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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2018-08-22 11:54:05 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2018-09-11 15:11:54 +0300 |
| commit | 6be8f3bd2c78915a9f3a058a346ae93068d35c01 (patch) | |
| tree | 79a2dabaeda21ce4a491778b76f0ed49736899f8 | |
| parent | da6c7707caf3736c1cf968606bd97c07e79625d4 (diff) | |
| download | linux-6be8f3bd2c78915a9f3a058a346ae93068d35c01.tar.xz | |
drm/fb: Stop leaking physical address
For buffer sharing, use dma-buf instead. We can't set smem_start to 0
unconditionally since that's used by the fbdev mmap default
implementation. And we have plenty of userspace which would like to
keep that working.
This might break legit userspace - if it does we need to look at a
case-by-cases basis how to handle that. Worst case I expect overrides
for only specific drivers, since anything remotely modern should be
using dma-buf/prime now (which is about 7 years old now for DRM
drivers).
This issue was uncovered because Noralf's rework to implement a
generic fb_probe also implements it's own fb_mmap callback. Which
means smem_start didn't have to be set anymore, which blew up some
blob in userspace rather badly.
Acked-by: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180822085405.10787-4-daniel.vetter@ffwll.ch
| -rw-r--r-- | drivers/gpu/drm/drm_fb_helper.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 73cf10adebbf..8e95d0f7c71d 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -2673,6 +2673,8 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper, info = fb_helper->fbdev; info->var.pixclock = 0; + /* don't leak any physical addresses to userspace */ + info->flags |= FBINFO_HIDE_SMEM_START; /* Need to drop locks to avoid recursive deadlock in * register_framebuffer. This is ok because the only thing left to do is |