Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760523AbaJ3R4h (ORCPT ); Thu, 30 Oct 2014 13:56:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60303 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757832AbaJ3R4g (ORCPT ); Thu, 30 Oct 2014 13:56:36 -0400 Subject: [PATCH 1/3] PCI: Restore detection of read-only BARs From: Myron Stowe To: bhelgaas@google.com, linux-pci@vger.kernel.org Cc: willy@linux.intel.com, unruh@physics.ubc.ca, linux-kernel@vger.kernel.org, martin@lucina.net Date: Thu, 30 Oct 2014 11:54:37 -0600 Message-ID: <20141030175437.22238.47243.stgit@amt.stowe> In-Reply-To: <20141030175430.22238.47671.stgit@amt.stowe> References: <20141030175430.22238.47671.stgit@amt.stowe> User-Agent: StGit/0.17-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 6ac665c63dca ("PCI: rewrite PCI BAR reading code") altered __pci_read_base's local variable 'l', masking off its lower non-addressing related bits, prior to it being passed in as the 'base' parameter to pci_size(). This masking broke pci_size's r/o BAR detection logic's comparison check for r/o BARs that have lower order bits set. For such occurrences, the 'base == maxbase' check will no longer ever be "true". This patch resolves this issue by also masking off the non-addressing related bits of 'sz' before passing it into pci_size() as the 'maxbase' parameter. With this change the r/o detection logic of pci_size() will once again catch known occurrences that have been encountered to date: - AGP aperture BAR of AMD-7xx host bridges; if the AGP window disabled, this BAR is read-only and read as 0x00000008 [1] - BAR0-4 of ALi IDE controllers can be non-zero and read-only [1] - Intel Sandy Bridge - Thermal Management Controller [8086:0103]; BAR 0 returning 0xfed98004 [2] - Intel Xeon E5 v3/Core i7 Power Control Unit [8086:2fc0]; Bar 0 returning 0x00001a [3] [1] From Thomas Gleixner's "Linux kernel history" repository: https://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/drivers/pci/probe.c?id=1307ef6621991f1c4bc3cec1b5a4ebd6fd3d66b9 pre-git commit 1307ef662199 "PCI: probing read-only Bars" [2] https://bugzilla.kernel.org/show_bug.cgi?id=43331 [3] https://bugzilla.kernel.org/show_bug.cgi?id=85991 Reported-by: William Unruh Reported-by: Martin Lucina Signed-off-by: Myron Stowe Cc: Matthew Wilcox --- drivers/pci/probe.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 5ed9930..19dc247 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -216,14 +216,17 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, res->flags |= IORESOURCE_SIZEALIGN; if (res->flags & IORESOURCE_IO) { l &= PCI_BASE_ADDRESS_IO_MASK; + sz &= PCI_BASE_ADDRESS_IO_MASK; mask = PCI_BASE_ADDRESS_IO_MASK & (u32) IO_SPACE_LIMIT; } else { l &= PCI_BASE_ADDRESS_MEM_MASK; + sz &= PCI_BASE_ADDRESS_MEM_MASK; mask = (u32)PCI_BASE_ADDRESS_MEM_MASK; } } else { res->flags |= (l & IORESOURCE_ROM_ENABLE); l &= PCI_ROM_ADDRESS_MASK; + sz &= PCI_ROM_ADDRESS_MASK; mask = (u32)PCI_ROM_ADDRESS_MASK; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/