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672a2bf840
There are 6 function definitions in trace_probe_tmpl.h, they are: 1, fetch_store_strlen 2, fetch_store_string 3, fetch_store_strlen_user 4, fetch_store_string_user 5, probe_mem_read 6, probe_mem_read_user Every C file which includes trace_probe_tmpl.h has to implement them, otherwise it gets warnings and errors. However, some of them are identical, like kprobe and eprobe, as a result, there is a lot redundant code in those 2 files. This patch would like to provide default behaviors for those functions which kprobe and eprobe can share by just including trace_probe_kernel.h with trace_probe_tmpl.h together. It removes redundant code, increases readability, and more importantly, makes it easier to introduce a new feature based on trace probe (it's possible). Link: https://lore.kernel.org/all/1672382018-18347-1-git-send-email-chensong_2000@189.cn/ Signed-off-by: Song Chen <chensong_2000@189.cn> Reported-by: kernel test robot <lkp@intel.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
133 lines
3.3 KiB
C
133 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __TRACE_PROBE_KERNEL_H_
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#define __TRACE_PROBE_KERNEL_H_
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#define FAULT_STRING "(fault)"
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/*
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* This depends on trace_probe.h, but can not include it due to
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* the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
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* Which means that any other user must include trace_probe.h before including
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* this file.
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*/
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/* Return the length of string -- including null terminal byte */
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static nokprobe_inline int
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fetch_store_strlen_user(unsigned long addr)
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{
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const void __user *uaddr = (__force const void __user *)addr;
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int ret;
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ret = strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
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/*
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* strnlen_user_nofault returns zero on fault, insert the
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* FAULT_STRING when that occurs.
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*/
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if (ret <= 0)
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return strlen(FAULT_STRING) + 1;
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return ret;
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}
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/* Return the length of string -- including null terminal byte */
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static nokprobe_inline int
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fetch_store_strlen(unsigned long addr)
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{
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int ret, len = 0;
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u8 c;
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#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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if (addr < TASK_SIZE)
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return fetch_store_strlen_user(addr);
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#endif
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do {
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ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
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len++;
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} while (c && ret == 0 && len < MAX_STRING_SIZE);
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/* For faults, return enough to hold the FAULT_STRING */
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return (ret < 0) ? strlen(FAULT_STRING) + 1 : len;
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}
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static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base, int len)
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{
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if (ret >= 0) {
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*(u32 *)dest = make_data_loc(ret, __dest - base);
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} else {
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strscpy(__dest, FAULT_STRING, len);
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ret = strlen(__dest) + 1;
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}
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}
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/*
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* Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
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* with max length and relative data location.
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*/
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static nokprobe_inline int
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fetch_store_string_user(unsigned long addr, void *dest, void *base)
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{
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const void __user *uaddr = (__force const void __user *)addr;
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int maxlen = get_loc_len(*(u32 *)dest);
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void *__dest;
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long ret;
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if (unlikely(!maxlen))
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return -ENOMEM;
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__dest = get_loc_data(dest, base);
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ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
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set_data_loc(ret, dest, __dest, base, maxlen);
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return ret;
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}
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/*
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* Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
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* length and relative data location.
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*/
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static nokprobe_inline int
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fetch_store_string(unsigned long addr, void *dest, void *base)
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{
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int maxlen = get_loc_len(*(u32 *)dest);
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void *__dest;
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long ret;
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#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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if ((unsigned long)addr < TASK_SIZE)
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return fetch_store_string_user(addr, dest, base);
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#endif
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if (unlikely(!maxlen))
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return -ENOMEM;
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__dest = get_loc_data(dest, base);
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/*
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* Try to get string again, since the string can be changed while
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* probing.
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*/
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ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
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set_data_loc(ret, dest, __dest, base, maxlen);
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return ret;
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}
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static nokprobe_inline int
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probe_mem_read_user(void *dest, void *src, size_t size)
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{
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const void __user *uaddr = (__force const void __user *)src;
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return copy_from_user_nofault(dest, uaddr, size);
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}
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static nokprobe_inline int
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probe_mem_read(void *dest, void *src, size_t size)
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{
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#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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if ((unsigned long)src < TASK_SIZE)
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return probe_mem_read_user(dest, src, size);
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#endif
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return copy_from_kernel_nofault(dest, src, size);
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}
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#endif /* __TRACE_PROBE_KERNEL_H_ */
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