[PATCH] drm/udl: Fix unaligned memory access in udl_render_hline

From: Jonathan NeuschÃfer
Date: Fri Apr 07 2017 - 16:03:43 EST


On SPARC, the udl driver filled my kernel log with these messages:

[186668.910612] Kernel unaligned access at TPC[76609c] udl_render_hline+0x13c/0x3a0

Use put_unaligned_be16 to avoid them. On x86 this results in the same
code, but on SPARC the compiler emits two single-byte stores.

Signed-off-by: Jonathan NeuschÃfer <j.neuschaefer@xxxxxxx>
---
drivers/gpu/drm/udl/udl_transfer.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/udl/udl_transfer.c b/drivers/gpu/drm/udl/udl_transfer.c
index 917dcb978c2c..0c87b1ac6b68 100644
--- a/drivers/gpu/drm/udl/udl_transfer.c
+++ b/drivers/gpu/drm/udl/udl_transfer.c
@@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <linux/fb.h>
#include <linux/prefetch.h>
+#include <asm/unaligned.h>

#include <drm/drmP.h>
#include "udl_drv.h"
@@ -163,7 +164,7 @@ static void udl_compress_hline16(
const u8 *const start = pixel;
const uint16_t repeating_pixel_val16 = pixel_val16;

- *(uint16_t *)cmd = cpu_to_be16(pixel_val16);
+ put_unaligned_be16(pixel_val16, cmd);

cmd += 2;
pixel += bpp;
--
2.11.0