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 1FB083B9D8B; Fri, 17 Jul 2026 07:59:54 +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=1784275196; cv=none; b=JgD/MJyKGtaX2ES0EFmZH2JjyO+mQQRiuNYA7GkOYQzhpYTczfcC+bkp5jpiBsIEjJINH/u2ZUmXGxniVzuYMMGUt4zmUzHbF0f22+Bf0WTM/fq0dHQUSphy2toLLKwtZzAZRzcKQEOFve3oIThf3+gcVgDa7GJaTemJfsN8+u4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784275196; c=relaxed/simple; bh=p5KCq4YPqauwiaiW8FyFswJzNFmBVRMt0L7Ku04ENt4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=No50agK1V5STr/eY6V1ayL2Boj4zUvsMx1GZObAkOxhHNhjy6UTG5zshdlBfbKRdLdmKNzMPCZPvw4wMxUDcTMrH+WyY2REM4k1nnSkNUwKDyixiGjNQ1q7DZD5lTNlp4EhYxgVgwKgKQGQx3yRMbWW4FqQuglbLO60lnjmAXC4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eA++MPQX; 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="eA++MPQX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9096D1F00A3D; Fri, 17 Jul 2026 07:59:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784275194; bh=61klz7YZTbndUJ+37lArltjTGqnZ+fmF1mrEjf6lblo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=eA++MPQXhcVWV9UuUluILHip3YSIyWjYLItCHZpI3xhcGbENPXF6IL+lP1pVdX9qj ls3g/sDV1Ok4sPkQbERGy+FWITnU5JUvhFjax8vMACNVMWjo0O6QrFOdEvqBL9Lwyh 7S1HsRN9xmvBzSNJvzsZBht2Hb+c0hS+S/6m/qQ6ovFtLbGvK6ZPn9cBVq2+d74d2L 1SXlZntqe4Dgi+lYoGDjMlLUplqIxqz0ydLq5ZUsSH9Gbmf/JfX66ysL2Erkh029Zm +d2XU1mxUTWxwhBu0ee/cz+ATruOV3Z7M9mBimdDZFklU0lqENO0P2ydW7LtRnuZql 0VcqgNqBVUGCQ== Date: Fri, 17 Jul 2026 07:59:51 +0000 From: Tzung-Bi Shih To: Hsin-Te Yuan Cc: Brian Norris , Julius Werner , chrome-platform@lists.linux.dev, linux-kernel@vger.kernel.org, Yidi Lin Subject: Re: [PATCH] firmware: google: coreboot_table: skip no-map CBMEM entries Message-ID: References: <20260714-coreboot-v1-1-f59754d71b55@chromium.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Jul 17, 2026 at 03:23:30PM +0800, Hsin-Te Yuan wrote: > On Thu, Jul 16, 2026 at 3:44 PM Tzung-Bi Shih wrote: > > > > On Tue, Jul 14, 2026 at 09:19:18AM +0000, Hsin-Te Yuan wrote: > > > @@ -147,6 +149,23 @@ static int coreboot_table_populate(struct device *dev, void *ptr, resource_size_ > > > > > > switch (device->entry.tag) { > > > case LB_TAG_CBMEM_ENTRY: > > > + /* > > > + * Skip entries that are not exclusively System RAM or > > > + * Reserved memory. > > > + * On ARM, no-map reserved regions are not System RAM. To be specific, On ARM, no-map reserved regions are IORESOURCE_MEM. > > > + * On x86, CBMEM often resides in IORES_DESC_RESERVED regions. > > > + */ > > > + if (region_intersects(device->cbmem_entry.address, > > > + device->cbmem_entry.entry_size, > > > + IORESOURCE_SYSTEM_RAM, > > > + IORES_DESC_NONE) != REGION_INTERSECTS && > > > + region_intersects(device->cbmem_entry.address, > > > + device->cbmem_entry.entry_size, > > > + IORESOURCE_MEM, > > > + IORES_DESC_RESERVED) != REGION_INTERSECTS) { > > > > Per comments of region_intersects(): > > Note that REGION_INTERSECTS is also returned in the case when the > > specified region overlaps RAM and undefined memory holes. > > > > Won't the check falsely be bypassed if the region overlaps SYSTEM_RAM > > and `no-map` memory? > > Just discussed this with Yidi Lin. > It seems that 'no-map' region will be marked as IORESOURCE_MEM instead > of undefined memory holes > (See arch/arm64/kernel/setup.c:request_standard_resources). If a cbmem > entry contains a real memory > hole, it is likely a coreboot bug. I see. Please rephrase the commit message and code comment to be clear. E.g.: 1. On ARM64, no-map regions are filtered out as they are IORESOURCE_MEM (See arch/arm64/kernel/setup.c:request_standard_resources). 2. On X86, standard reserved regions (IORES_DESC_RESERVED) ... 3. Mixed regions containing holes are safely skipped. Remove it as this is inaccurate (the patch can't skip holes).