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