From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 300A3CC6B34 for ; Thu, 15 Oct 2026 12:47:00 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7DDFE10E249; Thu, 15 Oct 2026 12:46:54 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id 09A8E10E257 for ; Thu, 15 Oct 2026 12:46:47 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2F2C514BF; Thu, 15 Oct 2026 05:46:44 -0700 (PDT) Received: from [10.0.129.161] (e122027.cambridge.arm.com [10.0.129.161]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 55F353F871; Thu, 15 Oct 2026 05:46:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1792068407; bh=MHqyqJ8nqxk2HWmhAAjqDD5cSOnfGjNnSG/JTJGDnto=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=s/ceTRPteRytnM2VUlFFpd3ajLmbf9y71fozwOhnWfl9d1peZZwdbWODz+wWdP4qQ IsiWzcmjk6b++lz8Gk76n+ZMIcTIA/P93lvj6klWQqIKiF+NyWLat507CUEhxpQF// 2Pt7jMrBcWUHXPyquAQ/APtA0UAWKt4FRZYyy41g= Message-ID: <2dffbbec-2702-45f3-a37e-c4c42553eca9@arm.com> Date: Thu, 15 Oct 2026 13:46:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] drm/panthor: Fix handling of NO_MMAP BOs To: Akash Goel , boris.brezillon@collabora.com, liviu.dudau@arm.com Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch, nd@arm.com References: <20261013125433.26432-1-akash.goel@arm.com> From: Steven Price Content-Language: en-GB In-Reply-To: <20261013125433.26432-1-akash.goel@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 13/10/2026 13:54, Akash Goel wrote: > The BOs created with DRM_PANTHOR_BO_NO_MMAP flag are not supposed to be > mmappable by the Userspace. But after the rework to support shrinker, > it became possible to mmap NO_MMAP BOs. Userspace could second guess > the file offset range, allocated unconditionally at the BO creation > time, and create a CPU mapping. There may not be any adverse effect of > such a CPU mapping though. > This commit adds a check in the mmap callback of Panthor driver to > fail the mmap() attempts on BOs created with NO_MMAP flag. The check > covers private BOs as well as the prime exported BOs that are mmapped > using prime fd. > > v2: > - Fix breakage of mmap() on exported BOs that didn't have > BO_MMAP_OFFSET ioctl invoked for them. > > Fixes: 68cbf96b1e9b ("drm/panthor: Part ways with drm_gem_shmem_object") > Suggested-by: Boris Brezillon > Signed-off-by: Akash Goel Reviewed-by: Steven Price > --- > drivers/gpu/drm/panthor/panthor_gem.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c > index c07a44057e42..22b57ab6f929 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.c > +++ b/drivers/gpu/drm/panthor/panthor_gem.c > @@ -744,6 +744,9 @@ static int panthor_gem_mmap(struct drm_gem_object *obj, struct vm_area_struct *v > struct panthor_gem_object *bo = to_panthor_bo(obj); > int ret; > > + if (bo->flags & DRM_PANTHOR_BO_NO_MMAP) > + return -EINVAL; > + > if (drm_gem_is_imported(obj)) { > /* Reset both vm_ops and vm_private_data, so we don't end up with > * vm_ops pointing to our implementation if the dma-buf backend