[PATCH 4/5] x86: acpi: Print warning for malformed host bridge resources

[Peter Hurley <peter@hurleysoftware.com>]

An incorrectly specified host bridge window may prevent
other devices from claiming assigned resources. For example,
this flawed _CRS resource descriptor from a Dell T5400:
     DWordMemory (ResourceProducer, PosDecode, MinFixed, MaxFixed, NonCacheable, ReadWrite,
     	 0x00000000,         // Granularity
         0xF0000000,         // Range Minimum
         0xFE000000,         // Range Maximum
         0x00000000,         // Translation Offset
         0x0E000000,         // Length
         ,, , AddressRangeMemory, TypeStatic)
prevents the adjacent device from claiming [mem 0xfe0000000-0xfe01ffff]

Sanity check that the resource at least conforms to a valid
PCI BAR; if not, emit a diagnostic warning.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: x86@kernel.org
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
 arch/x86/pci/acpi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 192397c..3468d16 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -298,6 +298,10 @@ setup_resource(struct acpi_resource *acpi_res, void *data)
 			"host bridge window [%#llx-%#llx] "
 			"([%#llx-%#llx] ignored, not CPU addressable)\n", 
 			start, orig_end, end + 1, orig_end);
+	} else if (flags & IORESOURCE_MEM && (start & 0x0f || ~end & 0x0f)) {
+		dev_warn(&info->bridge->dev,
+			 "invalid host bridge window [%#llx-%#llx]\n",
+			 start, end);
 	}
 
 	res = &info->res[info->res_num];
-- 
1.7.12.3