patch-2.4.22 linux-2.4.22/arch/sh64/mm/extable.c

• Lines: 96
• Date: 2003-08-25 04:44:40.000000000 -0700
• Orig file: linux-2.4.21/arch/sh64/mm/extable.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/arch/sh64/mm/extable.c linux-2.4.22/arch/sh64/mm/extable.c
@@ -0,0 +1,95 @@
+/*
+ * 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) 2000, 2001  Paolo Alberelli
+ *
+ * Completely coherent with i386/sh/...
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <asm/uaccess.h>
+
+extern const struct exception_table_entry __start___ex_table[];
+extern const struct exception_table_entry __stop___ex_table[];
+
+static inline unsigned long
+search_one_table(const struct exception_table_entry *first,
+		 const struct exception_table_entry *last,
+		 unsigned long value)
+{
+        while (first <= last) {
+		const struct exception_table_entry *mid;
+		long diff;
+
+		mid = (last - first) / 2 + first;
+		diff = mid->insn - value;
+                if (diff == 0)
+                        return mid->fixup;
+                else if (diff < 0)
+
+			/*
+			 * The dicotomic search assumes the same
+			 * upward assignement of linker addresses
+			 * for both .text and __ex_table sections.
+			 * __ex_table entries gets automagically
+			 * ordered.
+			 */
+                        first = mid+1;
+                else
+                        last = mid-1;
+        }
+        return 0;
+}
+
+
+/* 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. */
+unsigned long
+check_exception_ranges(unsigned long addr)
+{
+	extern unsigned long copy_user_memcpy, copy_user_memcpy_end, __copy_user_fixup;
+	if ((addr >= (unsigned long) &copy_user_memcpy) && (addr <= (unsigned long) &copy_user_memcpy_end)) {
+		return (unsigned long) &__copy_user_fixup;
+	}
+
+	return 0; /* no match */
+}
+
+
+unsigned long
+search_exception_table(unsigned long addr)
+{
+	unsigned long ret;
+
+	ret = check_exception_ranges(addr);
+	if (ret) return ret;
+
+#ifndef CONFIG_MODULES
+	/* There is only the kernel to search.  */
+	ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
+	if (ret) return ret;
+#else
+	/* The kernel is the last "module" -- no need to treat it special.  */
+	struct module *mp;
+	for (mp = module_list; mp != NULL; mp = mp->next) {
+		if (mp->ex_table_start == NULL)
+			continue;
+		ret = search_one_table(mp->ex_table_start,
+				       mp->ex_table_end - 1, addr);
+		if (ret) return ret;
+	}
+#endif
+
+	return 0;
+}