From patchwork Mon Aug 29 12:47:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 12957752 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78321C0502C for ; Mon, 29 Aug 2022 12:56:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230000AbiH2M45 (ORCPT ); Mon, 29 Aug 2022 08:56:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230207AbiH2M4Y (ORCPT ); Mon, 29 Aug 2022 08:56:24 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E980696DC for ; Mon, 29 Aug 2022 05:48:05 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id xc12-20020a170907074c00b007416699ea14so1121879ejb.19 for ; Mon, 29 Aug 2022 05:48:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=1tERDk4Y7XiUFi7foUICKHh8rrNwWwU5I8SMJsHxX4c=; b=LRs6v78+5zV31XmPhiGFaI8d9smXBgIGVT6nVR89fc5UTZbqJpASCbp8OzqwdJo0WN X50HlNQTkBztzM8bMAfsxW3ZMbXKbNqWzzhCmWXRtGLVM510jCvBX7oLyzzVuARxpNHm 9AonX8Qd10NaBeiwtbKaFe5cBQckgAKnxEE71EwpUZFx/aNS5vw1FonUbiF01IytjObS n8Dh1GNK3dBickyio3mTRV1yiaGNRQ1VMvwcGi/v7qpfhZBgl6yuTCbsFZhh4yT5ilJo 7vS+0TPd+ThWiAMA/rfOsW7qFg2fd7fhGjlipPHc/6KEppO4C/f7SNI637VFT7wvXhPX 7UMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=1tERDk4Y7XiUFi7foUICKHh8rrNwWwU5I8SMJsHxX4c=; b=c3FkwnTCM9lEKlu/s6FVckIg/EBEYjoE8Dl1fHR+ME295/MK8Nz+KS0NCbjmsIBOFD aqllKrgSsusPuM8xi8VjZImQ6zdEOSNTdMGz/uAfacvXx3rdbt2tfp64z3wBOiS2rfUd 8zhK0EN12rTsTktOVKidkt8UDCdCwz710Ib5uOqRmYaXAO9a1ctmaUk2y/L9O5svOO3a ZmEUXhotWrtEDHKFc3LiyaVgbyJUdADG3/vBWQSAP0WfFhj9J89M7pDyDVymxLA65o8R x79Zrunv7JPuYQ+eGdjN3fCz6SyGeaLUJxhtiURx2MUAhk8P8CiGZ4uXclsfYKD54wuY A+cQ== X-Gm-Message-State: ACgBeo0wxhwz1OvLSmxl002GusKp4My8IUZCZ9ARMFnl12u/vOHhWTL5 oxpy4UNvYlC+JWN+/HikSl6enIoOHQ== X-Google-Smtp-Source: AA6agR4xS4MVvlQxXwy93Y+GTWrZcSFKD+wMhZ6QqWvQdPyWAiU+olMFbA+DUyOWg5RwEscoM50Yu8cu3A== X-Received: from elver.muc.corp.google.com ([2a00:79e0:9c:201:196d:4fc7:fa9c:62e3]) (user=elver job=sendgmr) by 2002:a05:6402:2707:b0:448:ad8e:39c1 with SMTP id y7-20020a056402270700b00448ad8e39c1mr265466edd.315.1661777284113; Mon, 29 Aug 2022 05:48:04 -0700 (PDT) Date: Mon, 29 Aug 2022 14:47:07 +0200 In-Reply-To: <20220829124719.675715-1-elver@google.com> Mime-Version: 1.0 References: <20220829124719.675715-1-elver@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220829124719.675715-3-elver@google.com> Subject: [PATCH v4 02/14] perf/hw_breakpoint: Provide hw_breakpoint_is_used() and use in test From: Marco Elver To: elver@google.com, Peter Zijlstra , Frederic Weisbecker , Ingo Molnar Cc: Thomas Gleixner , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Dmitry Vyukov , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-perf-users@vger.kernel.org, x86@kernel.org, linux-sh@vger.kernel.org, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Ian Rogers Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org Provide hw_breakpoint_is_used() to check if breakpoints are in use on the system. Use it in the KUnit test to verify the global state before and after a test case. Signed-off-by: Marco Elver Reviewed-by: Dmitry Vyukov Acked-by: Ian Rogers --- v3: * New patch. --- include/linux/hw_breakpoint.h | 3 +++ kernel/events/hw_breakpoint.c | 29 +++++++++++++++++++++++++++++ kernel/events/hw_breakpoint_test.c | 12 +++++++++++- 3 files changed, 43 insertions(+), 1 deletion(-) diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h index 78dd7035d1e5..a3fb846705eb 100644 --- a/include/linux/hw_breakpoint.h +++ b/include/linux/hw_breakpoint.h @@ -74,6 +74,7 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, extern int register_perf_hw_breakpoint(struct perf_event *bp); extern void unregister_hw_breakpoint(struct perf_event *bp); extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events); +extern bool hw_breakpoint_is_used(void); extern int dbg_reserve_bp_slot(struct perf_event *bp); extern int dbg_release_bp_slot(struct perf_event *bp); @@ -121,6 +122,8 @@ register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } static inline void unregister_hw_breakpoint(struct perf_event *bp) { } static inline void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) { } +static inline bool hw_breakpoint_is_used(void) { return false; } + static inline int reserve_bp_slot(struct perf_event *bp) {return -ENOSYS; } static inline void release_bp_slot(struct perf_event *bp) { } diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index f32320ac02fd..fd5cd1f9e7fc 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -604,6 +604,35 @@ void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) } EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); +/** + * hw_breakpoint_is_used - check if breakpoints are currently used + * + * Returns: true if breakpoints are used, false otherwise. + */ +bool hw_breakpoint_is_used(void) +{ + int cpu; + + if (!constraints_initialized) + return false; + + for_each_possible_cpu(cpu) { + for (int type = 0; type < TYPE_MAX; ++type) { + struct bp_cpuinfo *info = get_bp_info(cpu, type); + + if (info->cpu_pinned) + return true; + + for (int slot = 0; slot < nr_slots[type]; ++slot) { + if (info->tsk_pinned[slot]) + return true; + } + } + } + + return false; +} + static struct notifier_block hw_breakpoint_exceptions_nb = { .notifier_call = hw_breakpoint_exceptions_notify, /* we need to be notified first */ diff --git a/kernel/events/hw_breakpoint_test.c b/kernel/events/hw_breakpoint_test.c index 433c5c45e2a5..5ced822df788 100644 --- a/kernel/events/hw_breakpoint_test.c +++ b/kernel/events/hw_breakpoint_test.c @@ -294,7 +294,14 @@ static struct kunit_case hw_breakpoint_test_cases[] = { static int test_init(struct kunit *test) { /* Most test cases want 2 distinct CPUs. */ - return num_online_cpus() < 2 ? -EINVAL : 0; + if (num_online_cpus() < 2) + return -EINVAL; + + /* Want the system to not use breakpoints elsewhere. */ + if (hw_breakpoint_is_used()) + return -EBUSY; + + return 0; } static void test_exit(struct kunit *test) @@ -308,6 +315,9 @@ static void test_exit(struct kunit *test) kthread_stop(__other_task); __other_task = NULL; } + + /* Verify that internal state agrees that no breakpoints are in use. */ + KUNIT_EXPECT_FALSE(test, hw_breakpoint_is_used()); } static struct kunit_suite hw_breakpoint_test_suite = {