kretprobe_example.c (58e16d792a6a8c6b750f637a4649967fcac853dc) kretprobe_example.c (d85eaa9411472a99de4b5732cb59c8bae629d5f1)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kretprobe_example.c
4 *
5 * Here's a sample kernel module showing the use of return probes to
6 * report the return value and total time taken for probed function
7 * to run.
8 *

--- 34 unchanged lines hidden (view full) ---

43
44 if (!current->mm)
45 return 1; /* Skip kernel threads */
46
47 data = (struct my_data *)ri->data;
48 data->entry_stamp = ktime_get();
49 return 0;
50}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kretprobe_example.c
4 *
5 * Here's a sample kernel module showing the use of return probes to
6 * report the return value and total time taken for probed function
7 * to run.
8 *

--- 34 unchanged lines hidden (view full) ---

43
44 if (!current->mm)
45 return 1; /* Skip kernel threads */
46
47 data = (struct my_data *)ri->data;
48 data->entry_stamp = ktime_get();
49 return 0;
50}
51NOKPROBE_SYMBOL(entry_handler);
51
52/*
53 * Return-probe handler: Log the return value and duration. Duration may turn
54 * out to be zero consistently, depending upon the granularity of time
55 * accounting on the platform.
56 */
57static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
58{
59 unsigned long retval = regs_return_value(regs);
60 struct my_data *data = (struct my_data *)ri->data;
61 s64 delta;
62 ktime_t now;
63
64 now = ktime_get();
65 delta = ktime_to_ns(ktime_sub(now, data->entry_stamp));
66 pr_info("%s returned %lu and took %lld ns to execute\n",
67 func_name, retval, (long long)delta);
68 return 0;
69}
52
53/*
54 * Return-probe handler: Log the return value and duration. Duration may turn
55 * out to be zero consistently, depending upon the granularity of time
56 * accounting on the platform.
57 */
58static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
59{
60 unsigned long retval = regs_return_value(regs);
61 struct my_data *data = (struct my_data *)ri->data;
62 s64 delta;
63 ktime_t now;
64
65 now = ktime_get();
66 delta = ktime_to_ns(ktime_sub(now, data->entry_stamp));
67 pr_info("%s returned %lu and took %lld ns to execute\n",
68 func_name, retval, (long long)delta);
69 return 0;
70}
71NOKPROBE_SYMBOL(ret_handler);
70
71static struct kretprobe my_kretprobe = {
72 .handler = ret_handler,
73 .entry_handler = entry_handler,
74 .data_size = sizeof(struct my_data),
75 /* Probe up to 20 instances concurrently. */
76 .maxactive = 20,
77};

--- 29 unchanged lines hidden --- 		72
73static struct kretprobe my_kretprobe = {
74 .handler = ret_handler,
75 .entry_handler = entry_handler,
76 .data_size = sizeof(struct my_data),
77 /* Probe up to 20 instances concurrently. */
78 .maxactive = 20,
79};

--- 29 unchanged lines hidden ---