2015-12-21 18:54:18

by Borislav Petkov

Subject: [PATCH] drm, i915: Fix pointer size cast

From: Borislav Petkov <[email protected]>

gcc complains on 32-bit like this:

drivers/gpu/drm/i915/intel_display.c: In function ‘intel_plane_obj_offset’:
drivers/gpu/drm/i915/intel_display.c:2954:11: warning: cast to pointer from \
integer of different size [-Wint-to-pointer-cast]
offset = (unsigned char *)vma->node.start;
^

because vma->node.start is u64 but a pointer on 32-bit is 4 bytes.

Do the calculations with an unsigned long directly and save us the
casts.

Cc: Daniel Vetter <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: David Airlie <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Borislav Petkov <[email protected]>
---
drivers/gpu/drm/i915/intel_display.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 62211abe4922..640cb7c9b7f3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2941,7 +2941,7 @@ unsigned long intel_plane_obj_offset(struct intel_plane *intel_plane,
{
const struct i915_ggtt_view *view = &i915_ggtt_view_normal;
struct i915_vma *vma;
- unsigned char *offset;
+ unsigned long offset;

if (intel_rotation_90_or_270(intel_plane->base.state->rotation))
view = &i915_ggtt_view_rotated;
@@ -2951,14 +2951,14 @@ unsigned long intel_plane_obj_offset(struct intel_plane *intel_plane,
view->type))
return -1;

- offset = (unsigned char *)vma->node.start;
+ offset = vma->node.start;

if (plane == 1) {
offset += vma->ggtt_view.rotation_info.uv_start_page *
PAGE_SIZE;
}

- return (unsigned long)offset;
+ return offset;
}

static void skl_detach_scaler(struct intel_crtc *intel_crtc, int id)
--
2.3.5

2015-12-21 19:20:24

by Daniel Vetter

Subject: Re: [Intel-gfx] [PATCH] drm, i915: Fix pointer size cast

On Mon, Dec 21, 2015 at 07:53:59PM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <[email protected]>
>
> gcc complains on 32-bit like this:
>
> drivers/gpu/drm/i915/intel_display.c: In function ‘intel_plane_obj_offset’:
> drivers/gpu/drm/i915/intel_display.c:2954:11: warning: cast to pointer from \
> integer of different size [-Wint-to-pointer-cast]
> offset = (unsigned char *)vma->node.start;
> ^
>
> because vma->node.start is u64 but a pointer on 32-bit is 4 bytes.
>
> Do the calculations with an unsigned long directly and save us the
> casts.
>
> Cc: Daniel Vetter <[email protected]>
> Cc: Jani Nikula <[email protected]>
> Cc: David Airlie <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Borislav Petkov <[email protected]>

This has been fixed already in

commit 44eb0cb9620c6a53ec8e7073262e2af8079b727f
Author: Mika Kuoppala <[email protected]>
Date: Fri Oct 30 13:26:15 2015 +0200

drm/i915: Avoid pointer arithmetic in calculating plane surface offset

Cheers,
Daniel
> ---
> drivers/gpu/drm/i915/intel_display.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 62211abe4922..640cb7c9b7f3 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2941,7 +2941,7 @@ unsigned long intel_plane_obj_offset(struct intel_plane *intel_plane,
> {
> const struct i915_ggtt_view *view = &i915_ggtt_view_normal;
> struct i915_vma *vma;
> - unsigned char *offset;
> + unsigned long offset;
>
> if (intel_rotation_90_or_270(intel_plane->base.state->rotation))
> view = &i915_ggtt_view_rotated;
> @@ -2951,14 +2951,14 @@ unsigned long intel_plane_obj_offset(struct intel_plane *intel_plane,
> view->type))
> return -1;
>
> - offset = (unsigned char *)vma->node.start;
> + offset = vma->node.start;
>
> if (plane == 1) {
> offset += vma->ggtt_view.rotation_info.uv_start_page *
> PAGE_SIZE;
> }
>
> - return (unsigned long)offset;
> + return offset;
> }
>
> static void skl_detach_scaler(struct intel_crtc *intel_crtc, int id)
> --
> 2.3.5
>
> _______________________________________________
> Intel-gfx mailing list
> [email protected]
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch