xref: /OK3568_Linux_fs/kernel/samples/bpf/test_overhead_kprobe_kern.c (revision 4882a59341e53eb6f0b4789bf948001014eff981) 
1*4882a593Smuzhiyun /* Copyright (c) 2016 Facebook
2*4882a593Smuzhiyun  *
3*4882a593Smuzhiyun  * This program is free software; you can redistribute it and/or
4*4882a593Smuzhiyun  * modify it under the terms of version 2 of the GNU General Public
5*4882a593Smuzhiyun  * License as published by the Free Software Foundation.
6*4882a593Smuzhiyun  */
7*4882a593Smuzhiyun #include <linux/version.h>
8*4882a593Smuzhiyun #include <linux/ptrace.h>
9*4882a593Smuzhiyun #include <uapi/linux/bpf.h>
10*4882a593Smuzhiyun #include <bpf/bpf_helpers.h>
11*4882a593Smuzhiyun #include <bpf/bpf_tracing.h>
12*4882a593Smuzhiyun 
13*4882a593Smuzhiyun #define _(P)                                                                   \
14*4882a593Smuzhiyun 	({                                                                     \
15*4882a593Smuzhiyun 		typeof(P) val = 0;                                             \
16*4882a593Smuzhiyun 		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \
17*4882a593Smuzhiyun 		val;                                                           \
18*4882a593Smuzhiyun 	})
19*4882a593Smuzhiyun 
20*4882a593Smuzhiyun SEC("kprobe/__set_task_comm")
prog(struct pt_regs * ctx)21*4882a593Smuzhiyun int prog(struct pt_regs *ctx)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun 	struct signal_struct *signal;
24*4882a593Smuzhiyun 	struct task_struct *tsk;
25*4882a593Smuzhiyun 	char oldcomm[16] = {};
26*4882a593Smuzhiyun 	char newcomm[16] = {};
27*4882a593Smuzhiyun 	u16 oom_score_adj;
28*4882a593Smuzhiyun 	u32 pid;
29*4882a593Smuzhiyun 
30*4882a593Smuzhiyun 	tsk = (void *)PT_REGS_PARM1(ctx);
31*4882a593Smuzhiyun 
32*4882a593Smuzhiyun 	pid = _(tsk->pid);
33*4882a593Smuzhiyun 	bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm);
34*4882a593Smuzhiyun 	bpf_probe_read_kernel(newcomm, sizeof(newcomm),
35*4882a593Smuzhiyun 			      (void *)PT_REGS_PARM2(ctx));
36*4882a593Smuzhiyun 	signal = _(tsk->signal);
37*4882a593Smuzhiyun 	oom_score_adj = _(signal->oom_score_adj);
38*4882a593Smuzhiyun 	return 0;
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun 
41*4882a593Smuzhiyun SEC("kprobe/urandom_read")
prog2(struct pt_regs * ctx)42*4882a593Smuzhiyun int prog2(struct pt_regs *ctx)
43*4882a593Smuzhiyun {
44*4882a593Smuzhiyun 	return 0;
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun 
47*4882a593Smuzhiyun char _license[] SEC("license") = "GPL";
48*4882a593Smuzhiyun u32 _version SEC("version") = LINUX_VERSION_CODE;
49