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Peter Anvin" , x86@kernel.org, Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Mathieu Desnoyers , David Hildenbrand , Jonathan Corbet , Matthew Wilcox , Alan Stern , Randy Dunlap , Alexander Potapenko , Marco Elver , Mike Rapoport , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-doc@vger.kernel.org, Jinchao Wang Subject: [RFC PATCH v2 01/13] arch: add HAVE_REINSTALL_HW_BREAKPOINT Date: Fri, 17 Jul 2026 09:02:27 -0400 Message-ID: <20260717130227.1901488-1-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260717125023.1895892-1-wangjinchao600@gmail.com> References: <20260717125023.1895892-1-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: 8bit Some architectures can update the address, length or type of an installed hardware breakpoint in place, without releasing and re-reserving its slot. Add an opt-in Kconfig symbol so generic code can offer such an operation on architectures that implement arch_reinstall_hw_breakpoint(). This is a prerequisite for KWatch, which re-points preallocated per-CPU breakpoints from atomic context, where the register/release path (which may sleep and rebalances slot constraints) cannot be used. Signed-off-by: Jinchao Wang --- arch/Kconfig | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index fa7507ac8e13..41b3784e0ddd 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -457,6 +457,16 @@ config HAVE_MIXED_BREAKPOINTS_REGS Select this option if your arch implements breakpoints under the latter fashion. +config HAVE_REINSTALL_HW_BREAKPOINT + bool + depends on HAVE_HW_BREAKPOINT + help + Depending on the arch implementation of hardware breakpoints, + some of them are able to update the breakpoint configuration + without release and reserve the hardware breakpoint register. + What configuration is able to update depends on hardware and + software implementation. + config HAVE_USER_RETURN_NOTIFIER bool -- 2.53.0