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1 /*
2  *  arch/arm/include/asm/opcodes.h
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #ifndef __ASM_ARM_OPCODES_H
10 #define __ASM_ARM_OPCODES_H
11 
12 #ifndef __ASSEMBLY__
13 #include <linux/linkage.h>
14 extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
15 #endif
16 
17 #define ARM_OPCODE_CONDTEST_FAIL   0
18 #define ARM_OPCODE_CONDTEST_PASS   1
19 #define ARM_OPCODE_CONDTEST_UNCOND 2
20 
21 
22 /*
23  * Assembler opcode byteswap helpers.
24  * These are only intended for use by this header: don't use them directly,
25  * because they will be suboptimal in most cases.
26  */
27 #define ___asm_opcode_swab32(x) (	\
28 	  (((x) << 24) & 0xFF000000)	\
29 	| (((x) <<  8) & 0x00FF0000)	\
30 	| (((x) >>  8) & 0x0000FF00)	\
31 	| (((x) >> 24) & 0x000000FF)	\
32 )
33 #define ___asm_opcode_swab16(x) (	\
34 	  (((x) << 8) & 0xFF00)		\
35 	| (((x) >> 8) & 0x00FF)		\
36 )
37 #define ___asm_opcode_swahb32(x) (	\
38 	  (((x) << 8) & 0xFF00FF00)	\
39 	| (((x) >> 8) & 0x00FF00FF)	\
40 )
41 #define ___asm_opcode_swahw32(x) (	\
42 	  (((x) << 16) & 0xFFFF0000)	\
43 	| (((x) >> 16) & 0x0000FFFF)	\
44 )
45 #define ___asm_opcode_identity32(x) ((x) & 0xFFFFFFFF)
46 #define ___asm_opcode_identity16(x) ((x) & 0xFFFF)
47 
48 
49 /*
50  * Opcode byteswap helpers
51  *
52  * These macros help with converting instructions between a canonical integer
53  * format and in-memory representation, in an endianness-agnostic manner.
54  *
55  * __mem_to_opcode_*() convert from in-memory representation to canonical form.
56  * __opcode_to_mem_*() convert from canonical form to in-memory representation.
57  *
58  *
59  * Canonical instruction representation:
60  *
61  *	ARM:		0xKKLLMMNN
62  *	Thumb 16-bit:	0x0000KKLL, where KK < 0xE8
63  *	Thumb 32-bit:	0xKKLLMMNN, where KK >= 0xE8
64  *
65  * There is no way to distinguish an ARM instruction in canonical representation
66  * from a Thumb instruction (just as these cannot be distinguished in memory).
67  * Where this distinction is important, it needs to be tracked separately.
68  *
69  * Note that values in the range 0x0000E800..0xE7FFFFFF intentionally do not
70  * represent any valid Thumb-2 instruction.  For this range,
71  * __opcode_is_thumb32() and __opcode_is_thumb16() will both be false.
72  *
73  * The ___asm variants are intended only for use by this header, in situations
74  * involving inline assembler.  For .S files, the normal __opcode_*() macros
75  * should do the right thing.
76  */
77 #ifdef __ASSEMBLY__
78 
79 #define ___opcode_swab32(x) ___asm_opcode_swab32(x)
80 #define ___opcode_swab16(x) ___asm_opcode_swab16(x)
81 #define ___opcode_swahb32(x) ___asm_opcode_swahb32(x)
82 #define ___opcode_swahw32(x) ___asm_opcode_swahw32(x)
83 #define ___opcode_identity32(x) ___asm_opcode_identity32(x)
84 #define ___opcode_identity16(x) ___asm_opcode_identity16(x)
85 
86 #else /* ! __ASSEMBLY__ */
87 
88 #include <linux/types.h>
89 #include <linux/swab.h>
90 
91 #define ___opcode_swab32(x) swab32(x)
92 #define ___opcode_swab16(x) swab16(x)
93 #define ___opcode_swahb32(x) swahb32(x)
94 #define ___opcode_swahw32(x) swahw32(x)
95 #define ___opcode_identity32(x) ((u32)(x))
96 #define ___opcode_identity16(x) ((u16)(x))
97 
98 #endif /* ! __ASSEMBLY__ */
99 
100 
101 #ifdef CONFIG_CPU_ENDIAN_BE8
102 
103 #define __opcode_to_mem_arm(x) ___opcode_swab32(x)
104 #define __opcode_to_mem_thumb16(x) ___opcode_swab16(x)
105 #define __opcode_to_mem_thumb32(x) ___opcode_swahb32(x)
106 #define ___asm_opcode_to_mem_arm(x) ___asm_opcode_swab32(x)
107 #define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_swab16(x)
108 #define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahb32(x)
109 
110 #else /* ! CONFIG_CPU_ENDIAN_BE8 */
111 
112 #define __opcode_to_mem_arm(x) ___opcode_identity32(x)
113 #define __opcode_to_mem_thumb16(x) ___opcode_identity16(x)
114 #define ___asm_opcode_to_mem_arm(x) ___asm_opcode_identity32(x)
115 #define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_identity16(x)
116 #ifndef CONFIG_CPU_ENDIAN_BE32
117 /*
118  * On BE32 systems, using 32-bit accesses to store Thumb instructions will not
119  * work in all cases, due to alignment constraints.  For now, a correct
120  * version is not provided for BE32.
