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[104.155.91.135]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6a67f8b47f7sm2104420a12.9.2026.09.03.03.03.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2026 03:03:16 -0700 (PDT) Date: Thu, 3 Sep 2026 11:03:12 +0100 From: Vincent Donnefort To: Rob Herring Cc: catalin.marinas@arm.com, will@kernel.org, rppt@kernel.org, akpm@linux-foundation.org, sudeep.holla@kernel.org, jenswi@kernel.org, mark.rutland@arm.com, sumit.garg@kernel.org, ardb@kernel.org, thierry.reding@kernel.org, david@kernel.org, danielmentz@google.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 02/10] of: reserved_mem: Introduce "ll-map" property Message-ID: References: <20260902104712.2399797-1-vdonnefort@google.com> <20260902104712.2399797-3-vdonnefort@google.com> <20260902172436.GB1440252-robh@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260902172436.GB1440252-robh@kernel.org> On Wed, Sep 02, 2026 at 12:24:36PM -0500, Rob Herring wrote: > On Wed, Sep 02, 2026 at 11:47:04AM +0100, Vincent Donnefort wrote: > > Keeping last-level mappings is interesting on some architectures as it > > allows mapping/unmapping pages from the kernel direct map without the > > risk of splitting blocks which, under the break-before-make rule, may > > trigger page-faults the kernel can't handle. > > > > Add an "ll-map" property for reserved-memory regions. When set, it > > splits the underlying memblock and sets the MEMBLOCK_LLMAP flag. > > Where is this documented? Any DT property must have a schema. Ack. > > Though I'm not thrilled about more flag properties. Handling all the > combinations of properties has proven to be painful. Can this be implied > from the compatible string instead? > > Rob We need this before the kernel direct map has been created (paging_init()). I would have moved that directly into the driver lend_pool.c, but then it is probed too late (unflatten_device_tree()). -- Vincent