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 4A6694C77D9; Mon, 7 Sep 2026 14:00:22 +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=1788789623; cv=none; b=NmYXEcAlLzCHIrG+YZzyIKx8ltrBh+MBWX3XPXVqCMPn37aBmvjgNt5yvG2UMEgdY8JP5hFJI77zb5Tz1d/uwW36a44vv1RN9gaXDahJaWpr335MeyYRrRFyABs9K/lQCGPRQlm6LHi8K8znrHIGeWC9h3+be9V6IaZpuBJxlwA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788789623; c=relaxed/simple; bh=EgLK3o+julTVE6C/8v3utQVcxVTdU7XWXdzws8YaC20=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rjS4YP3RasGJMMLDsHY7a/meNZrP4rH32NkA7BsxfE/NvafzDD7R3w9vBJ2TCL3htGXOY36S+fj9AQOnPUblyDWza9psWtHsc7n7zfAIIZ85yCDv85Jctlj41SC/ZPA3ppI9gZgC7hPWotTpzlmJS4lwontzWCbR7zS6oLeKbx4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gtOe0lI4; 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="gtOe0lI4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 985261F00A3D; Mon, 7 Sep 2026 14:00:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788789622; bh=EgLK3o+julTVE6C/8v3utQVcxVTdU7XWXdzws8YaC20=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=gtOe0lI4tICmFeXO0VXaSZWun1zD97NtGKzB00Fxz4Ka/Zpm56GHzGCFmpkzXvwya IjgdW5ASTJB+qKa5sg3xhHy+2z3Tif4EUzgG6v2G0AqXAMe/0BNO4ao6/A+PGKiEDt LiunuR042Q+3iJ1jf+LikMpBoAosls+iqBo1ld1uAEuNgD3FyixqBGd1NK8XwlELz8 0aXr47TpsMtDRS4WsQVvIrdjIekWTZVzwY14LA7ppw9cLIVA/gJznyINUg586mqoJr i4bMWj2QqqCUzgdxYWZPl2+vXlMSa8ApBf/xkklnj7o+nTfBb5pP16MUu53RogA7JW PhrukphYxcyLg== Date: Mon, 7 Sep 2026 16:00:19 +0200 From: Thierry Reding To: Vincent Donnefort Cc: Rob Herring , 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, 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: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="3ihzba4bzldpza5m" Content-Disposition: inline In-Reply-To: --3ihzba4bzldpza5m Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH v9 02/10] of: reserved_mem: Introduce "ll-map" property MIME-Version: 1.0 On Thu, Sep 03, 2026 at 11:03:12AM +0100, Vincent Donnefort wrote: > 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. > > >=20 > > > Add an "ll-map" property for reserved-memory regions. When set, it > > > splits the underlying memblock and sets the MEMBLOCK_LLMAP flag. > >=20 > > Where is this documented? Any DT property must have a schema. >=20 > Ack. >=20 > >=20 > > Though I'm not thrilled about more flag properties. Handling all the=20 > > combinations of properties has proven to be painful. Can this be implie= d=20 > > from the compatible string instead? > >=20 > > Rob >=20 > We need this before the kernel direct map has been created (paging_init()= ). >=20 > I would have moved that directly into the driver lend_pool.c, but then it= is > probed too late (unflatten_device_tree()). Any of the node_*() callbacks from struct reserved_mem_ops get called prior to paging_init(), so these could be used to manually set the memblock flags in the corresponding drivers. 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