1#include "vmlinux.h"
  2#include <bpf/bpf_helpers.h>
  3#include <bpf/bpf_core_read.h>
  4
  5const char LICENSE[] SEC("license") = "GPL";
  6
  7struct {
  8	__uint(type, BPF_MAP_TYPE_ARRAY);
  9	__uint(max_entries, 1);
 10	__type(key, __u32);
 11	__type(value, __u64);
 12} array SEC(".maps");
 13
 14__noinline int sub1(int x)
 15{
 16	int key = 0;
 17
 18	bpf_map_lookup_elem(&array, &key);
 19	return x + 1;
 20}
 21
 22static __noinline int sub5(int v);
 23
 24__noinline int sub2(int y)
 25{
 26	return sub5(y + 2);
 27}
 28
 29static __noinline int sub3(int z)
 30{
 31	return z + 3 + sub1(4);
 32}
 33
 34static __noinline int sub4(int w)
 35{
 36	int key = 0;
 37
 38	bpf_map_lookup_elem(&array, &key);
 39	return w + sub3(5) + sub1(6);
 40}
 41
 42/* sub5() is an identitify function, just to test weirder functions layout and
 43 * call patterns
 44 */
 45static __noinline int sub5(int v)
 46{
 47	return sub1(v) - 1; /* compensates sub1()'s + 1 */
 48}
 49
 50/* unfortunately verifier rejects `struct task_struct *t` as an unknown pointer
 51 * type, so we need to accept pointer as integer and then cast it inside the
 52 * function
 53 */
 54__noinline int get_task_tgid(uintptr_t t)
 55{
 56	/* this ensures that CO-RE relocs work in multi-subprogs .text */
 57	return BPF_CORE_READ((struct task_struct *)(void *)t, tgid);
 58}
 59
 60int res1 = 0;
 61int res2 = 0;
 62int res3 = 0;
 63int res4 = 0;
 64
 65SEC("raw_tp/sys_enter")
 66int prog1(void *ctx)
 67{
 68	/* perform some CO-RE relocations to ensure they work with multi-prog
 69	 * sections correctly
 70	 */
 71	struct task_struct *t = (void *)bpf_get_current_task();
 72
 73	if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
 74		return 1;
 75
 76	res1 = sub1(1) + sub3(2); /* (1 + 1) + (2 + 3 + (4 + 1)) = 12 */
 77	return 0;
 78}
 79
 80SEC("raw_tp/sys_exit")
 81int prog2(void *ctx)
 82{
 83	struct task_struct *t = (void *)bpf_get_current_task();
 84
 85	if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
 86		return 1;
 87
 88	res2 = sub2(3) + sub3(4); /* (3 + 2) + (4 + 3 + (4 + 1)) = 17 */
 89	return 0;
 90}
 91
 92static int empty_callback(__u32 index, void *data)
 93{
 94	return 0;
 95}
 96
 97/* prog3 has the same section name as prog1 */
 98SEC("raw_tp/sys_enter")
 99int prog3(void *ctx)
100{
101	struct task_struct *t = (void *)bpf_get_current_task();
102
103	if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
104		return 1;
105
106	/* test that ld_imm64 with BPF_PSEUDO_FUNC doesn't get blinded */
107	bpf_loop(1, empty_callback, NULL, 0);
108
109	res3 = sub3(5) + 6; /* (5 + 3 + (4 + 1)) + 6 = 19 */
110	return 0;
111}
112
113/* prog4 has the same section name as prog2 */
114SEC("raw_tp/sys_exit")
115int prog4(void *ctx)
116{
117	struct task_struct *t = (void *)bpf_get_current_task();
118
119	if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
120		return 1;
121
122	res4 = sub4(7) + sub1(8); /* (7 + (5 + 3 + (4 + 1)) + (6 + 1)) + (8 + 1) = 36 */
123	return 0;
124}