Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752501AbbBQRCJ (ORCPT ); Tue, 17 Feb 2015 12:02:09 -0500 Received: from mail-qg0-f44.google.com ([209.85.192.44]:56530 "EHLO mail-qg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752427AbbBQRCG (ORCPT ); Tue, 17 Feb 2015 12:02:06 -0500 MIME-Version: 1.0 In-Reply-To: References: From: Bjorn Helgaas Date: Tue, 17 Feb 2015 11:01:44 -0600 Message-ID: Subject: Re: [PATCH 3.2 015/152] PCI: Restore detection of read-only BARs To: Ben Hutchings Cc: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Andrew Morton , Matthew Wilcox , Myron Stowe , William Unruh , Martin Lucina Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3204 Lines: 72 On Mon, Feb 16, 2015 at 7:46 PM, Ben Hutchings wrote: > 3.2.67-rc1 review patch. If anyone has any objections, please let me know. No objections, but I think you want 06cf35f903aa ("PCI: Handle read-only BARs on AMD CS553x devices") at the same time. > ------------------ > > From: Myron Stowe > > commit 36e8164882ca6d3c41cb91e6f09a3ed236841f80 upstream. > > Commit 6ac665c63dca ("PCI: rewrite PCI BAR reading code") masked off > low-order bits from 'l', but not from 'sz'. Both are passed to pci_size(), > which compares 'base == maxbase' to check for read-only BARs. The masking > of 'l' means that comparison will never be 'true', so the check for > read-only BARs no longer works. > > Resolve this by also masking off the low-order bits of 'sz' before passing > it into pci_size() as 'maxbase'. With this change, pci_size() will once > again catch the problems that have been encountered to date: > > - AGP aperture BAR of AMD-7xx host bridges: if the AGP window is > disabled, this BAR is read-only and read as 0x00000008 [1] > > - BARs 0-4 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] > > Link: [1] https://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/drivers/pci/probe.c?id=1307ef6621991f1c4bc3cec1b5a4ebd6fd3d66b9 ("PCI: probing read-only BARs" (pre-git)) > Link: [2] https://bugzilla.kernel.org/show_bug.cgi?id=43331 > Link: [3] https://bugzilla.kernel.org/show_bug.cgi?id=85991 > Reported-by: William Unruh > Reported-by: Martin Lucina > Signed-off-by: Myron Stowe > Signed-off-by: Bjorn Helgaas > CC: Matthew Wilcox > Signed-off-by: Ben Hutchings > --- > drivers/pci/probe.c | 3 +++ > 1 file changed, 3 insertions(+) > > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -175,14 +175,17 @@ int __pci_read_base(struct pci_dev *dev, > 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/