[PATCH 3/8] drm/xen-front: fix 32-bit build warning

Arnd Bergmann arnd at arndb.de
Fri May 25 15:50:10 UTC 2018

In 32-bit kernel builds, we cannot cast between a pointer and a 64-bit

In file included from drivers/gpu/drm/xen/xen_drm_front_cfg.c:18:
drivers/gpu/drm/xen/xen_drm_front.h: In function 'xen_drm_front_fb_to_cookie':
drivers/gpu/drm/xen/xen_drm_front.h:129:9: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
  return (u64)fb;

drivers/gpu/drm/xen/xen_drm_front.h: In function 'xen_drm_front_dbuf_to_cookie':
drivers/gpu/drm/xen/xen_drm_front.h:134:9: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
  return (u64)gem_obj;

drivers/gpu/drm/xen/xen_drm_front_shbuf.c: In function 'backend_unmap':
drivers/gpu/drm/xen/xen_drm_front_shbuf.c:125:4: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]

Using uintptr_t instead probably does what we want here, although it's
not clear to me why we assign a virtual address pointer to a phys_addr_t
in backend_unmap().

Fixes: c575b7eeb89f ("drm/xen-front: Add support for Xen PV display frontend")
Signed-off-by: Arnd Bergmann <arnd at arndb.de>
 drivers/gpu/drm/xen/xen_drm_front.h       | 4 ++--
 drivers/gpu/drm/xen/xen_drm_front_shbuf.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xen/xen_drm_front.h b/drivers/gpu/drm/xen/xen_drm_front.h
index 2c2479b571ae..5693b4a4b02b 100644
--- a/drivers/gpu/drm/xen/xen_drm_front.h
+++ b/drivers/gpu/drm/xen/xen_drm_front.h
@@ -126,12 +126,12 @@ struct xen_drm_front_drm_info {
 static inline u64 xen_drm_front_fb_to_cookie(struct drm_framebuffer *fb)
-	return (u64)fb;
+	return (uintptr_t)fb;
 static inline u64 xen_drm_front_dbuf_to_cookie(struct drm_gem_object *gem_obj)
-	return (u64)gem_obj;
+	return (uintptr_t)gem_obj;
 int xen_drm_front_mode_set(struct xen_drm_front_drm_pipeline *pipeline,
diff --git a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c b/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
index 8099cb343ae3..d333b67cc1a0 100644
--- a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
+++ b/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
@@ -122,7 +122,7 @@ static void guest_calc_num_grefs(struct xen_drm_front_shbuf *buf)
 #define xen_page_to_vaddr(page) \
-		((phys_addr_t)pfn_to_kaddr(page_to_xen_pfn(page)))
+		((uintptr_t)pfn_to_kaddr(page_to_xen_pfn(page)))
 static int backend_unmap(struct xen_drm_front_shbuf *buf)

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