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Subject[PATCH bpf-next v1 5/8] bpf/selftests: ksyms_btf to test typed ksyms
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Selftests for typed ksyms. Tests two types of ksyms: one is a struct,
the other is a plain int. This tests two paths in the kernel. Struct
ksyms will be converted into PTR_TO_BTF_ID by the verifier while int
typed ksyms will be converted into PTR_TO_MEM.

Signed-off-by: Hao Luo <haoluo@google.com>
---
.../selftests/bpf/prog_tests/ksyms_btf.c | 77 +++++++++++++++++++
.../selftests/bpf/progs/test_ksyms_btf.c | 23 ++++++
2 files changed, 100 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
create mode 100644 tools/testing/selftests/bpf/progs/test_ksyms_btf.c

diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c b/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
new file mode 100644
index 000000000000..1dad61ba7e99
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Google */
+
+#include <test_progs.h>
+#include <bpf/libbpf.h>
+#include <bpf/btf.h>
+#include "test_ksyms_btf.skel.h"
+
+static int duration;
+
+static __u64 kallsyms_find(const char *sym)
+{
+ char type, name[500];
+ __u64 addr, res = 0;
+ FILE *f;
+
+ f = fopen("/proc/kallsyms", "r");
+ if (CHECK(!f, "kallsyms_fopen", "failed to open: %d\n", errno))
+ return 0;
+
+ while (fscanf(f, "%llx %c %499s%*[^\n]\n", &addr, &type, name) > 0) {
+ if (strcmp(name, sym) == 0) {
+ res = addr;
+ goto out;
+ }
+ }
+
+ CHECK(false, "not_found", "symbol %s not found\n", sym);
+out:
+ fclose(f);
+ return res;
+}
+
+void test_ksyms_btf(void)
+{
+ __u64 runqueues_addr = kallsyms_find("runqueues");
+ __u64 bpf_prog_active_addr = kallsyms_find("bpf_prog_active");
+ struct test_ksyms_btf *skel;
+ struct test_ksyms_btf__data *data;
+ struct btf *btf;
+ int percpu_datasec;
+ int err;
+
+ btf = libbpf_find_kernel_btf();
+ if (CHECK(IS_ERR(btf), "btf_exists", "failed to load kernel BTF: %ld\n",
+ PTR_ERR(btf)))
+ return;
+
+ percpu_datasec = btf__find_by_name_kind(btf, ".data..percpu",
+ BTF_KIND_DATASEC);
+ if (percpu_datasec < 0) {
+ printf("%s:SKIP:no PERCPU DATASEC in kernel btf\n",
+ __func__);
+ test__skip();
+ return;
+ }
+
+ skel = test_ksyms_btf__open_and_load();
+ if (CHECK(!skel, "skel_open", "failed to open and load skeleton\n"))
+ return;
+
+ err = test_ksyms_btf__attach(skel);
+ if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+ goto cleanup;
+
+ /* trigger tracepoint */
+ usleep(1);
+
+ data = skel->data;
+ CHECK(data->out__runqueues != runqueues_addr, "runqueues",
+ "got %llu, exp %llu\n", data->out__runqueues, runqueues_addr);
+ CHECK(data->out__bpf_prog_active != bpf_prog_active_addr, "bpf_prog_active",
+ "got %llu, exp %llu\n", data->out__bpf_prog_active, bpf_prog_active_addr);
+
+cleanup:
+ test_ksyms_btf__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_ksyms_btf.c b/tools/testing/selftests/bpf/progs/test_ksyms_btf.c
new file mode 100644
index 000000000000..e04e31117f84
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_ksyms_btf.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Google */
+
+#include "vmlinux.h"
+
+#include <bpf/bpf_helpers.h>
+
+__u64 out__runqueues = -1;
+__u64 out__bpf_prog_active = -1;
+
+extern const struct rq runqueues __ksym; /* struct type global var. */
+extern const int bpf_prog_active __ksym; /* int type global var. */
+
+SEC("raw_tp/sys_enter")
+int handler(const void *ctx)
+{
+ out__runqueues = (__u64)&runqueues;
+ out__bpf_prog_active = (__u64)&bpf_prog_active;
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.28.0.220.ged08abb693-goog
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