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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D058EB64DA for ; Mon, 19 Jun 2023 08:32:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230353AbjFSIcZ (ORCPT ); Mon, 19 Jun 2023 04:32:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230328AbjFSIcW (ORCPT ); Mon, 19 Jun 2023 04:32:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65294197; Mon, 19 Jun 2023 01:32:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F3AE2615E4; Mon, 19 Jun 2023 08:32:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81387C433C0; Mon, 19 Jun 2023 08:32:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687163533; bh=/WP7Oqb3gUygcJme/Qfhq25/WxnQQHPsXChiAPp7gy4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=p1iz1bwUIiae5MlMfwl1PhMaD8NFL9PqEmnIEXxSVu0juHbg0maV+YEchH3iW/j8d +ODAPF1kQKCyqhWau6fb/ofLSgswhN1lpbj1uX3ALp8CsX0wTD0wJxMGKR+LUYg+Ci qTXhTWk3Ij3zYf2tWIzxOwBqyvQvruh6rJAhyy9fU0IcNCfvDKR9VEDfsIckrG0ykd DlW7cYzLkiyEUzrZ2uzanjsxA5dwecKXiJSddTNCEU7avPucSaXbddS/pVykskPxro NGUnLtH42t98pAd+nkR8YwMm+Q4H6DTEhKvltPS24MSwQaU9nglCShDkTwh9KfpWBM YgFYPx0LvCs1w== Date: Mon, 19 Jun 2023 09:32:07 +0100 From: Lee Jones To: Thomas Zimmermann Cc: daniel@ffwll.ch, javierm@redhat.com, sam@ravnborg.org, deller@gmx.de, geert+renesas@glider.be, daniel.thompson@linaro.org, jingoohan1@gmail.com, dan.carpenter@linaro.org, michael.j.ruhl@intel.com, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-sh@vger.kernel.org, linux-omap@vger.kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 00/38] fbdev: Make userspace interfaces optional Message-ID: <20230619083207.GP3635807@google.com> References: <20230613110953.24176-1-tzimmermann@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230613110953.24176-1-tzimmermann@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Tue, 13 Jun 2023, Thomas Zimmermann wrote: > Add the new config option FB_DEVICE. If enabled, fbdev provides > traditional userspace interfaces in devfs, sysfs and procfs, such > as /dev/fb0 or /proc/fb. > > Modern Linux distrobutions have adopted DRM drivers for graphics > output and use fbdev only for the kernel's framebuffer console. > Userspace has also moved on, with no new fbdev code being written > and existing support being removed. > > OTOH, fbdev provides userspace a way of accessing kernel or I/O > memory, which might compromise the system's security. See the recent > commit c8687694bb1f ("drm/fbdev-generic: prohibit potential > out-of-bounds access") for an example. Disabling fbdev userspace > interfaces is therefore a useful feature to limit unnecessary > exposure of fbdev code to processes of low privilegues. > > Patches 1 to 31 fix various bugs and issues in fbdev-related code. > In most cases the code uses the fbdev device where it should use > the Linux hardware device or something else. Most of these patches > fix existing problems and should therefore be considered in any case. > > Patches 32 to 37 refactor the fbdev core code. The patches move > support for backlights, sysfs, procfs and devfs into separate files > and hide it behind simple interfaces. These changes will allow to > easily build the userspace support conditionally. > > Patch 38 introduces the config option FB_DEVICE and adapts the fbdev > core to support it. The field struct fb_info.dev is now optional, > hence the name of the config option. > > Tested on simpledrm and i915, including the device handover. > > Future directions: With the support for disabling fbdev userspace > interfaces in place, it will be possible to make most fbdev drivers' > file-I/O code in struct fb_ops optional as well. > > v3: > * add missing file fb_chrdev.c > * fix typo in Kconfig help (Daniel) > v2: > * fix fsl-diu-fb and sh7760fb > * split backlight patches > * set 'default y' for FB_CONFIG > * minor fixes and corrections > > Thomas Zimmermann (38): > backlight/bd6107: Compare against struct fb_info.device > backlight/bd6107: Rename struct bd6107_platform_data.fbdev to 'dev' > backlight/gpio_backlight: Compare against struct fb_info.device > backlight/gpio_backlight: Rename field 'fbdev' to 'dev' > backlight/lv5207lp: Compare against struct fb_info.device > backlight/lv5207lp: Rename struct lv5207lp_platform_data.fbdev to > 'dev' > fbdev/atyfb: Reorder backlight and framebuffer init/cleanup > fbdev/atyfb: Use hardware device as backlight parent > fbdev/aty128fb: Reorder backlight and framebuffer init/cleanup > fbdev/aty128fb: Use hardware device as backlight parent > fbdev/broadsheetfb: Call device_remove_file() with hardware device > fbdev/ep93xx-fb: Alloc DMA memory from hardware device > fbdev/ep93xx-fb: Output messages with fb_info() and fb_err() > fbdev/ep93xx-fb: Do not assign to struct fb_info.dev > fbdev/fsl-diu-fb: Output messages with fb_*() helpers > fbdev/mb862xxfb: Output messages with fb_dbg() > fbdev/metronomefb: Use hardware device for dev_err() > fbdev/nvidiafb: Reorder backlight and framebuffer init/cleanup > fbdev/nvidiafb: Use hardware device as backlight parent > fbdev/pxa168fb: Do not assign to struct fb_info.dev > fbdev/radeonfb: Reorder backlight and framebuffer cleanup > fbdev/radeonfb: Use hardware device as backlight parent > fbdev/rivafb: Reorder backlight and framebuffer init/cleanup > fbdev/rivafb: Use hardware device as backlight parent > fbdev/sh7760fb: Use fb_dbg() in sh7760fb_get_color_info() > fbdev/sh7760fb: Output messages with fb_dbg() > fbdev/sh7760fb: Alloc DMA memory from hardware device > fbdev/sh7760fb: Use hardware device with dev_() output during probe > fbdev/sm501fb: Output message with fb_err() > fbdev/smscufx: Detect registered fb_info from refcount > fbdev/tdfxfb: Set i2c adapter parent to hardware device > fbdev/core: Pass Linux device to pm_vt_switch_*() functions > fbdev/core: Move framebuffer and backlight helpers into separate files > fbdev/core: Add fb_device_{create,destroy}() > fbdev/core: Move procfs code to separate file > fbdev/core: Move file-I/O code into separate file > fbdev/core: Rework fb init code > fbdev: Make support for userspace interfaces configurable > > Documentation/gpu/todo.rst | 13 + > arch/sh/boards/mach-ecovec24/setup.c | 2 +- > arch/sh/boards/mach-kfr2r09/setup.c | 2 +- > drivers/staging/fbtft/Kconfig | 1 + > drivers/video/backlight/bd6107.c | 2 +- > drivers/video/backlight/gpio_backlight.c | 6 +- > drivers/video/backlight/lv5207lp.c | 2 +- Acked-by: Lee Jones -- Lee Jones [李琼斯]