Re: [PATCH v15 12/17] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl

[Kuehling, Felix]

On 2019-05-06 12:30 p.m., Andrey Konovalov wrote:
> [CAUTION: External Email]
>
> 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.
>
> 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().
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Acked-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>


> ---
>   drivers/gpu/drm/radeon/radeon_gem.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
> index 44617dec8183..90eb78fb5eb2 100644
> --- a/drivers/gpu/drm/radeon/radeon_gem.c
> +++ b/drivers/gpu/drm/radeon/radeon_gem.c
> @@ -291,6 +291,8 @@ 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;
>
> --
> 2.21.0.1020.gf2820cf01a-goog
>