[PATCH 04/13] vfio-pci: use 32-bit comparisons for register address for gcc-4.5

Arnd Bergmann
2016-12-16T10:55:46Z

Using ancient compilers (gcc-4.5 or older) on ARM, we get a link
failure with the vfio-pci driver:

ERROR: "__aeabi_lcmp" [drivers/vfio/pci/vfio-pci.ko] undefined!

The reason is that the compiler tries to do a comparison of
a 64-bit range. This changes it to convert to a 32-bit number
explicitly first, as newer compilers do for themselves.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/vfio/pci/vfio_pci_rdwr.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index 5ffd1d9ad4bd..357243d76f10 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -193,7 +193,10 @@ ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
if (!vdev->has_vga)
return -EINVAL;

- switch (pos) {
+ if (pos > 0xbfffful)
+ return -EINVAL;
+
+ switch ((u32)pos) {
case 0xa0000 ... 0xbffff:
count = min(count, (size_t)(0xc0000 - pos));
iomem = ioremap_nocache(0xa0000, 0xbffff - 0xa0000 + 1);
--
2.9.0