intel-iommu: Check for 'DMAR at zero' BIOS error earlier.
Chris Wright has some patches which let us fall back to swiotlb nicely
if IOMMU initialisation fails. But those are a bit much for 2.6.32.
Instead, let's shift the check for the biggest problem, the HP and Acer
BIOS bug which reports a DMAR at physical address zero. That one can
actually be checked much earlier -- before we even admit to having
detected an IOMMU in the first place. So the swiotlb init goes ahead as
we want.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 22b02c6..e5f8fc1 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -175,15 +175,6 @@
int ret = 0;
drhd = (struct acpi_dmar_hardware_unit *)header;
- if (!drhd->address) {
- /* Promote an attitude of violence to a BIOS engineer today */
- WARN(1, "Your BIOS is broken; DMAR reported at address zero!\n"
- "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
- dmi_get_system_info(DMI_BIOS_VENDOR),
- dmi_get_system_info(DMI_BIOS_VERSION),
- dmi_get_system_info(DMI_PRODUCT_VERSION));
- return -ENODEV;
- }
dmaru = kzalloc(sizeof(*dmaru), GFP_KERNEL);
if (!dmaru)
return -ENOMEM;
@@ -591,12 +582,50 @@
return 0;
}
+int __init check_zero_address(void)
+{
+ struct acpi_table_dmar *dmar;
+ struct acpi_dmar_header *entry_header;
+ struct acpi_dmar_hardware_unit *drhd;
+
+ dmar = (struct acpi_table_dmar *)dmar_tbl;
+ entry_header = (struct acpi_dmar_header *)(dmar + 1);
+
+ while (((unsigned long)entry_header) <
+ (((unsigned long)dmar) + dmar_tbl->length)) {
+ /* Avoid looping forever on bad ACPI tables */
+ if (entry_header->length == 0) {
+ printk(KERN_WARNING PREFIX
+ "Invalid 0-length structure\n");
+ return 0;
+ }
+
+ if (entry_header->type == ACPI_DMAR_TYPE_HARDWARE_UNIT) {
+ drhd = (void *)entry_header;
+ if (!drhd->address) {
+ /* Promote an attitude of violence to a BIOS engineer today */
+ WARN(1, "Your BIOS is broken; DMAR reported at address zero!\n"
+ "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
+ dmi_get_system_info(DMI_BIOS_VENDOR),
+ dmi_get_system_info(DMI_BIOS_VERSION),
+ dmi_get_system_info(DMI_PRODUCT_VERSION));
+ return 0;
+ }
+ break;
+ }
+
+ entry_header = ((void *)entry_header + entry_header->length);
+ }
+ return 1;
+}
+
void __init detect_intel_iommu(void)
{
int ret;
ret = dmar_table_detect();
-
+ if (ret)
+ ret = check_zero_address();
{
#ifdef CONFIG_INTR_REMAP
struct acpi_table_dmar *dmar;