dmar: fix using early fixmap mapping for DMAR table parsing

Very early detection of the DMAR tables will setup fixmap mapping. For
parsing these tables later (while enabling dma and/or interrupt remapping),
early fixmap mapping shouldn't be used. Fix it by calling table detection
routines again, which will call generic apci_get_table() for setting up
the correct mapping.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 28 insertions, 22 deletions

diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index bd2c01674f5e..f2c5eb6e78f7 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -289,6 +289,24 @@ dmar_table_print_dmar_entry(struct acpi_dmar_header *header)
         }
 }
 
+/**
+ * dmar_table_detect - checks to see if the platform supports DMAR devices
+ */
+static int __init dmar_table_detect(void)
+{
+        acpi_status status = AE_OK;
+
+        /* if we could find DMAR table, then there are DMAR devices */
+        status = acpi_get_table(ACPI_SIG_DMAR, 0,
+                                (struct acpi_table_header **)&dmar_tbl);
+
+        if (ACPI_SUCCESS(status) && !dmar_tbl) {
+                printk (KERN_WARNING PREFIX "Unable to map DMAR\n");
+                status = AE_NOT_FOUND;
+        }
+
+        return (ACPI_SUCCESS(status) ? 1 : 0);
+}
 
 /**
  * parse_dmar_table - parses the DMA reporting table
@@ -300,6 +318,12 @@ parse_dmar_table(void)
         struct acpi_dmar_header *entry_header;
         int ret = 0;
 
+        /*
+         * Do it again, earlier dmar_tbl mapping could be mapped with
+         * fixed map.
+         */
+        dmar_table_detect();
+
         dmar = (struct acpi_table_dmar *)dmar_tbl;
         if (!dmar)
                 return -ENODEV;
@@ -430,30 +454,11 @@ int __init dmar_table_init(void)
         return 0;
 }
 
-/**
- * early_dmar_detect - checks to see if the platform supports DMAR devices
- */
-int __init early_dmar_detect(void)
-{
-        acpi_status status = AE_OK;
-
-        /* if we could find DMAR table, then there are DMAR devices */
-        status = acpi_get_table(ACPI_SIG_DMAR, 0,
-                                (struct acpi_table_header **)&dmar_tbl);
-
-        if (ACPI_SUCCESS(status) && !dmar_tbl) {
-                printk (KERN_WARNING PREFIX "Unable to map DMAR\n");
-                status = AE_NOT_FOUND;
-        }
-
-        return (ACPI_SUCCESS(status) ? 1 : 0);
-}
-
 void __init detect_intel_iommu(void)
 {
         int ret;
 
-        ret = early_dmar_detect();
+        ret = dmar_table_detect();
 
 #ifdef CONFIG_DMAR
         {
@@ -479,14 +484,16 @@ void __init detect_intel_iommu(void)
                                " x2apic support\n");
 
                         dmar_disabled = 1;
-                        return;
+                        goto end;
                 }
 
                 if (ret && !no_iommu && !iommu_detected && !swiotlb &&
                     !dmar_disabled)
                         iommu_detected = 1;
         }
+end:
 #endif
+        dmar_tbl = NULL;
 }
 
 
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index c360c558e59e..f1984fc3e06d 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -45,7 +45,6 @@ extern struct list_head dmar_drhd_units;
         list_for_each_entry(drhd, &dmar_drhd_units, list)
 
 extern int dmar_table_init(void);
-extern int early_dmar_detect(void);
 extern int dmar_dev_scope_init(void);
 
 /* Intel IOMMU detection */