From patchwork Mon Jul 10 21:13:05 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 9833797 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A8D1B60318 for ; Mon, 10 Jul 2017 21:13:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 94D9328462 for ; Mon, 10 Jul 2017 21:13:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8769A284B5; Mon, 10 Jul 2017 21:13:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2DCD328462 for ; Mon, 10 Jul 2017 21:13:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752191AbdGJVN0 (ORCPT ); Mon, 10 Jul 2017 17:13:26 -0400 Received: from mail-wr0-f179.google.com ([209.85.128.179]:36476 "EHLO mail-wr0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754152AbdGJVNZ (ORCPT ); Mon, 10 Jul 2017 17:13:25 -0400 Received: by mail-wr0-f179.google.com with SMTP id c11so155842808wrc.3 for ; Mon, 10 Jul 2017 14:13:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=Xb+W1+RYv1Js0fYV2capmE8rGL86L56xTe15GopjpBE=; b=M2A2aCDYK44J+a71rR6977sVK2Rah99DLHsa0uUkXXUFH9GrXaH+ZNiDnTRWpGSMkI DE3ARI07TNVGd8J70znsEO41isGycB4eZWsRaQfOQ7Mal5ONuuWUCN/NSh3IlpHCbQl9 it5U8NzI+DLaoOlavE10xwHNmz+a6O/vNO2uk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=Xb+W1+RYv1Js0fYV2capmE8rGL86L56xTe15GopjpBE=; b=uHwLnoRsckeBPfPGexMlPJYuSv+LUGsp0sGgb1BM1dvx0MtPbiLiS4RMq2sTknYDHI Q7+npsm274hC05pjoPsx7PbaoRpxw7cjlJdRSx9l8hRnlvFbiUhHAZw7tHPYF0rJEhbr rg6yjahiWHxw1Rdl6VlRGSRjv7QeHTmBVhidQXZfQGcmprL1cGzqGiN9171RTJxZ1UeR 4Uwtt6PYt+eGBo9PbQNCLlpyiiiLToKq1pJlbWxitEm27M/Pi4jzCdRQ7XIu7RFyZI4F 0SBFS+QJeLyxYce1+rc5fj0iN2cgSXQD7uC3dPLR8NxFt1tjxHMSsTU37+4j6PWmgjhA wsYA== X-Gm-Message-State: AIVw113hPcJCdcAjXqPMMPLmJrNO02d4k7gJdlfwZR4PFT8zNMMIosAU FxLNaatj7GmidJb0RPlziw== X-Received: by 10.28.113.214 with SMTP id d83mr9080680wmi.62.1499721203501; Mon, 10 Jul 2017 14:13:23 -0700 (PDT) Received: from localhost.localdomain ([154.149.70.241]) by smtp.gmail.com with ESMTPSA id 185sm9526584wmn.33.2017.07.10.14.13.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Jul 2017 14:13:22 -0700 (PDT) From: Ard Biesheuvel To: linux-pci@vger.kernel.org, bhelgaas@google.com, pjones@redhat.com Cc: linux-fbdev@vger.kernel.org, linux-efi@vger.kernel.org, matt@codeblueprint.co.uk, b.zolnierkie@samsung.com, lorenzo.pieralisi@arm.com, Ard Biesheuvel Subject: [PATCH v2] drivers/fbdev: efifb: allow BAR to be moved instead of claiming it Date: Mon, 10 Jul 2017 22:13:05 +0100 Message-Id: <20170710211305.6475-1-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.11.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On UEFI systems, the firmware may expose a Graphics Output Protocol (GOP) instance to which the efifb driver attempts to attach in order to provide a minimal, unaccelerated framebuffer. The GOP protocol itself is not very sophisticated, and only describes the offset and size of the framebuffer in memory, and the pixel format. If the GOP framebuffer is provided by a PCI device, it will have been configured and enabled by the UEFI firmware, and the GOP protocol will simply point into a live BAR region. However, the GOP protocol itself does not describe this relation, and so we have to take care not to reconfigure the BAR without taking efifb's dependency on it into account. Commit 55d728a40d36 ("efi/fb: Avoid reconfiguration of BAR that covers the framebuffer") attempted to do so by claiming the BAR resource early on, which prevents the PCI resource allocation routines from changing it. However, it turns out that this only works if the PCI device is not behind any bridges, since the bridge resources need to be claimed first. So instead, allow the BAR to be moved, but make the efifb driver deal with that gracefully. So record the resource that covers the BAR early on, and if it turns out to have moved by the time we probe the efifb driver, update the framebuffer address accordingly. While this is less likely to occur on x86, given that the firmware's PCI resource allocation is more likely to be preserved, this is a worthwhile sanity check to have in place, and so let's remove the Signed-off-by: Ard Biesheuvel Signed-off-by: Peter Jones Acked-by: Bartlomiej Zolnierkiewicz Acked-by: Bjorn Helgaas --- v2: - use pr_info() not pr_warn() for non-error condition drivers/video/fbdev/efifb.c | 24 ++++++++++++-------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c index ff01bed7112f..0dd7e5eb051f 100644 --- a/drivers/video/fbdev/efifb.c +++ b/drivers/video/fbdev/efifb.c @@ -146,6 +146,9 @@ ATTRIBUTE_GROUPS(efifb); static bool pci_dev_disabled; /* FB base matches BAR of a disabled device */ +static struct resource *bar_resource; +static u64 bar_offset; + static int efifb_probe(struct platform_device *dev) { struct fb_info *info; @@ -200,6 +203,13 @@ static int efifb_probe(struct platform_device *dev) efifb_fix.smem_start |= ext_lfb_base; } + if (bar_resource && + bar_resource->start + bar_offset != efifb_fix.smem_start) { + + pr_info("efifb: PCI BAR has moved, updating fb address\n"); + efifb_fix.smem_start = bar_resource->start + bar_offset; + } + efifb_defined.bits_per_pixel = screen_info.lfb_depth; efifb_defined.xres = screen_info.lfb_width; efifb_defined.yres = screen_info.lfb_height; @@ -364,11 +374,11 @@ static struct platform_driver efifb_driver = { builtin_platform_driver(efifb_driver); -#if defined(CONFIG_PCI) && !defined(CONFIG_X86) +#if defined(CONFIG_PCI) static bool pci_bar_found; /* did we find a BAR matching the efifb base? */ -static void claim_efifb_bar(struct pci_dev *dev, int idx) +static void record_efifb_bar_resource(struct pci_dev *dev, int idx, u64 offset) { u16 word; @@ -383,12 +393,8 @@ static void claim_efifb_bar(struct pci_dev *dev, int idx) return; } - if (pci_claim_resource(dev, idx)) { - pci_dev_disabled = true; - dev_err(&dev->dev, - "BAR %d: failed to claim resource for efifb!\n", idx); - return; - } + bar_resource = &dev->resource[idx]; + bar_offset = offset; dev_info(&dev->dev, "BAR %d: assigned to efifb\n", idx); } @@ -415,7 +421,7 @@ static void efifb_fixup_resources(struct pci_dev *dev) continue; if (res->start <= base && res->end >= base + size - 1) { - claim_efifb_bar(dev, i); + record_efifb_bar_resource(dev, i, base - res->start); break; } }