patch-2.4.22 linux-2.4.22/arch/sh64/mm/extable.c
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- 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) ©_user_memcpy) && (addr <= (unsigned long) ©_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;
+}
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