kernel/trace/trace_probe_kernel.h

   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 */
  12 static nokprobe_inline int
  13 fetch_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 */
  21 static nokprobe_inline int
  22 fetch_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
  40 static 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  */
  51 static nokprobe_inline int
  52 fetch_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  */
  74 static nokprobe_inline int
  75 fetch_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
 101 static nokprobe_inline int
 102 probe_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
 109 static nokprobe_inline int
 110 probe_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_ */