From mboxrd@z Thu Jan 1 00:00:00 1970 From: panand@redhat.com (Pratyush Anand) Date: Wed, 23 Nov 2016 07:16:26 +0530 Subject: [PATCH 2/2] arm64: Pass RAM boundary and enable-dcache flag to purgatory In-Reply-To: <53ee2a62-7822-5457-e59f-e65e64a57019@infradead.org> References: <53ee2a62-7822-5457-e59f-e65e64a57019@infradead.org> Message-ID: <54cad725-90f0-8dfe-bee6-fe1d3e02175d@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Geoff, On Wednesday 23 November 2016 12:27 AM, Geoff Levand wrote: > Hi Pratyush, > > On 11/21/2016 08:32 PM, Pratyush Anand wrote: >> When "enable-dcache" is passed to the kexec() command line, kexec-tools >> passes this information to purgatory, which in turn enables cache during >> sha-256 verification. > > What's the point of this enable-dcache option? Why not just > always enable the cache if we can? As I have written in changelog of patch 1/2 "We are supporting only 4K and 64K page sizes. This code will not work if a hardware is not supporting at least one of these page sizes. Therefore, D-cache is disabled by default and enabled only when "enable-dcache" is passed to the kexec()." Although this is very unlikely that a hardware will support only 16K page sizes, however it is possible. Therefore, its better to keep it disabled by default. ~Pratyush