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#include "bpf_experimental.h"
struct val_t {
long b, c, d;
};
struct elem {
long sum;
struct val_t __percpu_kptr *pc;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, struct elem);
} array SEC(".maps");
void bpf_rcu_read_lock(void) __ksym;
void bpf_rcu_read_unlock(void) __ksym;
const volatile int nr_cpus;
/* Initialize the percpu object */
SEC("?fentry/bpf_fentry_test1")
int BPF_PROG(test_array_map_1)
{
struct val_t __percpu_kptr *p;
struct elem *e;
int index = 0;
e = bpf_map_lookup_elem(&array, &index);
if (!e)
return 0;
p = bpf_percpu_obj_new(struct val_t);
if (!p)
return 0;
p = bpf_kptr_xchg(&e->pc, p);
if (p)
bpf_percpu_obj_drop(p);
return 0;
}
/* Update percpu data */
SEC("?fentry/bpf_fentry_test2")
int BPF_PROG(test_array_map_2)
{
struct val_t __percpu_kptr *p;
struct val_t *v;
struct elem *e;
int index = 0;
e = bpf_map_lookup_elem(&array, &index);
if (!e)
return 0;
p = e->pc;
if (!p)
return 0;
v = bpf_per_cpu_ptr(p, 0);
if (!v)
return 0;
v->c = 1;
v->d = 2;
return 0;
}
int cpu0_field_d, sum_field_c;
int my_pid;
/* Summarize percpu data */
SEC("?fentry/bpf_fentry_test3")
int BPF_PROG(test_array_map_3)
{
struct val_t __percpu_kptr *p;
int i, index = 0;
struct val_t *v;
struct elem *e;
if ((bpf_get_current_pid_tgid() >> 32) != my_pid)
return 0;
e = bpf_map_lookup_elem(&array, &index);
if (!e)
return 0;
p = e->pc;
if (!p)
return 0;
bpf_for(i, 0, nr_cpus) {
v = bpf_per_cpu_ptr(p, i);
if (v) {
if (i == 0)
cpu0_field_d = v->d;
sum_field_c += v->c;
}
}
return 0;
}
/* Explicitly free allocated percpu data */
SEC("?fentry/bpf_fentry_test4")
int BPF_PROG(test_array_map_4)
{
struct val_t __percpu_kptr *p;
struct elem *e;
int index = 0;
e = bpf_map_lookup_elem(&array, &index);
if (!e)
return 0;
/* delete */
p = bpf_kptr_xchg(&e->pc, NULL);
if (p) {
bpf_percpu_obj_drop(p);
}
return 0;
}
SEC("?fentry.s/bpf_fentry_test1")
int BPF_PROG(test_array_map_10)
{
struct val_t __percpu_kptr *p, *p1;
int i, index = 0;
struct val_t *v;
struct elem *e;
if ((bpf_get_current_pid_tgid() >> 32) != my_pid)
return 0;
e = bpf_map_lookup_elem(&array, &index);
if (!e)
return 0;
bpf_rcu_read_lock();
p = e->pc;
if (!p) {
p = bpf_percpu_obj_new(struct val_t);
if (!p)
goto out;
p1 = bpf_kptr_xchg(&e->pc, p);
if (p1) {
/* race condition */
bpf_percpu_obj_drop(p1);
}
}
v = bpf_this_cpu_ptr(p);
v->c = 3;
v = bpf_this_cpu_ptr(p);
v->c = 0;
v = bpf_per_cpu_ptr(p, 0);
if (!v)
goto out;
v->c = 1;
v->d = 2;
/* delete */
p1 = bpf_kptr_xchg(&e->pc, NULL);
if (!p1)
goto out;
bpf_for(i, 0, nr_cpus) {
v = bpf_per_cpu_ptr(p, i);
if (v) {
if (i == 0)
cpu0_field_d = v->d;
sum_field_c += v->c;
}
}
/* finally release p */
bpf_percpu_obj_drop(p1);
out:
bpf_rcu_read_unlock();
return 0;
}
char _license[] SEC("license") = "GPL";
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