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(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(&c, (u8 *)addr + len, 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(dest, base);
 63
 64	ret = strncpy_from_user_nofault(__dest, uaddr, 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(dest, 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(__dest, (void *)addr, 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(dest, 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(dest, src, size);
117}
118
119#endif /* __TRACE_PROBE_KERNEL_H_ */