From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/frv/mm/extable.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 arch/frv/mm/extable.c

(limited to 'arch/frv/mm/extable.c')

diff --git a/arch/frv/mm/extable.c b/arch/frv/mm/extable.c
new file mode 100644
index 000000000..8863d6c1d
--- /dev/null
+++ b/arch/frv/mm/extable.c
@@ -0,0 +1,49 @@
+/*
+ * linux/arch/frv/mm/extable.c
+ */
+
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <asm/uaccess.h>
+
+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;
+
+
+/*****************************************************************************/
+/*
+ * 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() */
-- 
cgit v1.2.3-54-g00ecf