1 files changed, 79 insertions, 0 deletions

diff --git a/arch/x86/kernel/pci-iommu_table.c b/arch/x86/kernel/pci-iommu_table.c
new file mode 100644
index 000000000000..35ccf75696eb
--- /dev/null
+++ b/arch/x86/kernel/pci-iommu_table.c
@@ -0,0 +1,79 @@
+#include <linux/dma-mapping.h>
+#include <asm/iommu_table.h>
+#include <linux/string.h>
+#include <linux/kallsyms.h>
+
+
+#define DEBUG 1
+
+static struct iommu_table_entry * __init
+find_dependents_of(struct iommu_table_entry *start,
+                   struct iommu_table_entry *finish,
+                   struct iommu_table_entry *q)
+{
+        struct iommu_table_entry *p;
+
+        if (!q)
+                return NULL;
+
+        for (p = start; p < finish; p++)
+                if (p->detect == q->depend)
+                        return p;
+
+        return NULL;
+}
+
+
+void __init sort_iommu_table(struct iommu_table_entry *start,
+                             struct iommu_table_entry *finish) {
+
+        struct iommu_table_entry *p, *q, tmp;
+
+        for (p = start; p < finish; p++) {
+again:
+                q = find_dependents_of(start, finish, p);
+                /* We are bit sneaky here. We use the memory address to figure
+                 * out if the node we depend on is past our point, if so, swap.
+                 */
+                if (q > p) {
+                        tmp = *p;
+                        memmove(p, q, sizeof(*p));
+                        *q = tmp;
+                        goto again;
+                }
+        }
+
+}
+
+#ifdef DEBUG
+void __init check_iommu_entries(struct iommu_table_entry *start,
+                                struct iommu_table_entry *finish)
+{
+        struct iommu_table_entry *p, *q, *x;
+
+        /* Simple cyclic dependency checker. */
+        for (p = start; p < finish; p++) {
+                q = find_dependents_of(start, finish, p);
+                x = find_dependents_of(start, finish, q);
+                if (p == x) {
+                        printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
+                               p->detect, q->detect);
+                        /* Heavy handed way..*/
+                        x->depend = 0;
+                }
+        }
+
+        for (p = start; p < finish; p++) {
+                q = find_dependents_of(p, finish, p);
+                if (q && q > p) {
+                        printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
+                               p->detect, q->detect);
+                }
+        }
+}
+#else
+inline void check_iommu_entries(struct iommu_table_entry *start,
+                                       struct iommu_table_entry *finish)
+{
+}
+#endif