xref: /openbmc/linux/arch/arm/lib/getuser.S (revision d2912cb1)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 *  linux/arch/arm/lib/getuser.S
4 *
5 *  Copyright (C) 2001 Russell King
6 *
7 *  Idea from x86 version, (C) Copyright 1998 Linus Torvalds
8 *
9 * These functions have a non-standard call interface to make them more
10 * efficient, especially as they return an error value in addition to
11 * the "real" return value.
12 *
13 * __get_user_X
14 *
15 * Inputs:	r0 contains the address
16 *		r1 contains the address limit, which must be preserved
17 * Outputs:	r0 is the error code
18 *		r2, r3 contains the zero-extended value
19 *		lr corrupted
20 *
21 * No other registers must be altered.  (see <asm/uaccess.h>
22 * for specific ASM register usage).
23 *
24 * Note that ADDR_LIMIT is either 0 or 0xc0000000.
25 * Note also that it is intended that __get_user_bad is not global.
26 */
27#include <linux/linkage.h>
28#include <asm/assembler.h>
29#include <asm/errno.h>
30#include <asm/domain.h>
31
32ENTRY(__get_user_1)
33	check_uaccess r0, 1, r1, r2, __get_user_bad
341: TUSER(ldrb)	r2, [r0]
35	mov	r0, #0
36	ret	lr
37ENDPROC(__get_user_1)
38_ASM_NOKPROBE(__get_user_1)
39
40ENTRY(__get_user_2)
41	check_uaccess r0, 2, r1, r2, __get_user_bad
42#if __LINUX_ARM_ARCH__ >= 6
43
442: TUSER(ldrh)	r2, [r0]
45
46#else
47
48#ifdef CONFIG_CPU_USE_DOMAINS
49rb	.req	ip
502:	ldrbt	r2, [r0], #1
513:	ldrbt	rb, [r0], #0
52#else
53rb	.req	r0
542:	ldrb	r2, [r0]
553:	ldrb	rb, [r0, #1]
56#endif
57#ifndef __ARMEB__
58	orr	r2, r2, rb, lsl #8
59#else
60	orr	r2, rb, r2, lsl #8
61#endif
62
63#endif /* __LINUX_ARM_ARCH__ >= 6 */
64
65	mov	r0, #0
66	ret	lr
67ENDPROC(__get_user_2)
68_ASM_NOKPROBE(__get_user_2)
69
70ENTRY(__get_user_4)
71	check_uaccess r0, 4, r1, r2, __get_user_bad
724: TUSER(ldr)	r2, [r0]
73	mov	r0, #0
74	ret	lr
75ENDPROC(__get_user_4)
76_ASM_NOKPROBE(__get_user_4)
77
78ENTRY(__get_user_8)
79	check_uaccess r0, 8, r1, r2, __get_user_bad8
80#ifdef CONFIG_THUMB2_KERNEL
815: TUSER(ldr)	r2, [r0]
826: TUSER(ldr)	r3, [r0, #4]
83#else
845: TUSER(ldr)	r2, [r0], #4
856: TUSER(ldr)	r3, [r0]
86#endif
87	mov	r0, #0
88	ret	lr
89ENDPROC(__get_user_8)
90_ASM_NOKPROBE(__get_user_8)
91
92#ifdef __ARMEB__
93ENTRY(__get_user_32t_8)
94	check_uaccess r0, 8, r1, r2, __get_user_bad
95#ifdef CONFIG_CPU_USE_DOMAINS
96	add	r0, r0, #4
977:	ldrt	r2, [r0]
98#else
997:	ldr	r2, [r0, #4]
100#endif
101	mov	r0, #0
102	ret	lr
103ENDPROC(__get_user_32t_8)
104_ASM_NOKPROBE(__get_user_32t_8)
105
106ENTRY(__get_user_64t_1)
107	check_uaccess r0, 1, r1, r2, __get_user_bad8
1088: TUSER(ldrb)	r3, [r0]
109	mov	r0, #0
110	ret	lr
111ENDPROC(__get_user_64t_1)
112_ASM_NOKPROBE(__get_user_64t_1)
113
114ENTRY(__get_user_64t_2)
115	check_uaccess r0, 2, r1, r2, __get_user_bad8
116#ifdef CONFIG_CPU_USE_DOMAINS
117rb	.req	ip
1189:	ldrbt	r3, [r0], #1
11910:	ldrbt	rb, [r0], #0
120#else
121rb	.req	r0
1229:	ldrb	r3, [r0]
12310:	ldrb	rb, [r0, #1]
124#endif
125	orr	r3, rb, r3, lsl #8
126	mov	r0, #0
127	ret	lr
128ENDPROC(__get_user_64t_2)
129_ASM_NOKPROBE(__get_user_64t_2)
130
131ENTRY(__get_user_64t_4)
132	check_uaccess r0, 4, r1, r2, __get_user_bad8
13311: TUSER(ldr)	r3, [r0]
134	mov	r0, #0
135	ret	lr
136ENDPROC(__get_user_64t_4)
137_ASM_NOKPROBE(__get_user_64t_4)
138#endif
139
140__get_user_bad8:
141	mov	r3, #0
142__get_user_bad:
143	mov	r2, #0
144	mov	r0, #-EFAULT
145	ret	lr
146ENDPROC(__get_user_bad)
147ENDPROC(__get_user_bad8)
148_ASM_NOKPROBE(__get_user_bad)
149_ASM_NOKPROBE(__get_user_bad8)
150
151.pushsection __ex_table, "a"
152	.long	1b, __get_user_bad
153	.long	2b, __get_user_bad
154#if __LINUX_ARM_ARCH__ < 6
155	.long	3b, __get_user_bad
156#endif
157	.long	4b, __get_user_bad
158	.long	5b, __get_user_bad8
159	.long	6b, __get_user_bad8
160#ifdef __ARMEB__
161	.long   7b, __get_user_bad
162	.long	8b, __get_user_bad8
163	.long	9b, __get_user_bad8
164	.long	10b, __get_user_bad8
165	.long	11b, __get_user_bad8
166#endif
167.popsection
168