initial_commit

1 files changed, 74 insertions, 0 deletions

diff --git a/arch/frv/mm/extable.c b/arch/frv/mm/extable.c
new file mode 100644
index 00000000..6aea124f
--- /dev/null
+++ b/arch/frv/mm/extable.c
@@ -0,0 +1,74 @@
+/*
+ * linux/arch/frv/mm/extable.c
+ */
+
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <asm/uaccess.h>
+
+extern const struct exception_table_entry __attribute__((aligned(8))) __start___ex_table[];
+extern const struct exception_table_entry __attribute__((aligned(8))) __stop___ex_table[];
+extern const void __memset_end, __memset_user_error_lr, __memset_user_error_handler;
+extern const void __memcpy_end, __memcpy_user_error_lr, __memcpy_user_error_handler;
+extern spinlock_t modlist_lock;
+
+/*****************************************************************************/
+/*
+ *
+ */
+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 __attribute__((aligned(8))) *mid;
+		long diff;
+
+		mid = (last - first) / 2 + first;
+		diff = mid->insn - value;
+                if (diff == 0)
+                        return mid->fixup;
+                else if (diff < 0)
+                        first = mid + 1;
+                else
+                        last = mid - 1;
+        }
+        return 0;
+} /* end search_one_table() */
+
+/*****************************************************************************/
+/*
+ * see if there's a fixup handler available to deal with a kernel fault
+ */
+unsigned long search_exception_table(unsigned long pc)
+{
+	const struct exception_table_entry *extab;
+
+	/* determine if the fault lay during a memcpy_user or a memset_user */
+	if (__frame->lr == (unsigned long) &__memset_user_error_lr &&
+	    (unsigned long) &memset <= pc && pc < (unsigned long) &__memset_end
+	    ) {
+		/* the fault occurred in a protected memset
+		 * - we search for the return address (in LR) instead of the program counter
+		 * - it was probably during a clear_user()
+		 */
+		return (unsigned long) &__memset_user_error_handler;
+	}
+
+	if (__frame->lr == (unsigned long) &__memcpy_user_error_lr &&
+	    (unsigned long) &memcpy <= pc && pc < (unsigned long) &__memcpy_end
+	    ) {
+		/* the fault occurred in a protected memset
+		 * - we search for the return address (in LR) instead of the program counter
+		 * - it was probably during a copy_to/from_user()
+		 */
+		return (unsigned long) &__memcpy_user_error_handler;
+	}
+
+	extab = search_exception_tables(pc);
+	if (extab)
+		return extab->fixup;
+
+	return 0;
+
+} /* end search_exception_table() */