Commit 672a2bf8 authored by Song Chen's avatar Song Chen Committed by Masami Hiramatsu (Google)
Browse files

kernel/trace: Provide default impelentations defined in trace_probe_tmpl.h 

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: default avatarSong Chen <chensong_2000@189.cn>
Reported-by: default avatarkernel test robot <lkp@intel.com>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
parent 196b6389

kernel/trace/trace_eprobe.c

+2 −53
Original line number Diff line number Diff line
@@ -320,7 +320,8 @@ print_eprobe_event(struct trace_iterator *iter, int flags, 
	return trace_handle_return(s);

}



static unsigned long get_event_field(struct fetch_insn *code, void *rec)

static nokprobe_inline unsigned long

get_event_field(struct fetch_insn *code, void *rec)

{

	struct ftrace_event_field *field = code->data;

	unsigned long val;
@@ -454,58 +455,6 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, 
}

NOKPROBE_SYMBOL(process_fetch_insn)



/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

fetch_store_strlen_user(unsigned long addr)

{

	return kern_fetch_store_strlen_user(addr);

}



/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

fetch_store_strlen(unsigned long addr)

{

	return kern_fetch_store_strlen(addr);

}



/*

 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf

 * with max length and relative data location.

 */

static nokprobe_inline int

fetch_store_string_user(unsigned long addr, void *dest, void *base)

{

	return kern_fetch_store_string_user(addr, dest, base);

}



/*

 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max

 * length and relative data location.

 */

static nokprobe_inline int

fetch_store_string(unsigned long addr, void *dest, void *base)

{

	return kern_fetch_store_string(addr, dest, base);

}



static nokprobe_inline int

probe_mem_read_user(void *dest, void *src, size_t size)

{

	const void __user *uaddr =  (__force const void __user *)src;



	return copy_from_user_nofault(dest, uaddr, size);

}



static nokprobe_inline int

probe_mem_read(void *dest, void *src, size_t size)

{

#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if ((unsigned long)src < TASK_SIZE)

		return probe_mem_read_user(dest, src, size);

#endif

	return copy_from_kernel_nofault(dest, src, size);

}



/* eprobe handler */

static inline void

__eprobe_trace_func(struct eprobe_data *edata, void *rec)

kernel/trace/trace_events_synth.c

+3 −3
Original line number Diff line number Diff line
@@ -420,12 +420,12 @@ static unsigned int trace_string(struct synth_trace_event *entry, 
		data_offset += event->n_u64 * sizeof(u64);

		data_offset += data_size;



		len = kern_fetch_store_strlen((unsigned long)str_val);

		len = fetch_store_strlen((unsigned long)str_val);



		data_offset |= len << 16;

		*(u32 *)&entry->fields[*n_u64] = data_offset;



		ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);

		ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);



		(*n_u64)++;

	} else {
@@ -473,7 +473,7 @@ static notrace void trace_event_raw_event_synth(void *__data, 
		val_idx = var_ref_idx[field_pos];

		str_val = (char *)(long)var_ref_vals[val_idx];



		len = kern_fetch_store_strlen((unsigned long)str_val);

		len = fetch_store_strlen((unsigned long)str_val);



		fields_size += len;

	}

kernel/trace/trace_kprobe.c

+0 −54
Original line number Diff line number Diff line
@@ -1218,60 +1218,6 @@ static const struct file_operations kprobe_profile_ops = { 
	.release        = seq_release,

};



/* Kprobe specific fetch functions */



/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

fetch_store_strlen_user(unsigned long addr)

{

	return kern_fetch_store_strlen_user(addr);

}



/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

fetch_store_strlen(unsigned long addr)

{

	return kern_fetch_store_strlen(addr);

}



/*

 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf

 * with max length and relative data location.

 */

static nokprobe_inline int

fetch_store_string_user(unsigned long addr, void *dest, void *base)

{

	return kern_fetch_store_string_user(addr, dest, base);

}



/*

 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max

 * length and relative data location.

 */

static nokprobe_inline int

fetch_store_string(unsigned long addr, void *dest, void *base)

{

	return kern_fetch_store_string(addr, dest, base);

}



static nokprobe_inline int

probe_mem_read_user(void *dest, void *src, size_t size)

{

	const void __user *uaddr =  (__force const void __user *)src;



	return copy_from_user_nofault(dest, uaddr, size);

}



static nokprobe_inline int

probe_mem_read(void *dest, void *src, size_t size)

{

#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if ((unsigned long)src < TASK_SIZE)

		return probe_mem_read_user(dest, src, size);

#endif

	return copy_from_kernel_nofault(dest, src, size);

}



/* Note that we don't verify it, since the code does not come from user space */

static int

process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,

kernel/trace/trace_probe_kernel.h

+24 −6
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ 
 */

/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

kern_fetch_store_strlen_user(unsigned long addr)

fetch_store_strlen_user(unsigned long addr)

{

	const void __user *uaddr =  (__force const void __user *)addr;

	int ret;
@@ -29,14 +29,14 @@ kern_fetch_store_strlen_user(unsigned long addr) 


/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

kern_fetch_store_strlen(unsigned long addr)

fetch_store_strlen(unsigned long addr)

{

	int ret, len = 0;

	u8 c;



#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if (addr < TASK_SIZE)

		return kern_fetch_store_strlen_user(addr);

		return fetch_store_strlen_user(addr);

#endif



	do {
@@ -63,7 +63,7 @@ static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void 
 * with max length and relative data location.

 */

static nokprobe_inline int

kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)

fetch_store_string_user(unsigned long addr, void *dest, void *base)

{

	const void __user *uaddr =  (__force const void __user *)addr;

	int maxlen = get_loc_len(*(u32 *)dest);
@@ -86,7 +86,7 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base) 
 * length and relative data location.

 */

static nokprobe_inline int

kern_fetch_store_string(unsigned long addr, void *dest, void *base)

fetch_store_string(unsigned long addr, void *dest, void *base)

{

	int maxlen = get_loc_len(*(u32 *)dest);

	void *__dest;
@@ -94,7 +94,7 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base) 


#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if ((unsigned long)addr < TASK_SIZE)

		return kern_fetch_store_string_user(addr, dest, base);

		return fetch_store_string_user(addr, dest, base);

#endif



	if (unlikely(!maxlen))
@@ -112,4 +112,22 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base) 
	return ret;

}



static nokprobe_inline int

probe_mem_read_user(void *dest, void *src, size_t size)

{

	const void __user *uaddr =  (__force const void __user *)src;



	return copy_from_user_nofault(dest, uaddr, size);

}



static nokprobe_inline int

probe_mem_read(void *dest, void *src, size_t size)

{

#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if ((unsigned long)src < TASK_SIZE)

		return probe_mem_read_user(dest, src, size);

#endif

	return copy_from_kernel_nofault(dest, src, size);

}



#endif /* __TRACE_PROBE_KERNEL_H_ */