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bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint 

Add .test_run for raw_tracepoint. Also, introduce a new feature that runs
the target program on a specific CPU. This is achieved by a new flag in
bpf_attr.test, BPF_F_TEST_RUN_ON_CPU. When this flag is set, the program
is triggered on cpu with id bpf_attr.test.cpu. This feature is needed for
BPF programs that handle perf_event and other percpu resources, as the
program can access these resource locally.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200925205432.1777-2-songliubraving@fb.com
This commit is contained in:
Song Liu 2020-09-25 13:54:29 -07:00 committed by Daniel Borkmann
parent 1fd17c8cd0
commit 1b4d60ec16
6 changed files with 110 additions and 1 deletions
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3
include/linux/bpf.h
View File

@ -1396,6 +1396,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr);
int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr);
bool btf_ctx_access(int off, int size, enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info);

7
include/uapi/linux/bpf.h
View File

@ -424,6 +424,11 @@ enum {
*/
#define BPF_F_QUERY_EFFECTIVE (1U << 0)
/* Flags for BPF_PROG_TEST_RUN */
/* If set, run the test on the cpu specified by bpf_attr.test.cpu */
#define BPF_F_TEST_RUN_ON_CPU (1U << 0)
/* type for BPF_ENABLE_STATS */
enum bpf_stats_type {
/* enabled run_time_ns and run_cnt */
@ -566,6 +571,8 @@ union bpf_attr {
*/
__aligned_u64 ctx_in;
__aligned_u64 ctx_out;
__u32 flags;
__u32 cpu;
} test;
struct { /* anonymous struct used by BPF_*_GET_*_ID */

2
kernel/bpf/syscall.c
View File

@ -2979,7 +2979,7 @@ static int bpf_prog_query(const union bpf_attr *attr,
}
}
#define BPF_PROG_TEST_RUN_LAST_FIELD test.ctx_out
#define BPF_PROG_TEST_RUN_LAST_FIELD test.cpu
static int bpf_prog_test_run(const union bpf_attr *attr,
union bpf_attr __user *uattr)

1
kernel/trace/bpf_trace.c
View File

@ -1678,6 +1678,7 @@ const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
};
const struct bpf_prog_ops raw_tracepoint_prog_ops = {
.test_run = bpf_prog_test_run_raw_tp,
};
const struct bpf_verifier_ops tracing_verifier_ops = {

91
net/bpf/test_run.c
View File

@ -11,6 +11,7 @@
#include <net/sock.h>
#include <net/tcp.h>
#include <linux/error-injection.h>
#include <linux/smp.h>
#define CREATE_TRACE_POINTS
#include <trace/events/bpf_test_run.h>
@ -204,6 +205,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
int b = 2, err = -EFAULT;
u32 retval = 0;
if (kattr->test.flags || kattr->test.cpu)
return -EINVAL;
switch (prog->expected_attach_type) {
case BPF_TRACE_FENTRY:
case BPF_TRACE_FEXIT:
@ -236,6 +240,87 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
return err;
}
struct bpf_raw_tp_test_run_info {
struct bpf_prog *prog;
void *ctx;
u32 retval;
};
static void
__bpf_prog_test_run_raw_tp(void *data)
{
struct bpf_raw_tp_test_run_info *info = data;
rcu_read_lock();
migrate_disable();
info->retval = BPF_PROG_RUN(info->prog, info->ctx);
migrate_enable();
rcu_read_unlock();
}
int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
void __user *ctx_in = u64_to_user_ptr(kattr->test.ctx_in);
__u32 ctx_size_in = kattr->test.ctx_size_in;
struct bpf_raw_tp_test_run_info info;
int cpu = kattr->test.cpu, err = 0;
/* doesn't support data_in/out, ctx_out, duration, or repeat */
if (kattr->test.data_in || kattr->test.data_out ||
kattr->test.ctx_out || kattr->test.duration ||
kattr->test.repeat)
return -EINVAL;
if (ctx_size_in < prog->aux->max_ctx_offset)
return -EINVAL;
if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 && cpu != 0)
return -EINVAL;
if (ctx_size_in) {
info.ctx = kzalloc(ctx_size_in, GFP_USER);
if (!info.ctx)
return -ENOMEM;
if (copy_from_user(info.ctx, ctx_in, ctx_size_in)) {
err = -EFAULT;
goto out;
}
} else {
info.ctx = NULL;
}
info.prog = prog;
if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 ||
cpu == smp_processor_id()) {
__bpf_prog_test_run_raw_tp(&info);
} else {
/* smp_call_function_single() also checks cpu_online()
* after csd_lock(). However, since cpu is from user
* space, let's do an extra quick check to filter out
* invalid value before smp_call_function_single().
*/
if (cpu >= nr_cpu_ids || !cpu_online(cpu)) {
err = -ENXIO;
goto out;
}
err = smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp,
&info, 1);
if (err)
goto out;
}
if (copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
err = -EFAULT;
out:
kfree(info.ctx);
return err;
}
static void *bpf_ctx_init(const union bpf_attr *kattr, u32 max_size)
{
void __user *data_in = u64_to_user_ptr(kattr->test.ctx_in);
@ -410,6 +495,9 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
void *data;
int ret;
if (kattr->test.flags || kattr->test.cpu)
return -EINVAL;
data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
if (IS_ERR(data))
@ -607,6 +695,9 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR)
return -EINVAL;
if (kattr->test.flags || kattr->test.cpu)
return -EINVAL;
if (size < ETH_HLEN)
return -EINVAL;

7
tools/include/uapi/linux/bpf.h
View File

@ -424,6 +424,11 @@ enum {
*/
#define BPF_F_QUERY_EFFECTIVE (1U << 0)
/* Flags for BPF_PROG_TEST_RUN */
/* If set, run the test on the cpu specified by bpf_attr.test.cpu */
#define BPF_F_TEST_RUN_ON_CPU (1U << 0)
/* type for BPF_ENABLE_STATS */
enum bpf_stats_type {
/* enabled run_time_ns and run_cnt */
@ -566,6 +571,8 @@ union bpf_attr {
*/
__aligned_u64 ctx_in;
__aligned_u64 ctx_out;
__u32 flags;
__u32 cpu;
} test;
struct { /* anonymous struct used by BPF_*_GET_*_ID */