From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 04C672E2EF5 for ; Thu, 9 Oct 2025 10:57:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760007462; cv=none; b=PiYhL6VQw2lsz/zF+9wCojeu/05vZoz4Awo8RrjYbeuLnoEdZ7zEJcLA4ZmiWOMuI1NlSKSka8FR3T4gPmY+hjY81r9QOLsiy4d/lOhedChmvxSOAECKDTA35MUPJW5IrW5elgEOMd873bROg6ppa/lX/GSEFi6rFlOEwP5y8EA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760007462; c=relaxed/simple; bh=9SDUPEZSlMV40T53tfVBMh3pQptZtl+KprWlK44Wx6c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=h4cOBP3ZmZmU3q82QJ/y3aX3QuWxHaVOsd8hr4YJqV5JU9YpC0EPNb+2dxIyqo2zFIgPSrNbbb3eETjWr09sqmoRmkJBb56J9ly+DCVeK3V0PIofbsm26foLUZdJB8POlp1uSZ7/7O3PJdv2mLKcL8m1FiQGl3876jqEEzm6ZbM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=U35YTGR1; arc=none smtp.client-ip=209.85.210.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="U35YTGR1" Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-781997d195aso575782b3a.3 for ; Thu, 09 Oct 2025 03:57:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1760007459; x=1760612259; 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=EtGUQc6HOhuSXywhIDZ+AUqHUInlRCKup6JfN/4+ZEc=; b=U35YTGR1XOw3Ox8Pl6Kjxy5ADSNVFT1SCGOzkwKooy6BBPrkchhq3AXydXskYQaRCW 5mgC0HgsqO1m+WKxJkjWjHotEhsW9znpzgI2ar7sKwyyG8nzBBEMfG/0OEoSH9hEv+Py 37mlt+O8C5R1KhfJwS2igzBWrQZu5Ls8w0e03JLTImEXg/ImzTadvfqynNMGUnRvxxlF 4Nfu0W5rjBILkUpqIdv/B5vqNVIQnMOQvpIZ1jd4MTKMXrMFn+RQMPtQiRd1EuzJcyyJ PgxIYOsfSAhOtPRIuiDu4Vv9wzfbj1c2jto3sxsMejwJDZIX0Q7v7RlvlgN79p4IdRXu yqbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760007459; x=1760612259; 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=EtGUQc6HOhuSXywhIDZ+AUqHUInlRCKup6JfN/4+ZEc=; b=thj0ODm3UltKaw5h1Dm3+mCMUmAm5Y3xZA9qCkgp29OcYgT6wcdEw0NRbCi5UUXhQL MABpCObF1rIzXVncCDVwKfvhoK0an09WRC2QLcB6tktpUgWRmfDIN8JegyraDGdjqT7S CPazOx0GuNNY8sCdzWplX+v1NXmcpEwmXTu8Bw2inF5+0Nffu7tDXVW2y9ltNs3YwIRW RFS3qz3/cfW6xuG7e6CsUR21yUs1O6TjkYqA9hog7vAhFV35eEzcdCHqoWZy2bkTtrwM /SxZQbOMlqRpeL/Z4RWWDz00FFRoTOj+hva2aGsbhKDyrL+4NmayeF2kFZCLz05y/0z5 zzgg== X-Forwarded-Encrypted: i=1; AJvYcCWHOfmf7AVvhSt9qhITUCPNhMIfv0QQsnIF3cXJmb3Rlsn7j7bFi6uzIylzH6OAHn2XQhMPYMQXy4k=@vger.kernel.org X-Gm-Message-State: AOJu0YzAs+abivVS49l/J+Z5fZHiW48Rsr/imcddimNrIpVxyWxCR9CK eStRpROxHrzHhOjLbv60gONt98n4elw74lhs+rYMjzUygI4iYvF3isMQ X-Gm-Gg: ASbGncsTbDUYMNaPxG4K6UoR0ZyRnY+QDlU4cmUtz1fnp8WaBt7x83fOA+emCWRRgUT 4jXQzSkwTp1dvqW0egMpp8JUI1gWDaV+nEW7ioLzuW12Hd7cc/mWGq0OUfvTVvcdKqn41BMJ78b sYyUKHwCneUAWlJGzLz7EX7/xTxlpU5ueOwpGP7IJhdeWpy6kM509Fcn8x5L4+DrfQSn7kLEpfh 18/CHcz/OfJxAZHgXOQFKTbqLLIE0Crn4idQMZwEBev11lku36wAloVuyUm7rUqhK9vWCoz5bj3 Kc+XQJtsLYNroXjxDzH96PjtELMsfY1Hlbs7SMUz6Gbh/JJjTk943xWLaPkEg5HiyXbZc9cAV2Y g4DsMZjpTENo9s48/qGrUHuNhSJxgUSBPYcIi7OjXGAF8kQ2C5Bia6/+zN+nf X-Google-Smtp-Source: AGHT+IGScwOqYQkzfr1btEBby7JhcFialvxPDnR54idjLQKUQn1BKVR6wxkZwyfRnUOrnLGfKhhFqw== X-Received: by 2002:a05:6a20:4305:b0:2cc:692a:3a30 with SMTP id adf61e73a8af0-32da8154253mr8702045637.13.1760007459212; Thu, 09 Oct 2025 03:57:39 -0700 (PDT) Received: from localhost ([45.142.165.62]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-b6099f3b041sm20710766a12.24.2025.10.09.03.57.