When using GCC on x86-64 to compile an usdt prog with -O1 or higher
optimization, the compiler will generate SIB addressing mode for global
array and PC-relative addressing mode for global variable,
e.g. "1@-96(%rbp,%rax,8)" and "-1@4+t1(%rip)".
In this patch:
- add usdt_o1 test case to cover SIB addressing usdt argument spec
handling logic
Signed-off-by: Jiawei Zhao <phoenix500...@163.com>
---
.../selftests/bpf/prog_tests/usdt_o1.c | 70 +++++++++++++++++++
.../selftests/bpf/progs/test_usdt_o1.c | 37 ++++++++++
2 files changed, 107 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/usdt_o1.c
create mode 100644 tools/testing/selftests/bpf/progs/test_usdt_o1.c
diff --git a/tools/testing/selftests/bpf/prog_tests/usdt_o1.c
b/tools/testing/selftests/bpf/prog_tests/usdt_o1.c
new file mode 100644
index 000000000000..706168e804cb
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/usdt_o1.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Jiawei Zhao <phoenix500...@163.com>. */
+#include <test_progs.h>
+
+#include "../sdt.h"
+#include "test_usdt_o1.skel.h"
+
+#if (defined(__GNUC__) && !defined(__clang__))
+#pragma GCC optimize("O1")
+#else
+#pragma message("non-gcc compiler: the correct probes might not be installed")
+#endif
+
+
+#define test_value 0xFEDCBA9876543210ULL
+#define SEC(name) __attribute__((section(name), used))
+
+int lets_test_this(int);
+static volatile __u64 array[1] = {test_value};
+
+static __always_inline void trigger_func(void)
+{
+ /* Base address + offset + (index * scale) */
+ for (volatile int i = 0; i <= 0; i++)
+ STAP_PROBE1(test, usdt1, array[i]);
+}
+
+static void basic_sib_usdt(void)
+{
+ LIBBPF_OPTS(bpf_usdt_opts, opts);
+ struct test_usdt_o1 *skel;
+ struct test_usdt_o1__bss *bss;
+ int err;
+
+ skel = test_usdt_o1__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ bss = skel->bss;
+ bss->my_pid = getpid();
+
+ err = test_usdt_o1__attach(skel);
+ if (!ASSERT_OK(err, "skel_attach"))
+ goto cleanup;
+
+ /* usdt1 won't be auto-attached */
+ opts.usdt_cookie = 0xcafedeadbeeffeed;
+ skel->links.usdt1 = bpf_program__attach_usdt(skel->progs.usdt1,
+ 0 /*self*/,
"/proc/self/exe",
+ "test", "usdt1", &opts);
+ if (!ASSERT_OK_PTR(skel->links.usdt1, "usdt1_link"))
+ goto cleanup;
+
+ trigger_func();
+
+ ASSERT_EQ(bss->usdt1_called, 1, "usdt1_called");
+ ASSERT_EQ(bss->usdt1_cookie, 0xcafedeadbeeffeed, "usdt1_cookie");
+ ASSERT_EQ(bss->usdt1_arg_cnt, 1, "usdt1_arg_cnt");
+ ASSERT_EQ(bss->usdt1_arg, test_value, "usdt1_arg");
+ ASSERT_EQ(bss->usdt1_arg_ret, 0, "usdt1_arg_ret");
+ ASSERT_EQ(bss->usdt1_arg_size, sizeof(array[0]), "usdt1_arg_size");
+
+cleanup:
+ test_usdt_o1__destroy(skel);
+}
+
+void test_usdt_o1(void)
+{
+ basic_sib_usdt();
+}
diff --git a/tools/testing/selftests/bpf/progs/test_usdt_o1.c
b/tools/testing/selftests/bpf/progs/test_usdt_o1.c
new file mode 100644
index 000000000000..14602aa54578
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_usdt_o1.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/usdt.bpf.h>
+
+int my_pid;
+
+int usdt1_called;
+u64 usdt1_cookie;
+int usdt1_arg_cnt;
+int usdt1_arg_ret;
+u64 usdt1_arg;
+int usdt1_arg_size;
+
+SEC("usdt")
+int usdt1(struct pt_regs *ctx)
+{
+ long tmp;
+
+ if (my_pid != (bpf_get_current_pid_tgid() >> 32))
+ return 0;
+
+ __sync_fetch_and_add(&usdt1_called, 1);
+
+ usdt1_cookie = bpf_usdt_cookie(ctx);
+ usdt1_arg_cnt = bpf_usdt_arg_cnt(ctx);
+
+ usdt1_arg_ret = bpf_usdt_arg(ctx, 0, &tmp);
+ usdt1_arg = (u64)tmp;
+ usdt1_arg_size = bpf_usdt_arg_size(ctx, 0);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.43.0
