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