diff mbox

drm/udl: Fix unaligned memory access in udl_render_hline

Message ID 20170407200229.20642-1-j.neuschaefer@gmx.net (mailing list archive)
State New, archived
Headers show

Commit Message

Jonathan Neuschäfer April 7, 2017, 8:02 p.m. UTC 
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 Neuschäfer <j.neuschaefer@gmx.net>
---
 drivers/gpu/drm/udl/udl_transfer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Sean Paul April 11, 2017, 1:30 p.m. UTC | #1 
On Fri, Apr 07, 2017 at 10:02:29PM +0200, Jonathan Neuschäfer wrote:
> 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.
> 

Pushed to drm-misc-fixes with Dave's IRC Ack.

Thanks,

Sean

> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> ---
>  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
Jonathan Neuschäfer April 11, 2017, 3:34 p.m. UTC | #2 
On Tue, Apr 11, 2017 at 09:30:53AM -0400, Sean Paul wrote:
> On Fri, Apr 07, 2017 at 10:02:29PM +0200, Jonathan Neuschäfer wrote:
> > 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.
> > 
> 
> Pushed to drm-misc-fixes with Dave's IRC Ack.
> 
> Thanks,
> 
> Sean

Thanks as well :-)


Jonathan
diff mbox

Patch

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;