Commit 50c6b8a9 authored by Hao Luo's avatar Hao Luo Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add a test for btf_type_tag "percpu" 



Add test for percpu btf_type_tag. Similar to the "user" tag, we test
the following cases:

 1. __percpu struct field.
 2. __percpu as function parameter.
 3. per_cpu_ptr() accepts dynamically allocated __percpu memory.

Because the test for "user" and the test for "percpu" are very similar,
a little bit of refactoring has been done in btf_tag.c. Basically, both
tests share the same function for loading vmlinux and module btf.

Example output from log:

 > ./test_progs -v -t btf_tag

 libbpf: prog 'test_percpu1': BPF program load failed: Permission denied
 libbpf: prog 'test_percpu1': -- BEGIN PROG LOAD LOG --
 ...
 ; g = arg->a;
 1: (61) r1 = *(u32 *)(r1 +0)
 R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
 ...
 test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
 #26/6 btf_tag/btf_type_tag_percpu_mod1:OK

 libbpf: prog 'test_percpu2': BPF program load failed: Permission denied
 libbpf: prog 'test_percpu2': -- BEGIN PROG LOAD LOG --
 ...
 ; g = arg->p->a;
 2: (61) r1 = *(u32 *)(r1 +0)
 R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
 ...
 test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
 #26/7 btf_tag/btf_type_tag_percpu_mod2:OK

 libbpf: prog 'test_percpu_load': BPF program load failed: Permission denied
 libbpf: prog 'test_percpu_load': -- BEGIN PROG LOAD LOG --
 ...
 ; g = (__u64)cgrp->rstat_cpu->updated_children;
 2: (79) r1 = *(u64 *)(r1 +48)
 R1 is ptr_cgroup_rstat_cpu access percpu memory: off=48
 ...
 test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_load 0 nsec
 #26/8 btf_tag/btf_type_tag_percpu_vmlinux_load:OK

 load_btfs:PASS:could not load vmlinux BTF 0 nsec
 test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu 0 nsec
 test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_helper 0 nsec
 #26/9 btf_tag/btf_type_tag_percpu_vmlinux_helper:OK

Signed-off-by: default avatarHao Luo <haoluo@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-5-haoluo@google.com
parent 5844101a

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c

+14 −0
Original line number Diff line number Diff line
@@ -33,6 +33,10 @@ struct bpf_testmod_btf_type_tag_2 { 
	struct bpf_testmod_btf_type_tag_1 __user *p;

};



struct bpf_testmod_btf_type_tag_3 {

	struct bpf_testmod_btf_type_tag_1 __percpu *p;

};



noinline int

bpf_testmod_test_btf_type_tag_user_1(struct bpf_testmod_btf_type_tag_1 __user *arg) {

	BTF_TYPE_EMIT(func_proto_typedef);
@@ -46,6 +50,16 @@ bpf_testmod_test_btf_type_tag_user_2(struct bpf_testmod_btf_type_tag_2 *arg) { 
	return arg->p->a;

}



noinline int

bpf_testmod_test_btf_type_tag_percpu_1(struct bpf_testmod_btf_type_tag_1 __percpu *arg) {

	return arg->a;

}



noinline int

bpf_testmod_test_btf_type_tag_percpu_2(struct bpf_testmod_btf_type_tag_3 *arg) {

	return arg->p->a;

}



noinline int bpf_testmod_loop_test(int n)

{

	int i, sum = 0;

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

+135 −29
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ struct btf_type_tag_test { 
};

#include "btf_type_tag.skel.h"

#include "btf_type_tag_user.skel.h"

#include "btf_type_tag_percpu.skel.h"



static void test_btf_decl_tag(void)

{
@@ -43,38 +44,81 @@ static void test_btf_type_tag(void) 
	btf_type_tag__destroy(skel);

}



static void test_btf_type_tag_mod_user(bool load_test_user1)

/* loads vmlinux_btf as well as module_btf. If the caller passes NULL as

 * module_btf, it will not load module btf.

 *

 * Returns 0 on success.

 * Return -1 On error. In case of error, the loaded btf will be freed and the

 * input parameters will be set to pointing to NULL.

