[PATCH v13 15/20] drm/radeon, arm64: untag user pointers in radeon_ttm_tt_pin_userptr

[Catalin Marinas]

On Wed, Mar 20, 2019 at 03:51:29PM +0100, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> radeon_ttm_tt_pin_userptr() uses provided user pointers for vma
> lookups, which can only by done with untagged pointers.
> 
> Untag user pointers in this function.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
> ---
>  drivers/gpu/drm/radeon/radeon_ttm.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
> index 9920a6fc11bf..872a98796117 100644
> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
> @@ -497,9 +497,10 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
>  	if (gtt->userflags & RADEON_GEM_USERPTR_ANONONLY) {
>  		/* check that we only pin down anonymous memory
>  		   to prevent problems with writeback */
> -		unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE;
> +		unsigned long userptr = untagged_addr(gtt->userptr);
> +		unsigned long end = userptr + ttm->num_pages * PAGE_SIZE;
>  		struct vm_area_struct *vma;
> -		vma = find_vma(gtt->usermm, gtt->userptr);
> +		vma = find_vma(gtt->usermm, userptr);
>  		if (!vma || vma->vm_file || vma->vm_end < end)
>  			return -EPERM;
>  	}

Same comment as on the previous patch.

-- 
Catalin