drm/radeon: untag user pointers in radeon_gem_userptr_ioctl

This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.

In radeon_gem_userptr_ioctl() an MMU notifier is set up with a (tagged)
userspace pointer.  The untagged address should be used so that MMU
notifiers for the untagged address get correctly matched up with the right
BO.  This funcation also calls radeon_ttm_tt_pin_userptr(), which uses
provided user pointers for vma lookups, which can only by done with
untagged pointers.

This patch untags user pointers in radeon_gem_userptr_ioctl().

Link: http://lkml.kernel.org/r/c856babeb67195b35603b8d5ba386a2819cec5ff.1563904656.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <[email protected]>
Reviewed-by: Khalid Aziz <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Suggested-by: Felix Kuehling <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Eric Auger <[email protected]>
Cc: Jens Wiklander <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Vincenzo Frascino <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
index 4cf58dbbe439c0786678bed10457686eaabf3589..b2b076606f54bbc9240944b7ce4546f056780955 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -296,6 +296,8 @@ int radeon_gem_userptr_ioctl(struct drm_device *dev, void *data,
        uint32_t handle;
        int r;
 
+       args->addr = untagged_addr(args->addr);
+
        if (offset_in_page(args->addr | args->size))
                return -EINVAL;