| Message ID | 1396603322-13585-1-git-send-email-djkurtz@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 4 Apr 2014 17:22:01 +0800 Daniel Kurtz <djkurtz@chromium.org> wrote: > Kernel access to the eyxnos fbdev framebuffer is via its gem object's > kernel mapping (kvaddr, stored in info->screen_base). > > User space access is provided by mmap(), read() and write() of /dev/fb/fb0. > These functions also only use screen_base/screen_size(). > > Therefore, it is not necessary to set fix->smem_{start,len} or > fix->mmio_{start,len} fields. > > This avoids leaking kernel, physical and dma mapped addresses to user > space via the ioctls FBIOGET_VSCREENINFO and FBIOGET_FSCREENINFO. > > Signed-off-by: Daniel Kurtz <djkurtz@chromium.org> > --- > drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > index 5fa342e..2dcc589 100644 > --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > @@ -123,14 +123,7 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper, > > dev->mode_config.fb_base = (resource_size_t)buffer->dma_addr; > fbi->screen_base = buffer->kvaddr + offset; > - if (is_drm_iommu_supported(dev)) > - fbi->fix.smem_start = (unsigned long) > - (page_to_phys(sg_page(buffer->sgt->sgl)) + offset); > - else > - fbi->fix.smem_start = (unsigned long)buffer->dma_addr; > - > fbi->screen_size = size; > - fbi->fix.smem_len = size; Can we keep proper initialization of 'smem_len'? Some userland applications use it for calculating the size for mmap: http://cgit.freedesktop.org/xorg/xserver/tree/hw/xfree86/fbdevhw/fbdevhw.c?id=xorg-server-1.15.99.903#n571 > > return 0; > } Basically, this patch breaks the xf86-video-fbdev ddx and some users are already unhappy.
On Fri, Jun 20, 2014 at 7:59 AM, Siarhei Siamashka <siarhei.siamashka@gmail.com> wrote: > > On Fri, 4 Apr 2014 17:22:01 +0800 > Daniel Kurtz <djkurtz@chromium.org> wrote: > > > Kernel access to the eyxnos fbdev framebuffer is via its gem object's > > kernel mapping (kvaddr, stored in info->screen_base). > > > > User space access is provided by mmap(), read() and write() of /dev/fb/fb0. > > These functions also only use screen_base/screen_size(). > > > > Therefore, it is not necessary to set fix->smem_{start,len} or > > fix->mmio_{start,len} fields. > > > > This avoids leaking kernel, physical and dma mapped addresses to user > > space via the ioctls FBIOGET_VSCREENINFO and FBIOGET_FSCREENINFO. > > > > Signed-off-by: Daniel Kurtz <djkurtz@chromium.org> > > --- > > drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 7 ------- > > 1 file changed, 7 deletions(-) > > > > diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > > index 5fa342e..2dcc589 100644 > > --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > > +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > > @@ -123,14 +123,7 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper, > > > > dev->mode_config.fb_base = (resource_size_t)buffer->dma_addr; > > fbi->screen_base = buffer->kvaddr + offset; > > - if (is_drm_iommu_supported(dev)) > > - fbi->fix.smem_start = (unsigned long) > > - (page_to_phys(sg_page(buffer->sgt->sgl)) + offset); > > - else > > - fbi->fix.smem_start = (unsigned long)buffer->dma_addr; > > - > > fbi->screen_size = size; > > - fbi->fix.smem_len = size; > > Can we keep proper initialization of 'smem_len'? Some userland > applications use it for calculating the size for mmap: > > http://cgit.freedesktop.org/xorg/xserver/tree/hw/xfree86/fbdevhw/fbdevhw.c?id=xorg-server-1.15.99.903#n571 > > > > > return 0; > > } > > Basically, this patch breaks the xf86-video-fbdev ddx and some users > are already unhappy. I'm so sorry this patch broke things for some users. Can you upload a patch to correct it? I'll happily review it. -djk > > > -- > Best regards, > Siarhei Siamashka
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c index 5fa342e..2dcc589 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c @@ -123,14 +123,7 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper, dev->mode_config.fb_base = (resource_size_t)buffer->dma_addr; fbi->screen_base = buffer->kvaddr + offset; - if (is_drm_iommu_supported(dev)) - fbi->fix.smem_start = (unsigned long) - (page_to_phys(sg_page(buffer->sgt->sgl)) + offset); - else - fbi->fix.smem_start = (unsigned long)buffer->dma_addr; - fbi->screen_size = size; - fbi->fix.smem_len = size; return 0; }
Kernel access to the eyxnos fbdev framebuffer is via its gem object's kernel mapping (kvaddr, stored in info->screen_base). User space access is provided by mmap(), read() and write() of /dev/fb/fb0. These functions also only use screen_base/screen_size(). Therefore, it is not necessary to set fix->smem_{start,len} or fix->mmio_{start,len} fields. This avoids leaking kernel, physical and dma mapped addresses to user space via the ioctls FBIOGET_VSCREENINFO and FBIOGET_FSCREENINFO. Signed-off-by: Daniel Kurtz <djkurtz@chromium.org> --- drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 7 ------- 1 file changed, 7 deletions(-)