 */

static int load_btfs(struct btf **vmlinux_btf, struct btf **module_btf,

		     bool needs_vmlinux_tag)

{

	const char *module_name = "bpf_testmod";

	struct btf *vmlinux_btf, *module_btf;

	struct btf_type_tag_user *skel;

	__s32 type_id;

	int err;



	if (!env.has_testmod) {

		test__skip();

		return;

		return -1;

	}



	/* skip the test if the module does not have __user tags */

	vmlinux_btf = btf__load_vmlinux_btf();

	if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF"))

		return;

	*vmlinux_btf = btf__load_vmlinux_btf();

	if (!ASSERT_OK_PTR(*vmlinux_btf, "could not load vmlinux BTF"))

		return -1;



	if (!needs_vmlinux_tag)

		goto load_module_btf;



	module_btf = btf__load_module_btf(module_name, vmlinux_btf);

	if (!ASSERT_OK_PTR(module_btf, "could not load module BTF"))

	/* skip the test if the vmlinux does not have __user tags */

	type_id = btf__find_by_name_kind(*vmlinux_btf, "user", BTF_KIND_TYPE_TAG);

	if (type_id <= 0) {

		printf("%s:SKIP: btf_type_tag attribute not in vmlinux btf", __func__);

		test__skip();

		goto free_vmlinux_btf;

	}



	type_id = btf__find_by_name_kind(module_btf, "user", BTF_KIND_TYPE_TAG);

load_module_btf:

	/* skip loading module_btf, if not requested by caller */

	if (!module_btf)

		return 0;



	*module_btf = btf__load_module_btf(module_name, *vmlinux_btf);

	if (!ASSERT_OK_PTR(*module_btf, "could not load module BTF"))

		goto free_vmlinux_btf;



	/* skip the test if the module does not have __user tags */

	type_id = btf__find_by_name_kind(*module_btf, "user", BTF_KIND_TYPE_TAG);

	if (type_id <= 0) {

		printf("%s:SKIP: btf_type_tag attribute not in %s", __func__, module_name);

		test__skip();

		goto free_module_btf;

	}



	return 0;



free_module_btf:

	btf__free(*module_btf);

free_vmlinux_btf:

	btf__free(*vmlinux_btf);



	*vmlinux_btf = NULL;

	if (module_btf)

		*module_btf = NULL;

	return -1;

}



static void test_btf_type_tag_mod_user(bool load_test_user1)

{

	struct btf *vmlinux_btf = NULL, *module_btf = NULL;

	struct btf_type_tag_user *skel;

	int err;



	if (load_btfs(&vmlinux_btf, &module_btf, /*needs_vmlinux_tag=*/false))

		return;



	skel = btf_type_tag_user__open();

	if (!ASSERT_OK_PTR(skel, "btf_type_tag_user"))

		goto free_module_btf;

		goto cleanup;



	bpf_program__set_autoload(skel->progs.test_sys_getsockname, false);

	if (load_test_user1)
@@ -87,34 +131,23 @@ static void test_btf_type_tag_mod_user(bool load_test_user1) 


	btf_type_tag_user__destroy(skel);



free_module_btf:

cleanup:

	btf__free(module_btf);

free_vmlinux_btf:

	btf__free(vmlinux_btf);

}



static void test_btf_type_tag_vmlinux_user(void)

{

	struct btf_type_tag_user *skel;

	struct btf *vmlinux_btf;

	__s32 type_id;

	struct btf *vmlinux_btf = NULL;

	int err;



	/* skip the test if the vmlinux does not have __user tags */

	vmlinux_btf = btf__load_vmlinux_btf();

	if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF"))

	if (load_btfs(&vmlinux_btf, NULL, /*needs_vmlinux_tag=*/true))

		return;



	type_id = btf__find_by_name_kind(vmlinux_btf, "user", BTF_KIND_TYPE_TAG);

	if (type_id <= 0) {

		printf("%s:SKIP: btf_type_tag attribute not in vmlinux btf", __func__);

		test__skip();

		goto free_vmlinux_btf;

	}



	skel = btf_type_tag_user__open();

	if (!ASSERT_OK_PTR(skel, "btf_type_tag_user"))

		goto free_vmlinux_btf;

		goto cleanup;



	bpf_program__set_autoload(skel->progs.test_user2, false);

	bpf_program__set_autoload(skel->progs.test_user1, false);
@@ -124,7 +157,70 @@ static void test_btf_type_tag_vmlinux_user(void) 


	btf_type_tag_user__destroy(skel);



free_vmlinux_btf:

cleanup:

	btf__free(vmlinux_btf);

}



static void test_btf_type_tag_mod_percpu(bool load_test_percpu1)

{

	struct btf *vmlinux_btf, *module_btf;

	struct btf_type_tag_percpu *skel;

	int err;



	if (load_btfs(&vmlinux_btf, &module_btf, /*needs_vmlinux_tag=*/false))

		return;



	skel = btf_type_tag_percpu__open();

	if (!ASSERT_OK_PTR(skel, "btf_type_tag_percpu"))

		goto cleanup;



	bpf_program__set_autoload(skel->progs.test_percpu_load, false);

	bpf_program__set_autoload(skel->progs.test_percpu_helper, false);

	if (load_test_percpu1)

		bpf_program__set_autoload(skel->progs.test_percpu2, false);

	else

		bpf_program__set_autoload(skel->progs.test_percpu1, false);



	err = btf_type_tag_percpu__load(skel);