121  */
122 #define __opcode_to_mem_thumb32(x) ___opcode_swahw32(x)
123 #define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahw32(x)
124 #endif
125 
126 #endif /* ! CONFIG_CPU_ENDIAN_BE8 */
127 
128 #define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x)
129 #define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x)
130 #ifndef CONFIG_CPU_ENDIAN_BE32
131 #define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x)
132 #endif
133 
134 /* Operations specific to Thumb opcodes */
135 
136 /* Instruction size checks: */
137 #define __opcode_is_thumb32(x) (		\
138 	   ((x) & 0xF8000000) == 0xE8000000	\
139 	|| ((x) & 0xF0000000) == 0xF0000000	\
140 )
141 #define __opcode_is_thumb16(x) (					\
142 	   ((x) & 0xFFFF0000) == 0					\
143 	&& !(((x) & 0xF800) == 0xE800 || ((x) & 0xF000) == 0xF000)	\
144 )
145 
146 /* Operations to construct or split 32-bit Thumb instructions: */
147 #define __opcode_thumb32_first(x) (___opcode_identity16((x) >> 16))
148 #define __opcode_thumb32_second(x) (___opcode_identity16(x))
149 #define __opcode_thumb32_compose(first, second) (			\
150 	  (___opcode_identity32(___opcode_identity16(first)) << 16)	\
151 	| ___opcode_identity32(___opcode_identity16(second))		\
152 )
153 #define ___asm_opcode_thumb32_first(x) (___asm_opcode_identity16((x) >> 16))
154 #define ___asm_opcode_thumb32_second(x) (___asm_opcode_identity16(x))
155 #define ___asm_opcode_thumb32_compose(first, second) (			    \
156 	  (___asm_opcode_identity32(___asm_opcode_identity16(first)) << 16) \
157 	| ___asm_opcode_identity32(___asm_opcode_identity16(second))	    \
158 )
159 
160 /*
161  * Opcode injection helpers
162  *
163  * In rare cases it is necessary to assemble an opcode which the
164  * assembler does not support directly, or which would normally be
165  * rejected because of the CFLAGS or AFLAGS used to build the affected
166  * file.
167  *
168  * Before using these macros, consider carefully whether it is feasible
169  * instead to change the build flags for your file, or whether it really
170  * makes sense to support old assembler versions when building that
171  * particular kernel feature.
172  *
173  * The macros defined here should only be used where there is no viable
174  * alternative.
175  *
176  *
177  * __inst_arm(x): emit the specified ARM opcode
178  * __inst_thumb16(x): emit the specified 16-bit Thumb opcode
179  * __inst_thumb32(x): emit the specified 32-bit Thumb opcode
180  *
181  * __inst_arm_thumb16(arm, thumb): emit either the specified arm or
182  *	16-bit Thumb opcode, depending on whether an ARM or Thumb-2
183  *	kernel is being built
184  *
185  * __inst_arm_thumb32(arm, thumb): emit either the specified arm or
186  *	32-bit Thumb opcode, depending on whether an ARM or Thumb-2
187  *	kernel is being built
188  *
189  *
190  * Note that using these macros directly is poor practice.  Instead, you
191  * should use them to define human-readable wrapper macros to encode the
192  * instructions that you care about.  In code which might run on ARMv7 or
193  * above, you can usually use the __inst_arm_thumb{16,32} macros to
194  * specify the ARM and Thumb alternatives at the same time.  This ensures
195  * that the correct opcode gets emitted depending on the instruction set
196  * used for the kernel build.
197  *
198  * Look at opcodes-virt.h for an example of how to use these macros.
199  */
200 #include <linux/stringify.h>
201 
202 #define __inst_arm(x) ___inst_arm(___asm_opcode_to_mem_arm(x))
203 #define __inst_thumb32(x) ___inst_thumb32(				\
204 	___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_first(x)),	\
205 	___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_second(x))	\
206 )
207 #define __inst_thumb16(x) ___inst_thumb16(___asm_opcode_to_mem_thumb16(x))
208 
209 #ifdef CONFIG_THUMB2_KERNEL
210 #define __inst_arm_thumb16(arm_opcode, thumb_opcode) \
211 	__inst_thumb16(thumb_opcode)
212 #define __inst_arm_thumb32(arm_opcode, thumb_opcode) \
213 	__inst_thumb32(thumb_opcode)
214 #else
215 #define __inst_arm_thumb16(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
216 #define __inst_arm_thumb32(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
217 #endif
218 
219 /* Helpers for the helpers.  Don't use these directly. */
220 #ifdef __ASSEMBLY__
221 #define ___inst_arm(x) .long x
222 #define ___inst_thumb16(x) .short x
223 #define ___inst_thumb32(first, second) .short first, second
224 #else
225 #define ___inst_arm(x) ".long " __stringify(x) "\n\t"
226 #define ___inst_thumb16(x) ".short " __stringify(x) "\n\t"
227 #define ___inst_thumb32(first, second) \
228 	".short " __stringify(first) ", " __stringify(second) "\n\t"
229 #endif
230 
231 #endif /* __ASM_ARM_OPCODES_H */
232