x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1

Yanko's GA-MA78GM-S2H (BIOS F11) reports the following resource in a PCI
host bridge _CRS:

[07] 32-Bit DWORD Address Space Resource
Min Relocatability : MinFixed
Max Relocatability : MaxFixed
Address Minimum : CFF00000 (_MIN)
Address Maximum : FEBFFFFF (_MAX)
Address Length : 3EE10000 (_LEN)

This is invalid per spec (ACPI 4.0, 6.4.3.5) because it's a fixed size,
fixed location descriptor, but _LEN != _MAX - _MIN + 1.

Based on https://bugzilla.kernel.org/show_bug.cgi?id=15480#c15, I think
Windows handles this by truncating the window so it fits between _MIN and
_MAX. I also verified this by modifying the SeaBIOS DSDT and booting
Windows 2008 R2 with qemu.

This patch makes Linux truncate the window, too, which fixes:
http://bugzilla.kernel.org/show_bug.cgi?id=15480

Signed-off-by: Bjorn Helgaas <[e-mail]>
Tested-by: Yanko Kaneti <[e-mail]>
Signed-off-by: Jesse Barnes <[e-mail]>

arch/x86/pci/acpi.c

···
 	acpi_status status;
 	unsigned long flags;
 	struct resource *root, *conflict;
-	u64 start, end;
+	u64 start, end, max_len;
 
 	status = resource_to_addr(acpi_res, &addr);
 	if (!ACPI_SUCCESS(status))
···
 		flags = IORESOURCE_IO;
 	} else
 		return AE_OK;
+
+	max_len = addr.maximum - addr.minimum + 1;
+	if (addr.address_length > max_len) {
+		dev_printk(KERN_DEBUG, &info->bridge->dev,
+			   "host bridge window length %#llx doesn't fit in "
+			   "%#llx-%#llx, trimming\n",
+			   (unsigned long long) addr.address_length,
+			   (unsigned long long) addr.minimum,
+			   (unsigned long long) addr.maximum);
+		addr.address_length = max_len;
+	}
 
 	start = addr.minimum + addr.translation_offset;
 	end = start + addr.address_length - 1;