From patchwork Mon Dec 11 04:55:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kyle Huey X-Patchwork-Id: 13486658 X-Patchwork-Delegate: bpf@iogearbox.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kylehuey.com header.i=@kylehuey.com header.b="MKSRvC1O" Received: from mail-pl1-x634.google.com (mail-pl1-x634.google.com [IPv6:2607:f8b0:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 438C419B for ; Sun, 10 Dec 2023 20:56:30 -0800 (PST) Received: by mail-pl1-x634.google.com with SMTP id d9443c01a7336-1d319a7a35bso5360275ad.1 for ; Sun, 10 Dec 2023 20:56:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kylehuey.com; s=google; t=1702270590; x=1702875390; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=f/uOwN8/AYKX/iTSNcMtLhs7X+zpyhpj6oRruBreRa4=; b=MKSRvC1OxyjdP7zrUzYvQsbx6mJ74RpWWf1U6sy8Yn3lqxzf5ZqLSo8OeWz9ipEDm6 7W7bubSjoonHVa4aoZuJvUXxlxiUCQkvjbMsCUjiQX98riXNOgWNNrUgoug0opr7JOQQ MUMj8QHvTosq/9WO6urCr8IX49gUENbTMs55EhHuR3IjdOjBAT4DXImbI9Oavf+vvOO2 WknaPCL1RxrYAILMHixVA5da0s7EndwQBJlcoi7Gw6gueeWJvWA8+3JZ4OtW1IkxzQQY p6c5tr6SHhBtT64l0sAoQrMp4q+UTPBIZefdVufgHcLstbOepIhZ6+xMu4UP3/Chwoa3 nL1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702270590; x=1702875390; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=f/uOwN8/AYKX/iTSNcMtLhs7X+zpyhpj6oRruBreRa4=; b=Wg83YUMgGPDlBMPu8xeWINZvGitDxM2wwlMouAZXO0/KCWv7sTNySjK8BoDZfZmZr1 eF8eFEFCnYKSe/5L9C7FPgMXxwT9bZkDiCDDdneNNZ6tPgbhIOx+0kh/fdcuvmn1POqd RluMCnKUGRH/Oi5CvOSDQw0EQ+KJN3FydpR/2kf9jBnTDz/XVBaOWutktHiCtRLrJimz ZIbhwlFIxH54SQc1y3iOziCstIcRAVvVvlBK1LeNoezGvmmGLBkne0Bt25gnWRSoIV3c SvImLgf93GH65O0bXJYm/AVFRY9Ln8uA9r7M7wwHV4d2eR5vGRMGcjoOYeO38rCOCmE2 WeFA== X-Gm-Message-State: AOJu0Yy9YpQYzCphZCvO/8JflXNThfDLyiC8XEmZ8emEbVUSW8vj4rq1 54LSlM2KPhR6dnigIGJNsmuuYg== X-Google-Smtp-Source: AGHT+IHgP24C9H6TC1qkhK0WnVUgjdIKQD/L+UmDGrOm9ocb3UIOQduZF38TYB04xwZtzp9Bl64vMA== X-Received: by 2002:a17:902:c3d1:b0:1d0:d168:daae with SMTP id j17-20020a170902c3d100b001d0d168daaemr4338646plj.95.1702270589707; Sun, 10 Dec 2023 20:56:29 -0800 (PST) Received: from zhadum.home.kylehuey.com (c-76-126-33-191.hsd1.ca.comcast.net. [76.126.33.191]) by smtp.gmail.com with ESMTPSA id e11-20020a170902b78b00b001d2ffeac9d3sm3300623pls.186.2023.12.10.20.56.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 10 Dec 2023 20:56:29 -0800 (PST) From: Kyle Huey X-Google-Original-From: Kyle Huey To: Kyle Huey , linux-kernel@vger.kernel.org, Andrii Nakryiko , Jiri Olsa , Namhyung Kim , Marco Elver , Yonghong Song Cc: Robert O'Callahan , Andrii Nakryiko , Mykola Lysenko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Shuah Khan , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v3 4/4] selftest/bpf: Test a perf bpf program that suppresses side effects. Date: Sun, 10 Dec 2023 20:55:43 -0800 Message-Id: <20231211045543.31741-5-khuey@kylehuey.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231211045543.31741-1-khuey@kylehuey.com> References: <20231211045543.31741-1-khuey@kylehuey.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net The test sets a hardware breakpoint and uses a bpf program to suppress the side effects of a perf event sample, including I/O availability signals, SIGTRAPs, and decrementing the event counter limit, if the ip matches the expected value. Then the function with the breakpoint is executed multiple times to test that all effects behave as expected. Signed-off-by: Kyle Huey --- .../selftests/bpf/prog_tests/perf_skip.c | 140 ++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 15 ++ 2 files changed, 155 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..0200736a8baf --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE + +#include +#include "test_perf_skip.skel.h" +#include +#include +#include + +#ifndef TRAP_PERF +#define TRAP_PERF 6 +#endif + +int signals_unexpected = 1; +int sigio_count, sigtrap_count; + +static void handle_sigio(int sig __always_unused) +{ + ASSERT_OK(signals_unexpected, "perf event not skipped"); + ++sigio_count; +} + +static void handle_sigtrap(int signum __always_unused, + siginfo_t *info, + void *ucontext __always_unused) +{ + ASSERT_OK(signals_unexpected, "perf event not skipped"); + ASSERT_EQ(info->si_code, TRAP_PERF, "wrong si_code"); + ++sigtrap_count; +} + +static noinline int test_function(void) +{ + asm volatile (""); + return 0; +} + +void serial_test_perf_skip(void) +{ + struct sigaction action = {}; + struct sigaction previous_sigtrap; + sighandler_t previous_sigio; + struct test_perf_skip *skel = NULL; + struct perf_event_attr attr = {}; + int perf_fd = -1; + int err; + struct f_owner_ex owner; + struct bpf_link *prog_link = NULL; + + action.sa_flags = SA_SIGINFO | SA_NODEFER; + action.sa_sigaction = handle_sigtrap; + sigemptyset(&action.sa_mask); + if (!ASSERT_OK(sigaction(SIGTRAP, &action, &previous_sigtrap), "sigaction")) + return; + + previous_sigio = signal(SIGIO, handle_sigio); + + skel = test_perf_skip__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + goto cleanup; + + 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; + attr.sigtrap = 1; + attr.remove_on_exec = 1; + + perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); + if (perf_fd < 0 && (errno == ENOENT || errno == EOPNOTSUPP)) { + printf("SKIP:no PERF_TYPE_BREAKPOINT/HW_BREAKPOINT_X\n"); + test__skip(); + goto cleanup; + } + if (!ASSERT_OK(perf_fd < 0, "perf_event_open")) + goto cleanup; + + /* Configure the perf event to signal on sample. */ + 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 = syscall(__NR_gettid); + err = fcntl(perf_fd, F_SETOWN_EX, &owner); + if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)")) + goto cleanup; + + /* + * Allow at most one sample. A sample rejected by bpf should + * not count against this. + */ + err = ioctl(perf_fd, PERF_EVENT_IOC_REFRESH, 1); + if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_REFRESH)")) + goto cleanup; + + prog_link = bpf_program__attach_perf_event(skel->progs.handler, perf_fd); + if (!ASSERT_OK_PTR(prog_link, "bpf_program__attach_perf_event")) + goto cleanup; + + /* Configure the bpf program to suppress the sample. */ + skel->bss->ip = (uintptr_t)test_function; + test_function(); + + ASSERT_EQ(sigio_count, 0, "sigio_count"); + ASSERT_EQ(sigtrap_count, 0, "sigtrap_count"); + + /* Configure the bpf program to allow the sample. */ + skel->bss->ip = 0; + signals_unexpected = 0; + test_function(); + + ASSERT_EQ(sigio_count, 1, "sigio_count"); + ASSERT_EQ(sigtrap_count, 1, "sigtrap_count"); + + /* + * Test that the sample above is the only one allowed (by perf, not + * by bpf) + */ + test_function(); + + ASSERT_EQ(sigio_count, 1, "sigio_count"); + ASSERT_EQ(sigtrap_count, 1, "sigtrap_count"); + +cleanup: + bpf_link__destroy(prog_link); + if (perf_fd >= 0) + close(perf_fd); + test_perf_skip__destroy(skel); + + signal(SIGIO, previous_sigio); + sigaction(SIGTRAP, &previous_sigtrap, NULL); +} 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..7eb8b6de7a57 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include +#include + +uintptr_t ip; + +SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{ + /* Skip events that have the correct ip. */ + return ip != PT_REGS_IP(&data->regs); +} + +char _license[] SEC("license") = "GPL";