From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A8982F616B; Sun, 2 Aug 2026 08:19:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785658746; cv=none; b=g0GxVP3c2FRm5npKT7ntMovapOLEAKNvYE9Se8UxUs9gZWGL3myJjMuoxCCq9jHWPtEihAXOdIidkf5zIEh2G00/bjlH+alJG2COLm1OMmy31QBc4jxpqgmhlC+XvfmiJbCxy/3jR7LFXEmNHHwFNC9ZA98sUWPTYE/C3H/0qI0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785658746; c=relaxed/simple; bh=WLSMomGHYuU3/xj6iFrupqQ0v3LAL6oPKQv+ueIKDmc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=F5wNfYGRqkxBqSO9i5Ltgn0+Etq85OvXJtKIrkJ+PC9E7MnuMAZVBteeb1CqyiwpXQKj4wpBppXzn2FBteItXgUiQ+HuwrnyL4rFB7tnUJF+XNJ4BaRGRGyS3S5NjLJ43DmxDjU6wGJjpOSWXCuiRLqyYeZUKnpnwT4Wbb0Jx88= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ju2oTGJh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ju2oTGJh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A64CB1F00AC4; Sun, 2 Aug 2026 08:19:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785658745; bh=efYS360pd6ZZxxCBl/VvK2sP6q43hqiJMFfCbWEkZZk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ju2oTGJhdnvUu8t0fuLMOyx5lSAxE4laeLLdVIgASrcsHvwiy5l4DPMvacgtgle3L V0J0x9KHWS/yyrQvryEGLkb/WcSkLPsDv1AhbS8E4eGDHjNCrS2K4bsZIDzj9f1+dw MDycSl3LpZcivqCFOdqSDT8hFkecSoIynjozfoxbj9kssd1QtI9gvaZfUul4XeF9qD gTj3I6nHqJt2e9MAF0MleW5IXeDb7bXbJiEI70i9MTgkd7cUOW7aaH3TwCONk+C62W 2fsSZBdQtd/H1bCRjBA7I1dxMbP8Am2+HE44UswuXiy3DM5yrVB2/mCAvh4SInUV7q 92aLJD/b3oJWw== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v11 03/11] HWBP: Add modify_local_hw_breakpoint_addr() API Date: Sun, 2 Aug 2026 17:18:59 +0900 Message-ID: <178565873951.714490.18157944268328517957.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <178565870538.714490.11309825813968306287.stgit@devnote2> References: <178565870538.714490.11309825813968306287.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit From: Masami Hiramatsu (Google) Add modify_local_hw_breakpoint_addr() to update only the watched address of an installed hardware breakpoint on the local CPU without releasing and reserving its hardware slot. This is available when the architecture selects CONFIG_HAVE_MODIFY_LOCAL_HW_BREAKPOINT_ADDR. The caller must provide an installed local event and a valid address, and update other CPUs separately. Link: https://lore.kernel.org/all/f9c49dfa49bdc57ba8c0574bc9981c1e581acf92.1785067572.git.wangjinchao600@gmail.com/ Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Jinchao Wang --- Changes in v11: - Check return value of arch_modify_local_hw_breakpoint_addr() and return error on failure. - Update bp->attr.bp_addr and counter_arch_bp(bp)->address only after arch modification succeeds. --- arch/Kconfig | 8 ++++++++ arch/x86/Kconfig | 1 + include/linux/hw_breakpoint.h | 6 ++++++ kernel/events/hw_breakpoint.c | 35 +++++++++++++++++++++++++++++++++++ 4 files changed, 50 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index fa7507ac8e13..bea383408e32 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -457,6 +457,14 @@ config HAVE_MIXED_BREAKPOINTS_REGS Select this option if your arch implements breakpoints under the latter fashion. +config HAVE_MODIFY_LOCAL_HW_BREAKPOINT_ADDR + bool + depends on HAVE_HW_BREAKPOINT + help + Select this if the architecture can modify the address of an + installed hardware breakpoint on the local CPU without releasing + and reserving its hardware slot. + config HAVE_USER_RETURN_NOTIFIER bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index fd979e0be1f0..33908103d9a0 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -247,6 +247,7 @@ config X86 select HAVE_FUNCTION_TRACER select HAVE_GCC_PLUGINS select HAVE_HW_BREAKPOINT + select HAVE_MODIFY_LOCAL_HW_BREAKPOINT_ADDR select HAVE_IOREMAP_PROT select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 select HAVE_IRQ_TIME_ACCOUNTING diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h index db199d653dd1..bf65c7fffd99 100644 --- a/include/linux/hw_breakpoint.h +++ b/include/linux/hw_breakpoint.h @@ -81,6 +81,9 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, perf_overflow_handler_t triggered, void *context); +int modify_local_hw_breakpoint_addr(struct perf_event *bp, + unsigned long addr); + 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); @@ -124,6 +127,9 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, perf_overflow_handler_t triggered, void *context) { return NULL; } static inline int +modify_local_hw_breakpoint_addr(struct perf_event *bp, + unsigned long addr) { return -EOPNOTSUPP; } +static inline int register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } static inline void unregister_hw_breakpoint(struct perf_event *bp) { } static inline void diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index 789add0c185a..3c799c88160c 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -888,6 +888,41 @@ void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) } EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); +/** + * modify_local_hw_breakpoint_addr - update a local breakpoint address + * @bp: the hwbp perf event for this CPU + * @addr: the new address for @bp + * + * Update only the address of an installed breakpoint on the local CPU without + * releasing and reserving its hardware slot. The caller must update other CPUs. + * Return 0, or -EOPNOTSUPP if the architecture does not support this operation. + */ +#ifdef CONFIG_HAVE_MODIFY_LOCAL_HW_BREAKPOINT_ADDR +int modify_local_hw_breakpoint_addr(struct perf_event *bp, + unsigned long addr) +{ + int ret; + + lockdep_assert_irqs_disabled(); + + ret = arch_modify_local_hw_breakpoint_addr(bp, addr); + if (ret) + return ret; + + counter_arch_bp(bp)->address = addr; + bp->attr.bp_addr = addr; + + return 0; +} +#else +int modify_local_hw_breakpoint_addr(struct perf_event *bp, + unsigned long addr) +{ + return -EOPNOTSUPP; +} +#endif +EXPORT_SYMBOL_GPL(modify_local_hw_breakpoint_addr); + /** * hw_breakpoint_is_used - check if breakpoints are currently used *