| Message ID | 20141030175437.22238.47243.stgit@amt.stowe (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Thu, Oct 30, 2014 at 11:54:37AM -0600, Myron Stowe wrote: > 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 I like this patch and I think it's correct. The only thing that bothers me is that Martin reported that lspci showed "Memory at <ignored>" for this BAR: https://bugzilla.kernel.org/show_bug.cgi?id=43331#c36 . I guess this is because lspci reads the BAR values from /sys/bus/pci/devices/.../config, which uses pci_read_config(), which actually reads config space again, so it sees whatever is actually in the BAR, not the cleared out resource in the pci_dev. Oh well, I guess that's OK. > Reported-by: William Unruh <unruh@physics.ubc.ca> > Reported-by: Martin Lucina <martin@lucina.net> > Signed-off-by: Myron Stowe <myron.stowe@redhat.com> > Cc: Matthew Wilcox <willy@linux.intel.com> > --- > 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-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; }
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 <unruh@physics.ubc.ca> Reported-by: Martin Lucina <martin@lucina.net> Signed-off-by: Myron Stowe <myron.stowe@redhat.com> Cc: Matthew Wilcox <willy@linux.intel.com> --- drivers/pci/probe.c | 3 +++ 1 file changed, 3 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html