1 /* SPDX-License-Identifier: GPL-2.0-only */
2 #ifndef __ASM_ASM_EXTABLE_H
3 #define __ASM_ASM_EXTABLE_H
4 
5 #include <linux/bits.h>
6 #include <asm/gpr-num.h>
7 
8 #define EX_TYPE_NONE			0
9 #define EX_TYPE_BPF			1
10 #define EX_TYPE_UACCESS_ERR_ZERO	2
11 #define EX_TYPE_KACCESS_ERR_ZERO	3
12 #define EX_TYPE_LOAD_UNALIGNED_ZEROPAD	4
13 
14 /* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
15 #define EX_DATA_REG_ERR_SHIFT	0
16 #define EX_DATA_REG_ERR		GENMASK(4, 0)
17 #define EX_DATA_REG_ZERO_SHIFT	5
18 #define EX_DATA_REG_ZERO	GENMASK(9, 5)
19 
20 /* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
21 #define EX_DATA_REG_DATA_SHIFT	0
22 #define EX_DATA_REG_DATA	GENMASK(4, 0)
23 #define EX_DATA_REG_ADDR_SHIFT	5
24 #define EX_DATA_REG_ADDR	GENMASK(9, 5)
25 
26 #ifdef __ASSEMBLY__
27 
28 #define __ASM_EXTABLE_RAW(insn, fixup, type, data)	\
29 	.pushsection	__ex_table, "a";		\
30 	.align		2;				\
31 	.long		((insn) - .);			\
32 	.long		((fixup) - .);			\
33 	.short		(type);				\
34 	.short		(data);				\
35 	.popsection;
36 
37 #define EX_DATA_REG(reg, gpr)	\
38 	(.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)
39 
40 #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)		\
41 	__ASM_EXTABLE_RAW(insn, fixup, 					\
42 			  EX_TYPE_UACCESS_ERR_ZERO,			\
43 			  (						\
44 			    EX_DATA_REG(ERR, err) |			\
45 			    EX_DATA_REG(ZERO, zero)			\
46 			  ))
47 
48 #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)			\
49 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
50 
51 #define _ASM_EXTABLE_UACCESS(insn, fixup)				\
52 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
53 
54 /*
55  * Create an exception table entry for uaccess `insn`, which will branch to `fixup`
56  * when an unhandled fault is taken.
57  */
58 	.macro          _asm_extable_uaccess, insn, fixup
59 	_ASM_EXTABLE_UACCESS(\insn, \fixup)
60 	.endm
61 
62 /*
63  * Create an exception table entry for `insn` if `fixup` is provided. Otherwise
64  * do nothing.
65  */
66 	.macro		_cond_uaccess_extable, insn, fixup
67 	.ifnc			\fixup,
68 	_asm_extable_uaccess	\insn, \fixup
69 	.endif
70 	.endm
71 
72 #else /* __ASSEMBLY__ */
73 
74 #include <linux/stringify.h>
75 
76 #define __ASM_EXTABLE_RAW(insn, fixup, type, data)	\
77 	".pushsection	__ex_table, \"a\"\n"		\
78 	".align		2\n"				\
79 	".long		((" insn ") - .)\n"		\
80 	".long		((" fixup ") - .)\n"		\
81 	".short		(" type ")\n"			\
82 	".short		(" data ")\n"			\
83 	".popsection\n"
84 
85 #define EX_DATA_REG(reg, gpr)						\
86 	"((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
87 
88 #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)		\
89 	__DEFINE_ASM_GPR_NUMS						\
90 	__ASM_EXTABLE_RAW(#insn, #fixup, 				\
91 			  __stringify(EX_TYPE_UACCESS_ERR_ZERO),	\
92 			  "("						\
93 			    EX_DATA_REG(ERR, err) " | "			\
94 			    EX_DATA_REG(ZERO, zero)			\
95 			  ")")
96 
97 #define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero)		\
98 	__DEFINE_ASM_GPR_NUMS						\
99 	__ASM_EXTABLE_RAW(#insn, #fixup, 				\
100 			  __stringify(EX_TYPE_KACCESS_ERR_ZERO),	\
101 			  "("						\
102 			    EX_DATA_REG(ERR, err) " | "			\
103 			    EX_DATA_REG(ZERO, zero)			\
104 			  ")")
105 
106 #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)			\
107 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
108 
109 #define _ASM_EXTABLE_UACCESS(insn, fixup)				\
110 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
111 
112 #define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err)			\
113 	_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
114 
115 #define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr)		\
116 	__DEFINE_ASM_GPR_NUMS							\
117 	__ASM_EXTABLE_RAW(#insn, #fixup,					\
118 			  __stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD),		\
119 			  "("							\
120 			    EX_DATA_REG(DATA, data) " | "			\
121 			    EX_DATA_REG(ADDR, addr)				\
122 			  ")")
123 
124 #endif /* __ASSEMBLY__ */
125 
126 #endif /* __ASM_ASM_EXTABLE_H */
127