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authorPaul Burton <paul.burton@imgtec.com>2016-09-23 16:38:27 +0100
committerRalf Baechle <ralf@linux-mips.org>2017-01-03 16:34:48 +0100
commitde96ec2a77c6d06a423c2c495bb4a2f4299f3d9e (patch)
treee56858634ec3b7e00fd0050fc084d3708b113f10
parent5c01918068ecc673dcea265e71ad95f949f28e2d (diff)
downloadlinux-de96ec2a77c6d06a423c2c495bb4a2f4299f3d9e.tar.bz2
OF: Prevent unaligned access in of_alias_scan()
When allocating a struct alias_prop, of_alias_scan() only requested that it be aligned on a 4 byte boundary. The struct contains pointers which leads to us attempting 64 bit writes on 64 bit systems, and if the CPU doesn't support unaligned memory accesses then this causes problems - for example on some MIPS64r2 CPUs including the "mips64r2-generic" QEMU emulated CPU it will trigger an address error exception. Fix this by requesting alignment for the struct alias_prop allocation matching that which the compiler expects, using the __alignof__ keyword. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Acked-by: Rob Herring <robh@kernel.org> Reviewed-by: Grant Likely <grant.likely@secretlab.ca> Cc: Frank Rowand <frowand.list@gmail.com> Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14306/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--drivers/of/base.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c
index d4bea3c797d6..84cf2f3f396c 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2112,7 +2112,7 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
continue;
/* Allocate an alias_prop with enough space for the stem */
- ap = dt_alloc(sizeof(*ap) + len + 1, 4);
+ ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
if (!ap)
continue;
memset(ap, 0, sizeof(*ap) + len + 1);