Add a writable bare tracepoint in bpf_testmod module, and
trigger its calling when reading /sys/kernel/bpf_testmod
with a specific buffer length. The reading will return
the value in writable context if the early return flag
is enabled in writable context.
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
.../bpf/bpf_testmod/bpf_testmod-events.h | 15 ++++++++
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 10 ++++++
.../selftests/bpf/bpf_testmod/bpf_testmod.h | 5 +++
.../selftests/bpf/prog_tests/module_attach.c | 36 +++++++++++++++++++
.../selftests/bpf/progs/test_module_attach.c | 14 ++++++++
5 files changed, 80 insertions(+)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h
index 89c6d58e5dd6..11ee801e75e7 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h
@@ -34,6 +34,21 @@ DECLARE_TRACE(bpf_testmod_test_write_bare,
TP_ARGS(task, ctx)
);
+#undef BPF_TESTMOD_DECLARE_TRACE
+#ifdef DECLARE_TRACE_WRITABLE
+#define BPF_TESTMOD_DECLARE_TRACE(call, proto, args, size) \
+ DECLARE_TRACE_WRITABLE(call, PARAMS(proto), PARAMS(args), size)
+#else
+#define BPF_TESTMOD_DECLARE_TRACE(call, proto, args, size) \
+ DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))
+#endif
+
+BPF_TESTMOD_DECLARE_TRACE(bpf_testmod_test_writable_bare,
+ TP_PROTO(struct bpf_testmod_test_writable_ctx *ctx),
+ TP_ARGS(ctx),
+ sizeof(struct bpf_testmod_test_writable_ctx)
+);
+
#endif /* _BPF_TESTMOD_EVENTS_H */
#undef TRACE_INCLUDE_PATH
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 50fc5561110a..1cc1d315ccf5 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -42,6 +42,16 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
if (bpf_testmod_loop_test(101) > 100)
trace_bpf_testmod_test_read(current, &ctx);
+ /* Magic number to enable writable tp */
+ if (len == 64) {
+ struct bpf_testmod_test_writable_ctx writable = {
+ .val = 1024,
+ };
+ trace_bpf_testmod_test_writable_bare(&writable);
+ if (writable.early_ret)
+ return snprintf(buf, len, "%d\n", writable.val);
+ }
+
return -EIO; /* always fail */
}
EXPORT_SYMBOL(bpf_testmod_test_read);
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
index b3892dc40111..0d71e2607832 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
@@ -17,4 +17,9 @@ struct bpf_testmod_test_write_ctx {
size_t len;
};
+struct bpf_testmod_test_writable_ctx {
+ bool early_ret;
+ int val;
+};
+
#endif /* _BPF_TESTMOD_H */
diff --git a/tools/testing/selftests/bpf/prog_tests/module_attach.c b/tools/testing/selftests/bpf/prog_tests/module_attach.c
index 1797a6e4d6d8..e9c12d8cb457 100644
--- a/tools/testing/selftests/bpf/prog_tests/module_attach.c
+++ b/tools/testing/selftests/bpf/prog_tests/module_attach.c
@@ -2,10 +2,37 @@
/* Copyright (c) 2020 Facebook */
#include <test_progs.h>
+#include <stdbool.h>
#include "test_module_attach.skel.h"
static int duration;
+static int trigger_module_test_writable(int *val)
+{
+ int fd, err;
+ char buf[65];
+ ssize_t rd;
+
+ fd = open("/sys/kernel/bpf_testmod", O_RDONLY);
+ err = -errno;
+ if (CHECK(fd < 0, "testmod_file_open", "failed: %d\n", err))
+ return err;
+
+ rd = read(fd, buf, sizeof(buf) - 1);
+ err = rd < 0 ? -errno : -ENODATA;
+ if (CHECK(rd <= 0, "testmod_file_rd_val", "failed: rd %zd errno %d\n",
+ rd, errno)) {
+ close(fd);
+ return err;
+ }
+
+ buf[rd] = '\0';
+ *val = strtol(buf, NULL, 0);
+ close(fd);
+
+ return 0;
+}
+
static int delete_module(const char *name, int flags)
{
return syscall(__NR_delete_module, name, flags);
@@ -19,6 +46,7 @@ void test_module_attach(void)
struct test_module_attach__bss *bss;
struct bpf_link *link;
int err;
+ int writable_val = 0;
skel = test_module_attach__open();
if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
@@ -51,6 +79,14 @@ void test_module_attach(void)
ASSERT_EQ(bss->fexit_ret, -EIO, "fexit_tet");
ASSERT_EQ(bss->fmod_ret_read_sz, READ_SZ, "fmod_ret");
+ bss->raw_tp_writable_bare_early_ret = true;
+ bss->raw_tp_writable_bare_out_val = 0xf1f2f3f4;
+ ASSERT_OK(trigger_module_test_writable(&writable_val),
+ "trigger_writable");
+ ASSERT_EQ(bss->raw_tp_writable_bare_in_val, 1024, "writable_test");
+ ASSERT_EQ(bss->raw_tp_writable_bare_out_val, writable_val,
+ "writable_test");
+
test_module_attach__detach(skel);
/* attach fentry/fexit and make sure it get's module reference */
diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c
index bd37ceec5587..c7a97d268ce3 100644
--- a/tools/testing/selftests/bpf/progs/test_module_attach.c
+++ b/tools/testing/selftests/bpf/progs/test_module_attach.c
@@ -27,6 +27,20 @@ int BPF_PROG(handle_raw_tp_bare,
return 0;
}
+int raw_tp_writable_bare_in_val = 0;
+int raw_tp_writable_bare_early_ret = 0;
+int raw_tp_writable_bare_out_val = 0;
+
+SEC("raw_tp_writable/bpf_testmod_test_writable_bare")
+int BPF_PROG(handle_raw_tp_writable_bare,
+ struct bpf_testmod_test_writable_ctx *writable)
+{
+ raw_tp_writable_bare_in_val = writable->val;
+ writable->early_ret = raw_tp_writable_bare_early_ret;
+ writable->val = raw_tp_writable_bare_out_val;
+ return 0;
+}
+
__u32 tp_btf_read_sz = 0;
SEC("tp_btf/bpf_testmod_test_read")
--
2.29.2
