From nobody Thu Oct 2 23:49:49 2025 Received: from mail-pl1-f170.google.com (mail-pl1-f170.google.com [209.85.214.170]) (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 7F9A3270542; Wed, 10 Sep 2025 05:25:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757481956; cv=none; b=BJlmaexnn+AsYOrfV/MZbWK6tLdxNEmS+POCgB/QnbWwnYHqtj7NwWxjqQIWdM/Xi3WELeTuoDzyMU4N0+dgQ8EHrC7pnUE8VECpM1ZS1Y9t963M1UmNMCoqBp1jng/uV8ZWQgOiq8QeCanW3hjL7m5U3eYtKI/5n9J6o6e2b3c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757481956; c=relaxed/simple; bh=YB+3r6DZaWoq0w2fIDHea418Mq4qZBHZObo3HzPDBB4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LBwImQB7aY/a3aWzNKgi37KIch2kBwkzFO/zsu9iQ+RXyROySdjWeWOthHGiQ97gaE1LERVbGqb/WcnlWBDdWBrpPvoFpAtW4mAK4MBicei5CNd4OLd+/EwapbJSsIlaVNdqMsUimneSvriaM1e14LUn4+lS6a0dx8sOodpGlJ8= 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=BOcNULfZ; arc=none smtp.client-ip=209.85.214.170 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="BOcNULfZ" Received: by mail-pl1-f170.google.com with SMTP id d9443c01a7336-24c784130e6so71284125ad.3; Tue, 09 Sep 2025 22:25:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1757481953; x=1758086753; 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=mOx6p8YhFEr+hG/yZ9Zg64+RQ0caUuIY8LjmjDVRe3w=; b=BOcNULfZQfiWohw0IrkESSgU3GMuj5RjaZN7Rt94Pee/BcIkfPgxMZ5uBdoV2GHxAA G77DZRWyMtcMhsEVuD/ZeQTGAG016quDTmx39yvGpnB7Ltv31tTvFmDJsp/cv8Es1N1v jHqtDbrtPzHYRkKoMUd19puSwDQGfyNwTvaiCVGiLfBk7z5Q4OaNuRvP8wynn0JEo4lC 2yjZ69sraRZCpABhJctAb1qXW2F+vbYarzHk6mv3jT529GOtEjxWiT8BkEF/EddwB+c3 w703CNK/vMiuhZKyVw/F5yCKzMaljBsm/lBymul/apW4Cm9+Z5ooW4+kZg4EoIABxuf0 fy9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757481953; x=1758086753; 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=mOx6p8YhFEr+hG/yZ9Zg64+RQ0caUuIY8LjmjDVRe3w=; b=CGjoBBEAHSxWT7hZJEnbIw/R1JYh9OsXr+3DWy0tF/dYKX29ANkM46kfbfJVKXkGRr zDZf/PANaHfvjgdHKRH1hZ/S2dUXkjrRHZ81GrtEq6UI3ZL4FnWuenjA4k447Fiq1Bt8 pp9OV89lhNxkHYeAcfAVx1OIJVcDNOb3SzhBRiLX+J8cDvy908UStY6Sii8NWcR6JeBj HrmC7puQ4AxVtAtVbJil1xjPpVo23NhgHVvFfyyXIYwfUOj0GOwRVbkOdLySBfJaEDWj b3wg+6FovbF+7NyTsGSqzCcAjW+9dQ5HVZsDnfBPQUPLGCpKso3bYNi/6++VjzCW+8NF ZZXw== X-Forwarded-Encrypted: i=1; AJvYcCXknbBfQIMTXTLbFaIAo4c1VbCR93HWPjb/l6T8pJ40asaPwN8pTHmb06Di4qTRaJ4L2TG5WpyrnK5URyPO8yPpBXxK@vger.kernel.org, AJvYcCXs+OkMV4wwAFUvTrWnf7c3Fo6I7Fadl7IIbAOm19JuVvDbUvpEqK6jjorYIimBwCemg8cf4ZB1qGR0mI08+tUA@vger.kernel.org X-Gm-Message-State: AOJu0YwwqSQExzMwX95IrvQjUUZkxo+NBbNZfvq7l4jR8MxEziLtnHuw h7s0+PAuzSWRMf6ygGkJCFkAqEBrVYuTOq6duqldQI8/vWOlSmxgKWBq X-Gm-Gg: ASbGncsTvSOAjAMg3grxv1S+8VoNWmJvOMja15oZENIBLbKKziqFpzEv+Vv2i1O67xI bQnA40XKintnZis9MT0DEaiRB2ePTeKVFvapBIHDGuGNnIBP5EFHQoFmMQ1cxE91LZO5jRlBbWS EDX000kjxHQEZLCL07/sbuooV97MWTb4MWprItTSfRNBK6JRrK3ZF2WvGEjUKP7qte4AuNCxeMh dCi/kvU5exrnEoMc3uA5haYH0FOY7HYpVuNFaKsNWps5YafN7WZU1E+QG0qpMMdcpnXS4i3f9zN mhjP4gHpisJ+ISyU5Qf61RbN1IZ28UMjhv5SDZ0shD4NUkoDBuZNP2Fw6wkwCwn7dgwkzAITN5m nOYE58c8Pr9KKZ+HXRvxoUok/n5ljUL/fhg== X-Google-Smtp-Source: AGHT+IE+2ZvUwlvbAD3bNh5YTXYd3TWYyXRPD2VsUudLsG3CxrebrDDY5hB3nLhTzBib0WtkqPJfKw== X-Received: by 2002:a17:902:ebc6:b0:246:255a:1913 with SMTP id d9443c01a7336-25171cbfd65mr173971245ad.39.1757481952659; Tue, 09 Sep 2025 22:25:52 -0700 (PDT) Received: from localhost.localdomain ([2403:2c80:17::10:4007]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-25a27422ebcsm14815125ad.29.2025.09.09.22.25.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Sep 2025 22:25:52 -0700 (PDT) From: Jinchao Wang To: Andrew Morton , Masami Hiramatsu , Peter Zijlstra , Mike Rapoport , "Naveen N . Rao" , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , kasan-dev@googlegroups.com, "David S. Miller" , Steven Rostedt , Mathieu Desnoyers , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jinchao Wang Subject: [PATCH v3 07/19] mm/ksw: add atomic watch on/off operations Date: Wed, 10 Sep 2025 13:23:16 +0800 Message-ID: <20250910052335.1151048-8-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250910052335.1151048-1-wangjinchao600@gmail.com> References: <20250910052335.1151048-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add support to atomically turn the hardware watch on and off without allocation overhead. The watch is pre-allocated and later retargeted. The current CPU is updated directly, while other CPUs are updated asynchronously via smp_call_function_single_async(). Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 2 + mm/kstackwatch/watch.c | 95 ++++++++++++++++++++++++++++++++++++ 2 files changed, 97 insertions(+) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index 3ea191370970..2fa377843f17 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -41,5 +41,7 @@ const struct ksw_config *ksw_get_config(void); /* watch management */ int ksw_watch_init(void); void ksw_watch_exit(void); +int ksw_watch_on(u64 watch_addr, u64 watch_len); +void ksw_watch_off(void); =20 #endif /* _KSTACKWATCH_H */ diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index d3399ac840b2..e02ffc3231ad 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -3,16 +3,23 @@ =20 #include #include +#include #include =20 #include "kstackwatch.h" =20 static struct perf_event *__percpu *watch_events; +static DEFINE_SPINLOCK(watch_lock); =20 static unsigned long watch_holder; =20 static struct perf_event_attr watch_attr; =20 +static void ksw_watch_on_local_cpu(void *info); + +static DEFINE_PER_CPU(call_single_data_t, + watch_csd) =3D CSD_INIT(ksw_watch_on_local_cpu, NULL); + bool panic_on_catch; module_param(panic_on_catch, bool, 0644); MODULE_PARM_DESC(panic_on_catch, "panic immediately on corruption catch"); @@ -29,6 +36,94 @@ static void ksw_watch_handler(struct perf_event *bp, panic("Stack corruption detected"); } =20 +static void ksw_watch_on_local_cpu(void *data) +{ + struct perf_event *bp; + int cpu; + int ret; + + preempt_disable(); + cpu =3D raw_smp_processor_id(); + bp =3D *per_cpu_ptr(watch_events, cpu); + if (!bp) { + preempt_enable(); + return; + } + + ret =3D modify_wide_hw_breakpoint_local(bp, &watch_attr); + preempt_enable(); + + if (ret) { + pr_err("failed to reinstall HWBP on CPU %d ret %d\n", cpu, + ret); + return; + } + + if (watch_attr.bp_addr =3D=3D (unsigned long)&watch_holder) { + pr_debug("watch off CPU %d\n", cpu); + } else { + pr_debug("watch on CPU %d at 0x%llx (len %llu)\n", cpu, + watch_attr.bp_addr, watch_attr.bp_len); + } +} + +int ksw_watch_on(u64 watch_addr, u64 watch_len) +{ + unsigned long flags; + int cpu; + call_single_data_t *csd; + + if (!watch_addr) { + pr_err("watch with invalid address\n"); + return -EINVAL; + } + + spin_lock_irqsave(&watch_lock, flags); + + /* + * enforce singleton watch: + * - if a watch is already active (bp_addr !=3D &watch_holder), + * - and not asking to reset it (watch_addr !=3D &watch_holder) + * then reject with -EBUSY. + */ + if (watch_attr.bp_addr !=3D (unsigned long)&watch_holder && + watch_addr !=3D (unsigned long)&watch_holder) { + spin_unlock_irqrestore(&watch_lock, flags); + return -EBUSY; + } + + watch_attr.bp_addr =3D watch_addr; + watch_attr.bp_len =3D watch_len; + + /* ensure watchpoint update is visible to other CPUs before IPI */ + smp_wmb(); + + spin_unlock_irqrestore(&watch_lock, flags); + + if (watch_addr =3D=3D (unsigned long)&watch_holder) + pr_debug("watch off starting\n"); + else + pr_debug("watch on starting\n"); + + cpus_read_lock(); + for_each_online_cpu(cpu) { + if (cpu =3D=3D raw_smp_processor_id()) { + ksw_watch_on_local_cpu(NULL); + } else { + csd =3D &per_cpu(watch_csd, cpu); + smp_call_function_single_async(cpu, csd); + } + } + cpus_read_unlock(); + + return 0; +} + +void ksw_watch_off(void) +{ + ksw_watch_on((unsigned long)&watch_holder, sizeof(watch_holder)); +} + int ksw_watch_init(void) { int ret; --=20 2.43.0