Commit 00dc73e4 authored by Hao Luo's avatar Hao Luo Committed by Alexei Starovoitov
Browse files

bpf/selftests: Test for bpf_per_cpu_ptr() and bpf_this_cpu_ptr() 



Test bpf_per_cpu_ptr() and bpf_this_cpu_ptr(). Test two paths in the
kernel. If the base pointer points to a struct, the returned reg is
of type PTR_TO_BTF_ID. Direct pointer dereference can be applied on
the returned variable. If the base pointer isn't a struct, the
returned reg is of type PTR_TO_MEM, which also supports direct pointer
dereference.

Signed-off-by: default avatarHao Luo <haoluo@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200929235049.2533242-7-haoluo@google.com
parent 63d9b80d

tools/testing/selftests/bpf/prog_tests/ksyms_btf.c

+18 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ static int duration; 
void test_ksyms_btf(void)

{

	__u64 runqueues_addr, bpf_prog_active_addr;

	__u32 this_rq_cpu;

	int this_bpf_prog_active;

	struct test_ksyms_btf *skel = NULL;

	struct test_ksyms_btf__data *data;

	struct btf *btf;
@@ -64,6 +66,22 @@ void test_ksyms_btf(void) 
	      (unsigned long long)data->out__bpf_prog_active_addr,

	      (unsigned long long)bpf_prog_active_addr);



	CHECK(data->out__rq_cpu == -1, "rq_cpu",

	      "got %u, exp != -1\n", data->out__rq_cpu);

	CHECK(data->out__bpf_prog_active < 0, "bpf_prog_active",

	      "got %d, exp >= 0\n", data->out__bpf_prog_active);

	CHECK(data->out__cpu_0_rq_cpu != 0, "cpu_rq(0)->cpu",

	      "got %u, exp 0\n", data->out__cpu_0_rq_cpu);



	this_rq_cpu = data->out__this_rq_cpu;

	CHECK(this_rq_cpu != data->out__rq_cpu, "this_rq_cpu",

	      "got %u, exp %u\n", this_rq_cpu, data->out__rq_cpu);



	this_bpf_prog_active = data->out__this_bpf_prog_active;

	CHECK(this_bpf_prog_active != data->out__bpf_prog_active, "this_bpf_prog_active",

	      "got %d, exp %d\n", this_bpf_prog_active,

	      data->out__bpf_prog_active);



cleanup:

	btf__free(btf);

	test_ksyms_btf__destroy(skel);

tools/testing/selftests/bpf/progs/test_ksyms_btf.c

+32 −0
Original line number Diff line number Diff line
@@ -8,15 +8,47 @@ 
__u64 out__runqueues_addr = -1;

__u64 out__bpf_prog_active_addr = -1;



__u32 out__rq_cpu = -1; /* percpu struct fields */

int out__bpf_prog_active = -1; /* percpu int */



__u32 out__this_rq_cpu = -1;

int out__this_bpf_prog_active = -1;



__u32 out__cpu_0_rq_cpu = -1; /* cpu_rq(0)->cpu */



extern const struct rq runqueues __ksym; /* struct type global var. */

extern const int bpf_prog_active __ksym; /* int type global var. */



SEC("raw_tp/sys_enter")

int handler(const void *ctx)

{

	struct rq *rq;

	int *active;

	__u32 cpu;



	out__runqueues_addr = (__u64)&runqueues;

	out__bpf_prog_active_addr = (__u64)&bpf_prog_active;



	cpu = bpf_get_smp_processor_id();



	/* test bpf_per_cpu_ptr() */

	rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, cpu);

	if (rq)

		out__rq_cpu = rq->cpu;

	active = (int *)bpf_per_cpu_ptr(&bpf_prog_active, cpu);

	if (active)

		out__bpf_prog_active = *active;



	rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0);

	if (rq) /* should always be valid, but we can't spare the check. */

		out__cpu_0_rq_cpu = rq->cpu;



	/* test bpf_this_cpu_ptr */

	rq = (struct rq *)bpf_this_cpu_ptr(&runqueues);

	out__this_rq_cpu = rq->cpu;

	active = (int *)bpf_this_cpu_ptr(&bpf_prog_active);

	out__this_bpf_prog_active = *active;



	return 0;

}