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: 9833799 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 B7AF160393 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 A5BFD2847D for ; Mon, 10 Jul 2017 21:13:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8942B28458; 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=-6.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=ham 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 CAFEC28458 for ; Mon, 10 Jul 2017 21:13:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754503AbdGJVN0 (ORCPT ); Mon, 10 Jul 2017 17:13:26 -0400 Received: from mail-wr0-f171.google.com ([209.85.128.171]:35800 "EHLO mail-wr0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754020AbdGJVNZ (ORCPT ); Mon, 10 Jul 2017 17:13:25 -0400 Received: by mail-wr0-f171.google.com with SMTP id k67so155213014wrc.2 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=FEqHkv/N90LgOwWdfvL9HMbaAZEFLSOSGPjsdSh5udN9fDVSbTGPDOun0z6OTHcLpo q4CgTY2hqfGQqmpRFmeo0B4nfRt/KMKMcpo8dBjwGhqqKp2gPq9btGGogMd0Sz7A7LRW eDJgt3iNJxqW52Aurk+vqs1GA3rqHsqV0bBB8J+PQvoEI6ixKWkZ0s+5w1H6yEU/D6xw zMaq/ddv5+QWBXzL7qfvIIMkD40+7iRGb2BCUd7Ho3gImSeEh8cMo9/LAnACkfZFbTUb uehY4906BECwevEF7QExqEowoE8MTtKy6Egm4Wpne6CsR6lAJ1cowvtdHaUKF81op1BL jYzA== X-Gm-Message-State: AIVw110YmQiwlZ1zQLzLs8+TzsM5bH/k6N/Fuha4nLiQfC3FMur7lwBo hL74KC41/kXllQGH 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-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@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; } }