linux/drivers/pci
Darrick J. Wong 8c05cd08a7 PCI: fix offset check for sysfs mmapped files
I just loaded 2.6.37-rc2 on my machines, and I noticed that X no longer starts.
Running an strace of the X server shows that it's doing this:

open("/sys/bus/pci/devices/0000:07:00.0/resource0", O_RDWR) = 10
mmap(NULL, 16777216, PROT_READ|PROT_WRITE, MAP_SHARED, 10, 0) = -1 EINVAL (Invalid argument)

This code seems to be asking for a shared read/write mapping of 16MB worth of
BAR0 starting at file offset 0, and letting the kernel assign a starting
address.  Unfortunately, this -EINVAL causes X not to start.  Looking into
dmesg, there's a complaint like so:

process "Xorg" tried to map 0x01000000 bytes at page 0x00000000 on 0000:07:00.0 BAR 0 (start 0x        96000000, size 0x         1000000)

...with the following code in pci_mmap_fits:

	pci_start = (mmap_api == PCI_MMAP_SYSFS) ?
		pci_resource_start(pdev, resno) >> PAGE_SHIFT : 0;
        if (start >= pci_start && start < pci_start + size &&
                        start + nr <= pci_start + size)

It looks like the logic here is set up such that when the mmap call comes via
sysfs, the check in pci_mmap_fits wants vma->vm_pgoff to be between the
resource's start and end address, and the end of the vma to be no farther than
the end.  However, the sysfs PCI resource files always start at offset zero,
which means that this test always fails for programs that mmap the sysfs files.
Given the comment in the original commit
3b519e4ea6, I _think_ the old procfs files
require that the file offset be equal to the resource's base address when
mmapping.

I think what we want here is for pci_start to be 0 when mmap_api ==
PCI_MMAP_PROCFS.  The following patch makes that change, after which the Matrox
and Mach64 X drivers work again.

Acked-by: Martin Wilck <martin.wilck@ts.fujitsu.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2010-11-16 09:15:39 -08:00
..
hotplug PCI hotplug: ibmphp: Add check to prevent reading beyond mapped area 2010-11-11 09:34:31 -08:00
pcie Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 2010-10-28 11:59:52 -07:00
.gitignore
access.c PCI: output FW warning in pci_read/write_vpd 2010-05-18 15:00:25 -07:00
bus.c PCI: fix pci_bus_alloc_resource() hang, prefer positive decode 2010-11-12 09:16:08 -08:00
dmar.c Merge branch 'x86-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 14:23:48 -07:00
hotplug-pci.c PCI: fix section mismatch warning in pci_scan_child_bus 2008-03-04 15:07:03 -08:00
hotplug.c
htirq.c ht: Convert to new irq_chip functions 2010-10-12 16:53:37 +02:00
intel-iommu.c Merge git://git.infradead.org/iommu-2.6 2010-09-27 12:25:10 -07:00
intr_remapping.c x86: Speed up the irq_remapped check in hot pathes 2010-10-12 16:53:42 +02:00
intr_remapping.h intr-remap: generic support for remapping HPET MSIs 2009-08-27 23:33:20 +02:00
ioapic.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
iov.c PCI: fix pci_resource_alignment prototype 2010-09-09 13:41:25 -07:00
iova.c intel-iommu: Remove superfluous iova_alloc_lock from IOVA code 2009-07-15 08:17:02 +01:00
irq.c PCI: struct device - replace bus_id with dev_name(), dev_set_name() 2009-01-07 11:12:23 -08:00
Kconfig xen-pcifront: Xen PCI frontend driver. 2010-10-18 10:49:37 -04:00
Makefile Merge branch 'stable/xen-pcifront-0.8.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2010-10-28 17:11:17 -07:00
msi.c msi: Introduce default_[teardown|setup]_msi_irqs with fallback. 2010-10-18 10:49:33 -04:00
msi.h PCI: add PCI_MSIX_TABLE/PBA defines 2010-10-17 20:03:03 -07:00
pci-acpi.c Merge branch 'acpica' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2010-08-07 17:08:30 -07:00
pci-driver.c PCI: change device runtime PM settings for probe and remove 2010-07-30 09:29:09 -07:00
pci-label.c PCI: update for owner removal from struct device_attribute 2010-08-04 14:23:55 -07:00
pci-stub.c PCI: pci-stub: add pci_stub.ids parameter 2009-09-09 13:44:34 -07:00
pci-sysfs.c PCI: fix offset check for sysfs mmapped files 2010-11-16 09:15:39 -08:00
pci.c PCI: read current power state at enable time 2010-11-11 09:38:14 -08:00
pci.h PCI: fix size checks for mmap() on /proc/bus/pci files 2010-11-11 09:34:32 -08:00
probe.c PCI: log vendor/device ID always 2010-10-17 20:03:05 -07:00
proc.c PCI: fix size checks for mmap() on /proc/bus/pci files 2010-11-11 09:34:32 -08:00
quirks.c Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 2010-10-28 11:59:52 -07:00
remove.c PCI: eliminate redundant pci_stop_dev() call from pci_destroy_dev() 2009-06-11 12:04:19 -07:00
rom.c PCI: fix rom.c kernel-doc warning 2009-02-13 12:01:56 -08:00
search.c PCI: use for_each_pci_dev() 2010-07-30 09:47:22 -07:00
setup-bus.c PCI hotplug: make sure child bridges are enabled at hotplug time 2010-07-30 09:29:16 -07:00
setup-irq.c PCI: use for_each_pci_dev() 2010-07-30 09:47:22 -07:00
setup-res.c PCI: fix message typo 2010-10-17 20:03:05 -07:00
slot.c PCI: bus speed strings should be const 2010-08-31 15:28:00 -07:00
syscall.c headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
vpd.c pci: Add helper to search for VPD keywords 2010-02-28 00:43:33 -08:00
xen-pcifront.c xen-pcifront: fix PCI reference leak 2010-11-08 11:41:15 -05:00