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 X-Spam-Level: X-Spam-Status: No, score=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0C07C433DB for ; Thu, 28 Jan 2021 04:02:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3FE1B64DD6 for ; Thu, 28 Jan 2021 04:02:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FE1B64DD6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4DR6Hl1kD1zDqD1 for ; Thu, 28 Jan 2021 15:02:27 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.microsoft.com (client-ip=13.77.154.182; helo=linux.microsoft.com; envelope-from=nramas@linux.microsoft.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.a=rsa-sha256 header.s=default header.b=XjFkrXhH; dkim-atps=neutral Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lists.ozlabs.org (Postfix) with ESMTP id 4DR6Ff5LKYzDrBr for ; Thu, 28 Jan 2021 15:00:37 +1100 (AEDT) Received: from [192.168.0.104] (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 68AA620B7192; Wed, 27 Jan 2021 20:00:35 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 68AA620B7192 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1611806436; bh=j2ytaqRDLSxdVnbORmC1VmYaP/7+dbpAQywJI7b00gU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=XjFkrXhHnyR53rne7WHNJDhhws91IZ+fiKsrlIcQYw4OfuqWziuNTJejFWJTYWfsT ReANiquNaEdr2UmAt9OkF/LasShgVDZT0lsMWLATFdmIKswUBTiXWvyfHyzINMiQoG QWAg7xvg2QTc/vkCRwtttTKCyBKFBTiHrO28Yypo= Subject: Re: [PATCH v15 09/10] arm64: Call kmalloc() to allocate DTB buffer To: Thiago Jung Bauermann , Will Deacon References: <20210115173017.30617-1-nramas@linux.microsoft.com> <20210115173017.30617-10-nramas@linux.microsoft.com> <20210127165208.GA358@willie-the-truck> <20210127184319.GA676@willie-the-truck> <871re5soof.fsf@manicouagan.localdomain> From: Lakshmi Ramasubramanian Message-ID: <58d3ffbf-4d80-c893-34d6-366ebfac55bd@linux.microsoft.com> Date: Wed, 27 Jan 2021 20:00:34 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <871re5soof.fsf@manicouagan.localdomain> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, bhsharma@redhat.com, tao.li@vivo.com, zohar@linux.ibm.com, paulus@samba.org, vincenzo.frascino@arm.com, frowand.list@gmail.com, sashal@kernel.org, robh@kernel.org, masahiroy@kernel.org, jmorris@namei.org, takahiro.akashi@linaro.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, serge@hallyn.com, devicetree@vger.kernel.org, pasha.tatashin@soleen.com, prsriva@linux.microsoft.com, hsinyi@chromium.org, allison@lohutok.net, christophe.leroy@c-s.fr, mbrugger@suse.com, balajib@linux.microsoft.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, james.morse@arm.com, dmitry.kasatkin@gmail.com, linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 1/27/21 7:52 PM, Thiago Jung Bauermann wrote: > > Will Deacon writes: > >> On Wed, Jan 27, 2021 at 09:59:38AM -0800, Lakshmi Ramasubramanian wrote: >>> On 1/27/21 8:52 AM, Will Deacon wrote: >>> >>> Hi Will, >>> >>>> On Fri, Jan 15, 2021 at 09:30:16AM -0800, Lakshmi Ramasubramanian wrote: >>>>> create_dtb() function allocates kernel virtual memory for >>>>> the device tree blob (DTB). This is not consistent with other >>>>> architectures, such as powerpc, which calls kmalloc() for allocating >>>>> memory for the DTB. >>>>> >>>>> Call kmalloc() to allocate memory for the DTB, and kfree() to free >>>>> the allocated memory. >>>>> >>>>> Co-developed-by: Prakhar Srivastava >>>>> Signed-off-by: Prakhar Srivastava >>>>> Signed-off-by: Lakshmi Ramasubramanian >>>>> --- >>>>> arch/arm64/kernel/machine_kexec_file.c | 12 +++++++----- >>>>> 1 file changed, 7 insertions(+), 5 deletions(-) >>>>> >>>>> diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c >>>>> index 7de9c47dee7c..51c40143d6fa 100644 >>>>> --- a/arch/arm64/kernel/machine_kexec_file.c >>>>> +++ b/arch/arm64/kernel/machine_kexec_file.c >>>>> @@ -29,7 +29,7 @@ const struct kexec_file_ops * const kexec_file_loaders[] = { >>>>> int arch_kimage_file_post_load_cleanup(struct kimage *image) >>>>> { >>>>> - vfree(image->arch.dtb); >>>>> + kfree(image->arch.dtb); >>>>> image->arch.dtb = NULL; >>>>> vfree(image->arch.elf_headers); >>>>> @@ -59,19 +59,21 @@ static int create_dtb(struct kimage *image, >>>>> + cmdline_len + DTB_EXTRA_SPACE; >>>>> for (;;) { >>>>> - buf = vmalloc(buf_size); >>>>> + buf = kmalloc(buf_size, GFP_KERNEL); >>>> >>>> Is there a functional need for this patch? I build the 'dtbs' target just >>>> now and sdm845-db845c.dtb is approaching 100K, which feels quite large >>>> for kmalloc(). >>> >>> Changing the allocation from vmalloc() to kmalloc() would help us further >>> consolidate the DTB setup code for powerpc and arm64. >> >> Ok, but at the risk of allocation failure. Can powerpc use vmalloc() >> instead? > > I believe this patch stems from this suggestion by Rob Herring: > >> This could be taken a step further and do the allocation of the new >> FDT. The difference is arm64 uses vmalloc and powerpc uses kmalloc. The >> arm64 version also retries with a bigger allocation. That seems >> unnecessary. > > in https://lore.kernel.org/linux-integrity/20201211221006.1052453-3-robh@kernel.org/ > > The problem is that this patch implements only part of the suggestion, > which isn't useful in itself. So the patch series should either drop > this patch or consolidate the FDT allocation between the arches. > > I just tested on powernv and pseries platforms and powerpc can use > vmalloc for the FDT buffer. > Thanks for verifying on powerpc platform Thiago. I'll update the patch to do the following: => Use vmalloc for FDT buffer allocation on powerpc => Keep vmalloc for arm64, but remove the retry on allocation. => Also, there was a memory leak of FDT buffer in the error code path on arm64, which I'll fix as well. Did I miss anything? thanks, -lakshmi