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Oct 2025 03:57:38 -0700 (PDT) From: Jinchao Wang To: Andrew Morton , Masami Hiramatsu , Peter Zijlstra , Mike Rapoport , Alexander Potapenko , Randy Dunlap , Marco Elver , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Kees Cook , Alice Ryhl , Sami Tolvanen , Miguel Ojeda , Masahiro Yamada , Rong Xu , Naveen N Rao , David Kaplan , Andrii Nakryiko , Jinjie Ruan , Nam Cao , workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-mm@kvack.org, llvm@lists.linux.dev, Andrey Ryabinin , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , kasan-dev@googlegroups.com, "David S. Miller" , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org Cc: Jinchao Wang Subject: [PATCH v7 08/23] mm/ksw: Add atomic watchpoint management api Date: Thu, 9 Oct 2025 18:55:44 +0800 Message-ID: <20251009105650.168917-9-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251009105650.168917-1-wangjinchao600@gmail.com> References: <20251009105650.168917-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: workflows@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add three functions for atomic lifecycle management of watchpoints: - ksw_watch_get(): Acquires a watchpoint from a llist. - ksw_watch_on(): Enables the watchpoint on all online CPUs. - ksw_watch_off(): Disables the watchpoint and returns it to the llist. For cross-CPU synchronization, updates are propagated using direct modification on the local CPU and asynchronous IPIs for remote CPUs. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 4 ++ mm/kstackwatch/watch.c | 85 +++++++++++++++++++++++++++++++++++- 2 files changed, 88 insertions(+), 1 deletion(-) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index 4eac1be3b325..850fc2b18a9c 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -38,11 +38,15 @@ const struct ksw_config *ksw_get_config(void); /* watch management */ struct ksw_watchpoint { struct perf_event *__percpu *event; + call_single_data_t __percpu *csd; struct perf_event_attr attr; struct llist_node node; // for atomic watch_on and off struct list_head list; // for cpu online and offline }; int ksw_watch_init(void); void ksw_watch_exit(void); +int ksw_watch_get(struct ksw_watchpoint **out_wp); +int ksw_watch_on(struct ksw_watchpoint *wp, ulong watch_addr, u16 watch_len); +int ksw_watch_off(struct ksw_watchpoint *wp); #endif /* _KSTACKWATCH_H */ diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index 1d8e24fede54..887cc13292dc 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -31,11 +31,83 @@ static