From: Alan Cox <alan@redhat.com>
Date: Fri, 10 Oct 2008 09:46:45 +0000 (+0100)
Subject: x86, early_ioremap: fix fencepost error
X-Git-Tag: v2.6.28-rc1~703^2~1
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=c613ec1a7ff3714da11c7c48a13bab03beb5c376;p=linux-2.6-omap-h63xx.git

x86, early_ioremap: fix fencepost error

The x86 implementation of early_ioremap has an off by one error. If we get
an object which ends on the first byte of a page we undermap by one page and
this causes a crash on boot with the ASUS P5QL whose DMI table happens to fit
this alignment.

The size computation is currently

	last_addr = phys_addr + size - 1;
	npages = (PAGE_ALIGN(last_addr) - phys_addr)

(Consider a request for 1 byte at alignment 0...)

Closes #11693

Debugging work by Ian Campbell/Felix Geyer

Signed-off-by: Alan Cox <alan@rehat.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 6ab3196d12b..10b52309aef 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -614,7 +614,7 @@ void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
 	 */
 	offset = phys_addr & ~PAGE_MASK;
 	phys_addr &= PAGE_MASK;
-	size = PAGE_ALIGN(last_addr) - phys_addr;
+	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 
 	/*
 	 * Mappings have to fit in the FIX_BTMAP area.