alpha: exception table sorting

[pandora-kernel.git] / arch / alpha / mm / extable.c

diff --git a/arch/alpha/mm/extable.c b/arch/alpha/mm/extable.c
index dc7aeda..62dc379 100644 (file)
--- a/arch/alpha/mm/extable.c
+++ b/arch/alpha/mm/extable.c
@@ -3,11 +3,49 @@
  */
 
 #include <linux/module.h>
+#include <linux/sort.h>
 #include <asm/uaccess.h>
 
+static inline unsigned long ex_to_addr(const struct exception_table_entry *x)
+{
+       return (unsigned long)&x->insn + x->insn;
+}
+
+static void swap_ex(void *a, void *b, int size)
+{
+       struct exception_table_entry *ex_a = a, *ex_b = b;
+       unsigned long addr_a = ex_to_addr(ex_a), addr_b = ex_to_addr(ex_b);
+       unsigned int t = ex_a->fixup.unit;
+
+       ex_a->fixup.unit = ex_b->fixup.unit;
+       ex_b->fixup.unit = t;
+       ex_a->insn = (int)(addr_b - (unsigned long)&ex_a->insn);
+       ex_b->insn = (int)(addr_a - (unsigned long)&ex_b->insn);
+}
+
+/*
+ * The exception table needs to be sorted so that the binary
+ * search that we use to find entries in it works properly.
+ * This is used both for the kernel exception table and for
+ * the exception tables of modules that get loaded.
+ */
+static int cmp_ex(const void *a, const void *b)
+{
+       const struct exception_table_entry *x = a, *y = b;
+
+       /* avoid overflow */
+       if (ex_to_addr(x) > ex_to_addr(y))
+               return 1;
+       if (ex_to_addr(x) < ex_to_addr(y))
+               return -1;
+       return 0;
+}
+
 void sort_extable(struct exception_table_entry *start,
                  struct exception_table_entry *finish)
 {
+       sort(start, finish - start, sizeof(struct exception_table_entry),
+            cmp_ex, swap_ex);
 }
 
 const struct exception_table_entry *
@@ -20,7 +58,7 @@ search_extable(const struct exception_table_entry *first,
                unsigned long mid_value;
 
                mid = (last - first) / 2 + first;
-               mid_value = (unsigned long)&mid->insn + mid->insn;
+               mid_value = ex_to_addr(mid);
                 if (mid_value == value)
                         return mid;
                 else if (mid_value < value)