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 phoenix500526@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 phoenix500526@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";