From mboxrd@z Thu Jan 1 00:00:00 1970 From: York Sun Date: Mon, 16 Nov 2015 09:24:11 -0800 Subject: [U-Boot] [PATCH v4 1/2] Reserve secure memory In-Reply-To: <1447693914.7686.84.camel@infinera.com> References: <1447691693-20318-1-git-send-email-yorksun@freescale.com> <1447691693-20318-2-git-send-email-yorksun@freescale.com> <1447693914.7686.84.camel@infinera.com> Message-ID: <564A113B.4090709@freescale.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 11/16/2015 09:11 AM, Joakim Tjernlund wrote: > On Mon, 2015-11-16 at 08:34 -0800, York Sun wrote: >> Secure memory is at the end of memory, separated and reserved >> from OS, tracked by gd->secure_ram. Secure memory can host >> MMU tables, security monitor, etc. > > Don't see the difference with pram here? > Also, do you really wan't to hide the memory from Linux or will > a resv map do? You get a lot of small TLB maps if memory is non power of 2 > Jocke, It is different from pram. First, it is at the end of memory, not the top of u-boot memory. The difference is where u-boot runs in memory. Second, the size is much bigger, even this patch doesn't limit the size. In my system, I reserve 2MB memory. Since we already have CONFIG_SYS_MEM_TOP_HIDE, I think it is a good way to reserve big chunk of memory without fragmentation. In my system, the end of usable memory is aligned with 512MB. York