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Commit 86cf898e authored by David Woodhouse's avatar David Woodhouse
Browse files

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: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 799dd75b

drivers/pci/dmar.c

+39 −10
Original line number Diff line number Diff line
@@ -175,15 +175,6 @@ dmar_parse_one_drhd(struct acpi_dmar_header *header) 
	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 @@ int __init dmar_table_init(void) 
	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;