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Linux kernel mirror (for testing)
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linux
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
38alternative_if_not ARM64_HAS_PAN
39 save_and_disable_irq \tmp2 // avoid preemption
40 __uaccess_ttbr0_disable \tmp1
41 restore_irq \tmp2
42alternative_else_nop_endif
43 .endm
44
45 .macro uaccess_ttbr0_enable, tmp1, tmp2, tmp3
46alternative_if_not ARM64_HAS_PAN
47 save_and_disable_irq \tmp3 // avoid preemption
48 __uaccess_ttbr0_enable \tmp1, \tmp2
49 restore_irq \tmp3
50alternative_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...) \
619999: 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
708888: ldtr \reg1, [\addr];
718889: 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
798888: sttr \reg1, [\addr];
808889: 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
888888: \inst \reg, [\addr];
89 add \addr, \addr, \post_inc;
90
91 _asm_extable_uaccess 8888b, \l;
92 .endm
93#endif