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 8830FC54E58 for ; Mon, 18 Mar 2024 15:25:11 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 04E8D10FA6D; Mon, 18 Mar 2024 15:25:11 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="cB4MHLv9"; dkim-atps=neutral Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) by gabe.freedesktop.org (Postfix) with ESMTPS id EF5DC10FA73 for ; Mon, 18 Mar 2024 15:25:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1710775508; bh=+lAMP2bPyceQMjBtZuwQsF36x3LW4dSq40R63uAKA0k=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=cB4MHLv9xDTIdv+y2IHKQE2AIoufoZbtLbIHejwMJavnkwP5dFncv3PolzcVVSZJV Sxvqjstl9f0iBwOL4cKJRfWGUPXUdK87dYMw/bkJhbHcMPhpUenj3KRFWyr5JW6of2 deMopx6nIOdG3oF7PxfKeVETTZV3NV+tMIKOLQ3RpmktulNfx95GFPIVsI5/UlKk78 /n+llYjuJJhy91Qa7R/xE96flaMH6KxAvhyBSeH0n8jfteAdRcxMN3Gtxf6Pfk/Wv+ bea9YtgUzAC4/r3FyyUyWsTqZ3tIprSnuZVUfMM7EToRMj7BLsTe4sL6wc2jjXNOiL SHiNLhDMLpMAA== Received: from localhost (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by madrid.collaboradmins.com (Postfix) with ESMTPSA id F0AEB378209D; Mon, 18 Mar 2024 15:25:07 +0000 (UTC) Date: Mon, 18 Mar 2024 16:25:06 +0100 From: Boris Brezillon To: Robin Murphy Cc: Steven Price , Liviu Dudau , dri-devel@lists.freedesktop.org Subject: Re: [PATCH] drm/panthor: Don't use virt_to_pfn() Message-ID: <20240318162506.7b115697@collabora.com> In-Reply-To: <5566e7e4-7c35-4939-9676-a739c96b8aa5@arm.com> References: <20240318145119.368582-1-steven.price@arm.com> <5566e7e4-7c35-4939-9676-a739c96b8aa5@arm.com> Organization: Collabora X-Mailer: Claws Mail 4.2.0 (GTK 3.24.38; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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 Mon, 18 Mar 2024 15:11:42 +0000 Robin Murphy wrote: > On 18/03/2024 2:51 pm, Steven Price wrote: > > virt_to_pfn() isn't available on x86 (except to xen) so breaks > > COMPILE_TEST builds. Avoid its use completely by instead storing the > > struct page pointer allocated in panthor_device_init() and using > > page_to_pfn() instead. > > > > Signed-off-by: Steven Price > > --- > > drivers/gpu/drm/panthor/panthor_device.c | 10 ++++++---- > > drivers/gpu/drm/panthor/panthor_device.h | 2 +- > > 2 files changed, 7 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c > > index 69deb8e17778..3c30da03fa48 100644 > > --- a/drivers/gpu/drm/panthor/panthor_device.c > > +++ b/drivers/gpu/drm/panthor/panthor_device.c > > @@ -154,6 +154,7 @@ int panthor_device_init(struct panthor_device *ptdev) > > { > > struct resource *res; > > struct page *p; > > + u32 *dummy_page_virt; > > int ret; > > > > ptdev->coherent = device_get_dma_attr(ptdev->base.dev) == DEV_DMA_COHERENT; > > @@ -172,9 +173,10 @@ int panthor_device_init(struct panthor_device *ptdev) > > if (!p) > > return -ENOMEM; > > > > - ptdev->pm.dummy_latest_flush = page_address(p); > > + ptdev->pm.dummy_latest_flush = p; > > + dummy_page_virt = page_address(p); > > ret = drmm_add_action_or_reset(&ptdev->base, panthor_device_free_page, > > - ptdev->pm.dummy_latest_flush); > > + dummy_page_virt); > > Nit: I was about to say I'd be inclined to switch the callback to > __free_page() instead, but then I realise there's no real need to be > reinventing that in the first place: > > dummy_page_virt = (void *)devm_get_free_pages(ptdev->base.dev, > GFP_KERNEL | GFP_ZERO, 0); IIRC, the drm_device object might outlive the device it's been created from if a process holds on the DRM dev FD after an unplug happened, which can happen if panthor_device_unplug() is called from the reset path (when a reset fails). > if (!dummy_page_virt) > return -ENOMEM; > > ptdev->pm.dummy_latest_flush = virt_to_page(dummy_page_virt); > > Cheers, > Robin. > > > if (ret) > > return ret; > > > > @@ -184,7 +186,7 @@ int panthor_device_init(struct panthor_device *ptdev) > > * happens while the dummy page is mapped. Zero cannot be used because > > * that means 'always flush'. > > */ > > - *ptdev->pm.dummy_latest_flush = 1; > > + *dummy_page_virt = 1; > > > > INIT_WORK(&ptdev->reset.work, panthor_device_reset_work); > > ptdev->reset.wq = alloc_ordered_workqueue("panthor-reset-wq", 0); > > @@ -353,7 +355,7 @@ static vm_fault_t panthor_mmio_vm_fault(struct vm_fault *vmf) > > if (active) > > pfn = __phys_to_pfn(ptdev->phys_addr + CSF_GPU_LATEST_FLUSH_ID); > > else > > - pfn = virt_to_pfn(ptdev->pm.dummy_latest_flush); > > + pfn = page_to_pfn(ptdev->pm.dummy_latest_flush); > > break; > > > > default: > > diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h > > index 51c9d61b6796..c84c27dcc92c 100644 > > --- a/drivers/gpu/drm/panthor/panthor_device.h > > +++ b/drivers/gpu/drm/panthor/panthor_device.h > > @@ -160,7 +160,7 @@ struct panthor_device { > > * Used to replace the real LATEST_FLUSH page when the GPU > > * is suspended. > > */ > > - u32 *dummy_latest_flush; > > + struct page *dummy_latest_flush; > > } pm; > > }; > >