asm-extable.h

  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_UACCESS_CPY		4
 13#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD	5
 14
 15/* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
 16#define EX_DATA_REG_ERR_SHIFT	0
 17#define EX_DATA_REG_ERR		GENMASK(4, 0)
 18#define EX_DATA_REG_ZERO_SHIFT	5
 19#define EX_DATA_REG_ZERO	GENMASK(9, 5)
 20
 21/* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
 22#define EX_DATA_REG_DATA_SHIFT	0
 23#define EX_DATA_REG_DATA	GENMASK(4, 0)
 24#define EX_DATA_REG_ADDR_SHIFT	5
 25#define EX_DATA_REG_ADDR	GENMASK(9, 5)
 26
 27/* Data fields for EX_TYPE_UACCESS_CPY */
 28#define EX_DATA_UACCESS_WRITE	BIT(0)
 29
 30#ifdef __ASSEMBLER__
 31
 32#define __ASM_EXTABLE_RAW(insn, fixup, type, data)	\
 33	.pushsection	__ex_table, "a";		\
 34	.align		2;				\
 35	.long		((insn) - .);			\
 36	.long		((fixup) - .);			\
 37	.short		(type);				\
 38	.short		(data);				\
 39	.popsection;
 40
 41#define EX_DATA_REG(reg, gpr)	\
 42	(.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)
 43
 44#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)		\
 45	__ASM_EXTABLE_RAW(insn, fixup, 					\
 46			  EX_TYPE_UACCESS_ERR_ZERO,			\
 47			  (						\
 48			    EX_DATA_REG(ERR, err) |			\
 49			    EX_DATA_REG(ZERO, zero)			\
 50			  ))
 51
 52#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)			\
 53	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
 54
 55#define _ASM_EXTABLE_UACCESS(insn, fixup)				\
 56	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
 57
 58/*
 59 * Create an exception table entry for uaccess `insn`, which will branch to `fixup`
 60 * when an unhandled fault is taken.
 61 */
 62	.macro          _asm_extable_uaccess, insn, fixup
 63	_ASM_EXTABLE_UACCESS(\insn, \fixup)
 64	.endm
 65
 66/*
 67 * Create an exception table entry for `insn` if `fixup` is provided. Otherwise
 68 * do nothing.
 69 */
 70	.macro		_cond_uaccess_extable, insn, fixup
 71	.ifnc			\fixup,
 72	_asm_extable_uaccess	\insn, \fixup
 73	.endif
 74	.endm
 75
 76	.macro		_asm_extable_uaccess_cpy, insn, fixup, uaccess_is_write
 77	__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_CPY, \uaccess_is_write)
 78	.endm
 79
 80#else /* __ASSEMBLER__ */
 81
 82#include <linux/stringify.h>
 83
 84#define __ASM_EXTABLE_RAW(insn, fixup, type, data)	\
 85	".pushsection	__ex_table, \"a\"\n"		\
 86	".align		2\n"				\
 87	".long		((" insn ") - .)\n"		\
 88	".long		((" fixup ") - .)\n"		\
 89	".short		(" type ")\n"			\
 90	".short		(" data ")\n"			\
 91	".popsection\n"
 92
 93#define EX_DATA_REG(reg, gpr)						\
 94	"((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
 95
 96#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)		\
 97	__DEFINE_ASM_GPR_NUMS						\
 98	__ASM_EXTABLE_RAW(#insn, #fixup, 				\
 99			  __stringify(EX_TYPE_UACCESS_ERR_ZERO),	\
100			  "("						\
101			    EX_DATA_REG(ERR, err) " | "			\
102			    EX_DATA_REG(ZERO, zero)			\
103			  ")")
104
105#define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero)		\
106	__DEFINE_ASM_GPR_NUMS						\
107	__ASM_EXTABLE_RAW(#insn, #fixup, 				\
108			  __stringify(EX_TYPE_KACCESS_ERR_ZERO),	\
109			  "("						\
110			    EX_DATA_REG(ERR, err) " | "			\
111			    EX_DATA_REG(ZERO, zero)			\
112			  ")")
113
114#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)			\
115	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
116
117#define _ASM_EXTABLE_UACCESS(insn, fixup)				\
118	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
119
120#define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err)			\
121	_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
122
123#define _ASM_EXTABLE_KACCESS(insn, fixup)				\
124	_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
125
126#define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr)		\
127	__DEFINE_ASM_GPR_NUMS							\
128	__ASM_EXTABLE_RAW(#insn, #fixup,					\
129			  __stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD),		\
130			  "("							\
131			    EX_DATA_REG(DATA, data) " | "			\
132			    EX_DATA_REG(ADDR, addr)				\
133			  ")")
134
135#endif /* __ASSEMBLER__ */
136
137#endif /* __ASM_ASM_EXTABLE_H */