From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAF2FC4332F for ; Tue, 11 Jan 2022 10:32:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E6FD26B0072; Tue, 11 Jan 2022 05:32:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E1F626B0073; Tue, 11 Jan 2022 05:32:10 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D0E8D6B0074; Tue, 11 Jan 2022 05:32:10 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0106.hostedemail.com [216.40.44.106]) by kanga.kvack.org (Postfix) with ESMTP id C06726B0072 for ; Tue, 11 Jan 2022 05:32:10 -0500 (EST) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 71DF992DE8 for ; Tue, 11 Jan 2022 10:32:10 +0000 (UTC) X-FDA: 79017641220.31.D449BEA Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf31.hostedemail.com (Postfix) with ESMTP id E98BC2000A for ; Tue, 11 Jan 2022 10:32:09 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 11CD861575; Tue, 11 Jan 2022 10:32:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A36BC36AE9; Tue, 11 Jan 2022 10:32:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641897128; bh=0rqIA4/jVYclQqB4xsgy2sHCQiJcK7V1GCT/RCzcwNA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GiO8Clp3cKZA4rIZp4mXsEZtFZFQIjGujQZVsgjW3KUTthAM6Og1vdB3sEDH7qcmN MIGhdJ+XFMo+Xg0jLuDpHnErkwvpSy67p/5UXrlZyHO+b74FlJL2hiPML5ZYg+vf8/ lGVi59S8akIRZPOpWFM7t9O1oUgnVqbuGgqRVPpxImW6qEFwAzqxvlTNAXseGOKGPa izbV7cKz0VTB4NWpjIx+mayXjchu19ZHo5ODX54W1eWwi2mKJwW94XmnJ21tmy4sQF BpyMsLHetjLj2AEGd9fmnUy1DjGjWtNTvqWy4yCMJKaOad/v4Rvlws90muDMMF0lE3 n4uyyryvSmreQ== Date: Tue, 11 Jan 2022 12:31:58 +0200 From: Mike Rapoport To: Frank van der Linden Cc: linux-arm-kernel@lists.infradead.org, robh+dt@kernel.org, frowand.list@gmail.com, ardb@kernel.org, linux-mm@kvack.org, devicetree@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, geert+renesas@glider.be Subject: Re: [PATCH 1/3] memblock: define functions to set the usable memory range Message-ID: References: <20220110210809.3528-1-fllinden@amazon.com> <20220110210809.3528-2-fllinden@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220110210809.3528-2-fllinden@amazon.com> X-Rspamd-Queue-Id: E98BC2000A X-Stat-Signature: z4rp9nmzrsqccdjsm1pw5ajfgmweix4z Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=GiO8Clp3; spf=pass (imf31.hostedemail.com: domain of rppt@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam07 X-HE-Tag: 1641897129-690335 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jan 10, 2022 at 09:08:07PM +0000, Frank van der Linden wrote: > Some architectures might limit the usable memory range based > on a firmware property, like "linux,usable-memory-range" > for ARM crash kernels. This limit needs to be enforced after > firmware memory map processing has been done, which might be > e.g. FDT or EFI, or both. > > Define an interface for it that is firmware type agnostic. > > Signed-off-by: Frank van der Linden > --- > include/linux/memblock.h | 2 ++ > mm/memblock.c | 37 +++++++++++++++++++++++++++++++++++++ > 2 files changed, 39 insertions(+) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 34de69b3b8ba..6128efa50d33 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -481,6 +481,8 @@ phys_addr_t memblock_reserved_size(void); > phys_addr_t memblock_start_of_DRAM(void); > phys_addr_t memblock_end_of_DRAM(void); > void memblock_enforce_memory_limit(phys_addr_t memory_limit); > +void memblock_set_usable_range(phys_addr_t base, phys_addr_t size); > +void memblock_enforce_usable_range(void); > void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size); > void memblock_mem_limit_remove_map(phys_addr_t limit); We already have 3 very similar interfaces that deal with memory capping. Now you suggest to add fourth that will "generically" solve a single use case of DT, EFI and kdump interaction on arm64. Looks like a workaround for a fundamental issue of incompatibility between DT and EFI wrt memory registration. > bool memblock_is_memory(phys_addr_t addr); > diff --git a/mm/memblock.c b/mm/memblock.c > index 5096500b2647..cb961965f3ad 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -101,6 +101,7 @@ unsigned long max_low_pfn; > unsigned long min_low_pfn; > unsigned long max_pfn; > unsigned long long max_possible_pfn; > +phys_addr_t usable_start, usable_size; > > static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock; > static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_RESERVED_REGIONS] __initdata_memblock; > @@ -1715,6 +1716,42 @@ void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size) > base + size, PHYS_ADDR_MAX); > } > > +/** > + * memblock_set_usable_range - set usable memory range > + * @base: physical address that is the start of the range > + * @size: size of the range. > + * > + * Used when a firmware property limits the range of usable > + * memory, like for the linux,usable-memory-range property > + * used by ARM crash kernels. > + */ > +void __init memblock_set_usable_range(phys_addr_t base, phys_addr_t size) > +{ > + usable_start = base; > + usable_size = size; > +} > + > +/** > + * memblock_enforce_usable_range - cap memory ranges to usable range > + * > + * Some architectures call this during boot after firmware memory ranges > + * have been scanned, to make sure they fall within the usable range > + * set by memblock_set_usable_range. > + * > + * This may be called more than once if there are multiple firmware sources > + * for memory ranges. > + * > + * Avoid "no memory registered" warning - the warning itself is > + * useful, but we know this can be called with no registered > + * memory (e.g. when the synthetic DT for the crash kernel has > + * been parsed on EFI arm64 systems). > + */ > +void __init memblock_enforce_usable_range(void) > +{ > + if (memblock_memory->total_size) > + memblock_cap_memory_range(usable_start, usable_size); > +} > + > void __init memblock_mem_limit_remove_map(phys_addr_t limit) > { > phys_addr_t max_addr; > -- > 2.32.0 > -- Sincerely yours, Mike.