From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [Question] Memory attribute reserved by Device Tree? Date: Thu, 30 Jun 2016 12:39:03 +0100 Message-ID: <577504D7.7080106@arm.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Masahiro Yamada , linux-arm-kernel , devicetree@vger.kernel.org Cc: Mark Rutland List-Id: devicetree@vger.kernel.org On 30/06/16 12:10, Masahiro Yamada wrote: > Hello. > > Which memory attribute will ARM/ARM64 Linux > set to the memory region reserved by > /memreserve/ of Device Tree? > > > Normal memory non-cacheable? > Or, cacheable? > Or, not defined? > > Perhaps actual behavior depends on whether the reserved area is > located in the low-memory region? Isn't the point of memreserve that the kernel avoids mapping it at all? If a reserved region is later mapped in by a driver using dma_declare_coherent_memory(), ioremap(), memremap() or whatever else, then the attributes will vary depending on the exact method used. Robin. > > > Thanks, > >