1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_ASM_UACCESS_H
3 #define __ASM_ASM_UACCESS_H
4 
5 #include <asm/alternative-macros.h>
6 #include <asm/kernel-pgtable.h>
7 #include <asm/mmu.h>
8 #include <asm/sysreg.h>
9 #include <asm/assembler.h>
10 
11 /*
12  * User access enabling/disabling macros.
13  */
14 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
15 	.macro	__uaccess_ttbr0_disable, tmp1
16 	mrs	\tmp1, ttbr1_el1			// swapper_pg_dir
17 	bic	\tmp1, \tmp1, #TTBR_ASID_MASK
18 	sub	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET	// reserved_pg_dir
19 	msr	ttbr0_el1, \tmp1			// set reserved TTBR0_EL1
20 	isb
21 	add	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET
22 	msr	ttbr1_el1, \tmp1		// set reserved ASID
23 	isb
24 	.endm
25 
26 	.macro	__uaccess_ttbr0_enable, tmp1, tmp2
27 	get_current_task \tmp1
28 	ldr	\tmp1, [\tmp1, #TSK_TI_TTBR0]	// load saved TTBR0_EL1
29 	mrs	\tmp2, ttbr1_el1
30 	extr    \tmp2, \tmp2, \tmp1, #48
31 	ror     \tmp2, \tmp2, #16
32 	msr	ttbr1_el1, \tmp2		// set the active ASID
33 	isb
34 	msr	ttbr0_el1, \tmp1		// set the non-PAN TTBR0_EL1
35 	isb
36 	.endm
37 
38 	.macro	uaccess_ttbr0_disable, tmp1, tmp2
39 alternative_if_not ARM64_HAS_PAN
40 	save_and_disable_irq \tmp2		// avoid preemption
41 	__uaccess_ttbr0_disable \tmp1
42 	restore_irq \tmp2
43 alternative_else_nop_endif
44 	.endm
45 
46 	.macro	uaccess_ttbr0_enable, tmp1, tmp2, tmp3
47 alternative_if_not ARM64_HAS_PAN
48 	save_and_disable_irq \tmp3		// avoid preemption
49 	__uaccess_ttbr0_enable \tmp1, \tmp2
50 	restore_irq \tmp3
51 alternative_else_nop_endif
52 	.endm
53 #else
54 	.macro	uaccess_ttbr0_disable, tmp1, tmp2
55 	.endm
56 
57 	.macro	uaccess_ttbr0_enable, tmp1, tmp2, tmp3
58 	.endm
59 #endif
60 
61 /*
62  * Generate the assembly for LDTR/STTR with exception table entries.
63  * This is complicated as there is no post-increment or pair versions of the
64  * unprivileged instructions, and USER() only works for single instructions.
65  */
66 	.macro user_ldp l, reg1, reg2, addr, post_inc
67 8888:		ldtr	\reg1, [\addr];
68 8889:		ldtr	\reg2, [\addr, #8];
69 		add	\addr, \addr, \post_inc;
70 
71 		_asm_extable	8888b,\l;
72 		_asm_extable	8889b,\l;
73 	.endm
74 
75 	.macro user_stp l, reg1, reg2, addr, post_inc
76 8888:		sttr	\reg1, [\addr];
77 8889:		sttr	\reg2, [\addr, #8];
78 		add	\addr, \addr, \post_inc;
79 
80 		_asm_extable	8888b,\l;
81 		_asm_extable	8889b,\l;
82 	.endm
83 
84 	.macro user_ldst l, inst, reg, addr, post_inc
85 8888:		\inst		\reg, [\addr];
86 		add		\addr, \addr, \post_inc;
87 
88 		_asm_extable	8888b,\l;
89 	.endm
90 #endif
91