This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / sh64 / mm / extable.c

diff --git a/arch/sh64/mm/extable.c b/arch/sh64/mm/extable.c
new file mode 100644 (file)
index 0000000..802eff8
--- /dev/null
+++ b/arch/sh64/mm/extable.c
@@ -0,0 +1,80 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * arch/sh64/mm/extable.c
+ *
+ * Copyright (C) 2003 Richard Curnow
+ * Copyright (C) 2003, 2004  Paul Mundt
+ *
+ * Cloned from the 2.5 SH version..
+ */
+#include <linux/config.h>
+#include <linux/rwsem.h>
+#include <linux/module.h>
+#include <asm/uaccess.h>
+
+extern unsigned long copy_user_memcpy, copy_user_memcpy_end, __copy_user_fixup;
+
+static const struct exception_table_entry __copy_user_fixup_ex = {
+       .fixup = (unsigned long)&__copy_user_fixup,
+};
+
+/* Some functions that may trap due to a bad user-mode address have too many loads
+   and stores in them to make it at all practical to label each one and put them all in
+   the main exception table.
+
+   In particular, the fast memcpy routine is like this.  It's fix-up is just to fall back
+   to a slow byte-at-a-time copy, which is handled the conventional way.  So it's functionally
+   OK to just handle any trap occurring in the fast memcpy with that fixup. */
+static const struct exception_table_entry *check_exception_ranges(unsigned long addr)
+{
+       if ((addr >= (unsigned long)&copy_user_memcpy) &&
+           (addr <= (unsigned long)&copy_user_memcpy_end))
+               return &__copy_user_fixup_ex;
+
+       return NULL;
+}
+
+/* Simple binary search */
+const struct exception_table_entry *
+search_extable(const struct exception_table_entry *first,
+                const struct exception_table_entry *last,
+                unsigned long value)
+{
+       const struct exception_table_entry *mid;
+
+       mid = check_exception_ranges(value);
+       if (mid)
+               return mid;
+
+        while (first <= last) {
+               long diff;
+
+               mid = (last - first) / 2 + first;
+               diff = mid->insn - value;
+                if (diff == 0)
+                        return mid;
+                else if (diff < 0)
+                        first = mid+1;
+                else
+                        last = mid-1;
+        }
+
+        return NULL;
+}
+
+int fixup_exception(struct pt_regs *regs)
+{
+       const struct exception_table_entry *fixup;
+
+       fixup = search_exception_tables(regs->pc);
+       if (fixup) {
+               regs->pc = fixup->fixup;
+               return 1;
+       }
+
+       return 0;
+}
+