From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f182.google.com (mail-pl1-f182.google.com [209.85.214.182]) (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 74E19287259 for ; Mon, 10 Nov 2025 16:37:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762792648; cv=none; b=FDkikJt7SSjWivQ0FL+PWGkanEcCLHW3vQ7P2eZ8phmlMybIpBkJDdh2wBbAz05cH3INPF5fYr25ZuSFd1UJdxPNcNwkM50t4QGIgJ0cNznKUbpPyKlgTkh+iUI7TmgxvaEfYWAV4biLLY69SLpvIaU+JY2G4OqhEMv1z5zMreA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762792648; c=relaxed/simple; bh=JF6+F5+AYlPr3XZARG3RggWEKB5pA9Os5BWchj7XHxM=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MenPPd4QwU+WYkPf+IbmAo+CK2vQATGJaM2e4yucH678NWKp94K3RRoepo9bEb2T7sUWQG3Jxe6ox3G69k+2oICaXgvZG76vKV5y+XH1GOdxlE3N/0MDmx2YX/MsGdgKjRqvIL2vGUPiLegLfDoQxp1NllB+mCJTnZuop8Yn594= 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=k0wF0nWt; arc=none smtp.client-ip=209.85.214.182 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="k0wF0nWt" Received: by mail-pl1-f182.google.com with SMTP id d9443c01a7336-2981f9ce15cso12850435ad.1 for ; Mon, 10 Nov 2025 08:37:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1762792637; x=1763397437; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=Xci1h+5LLX8h0ueKKgEGcPTmlGP88Cc5ZUWnC1Z7B10=; b=k0wF0nWtM//Sd97/ySB2HxCf4+leQEnK3IH6FZZ+gLR7io5I3SZF4VgPexqCNW4DG6 dxTnzIQQzD90r2k4IHjzPeFk+iPmKwkJkTefqJ+eFU07kF24Ybkv1HycBwYx+U5IjPUg cOnq4KQTms5RX0TbgKmXf2hcRWw6TkhUofLLIW0WO++Vp48kI9A6YJ4nnYvaOEml/llu QVrfeExL0j2s1h8BXZs9jW3MQqfq9yYhGYOVkWYI54J/KROsvea1N0f4KDF+jsAQSwML LFvOhzZ1EMToks84N1QMUpj5a9+DXD3LqgQJ+ChgGalO1yrO9Rz1ZejO1LaRJlxMVkUD gA5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762792637; x=1763397437; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=Xci1h+5LLX8h0ueKKgEGcPTmlGP88Cc5ZUWnC1Z7B10=; b=vmR3KC6ItMVWFzPBdk2F+07F/I6A4tJ2qBWAePXgBq+bBnyz9fVGbx/yjst+c0Bo2b ROeI0J8fjQq9/l3+OdDvhnJuJ5qDYMIrMldsfRQGlNeVngQUt3qS19etH803+vQuUncT 4xJmaOJJokbB187d+zUOLHIFpg3nc1BugGWer5jOdfX3WNG/u+xbSVy4gDnHNV12qKM/ enDhjNx5Q0lZ5u48XJxpyMZo6en2O0iVHrVME7H8NkQkMKJYN1An3a5ubDyam4aZFx5A vt4ZQ/U6W7wxC2fWHC5MimHbkKG/cWMCfUQ5tthdf/y2PmKobWULQ14yxOaGTBnLPN8b WFsA== X-Forwarded-Encrypted: i=1; AJvYcCWTIQIVEKf1cBIaoiZaQBphS3PLnSpYNaZftXQZmd5INZ7vD95SdyrgFBY85Peivz7HXOMtEXbixg1QN5TSy8na@vger.kernel.org X-Gm-Message-State: AOJu0YxNiaC31NhNuIr2TsmoKSGZk3YPA+VE1JpIVAJZ6b+t3CYb/wRj N+Qt17C2aWoGcPf/khh5uT9lqHxhHVcnpy4u98RZ/rEyUFrIWSlxJJz+ X-Gm-Gg: ASbGncucq2j6TBW46fu86kTLUCTDaR+MddY4i06oDNSNudEMZvij+JyS+OnHSL2rmzt jk6HIQ6puzboWq8Pl8e/XJaPKtU7SPxnp414H43h6P357fDjS2lzqgLHO9VqzitBHJAbkPtrBwy v2XfyQF/V4Hk5Eb9tDrlFMb1Uc3b9b+lN26ohklqsIRlG4hHWIfCw0suLKrM7FRp1eZHAkNjm0X pD5byE6GhAMONr5yxkUfWV1UgwrBgzb6RJ3ulV7H7lBuqBntVCA7o8UvE45HhGs4nDwT8YXcJFx +3bcHAenybpxKU6nPyLDcu0pNH91Wq71CI/3APiaR6XMIowNOC3sestAXMPKblMquWZAIp5siW+ bYSjKbvxOC/zgowaHx1GcEoS5crNMOMXEqux1Qd+POnVw2XKVcya7fi5vTnE0EnldX33QrTuLDG Szi7SHoLbGl5GC1gKBM7ayqrZiZTsnSv3D X-Google-Smtp-Source: AGHT+IEGWB34N8M9pAG46FEM6eUFu44tr8SQ44nAFlldnOd0ujaAQ7y38dVr1Lx0wQIkS529Z8I+TQ== X-Received: by 2002:a17:903:1a44:b0:298:68e:4057 with SMTP id d9443c01a7336-298068e42a0mr86330195ad.59.1762792636805; Mon, 10 Nov 2025 08:37:16 -0800 (PST) Received: from localhost ([103.88.46.62]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-ba901e312a2sm13029584a12.31.2025.11.10.08.37.