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[91.12.110.251]) by smtp.gmail.com with ESMTPSA id z10sm4064342wrg.69.2020.04.11.02.58.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 11 Apr 2020 02:58:29 -0700 (PDT) From: David Hildenbrand Mime-Version: 1.0 (1.0) Subject: Re: [PATCH 1/3] kexec: Prevent removal of memory in use by a loaded kexec image Date: Sat, 11 Apr 2020 11:58:28 +0200 Message-Id: References: <20200411093009.GH25745@shell.armlinux.org.uk> Cc: Baoquan He , Andrew Morton , David Hildenbrand , Catalin Marinas , Bhupesh Sharma , Anshuman Khandual , kexec@lists.infradead.org, linux-mm@kvack.org, James Morse , Eric Biederman , Will Deacon , linux-arm-kernel@lists.infradead.org In-Reply-To: <20200411093009.GH25745@shell.armlinux.org.uk> To: Russell King - ARM Linux admin X-Mailer: iPhone Mail (17D50) X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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: > Am 11.04.2020 um 11:40 schrieb Russell King - ARM Linux admin : >=20 > =EF=BB=BFOn Sat, Apr 11, 2020 at 11:44:14AM +0800, Baoquan He wrote: >> Because We tend to use kexec_file_load more and improve/enhance it in th= e >> future, and gradually obsolete the old kexec_load interface which this >> patchset is trying to fix on.=20 >=20 > That's not going to happen; 32-bit ARM kexec uses the kexec_load > interface rather than the kexec_file_load version, and I see no one > with any interest in changing that - and there's users of the former. >=20 > I don't see how it's possible to convert 32-bit ARM kexec to the > kexec_file_load interface - this assumes that all you have are the > kernel, initrd, and commandline, but on 32-bit ARM kexec, we have > kernel, initrd and the dtb blob which the user can specify. >=20 > So, if we wanted to obsolete the kexec_load interface, _first_ there > needs to be a way to provide users with the existing functionality > they have already in place on 32-bit ARM - otherwise we're looking > at a userspace regression. Especially as kexec_file_load takes > precedence on some distro patched versions of the kexec tool, > irrespective of which interface the user requests of the tool. >=20 On 32bit architectures we usually don=E2=80=98t really care about memory ho= tplug. So we could deprecate it only for 64bit architectures AFAIKS. > --=20 > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbp= s up >=20