PCI: Supply CPU physical address (not bus address) to iomem_is_exclusive()

iomem_is_exclusive() requires a CPU physical address, but on some arches we
supplied a PCI bus address instead.

On most arches, pci_resource_to_user(res) returns "res->start", which is a
CPU physical address.  But on microblaze, mips, powerpc, and sparc, it
returns the PCI bus address corresponding to "res->start".

The result is that pci_mmap_resource() may fail when it shouldn't (if the
bus address happens to match an existing resource), or it may succeed when
it should fail (if the resource is exclusive but the bus address doesn't
match it).

Call iomem_is_exclusive() with "res->start", which is always a CPU physical
address, not the result of pci_resource_to_user().

Fixes: e8de1481fd71 ("resource: allow MMIO exclusivity for device drivers")
Suggested-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Arjan van de Ven <arjan@linux.intel.com>
Orabug: 22855133
(cherry picked from commit ca620723d4ff9ea7ed484eab46264c3af871b9ae)
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
(cherry picked from commit aee594b88bfcb58f51e0070de06d3879b3ea4609)
Signed-off-by: Allen Pais <allen.pais@oracle.com>

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 0e1e8bbd34fdc36b0d081502da0e219d79fbd0f8..0f1d8479caa3034b765acf997be985a161d0f67f 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1016,6 +1016,9 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,
        if (i >= PCI_ROM_RESOURCE)
                return -ENODEV;
 
+       if (res->flags & IORESOURCE_MEM && iomem_is_exclusive(res->start))
+               return -EINVAL;
+
        if (!pci_mmap_fits(pdev, i, vma, PCI_MMAP_SYSFS)) {
                WARN(1, "process \"%s\" tried to map 0x%08lx bytes at page 0x%08lx on %s BAR %d (start 0x%16Lx, size 0x%16Lx)\n",
                        current->comm, vma->vm_end-vma->vm_start, vma->vm_pgoff,
@@ -1032,10 +1035,6 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,
        pci_resource_to_user(pdev, i, res, &start, &end);
        vma->vm_pgoff += start >> PAGE_SHIFT;
        mmap_type = res->flags & IORESOURCE_MEM ? pci_mmap_mem : pci_mmap_io;
-
-       if (res->flags & IORESOURCE_MEM && iomem_is_exclusive(start))
-               return -EINVAL;
-
        return pci_mmap_page_range(pdev, vma, mmap_type, write_combine);
 }