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Linux kernel mirror (for testing)
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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 isb
22 add \tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET
23 msr ttbr1_el1, \tmp1 // set reserved ASID
24 isb
25 .endm
26
27 .macro __uaccess_ttbr0_enable, tmp1, tmp2
28 get_current_task \tmp1
29 ldr \tmp1, [\tmp1, #TSK_TI_TTBR0] // load saved TTBR0_EL1
30 mrs \tmp2, ttbr1_el1
31 extr \tmp2, \tmp2, \tmp1, #48
32 ror \tmp2, \tmp2, #16
33 msr ttbr1_el1, \tmp2 // set the active ASID
34 isb
35 msr ttbr0_el1, \tmp1 // set the non-PAN TTBR0_EL1
36 isb
37 .endm
38
39 .macro uaccess_ttbr0_disable, tmp1, tmp2
40alternative_if_not ARM64_HAS_PAN
41 save_and_disable_irq \tmp2 // avoid preemption
42 __uaccess_ttbr0_disable \tmp1
43 restore_irq \tmp2
44alternative_else_nop_endif
45 .endm
46
47 .macro uaccess_ttbr0_enable, tmp1, tmp2, tmp3
48alternative_if_not ARM64_HAS_PAN
49 save_and_disable_irq \tmp3 // avoid preemption
50 __uaccess_ttbr0_enable \tmp1, \tmp2
51 restore_irq \tmp3
52alternative_else_nop_endif
53 .endm
54#else
55 .macro uaccess_ttbr0_disable, tmp1, tmp2
56 .endm
57
58 .macro uaccess_ttbr0_enable, tmp1, tmp2, tmp3
59 .endm
60#endif
61
62#define USER(l, x...) \
639999: x; \
64 _asm_extable_uaccess 9999b, l
65
66/*
67 * Generate the assembly for LDTR/STTR with exception table entries.
68 * This is complicated as there is no post-increment or pair versions of the
69 * unprivileged instructions, and USER() only works for single instructions.
70 */
71 .macro user_ldp l, reg1, reg2, addr, post_inc
728888: ldtr \reg1, [\addr];
738889: ldtr \reg2, [\addr, #8];
74 add \addr, \addr, \post_inc;
75
76 _asm_extable_uaccess 8888b, \l;
77 _asm_extable_uaccess 8889b, \l;
78 .endm
79
80 .macro user_stp l, reg1, reg2, addr, post_inc
818888: sttr \reg1, [\addr];
828889: sttr \reg2, [\addr, #8];
83 add \addr, \addr, \post_inc;
84
85 _asm_extable_uaccess 8888b,\l;
86 _asm_extable_uaccess 8889b,\l;
87 .endm
88
89 .macro user_ldst l, inst, reg, addr, post_inc
908888: \inst \reg, [\addr];
91 add \addr, \addr, \post_inc;
92
93 _asm_extable_uaccess 8888b, \l;
94 .endm
95#endif