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Nov 2025 08:37:16 -0800 (PST) From: Jinchao Wang To: Andrew Morton , "Masami Hiramatsu (Google)" , Peter Zijlstra , Randy Dunlap , Marco Elver , Mike Rapoport , Alexander Potapenko , Adrian Hunter , Alexander Shishkin , Alice Ryhl , Andrey Konovalov , Andrey Ryabinin , Andrii Nakryiko , Ard Biesheuvel , Arnaldo Carvalho de Melo , Ben Segall , Bill Wendling , Borislav Petkov , Catalin Marinas , Dave Hansen , David Hildenbrand , David Kaplan , "David S. Miller" , Dietmar Eggemann , Dmitry Vyukov , "H. Peter Anvin" , Ian Rogers , Ingo Molnar , James Clark , Jinchao Wang , Jinjie Ruan , Jiri Olsa , Jonathan Corbet , Juri Lelli , Justin Stitt , kasan-dev@googlegroups.com, Kees Cook , "Liam R. Howlett" , "Liang Kan" , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, llvm@lists.linux.dev, Lorenzo Stoakes , Mark Rutland , Masahiro Yamada , Mathieu Desnoyers , Mel Gorman , Michal Hocko , Miguel Ojeda , Nam Cao , Namhyung Kim , Nathan Chancellor , Naveen N Rao , Nick Desaulniers , Rong Xu , Sami Tolvanen , Steven Rostedt , Suren Baghdasaryan , Thomas Gleixner , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Valentin Schneider , Vincent Guittot , Vincenzo Frascino , Vlastimil Babka , Will Deacon , workflows@vger.kernel.org, x86@kernel.org Subject: [PATCH v8 08/27] mm/ksw: Add atomic watchpoint management api Date: Tue, 11 Nov 2025 00:36:03 +0800 Message-ID: <20251110163634.3686676-9-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251110163634.3686676-1-wangjinchao600@gmail.com> References: <20251110163634.3686676-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@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 --- include/linux/kstackwatch.h | 4 ++ mm/kstackwatch/watch.c | 85 ++++++++++++++++++++++++++++++++++++- 2 files changed, 88 insertions(+), 1 deletion(-) diff --git a/include/linux/kstackwatch.h b/include/linux/kstackwatch.h index eb9f2b4f2109..d7ea89c8c6af 100644 --- a/include/linux/kstackwatch.h +++ b/include/linux/kstackwatch.h @@ -44,11 +44,15 @@ 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 4947eac32c61..3817a172dc25 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -27,11 +27,83 @@ 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); @@ -41,6 +113,16 @@ 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; @@ -50,6 +132,7 @@ 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; } @@ -71,6 +154,7 @@ 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); @@ -84,7 +168,6 @@ int ksw_watch_init(void) if (ret <= 0) return -EBUSY; - return 0; } -- 2.43.0