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/asm-extable.h>
7 #include <asm/assembler.h>
8 #include <asm/kernel-pgtable.h>
9 #include <asm/mmu.h>
10 #include <asm/sysreg.h>
11 
12 /*
13  * User access enabling/disabling macros.
14  */
15 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
16 	.macro	__uaccess_ttbr0_disable, tmp1
17 	mrs	\tmp1, ttbr1_el1			// swapper_pg_dir
18 	bic	\tmp1, \tmp1, #TTBR_ASID_MASK
19 	sub	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET	// reserved_pg_dir
20 	msr	ttbr0_el1, \tmp1			// set reserved TTBR0_EL1
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 	msr	ttbr0_el1, \tmp1		// set the non-PAN TTBR0_EL1
34 	isb
35 	.endm
36 
37 	.macro	uaccess_ttbr0_disable, tmp1, tmp2
38 alternative_if_not ARM64_HAS_PAN
39 	save_and_disable_irq \tmp2		// avoid preemption
40 	__uaccess_ttbr0_disable \tmp1
41 	restore_irq \tmp2
42 alternative_else_nop_endif
43 	.endm
44 
45 	.macro	uaccess_ttbr0_enable, tmp1, tmp2, tmp3
46 alternative_if_not ARM64_HAS_PAN
47 	save_and_disable_irq \tmp3		// avoid preemption
48 	__uaccess_ttbr0_enable \tmp1, \tmp2
49 	restore_irq \tmp3
50 alternative_else_nop_endif
51 	.endm
52 #else
53 	.macro	uaccess_ttbr0_disable, tmp1, tmp2
54 	.endm
55 
56 	.macro	uaccess_ttbr0_enable, tmp1, tmp2, tmp3
57 	.endm
58 #endif
59 
60 #define USER(l, x...)				\
61 9999:	x;					\
62 	_asm_extable_uaccess	9999b, l
63 
64 /*
65  * Generate the assembly for LDTR/STTR with exception table entries.
66  * This is complicated as there is no post-increment or pair versions of the
67  * unprivileged instructions, and USER() only works for single instructions.
68  */
69 	.macro user_ldp l, reg1, reg2, addr, post_inc
70 8888:		ldtr	\reg1, [\addr];
71 8889:		ldtr	\reg2, [\addr, #8];
72 		add	\addr, \addr, \post_inc;
73 
74 		_asm_extable_uaccess	8888b, \l;
75 		_asm_extable_uaccess	8889b, \l;
76 	.endm
77 
78 	.macro user_stp l, reg1, reg2, addr, post_inc
79 8888:		sttr	\reg1, [\addr];
80 8889:		sttr	\reg2, [\addr, #8];
81 		add	\addr, \addr, \post_inc;
82 
83 		_asm_extable_uaccess	8888b,\l;
84 		_asm_extable_uaccess	8889b,\l;
85 	.endm
86 
87 	.macro user_ldst l, inst, reg, addr, post_inc
88 8888:		\inst		\reg, [\addr];
89 		add		\addr, \addr, \post_inc;
90 
91 		_asm_extable_uaccess	8888b, \l;
92 	.endm
93 #endif
94