The test sets a hardware breakpoint and uses a bpf program to suppress the I/O availability signal if the ip matches the expected value.
Signed-off-by: Kyle Huey khuey@kylehuey.com --- .../selftests/bpf/prog_tests/perf_skip.c | 95 +++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 23 +++++ 2 files changed, 118 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..b269a31669b7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/hw_breakpoint.h> +#include <sys/mman.h> + +#define BPF_OBJECT "test_perf_skip.bpf.o" + +static void handle_sig(int) +{ + ASSERT_OK(1, "perf event not skipped"); +} + +static noinline int test_function(void) +{ + return 0; +} + +void serial_test_perf_skip(void) +{ + sighandler_t previous; + int duration = 0; + struct test_perf_skip *skel = NULL; + int map_fd = -1; + long page_size = sysconf(_SC_PAGE_SIZE); + uintptr_t *ip = NULL; + int prog_fd = -1; + struct perf_event_attr attr = {0}; + int perf_fd = -1; + struct f_owner_ex owner; + int err; + + previous = signal(SIGIO, handle_sig); + + skel = test_perf_skip__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + goto cleanup; + + prog_fd = bpf_program__fd(skel->progs.handler); + if (!ASSERT_OK(prog_fd < 0, "bpf_program__fd")) + goto cleanup; + + map_fd = bpf_map__fd(skel->maps.ip); + if (!ASSERT_OK(map_fd < 0, "bpf_map__fd")) + goto cleanup; + + ip = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0); + if (!ASSERT_OK_PTR(ip, "mmap bpf map")) + goto cleanup; + + *ip = (uintptr_t)test_function; + + attr.type = PERF_TYPE_BREAKPOINT; + attr.size = sizeof(attr); + attr.bp_type = HW_BREAKPOINT_X; + attr.bp_addr = (uintptr_t)test_function; + attr.bp_len = sizeof(long); + attr.sample_period = 1; + attr.sample_type = PERF_SAMPLE_IP; + attr.pinned = 1; + attr.exclude_kernel = 1; + attr.exclude_hv = 1; + attr.precise_ip = 3; + + perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); + if (CHECK(perf_fd < 0, "perf_event_open", "err %d\n", perf_fd)) + goto cleanup; + + err = fcntl(perf_fd, F_SETFL, O_ASYNC); + if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)")) + goto cleanup; + + owner.type = F_OWNER_TID; + owner.pid = gettid(); + err = fcntl(perf_fd, F_SETOWN_EX, &owner); + if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)")) + goto cleanup; + + err = ioctl(perf_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); + if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_SET_BPF)")) + goto cleanup; + + test_function(); + +cleanup: + if (perf_fd >= 0) + close(perf_fd); + if (ip) + munmap(ip, page_size); + if (skel) + test_perf_skip__destroy(skel); + + signal(SIGIO, previous); +} diff --git a/tools/testing/selftests/bpf/progs/test_perf_skip.c b/tools/testing/selftests/bpf/progs/test_perf_skip.c new file mode 100644 index 000000000000..ef01a9161afe --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __uint(map_flags, BPF_F_MMAPABLE); + __type(key, uint32_t); + __type(value, uintptr_t); +} ip SEC(".maps"); + +SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{ + const uint32_t index = 0; + uintptr_t *v = bpf_map_lookup_elem(&ip, &index); + + return !(v && *v == PT_REGS_IP(&data->regs)); +} + +char _license[] SEC("license") = "GPL";