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

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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: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-5-haoluo@google.com
This commit is contained in:
Hao Luo 2022-03-04 11:16:57 -08:00 committed by Alexei Starovoitov
parent 5844101a1b
commit 50c6b8a9ae
3 changed files with 215 additions and 29 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

14
tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
View file

@ -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;

164
tools/testing/selftests/bpf/prog_tests/btf_tag.c
View file

@ -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;
module_btf = btf__load_module_btf(module_name, vmlinux_btf);
if (!ASSERT_OK_PTR(module_btf, "could not load module BTF"))
if (!needs_vmlinux_tag)
goto 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;
}
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;
type_id = btf__find_by_name_kind(module_btf, "user", BTF_KIND_TYPE_TAG);
/* 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);
}

66
tools/testing/selftests/bpf/progs/btf_type_tag_percpu.c Normal file
View file

@ -0,0 +1,66 @@
// 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;
}