1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __TRACE_PROBE_KERNEL_H_
3#define __TRACE_PROBE_KERNEL_H_
4
5/*
6 * This depends on trace_probe.h, but can not include it due to
7 * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
8 * Which means that any other user must include trace_probe.h before including
9 * this file.
10 */
11/* Return the length of string -- including null terminal byte */
12static nokprobe_inline int
13fetch_store_strlen_user(unsigned long addr)
14{
15 const void __user *uaddr = (__force const void __user *)addr;
16
17 return strnlen_user_nofault(unsafe_addr: uaddr, MAX_STRING_SIZE);
18}
19
20/* Return the length of string -- including null terminal byte */
21static nokprobe_inline int
22fetch_store_strlen(unsigned long addr)
23{
24 int ret, len = 0;
25 u8 c;
26
27#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
28 if (addr < TASK_SIZE)
29 return fetch_store_strlen_user(addr);
30#endif
31
32 do {
33 ret = copy_from_kernel_nofault(dst: &c, src: (u8 *)addr + len, size: 1);
34 len++;
35 } while (c && ret == 0 && len < MAX_STRING_SIZE);
36
37 return (ret < 0) ? ret : len;
38}
39
40static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base)
41{
42 if (ret < 0)
43 ret = 0;
44 *(u32 *)dest = make_data_loc(ret, __dest - base);
45}
46
47/*
48 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
49 * with max length and relative data location.
50 */
51static nokprobe_inline int
52fetch_store_string_user(unsigned long addr, void *dest, void *base)
53{
54 const void __user *uaddr = (__force const void __user *)addr;
55 int maxlen = get_loc_len(*(u32 *)dest);
56 void *__dest;
57 long ret;
58
59 if (unlikely(!maxlen))
60 return -ENOMEM;
61
62 __dest = get_loc_data(dl: dest, ent: base);
63
64 ret = strncpy_from_user_nofault(dst: __dest, unsafe_addr: uaddr, count: maxlen);
65 set_data_loc(ret, dest, __dest, base);
66
67 return ret;
68}
69
70/*
71 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
72 * length and relative data location.
73 */
74static nokprobe_inline int
75fetch_store_string(unsigned long addr, void *dest, void *base)
76{
77 int maxlen = get_loc_len(*(u32 *)dest);
78 void *__dest;
79 long ret;
80
81#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
82 if ((unsigned long)addr < TASK_SIZE)
83 return fetch_store_string_user(addr, dest, base);
84#endif
85
86 if (unlikely(!maxlen))
87 return -ENOMEM;
88
89 __dest = get_loc_data(dl: dest, ent: base);
90
91 /*
92 * Try to get string again, since the string can be changed while
93 * probing.
94 */
95 ret = strncpy_from_kernel_nofault(dst: __dest, unsafe_addr: (void *)addr, count: maxlen);
96 set_data_loc(ret, dest, __dest, base);
97
98 return ret;
99}
100
101static nokprobe_inline int
102probe_mem_read_user(void *dest, void *src, size_t size)
103{
104 const void __user *uaddr = (__force const void __user *)src;
105
106 return copy_from_user_nofault(dst: dest, src: uaddr, size);
107}
108
109static nokprobe_inline int
110probe_mem_read(void *dest, void *src, size_t size)
111{
112#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
113 if ((unsigned long)src < TASK_SIZE)
114 return probe_mem_read_user(dest, src, size);
115#endif
116 return copy_from_kernel_nofault(dst: dest, src, size);
117}
118
119#endif /* __TRACE_PROBE_KERNEL_H_ */
120

source code of linux/kernel/trace/trace_probe_kernel.h