From: Linas Vepstas <linas@linas.org>
Date: Fri, 4 Nov 2005 00:55:14 +0000 (-0600)
Subject: [PATCH] powerpc: IOMMU: don't ioremap null addresses
X-Git-Tag: v2.6.16-rc1~473^2~8
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d177c207ba16b1db31283e2d1fee7ad4a863584b;p=linux-2.6

[PATCH] powerpc: IOMMU: don't ioremap null addresses

240-ioremap-null-ptr-test.patch

Under highly unusual circumstances, a buggy driver will ask a null ptr
to be ioremapped, an operation that curently succeeds but leads to
later trouble.  Instead, refuse to remap the null pointer.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
(cherry picked from e71d9e598533c1889e7162f5f4647e5d378c102c commit)
---

diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 2ffca63602..7b278d8373 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -174,7 +174,7 @@ void __iomem * __ioremap(unsigned long addr, unsigned long size,
 	pa = addr & PAGE_MASK;
 	size = PAGE_ALIGN(addr + size) - pa;
 
-	if (size == 0)
+	if ((size == 0) || (pa == 0))
 		return NULL;
 
 	if (mem_init_done) {