1/* SPDX-License-Identifier: GPL-2.0-only */
2
3#ifndef __ASM_UACCESS_ASM_H__
4#define __ASM_UACCESS_ASM_H__
5
6#include <asm/asm-offsets.h>
7#include <asm/domain.h>
8#include <asm/page.h>
9#include <asm/thread_info.h>
10
11	.macro	csdb
12#ifdef CONFIG_THUMB2_KERNEL
13	.inst.w	0xf3af8014
14#else
15	.inst	0xe320f014
16#endif
17	.endm
18
19	.macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req
20#ifndef CONFIG_CPU_USE_DOMAINS
21	adds	\tmp, \addr, #\size - 1
22	sbcscc	\tmp, \tmp, \limit
23	bcs	\bad
24#ifdef CONFIG_CPU_SPECTRE
25	movcs	\addr, #0
26	csdb
27#endif
28#endif
29	.endm
30
31	.macro uaccess_mask_range_ptr, addr:req, size:req, limit:req, tmp:req
32#ifdef CONFIG_CPU_SPECTRE
33	sub	\tmp, \limit, #1
34	subs	\tmp, \tmp, \addr	@ tmp = limit - 1 - addr
35	addhs	\tmp, \tmp, #1		@ if (tmp >= 0) {
36	subshs	\tmp, \tmp, \size	@ tmp = limit - (addr + size) }
37	movlo	\addr, #0		@ if (tmp < 0) addr = NULL
38	csdb
39#endif
40	.endm
41
42	.macro	uaccess_disable, tmp, isb=1
43#ifdef CONFIG_CPU_SW_DOMAIN_PAN
44	/*
45	 * Whenever we re-enter userspace, the domains should always be
46	 * set appropriately.
47	 */
48	mov	\tmp, #DACR_UACCESS_DISABLE
49	mcr	p15, 0, \tmp, c3, c0, 0		@ Set domain register
50	.if	\isb
51	instr_sync
52	.endif
53#endif
54	.endm
55
56	.macro	uaccess_enable, tmp, isb=1
57#ifdef CONFIG_CPU_SW_DOMAIN_PAN
58	/*
59	 * Whenever we re-enter userspace, the domains should always be
60	 * set appropriately.
61	 */
62	mov	\tmp, #DACR_UACCESS_ENABLE
63	mcr	p15, 0, \tmp, c3, c0, 0
64	.if	\isb
65	instr_sync
66	.endif
67#endif
68	.endm
69
70#if defined(CONFIG_CPU_SW_DOMAIN_PAN) || defined(CONFIG_CPU_USE_DOMAINS)
71#define DACR(x...)	x
72#else
73#define DACR(x...)
74#endif
75
76	/*
77	 * Save the address limit on entry to a privileged exception.
78	 *
79	 * If we are using the DACR for kernel access by the user accessors
80	 * (CONFIG_CPU_USE_DOMAINS=y), always reset the DACR kernel domain
81	 * back to client mode, whether or not \disable is set.
82	 *
83	 * If we are using SW PAN, set the DACR user domain to no access
84	 * if \disable is set.
85	 */
86	.macro	uaccess_entry, tsk, tmp0, tmp1, tmp2, disable
87 DACR(	mrc	p15, 0, \tmp0, c3, c0, 0)
88 DACR(	str	\tmp0, [sp, #SVC_DACR])
89	.if \disable && IS_ENABLED(CONFIG_CPU_SW_DOMAIN_PAN)
90	/* kernel=client, user=no access */
91	mov	\tmp2, #DACR_UACCESS_DISABLE
92	mcr	p15, 0, \tmp2, c3, c0, 0
93	instr_sync
94	.elseif IS_ENABLED(CONFIG_CPU_USE_DOMAINS)
95	/* kernel=client */
96	bic	\tmp2, \tmp0, #domain_mask(DOMAIN_KERNEL)
97	orr	\tmp2, \tmp2, #domain_val(DOMAIN_KERNEL, DOMAIN_CLIENT)
98	mcr	p15, 0, \tmp2, c3, c0, 0
99	instr_sync
100	.endif
101	.endm
102
103	/* Restore the user access state previously saved by uaccess_entry */
104	.macro	uaccess_exit, tsk, tmp0, tmp1
105 DACR(	ldr	\tmp0, [sp, #SVC_DACR])
106 DACR(	mcr	p15, 0, \tmp0, c3, c0, 0)
107	.endm
108
109#undef DACR
110
111#endif /* __ASM_UACCESS_ASM_H__ */
112