void ksw_watch_handler(struct perf_event *bp, panic("Stack corruption detected"); } +static void ksw_watch_on_local_cpu(void *info) +{ + struct ksw_watchpoint *wp = info; + struct perf_event *bp; + ulong flags; + int cpu; + int ret; + + local_irq_save(flags); + cpu = raw_smp_processor_id(); + bp = per_cpu(*wp->event, cpu); + if (!bp) { + local_irq_restore(flags); + return; + } + + ret = modify_wide_hw_breakpoint_local(bp, &wp->attr); + local_irq_restore(flags); + WARN(ret, "fail to reinstall HWBP on CPU%d ret %d", cpu, ret); +} + +static void ksw_watch_update(struct ksw_watchpoint *wp, ulong addr, u16 len) +{ + call_single_data_t *csd; + int cur_cpu; + int cpu; + + wp->attr.bp_addr = addr; + wp->attr.bp_len = len; + + cur_cpu = raw_smp_processor_id(); + for_each_online_cpu(cpu) { + /* remote cpu first */ + if (cpu == cur_cpu) + continue; + csd = per_cpu_ptr(wp->csd, cpu); + smp_call_function_single_async(cpu, csd); + } + ksw_watch_on_local_cpu(wp); +} + +int ksw_watch_get(struct ksw_watchpoint **out_wp) +{ + struct ksw_watchpoint *wp; + struct llist_node *node; + + node = llist_del_first(&free_wp_list); + if (!node) + return -EBUSY; + + wp = llist_entry(node, struct ksw_watchpoint, node); + WARN_ON_ONCE(wp->attr.bp_addr != (u64)&holder); + + *out_wp = wp; + return 0; +} +int ksw_watch_on(struct ksw_watchpoint *wp, ulong watch_addr, u16 watch_len) +{ + ksw_watch_update(wp, watch_addr, watch_len); + return 0; +} + +int ksw_watch_off(struct ksw_watchpoint *wp) +{ + WARN_ON_ONCE(wp->attr.bp_addr == (u64)&holder); + ksw_watch_update(wp, (ulong)&holder, sizeof(ulong)); + llist_add(&wp->node, &free_wp_list); + return 0; +} + static int ksw_watch_alloc(void) { int max_watch = ksw_get_config()->max_watch; struct ksw_watchpoint *wp; + call_single_data_t *csd; int success = 0; + int cpu; int ret; init_llist_head(&free_wp_list); @@ -45,6 +117,16 @@ static int ksw_watch_alloc(void) wp = kzalloc(sizeof(*wp), GFP_KERNEL); if (!wp) return success > 0 ? success : -EINVAL; + wp->csd = alloc_percpu(call_single_data_t); + if (!wp->csd) { + kfree(wp); + return success > 0 ? success : -EINVAL; + } + + for_each_possible_cpu(cpu) { + csd = per_cpu_ptr(wp->csd, cpu); + INIT_CSD(csd, ksw_watch_on_local_cpu, wp); + } hw_breakpoint_init(&wp->attr); wp->attr.bp_addr = (ulong)&holder; @@ -54,6 +136,7 @@ static int ksw_watch_alloc(void) ksw_watch_handler, wp); if (IS_ERR((void *)wp->event)) { ret = PTR_ERR((void *)wp->event); + free_percpu(wp->csd); kfree(wp); return success > 0 ? success : ret; } @@ -75,6 +158,7 @@ static void ksw_watch_free(void) list_for_each_entry_safe(wp, tmp, &all_wp_list, list) { list_del(&wp->list); unregister_wide_hw_breakpoint(wp->event); + free_percpu(wp->csd); kfree(wp); } mutex_unlock(&all_wp_mutex); @@ -88,7 +172,6 @@ int ksw_watch_init(void) if (ret <= 0) return -EBUSY; - return 0; } -- 2.43.0