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Date: Wed, 23 Sep 2020 14:33:35 -0700
From: Song Liu <songliubraving@...com>
To: <netdev@...r.kernel.org>, <bpf@...r.kernel.org>
CC: <kernel-team@...com>, <ast@...nel.org>, <daniel@...earbox.net>,
<john.fastabend@...il.com>, <kpsingh@...omium.org>,
Song Liu <songliubraving@...com>
Subject: [PATCH v3 bpf-next 1/3] 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, cpu_plus. For compatibility, cpu_plus == 0 means run the
program on current cpu, cpu_plus > 0 means run the program on cpu with id
(cpu_plus - 1). This feature is needed for BPF programs that handle
perf_event and other percpu resources, as the program can access these
resource locally.
Acked-by: John Fastabend <john.fastabend@...il.com>
Signed-off-by: Song Liu <songliubraving@...com>
---
include/linux/bpf.h | 3 ++
include/uapi/linux/bpf.h | 5 ++
kernel/bpf/syscall.c | 2 +-
kernel/trace/bpf_trace.c | 1 +
net/bpf/test_run.c | 88 ++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 5 ++
6 files changed, 103 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d7c5a6ed87e30..23758c282eb4b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1376,6 +1376,9 @@ 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);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a22812561064a..89acf41913e70 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -566,6 +566,11 @@ union bpf_attr {
*/
__aligned_u64 ctx_in;
__aligned_u64 ctx_out;
+ __u32 cpu_plus; /* run this program on cpu
+ * (cpu_plus - 1).
+ * If cpu_plus == 0, run on
+ * current cpu.
+ */
} test;
struct { /* anonymous struct used by BPF_*_GET_*_ID */
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ec68d3a23a2b7..4664531ff92ea 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2975,7 +2975,7 @@ 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_plus
static int bpf_prog_test_run(const union bpf_attr *attr,
union bpf_attr __user *uattr)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b2a5380eb1871..4553aebf53862 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1675,6 +1675,7 @@ 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 = {
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 99eb8c6c0fbcc..b32e22f0ee16f 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -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.cpu_plus)
+ return -EINVAL;
+
switch (prog->expected_attach_type) {
case BPF_TRACE_FENTRY:
case BPF_TRACE_FEXIT:
@@ -236,6 +240,84 @@ 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, 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 (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;
+ cpu = kattr->test.cpu_plus - 1;
+
+ if (!kattr->test.cpu_plus || 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_plus is from user
+ * space, let's do an extra quick check to filter out
+ * invalid value before smp_call_function_single().
+ */
+ if (!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 +492,9 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
void *data;
int ret;
+ if (kattr->test.cpu_plus)
+ 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 +692,9 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR)
return -EINVAL;
+ if (kattr->test.cpu_plus)
+ return -EINVAL;
+
if (size < ETH_HLEN)
return -EINVAL;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a22812561064a..89acf41913e70 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -566,6 +566,11 @@ union bpf_attr {
*/
__aligned_u64 ctx_in;
__aligned_u64 ctx_out;
+ __u32 cpu_plus; /* run this program on cpu
+ * (cpu_plus - 1).
+ * If cpu_plus == 0, run on
+ * current cpu.
+ */
} test;
struct { /* anonymous struct used by BPF_*_GET_*_ID */
--
2.24.1
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