From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: Re: [PATCH v18 10/15] drm/radeon: untag user pointers in radeon_gem_userptr_ioctl Date: Mon, 24 Jun 2019 08:01:10 -0700 Message-ID: <201906240801.F35CE2641@keescook> References: <61d800c35a4f391218fbca6f05ec458557d8d097.1561386715.git.andreyknvl@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <61d800c35a4f391218fbca6f05ec458557d8d097.1561386715.git.andreyknvl@google.com> Sender: linux-kernel-owner@vger.kernel.org To: Andrey Konovalov Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, Catalin Marinas , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander List-Id: linux-rdma@vger.kernel.org On Mon, Jun 24, 2019 at 04:32:55PM +0200, Andrey Konovalov wrote: > 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(). > > Suggested-by: Felix Kuehling > Acked-by: Felix Kuehling > Signed-off-by: Andrey Konovalov Reviewed-by: Kees Cook -Kees > --- > 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; > > -- > 2.22.0.410.gd8fdbe21b5-goog > -- Kees Cook