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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sh64/mm/extable.c
downloadconfigs-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/sh64/mm/extable.c')
-rw-r--r--arch/sh64/mm/extable.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/arch/sh64/mm/extable.c b/arch/sh64/mm/extable.c
new file mode 100644
index 00000000000..9da50e28b3f
--- /dev/null
+++ b/arch/sh64/mm/extable.c
@@ -0,0 +1,81 @@
+/*
+ * 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;
+extern void __copy_user_fixup(void);
+
+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;
+}
+