1. 17 11月, 2010 1 次提交
    • D
      PCI: fix offset check for sysfs mmapped files · 8c05cd08
      Darrick J. Wong 提交于
      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
      3b519e4e, 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: NMartin Wilck <martin.wilck@ts.fujitsu.com>
      Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
      Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
      8c05cd08
  2. 16 11月, 2010 27 次提交
  3. 15 11月, 2010 9 次提交
  4. 14 11月, 2010 3 次提交