	ASSERT_ERR(err, "btf_type_tag_percpu");



	btf_type_tag_percpu__destroy(skel);



cleanup:

	btf__free(module_btf);

	btf__free(vmlinux_btf);

}



static void test_btf_type_tag_vmlinux_percpu(bool load_test)

{

	struct btf_type_tag_percpu *skel;

	struct btf *vmlinux_btf = NULL;

	int err;



	if (load_btfs(&vmlinux_btf, NULL, /*needs_vmlinux_tag=*/true))

		return;



	skel = btf_type_tag_percpu__open();

	if (!ASSERT_OK_PTR(skel, "btf_type_tag_percpu"))

		goto cleanup;



	bpf_program__set_autoload(skel->progs.test_percpu2, false);

	bpf_program__set_autoload(skel->progs.test_percpu1, false);

	if (load_test) {

		bpf_program__set_autoload(skel->progs.test_percpu_helper, false);



		err = btf_type_tag_percpu__load(skel);

		ASSERT_ERR(err, "btf_type_tag_percpu_load");

	} else {

		bpf_program__set_autoload(skel->progs.test_percpu_load, false);



		err = btf_type_tag_percpu__load(skel);

		ASSERT_OK(err, "btf_type_tag_percpu_helper");

	}



	btf_type_tag_percpu__destroy(skel);



cleanup:

	btf__free(vmlinux_btf);

}
@@ -134,10 +230,20 @@ void test_btf_tag(void) 
		test_btf_decl_tag();

	if (test__start_subtest("btf_type_tag"))

		test_btf_type_tag();



	if (test__start_subtest("btf_type_tag_user_mod1"))

		test_btf_type_tag_mod_user(true);

	if (test__start_subtest("btf_type_tag_user_mod2"))

		test_btf_type_tag_mod_user(false);

	if (test__start_subtest("btf_type_tag_sys_user_vmlinux"))

		test_btf_type_tag_vmlinux_user();



	if (test__start_subtest("btf_type_tag_percpu_mod1"))

		test_btf_type_tag_mod_percpu(true);

	if (test__start_subtest("btf_type_tag_percpu_mod2"))

		test_btf_type_tag_mod_percpu(false);

	if (test__start_subtest("btf_type_tag_percpu_vmlinux_load"))

		test_btf_type_tag_vmlinux_percpu(true);

	if (test__start_subtest("btf_type_tag_percpu_vmlinux_helper"))

		test_btf_type_tag_vmlinux_percpu(false);

}

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

0 → 100644
+66 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2022 Google */

#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



struct bpf_testmod_btf_type_tag_1 {

	int a;

};



struct bpf_testmod_btf_type_tag_2 {

	struct bpf_testmod_btf_type_tag_1 *p;

};



__u64 g;



SEC("fentry/bpf_testmod_test_btf_type_tag_percpu_1")

int BPF_PROG(test_percpu1, struct bpf_testmod_btf_type_tag_1 *arg)

{

	g = arg->a;

	return 0;

}



SEC("fentry/bpf_testmod_test_btf_type_tag_percpu_2")

int BPF_PROG(test_percpu2, struct bpf_testmod_btf_type_tag_2 *arg)

{

	g = arg->p->a;

	return 0;

}



/* trace_cgroup_mkdir(struct cgroup *cgrp, const char *path)

 *

 * struct cgroup_rstat_cpu {

 *   ...

 *   struct cgroup *updated_children;

 *   ...

 * };

 *

 * struct cgroup {

 *   ...

 *   struct cgroup_rstat_cpu __percpu *rstat_cpu;

 *   ...

 * };

 */

SEC("tp_btf/cgroup_mkdir")

int BPF_PROG(test_percpu_load, struct cgroup *cgrp, const char *path)

{

	g = (__u64)cgrp->rstat_cpu->updated_children;

	return 0;

}



SEC("tp_btf/cgroup_mkdir")

int BPF_PROG(test_percpu_helper, struct cgroup *cgrp, const char *path)

{

	struct cgroup_rstat_cpu *rstat;

	__u32 cpu;



	cpu = bpf_get_smp_processor_id();

	rstat = (struct cgroup_rstat_cpu *)bpf_per_cpu_ptr(cgrp->rstat_cpu, cpu);

	if (rstat) {

		/* READ_ONCE */

		*(volatile int *)rstat;

	}



	return 0;

}