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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 C3AE5C4167B for ; Thu, 10 Dec 2020 04:18:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 59BCD23A02 for ; Thu, 10 Dec 2020 04:18:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59BCD23A02 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 786446B0068; Wed, 9 Dec 2020 23:18:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 736406B006C; Wed, 9 Dec 2020 23:18:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5FD026B006E; Wed, 9 Dec 2020 23:18:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0123.hostedemail.com [216.40.44.123]) by kanga.kvack.org (Postfix) with ESMTP id 456A46B0068 for ; Wed, 9 Dec 2020 23:18:18 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0B931180AD815 for ; Thu, 10 Dec 2020 04:18:18 +0000 (UTC) X-FDA: 77576065476.11.tub31_2507599273f5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin11.hostedemail.com (Postfix) with ESMTP id D909D180F8B80 for ; Thu, 10 Dec 2020 04:18:17 +0000 (UTC) X-HE-Tag: tub31_2507599273f5 X-Filterd-Recvd-Size: 6316 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Thu, 10 Dec 2020 04:18:17 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 58E8631B; Wed, 9 Dec 2020 20:18:16 -0800 (PST) Received: from [10.163.83.83] (unknown [10.163.83.83]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 360093F66B; Wed, 9 Dec 2020 20:18:10 -0800 (PST) Subject: Re: [PATCH 3/3] s390/mm: Define arch_get_mappable_range() To: Heiko Carstens Cc: linux-mm@kvack.org, akpm@linux-foundation.org, david@redhat.com, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Vasily Gorbik , Will Deacon , Ard Biesheuvel , Mark Rutland References: <1607400978-31595-1-git-send-email-anshuman.khandual@arm.com> <1607400978-31595-4-git-send-email-anshuman.khandual@arm.com> <20201208152709.GA26979@osiris> <7484e153-6c77-8325-6195-621fe144011e@arm.com> <20201209145717.GD7160@osiris> From: Anshuman Khandual Message-ID: <04da0f9c-d50e-7729-5e4c-b0dc4e76d608@arm.com> Date: Thu, 10 Dec 2020 09:48:11 +0530 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: <20201209145717.GD7160@osiris> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 12/9/20 8:27 PM, Heiko Carstens wrote: > On Wed, Dec 09, 2020 at 08:07:04AM +0530, Anshuman Khandual wrote: >>>> + if (seg->end + 1 > VMEM_MAX_PHYS || seg->end + 1 < seg->start_addr) { >>>> + rc = -ERANGE; >>>> + goto out_resource; >>>> + } >>>> + > ... >>>> +struct range arch_get_mappable_range(void) >>>> +{ >>>> + struct range memhp_range; >>>> + >>>> + memhp_range.start = 0; >>>> + memhp_range.end = VMEM_MAX_PHYS; >>>> + return memhp_range; >>>> +} >>>> + >>>> int arch_add_memory(int nid, u64 start, u64 size, >>>> struct mhp_params *params) >>>> { >>>> @@ -291,6 +300,7 @@ int arch_add_memory(int nid, u64 start, u64 size, >>>> if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot)) >>>> return -EINVAL; >>>> >>>> + VM_BUG_ON(!memhp_range_allowed(start, size, 1)); >>>> rc = vmem_add_mapping(start, size); >>>> if (rc) >>> Is there a reason why you added the memhp_range_allowed() check call >>> to arch_add_memory() instead of vmem_add_mapping()? If you would do >> >> As I had mentioned previously, memhp_range_allowed() is available with >> CONFIG_MEMORY_HOTPLUG but vmem_add_mapping() is always available. Hence >> there will be a build failure in vmem_add_mapping() for the range check >> memhp_range_allowed() without memory hotplug enabled. >> >>> that, then the extra code in __segment_load() wouldn't be >>> required. >>> Even though the error message from memhp_range_allowed() might be >>> highly confusing. >> >> Alternatively leaving __segment_load() and vmem_add_memory() unchanged >> will create three range checks i.e two memhp_range_allowed() and the >> existing VMEM_MAX_PHYS check in vmem_add_mapping() on all the hotplug >> paths, which is not optimal. > > Ah, sorry. I didn't follow this discussion too closely. I just thought > my point of view would be clear: let's not have two different ways to > check for the same thing which must be kept in sync. > Therefore I was wondering why this next version is still doing > that. Please find a way to solve this. The following change is after the current series and should work with and without memory hotplug enabled. There will be just a single place i.e vmem_get_max_addr() to update in case the maximum address changes from VMEM_MAX_PHYS to something else later. diff --git a/arch/s390/include/asm/sections.h b/arch/s390/include/asm/sections.h index 0c21514..2da496f 100644 --- a/arch/s390/include/asm/sections.h +++ b/arch/s390/include/asm/sections.h @@ -16,6 +16,7 @@ static inline int arch_is_kernel_initmem_freed(unsigned long addr) addr < (unsigned long)__init_end; } +unsigned long vmem_get_max_addr(void); /* * .boot.data section contains variables "shared" between the decompressor and * the decompressed kernel. The decompressor will store values in them, and diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c index cc055a7..1bddd6f 100644 --- a/arch/s390/mm/extmem.c +++ b/arch/s390/mm/extmem.c @@ -28,6 +28,7 @@ #include #include #include +#include #define DCSS_PURGESEG 0x08 #define DCSS_LOADSHRX 0x20 @@ -287,6 +288,13 @@ segment_overlaps_others (struct dcss_segment *seg) return 0; } +static bool segment_outside_range(struct dcss_segment *seg) +{ + unsigned long max_addr = vmem_get_max_addr(); + + return (seg->end + 1 > max_addr || seg->end + 1 < seg->start_addr); +} + /* * real segment loading function, called from segment_load */ @@ -337,7 +345,7 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long goto out_free_resource; } - if (seg->end + 1 > VMEM_MAX_PHYS || seg->end + 1 < seg->start_addr) { + if (segment_outside_range(seg)) { rc = -ERANGE; goto out_resource; } diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 64937ba..5c6ee9f 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -283,7 +283,7 @@ struct range arch_get_mappable_range(void) struct range memhp_range; memhp_range.start = 0; - memhp_range.end = VMEM_MAX_PHYS; + memhp_range.end = vmem_get_max_addr(); return memhp_range; } diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index 749eab4..6044e85 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -532,6 +532,11 @@ void vmem_remove_mapping(unsigned long start, unsigned long size) mutex_unlock(&vmem_mutex); } +unsigned long vmem_get_max_addr(void) +{ + return VMEM_MAX_PHYS; +} + int vmem_add_mapping(unsigned long start, unsigned long size) { int ret; -- 2.7.4