternative.
177  *
178  *
179  * __inst_arm(x): emit the specified ARM opcode
180  * __inst_thumb16(x): emit the specified 16-bit Thumb opcode
181  * __inst_thumb32(x): emit the specified 32-bit Thumb opcode
182  *
183  * __inst_arm_thumb16(arm, thumb): emit either the specified arm or
184  *	16-bit Thumb opcode, depending on whether an ARM or Thumb-2
185  *	kernel is being built
186  *
187  * __inst_arm_thumb32(arm, thumb): emit either the specified arm or
188  *	32-bit Thumb opcode, depending on whether an ARM or Thumb-2
189  *	kernel is being built
190  *
191  *
192  * Note that using these macros directly is poor practice.  Instead, you
193  * should use them to define human-readable wrapper macros to encode the
194  * instructions that you care about.  In code which might run on ARMv7 or
195  * above, you can usually use the __inst_arm_thumb{16,32} macros to
196  * specify the ARM and Thumb alternatives at the same time.  This ensures
197  * that the correct opcode gets emitted depending on the instruction set
198  * used for the kernel build.
199  *
200  * Look at opcodes-virt.h for an example of how to use these macros.
201  */
202 #include <linux/stringify.h>
203 
204 #define __inst_arm(x) ___inst_arm(___asm_opcode_to_mem_arm(x))
205 #define __inst_thumb32(x) ___inst_thumb32(				\
206 	___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_first(x)),	\
207 	___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_second(x))	\
208 )
209 #define __inst_thumb16(x) ___inst_thumb16(___asm_opcode_to_mem_thumb16(x))
210 
211 #ifdef CONFIG_THUMB2_KERNEL
212 #define __inst_arm_thumb16(arm_opcode, thumb_opcode) \
213 	__inst_thumb16(thumb_opcode)
214 #define __inst_arm_thumb32(arm_opcode, thumb_opcode) \
215 	__inst_thumb32(thumb_opcode)
216 #else
217 #define __inst_arm_thumb16(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
218 #define __inst_arm_thumb32(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
219 #endif
220 
221 /* Helpers for the helpers.  Don't use these directly. */
222 #ifdef __ASSEMBLY__
223 #define ___inst_arm(x) .long x
224 #define ___inst_thumb16(x) .short x
225 #define ___inst_thumb32(first, second) .short first, second
226 #else
227 #define ___inst_arm(x) ".long " __stringify(x) "\n\t"
228 #define ___inst_thumb16(x) ".short " __stringify(x) "\n\t"
229 #define ___inst_thumb32(first, second) \
230 	".short " __stringify(first) ", " __stringify(second) "\n\t"
231 #endif
232 
233 #endif /* __ASM_ARM_OPCODES_H */
234