From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Deegan Subject: Re: [PATCH 4/7] arm: map device tree blob in initial page tables Date: Fri, 3 Feb 2012 21:18:36 +0000 Message-ID: <20120203211836.GD78380@ocelot.phlegethon.org> References: <1328296515-25876-1-git-send-email-david.vrabel@citrix.com> <1328296515-25876-5-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1328296515-25876-5-git-send-email-david.vrabel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: David Vrabel Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org At 19:15 +0000 on 03 Feb (1328296512), David Vrabel wrote: > From: David Vrabel > > Add a 1:1 mapping for the device tree blob in the initial page tables. > This will allow the DTB to be parsed for memory information prior to > setting up the real page tables. > > Signed-off-by: David Vrabel > --- > xen/arch/arm/head.S | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/xen/arch/arm/head.S b/xen/arch/arm/head.S > index 9951f37..8385481 100644 > --- a/xen/arch/arm/head.S > +++ b/xen/arch/arm/head.S > @@ -202,6 +202,11 @@ hyp: > add r4, r4, #8 > strd r2, r3, [r1, r4] /* Map it in the fixmap's slot */ > #endif > + mov r3, #0x0 > + orr r2, r8, #0xe00 > + orr r2, r2, #0x07d > + mov r4, r8, lsr #18 /* Slot for (r8 == atag_paddr) */ > + strd r2, r3, [r1, r4] /* Map DTB there */ It might be better to map the DTB at a fixed VA (say, the next second-level slot up from the fixmap one) so we don't have to worry about the DTB's PA clashing with Xen's VAs. Tim.