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__ */