1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020 ARM Ltd.
*/
#ifndef __ASM_MTE_H
#define __ASM_MTE_H
#include <asm/compiler.h>
#include <asm/mte-def.h>
#ifndef __ASSEMBLY__
#include <linux/bitfield.h>
#include <linux/kasan-enabled.h>
#include <linux/page-flags.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <asm/pgtable-types.h>
void mte_clear_page_tags(void *addr);
unsigned long mte_copy_tags_from_user(void *to, const void __user *from,
unsigned long n);
unsigned long mte_copy_tags_to_user(void __user *to, void *from,
unsigned long n);
int mte_save_tags(struct page *page);
void mte_save_page_tags(const void *page_addr, void *tag_storage);
bool mte_restore_tags(swp_entry_t entry, struct page *page);
void mte_restore_page_tags(void *page_addr, const void *tag_storage);
void mte_invalidate_tags(int type, pgoff_t offset);
void mte_invalidate_tags_area(int type);
void *mte_allocate_tag_storage(void);
void mte_free_tag_storage(char *storage);
#ifdef CONFIG_ARM64_MTE
/* track which pages have valid allocation tags */
#define PG_mte_tagged PG_arch_2
void mte_zero_clear_page_tags(void *addr);
void mte_sync_tags(pte_t old_pte, pte_t pte);
void mte_copy_page_tags(void *kto, const void *kfrom);
void mte_thread_init_user(void);
void mte_thread_switch(struct task_struct *next);
void mte_cpu_setup(void);
void mte_suspend_enter(void);
void mte_suspend_exit(void);
long set_mte_ctrl(struct task_struct *task, unsigned long arg);
long get_mte_ctrl(struct task_struct *task);
int mte_ptrace_copy_tags(struct task_struct *child, long request,
unsigned long addr, unsigned long data);
size_t mte_probe_user_range(const char __user *uaddr, size_t size);
#else /* CONFIG_ARM64_MTE */
/* unused if !CONFIG_ARM64_MTE, silence the compiler */
#define PG_mte_tagged 0
static inline void mte_zero_clear_page_tags(void *addr)
{
}
static inline void mte_sync_tags(pte_t old_pte, pte_t pte)
{
}
static inline void mte_copy_page_tags(void *kto, const void *kfrom)
{
}
static inline void mte_thread_init_user(void)
{
}
static inline void mte_thread_switch(struct task_struct *next)
{
}
static inline void mte_suspend_enter(void)
{
}
static inline void mte_suspend_exit(void)
{
}
static inline long set_mte_ctrl(struct task_struct *task, unsigned long arg)
{
return 0;
}
static inline long get_mte_ctrl(struct task_struct *task)
{
return 0;
}
static inline int mte_ptrace_copy_tags(struct task_struct *child,
long request, unsigned long addr,
unsigned long data)
{
return -EIO;
}
#endif /* CONFIG_ARM64_MTE */
static inline void mte_disable_tco_entry(struct task_struct *task)
{
if (!system_supports_mte())
return;
/*
* Re-enable tag checking (TCO set on exception entry). This is only
* necessary if MTE is enabled in either the kernel or the userspace
* task in synchronous or asymmetric mode (SCTLR_EL1.TCF0 bit 0 is set
* for both). With MTE disabled in the kernel and disabled or
* asynchronous in userspace, tag check faults (including in uaccesses)
* are not reported, therefore there is no need to re-enable checking.
* This is beneficial on microarchitectures where re-enabling TCO is
* expensive.
*/
if (kasan_hw_tags_enabled() ||
(task->thread.sctlr_user & (1UL << SCTLR_EL1_TCF0_SHIFT)))
asm volatile(SET_PSTATE_TCO(0));
}
#ifdef CONFIG_KASAN_HW_TAGS
/* Whether the MTE asynchronous mode is enabled. */
DECLARE_STATIC_KEY_FALSE(mte_async_or_asymm_mode);
static inline bool system_uses_mte_async_or_asymm_mode(void)
{
return static_branch_unlikely(&mte_async_or_asymm_mode);
}
void mte_check_tfsr_el1(void);
static inline void mte_check_tfsr_entry(void)
{
if (!system_supports_mte())
return;
mte_check_tfsr_el1();
}
static inline void mte_check_tfsr_exit(void)
{
if (!system_supports_mte())
return;
/*
* The asynchronous faults are sync'ed automatically with
* TFSR_EL1 on kernel entry but for exit an explicit dsb()
* is required.
*/
dsb(nsh);
isb();
mte_check_tfsr_el1();
}
#else
static inline bool system_uses_mte_async_or_asymm_mode(void)
{
return false;
}
static inline void mte_check_tfsr_el1(void)
{
}
static inline void mte_check_tfsr_entry(void)
{
}
static inline void mte_check_tfsr_exit(void)
{
}
#endif /* CONFIG_KASAN_HW_TAGS */
#endif /* __ASSEMBLY__ */
#endif /* __ASM_MTE_H */
|
