1 files changed, 50 insertions, 0 deletions
diff --git a/arch/s390/mm/extable.c b/arch/s390/mm/extable.c
new file mode 100644
index 000000000000..8ac8ad2474a0
--- /dev/null
+++ b/arch/s390/mm/extable.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/extable.h>
+#include <linux/errno.h>
+#include <linux/panic.h>
+#include <asm/asm-extable.h>
+#include <asm/extable.h>
+
+const struct exception_table_entry *s390_search_extables(unsigned long addr)
+{
+	const struct exception_table_entry *fixup;
+	size_t num;
+
+	fixup = search_exception_tables(addr);
+	if (fixup)
+		return fixup;
+	num = __stop_amode31_ex_table - __start_amode31_ex_table;
+	return search_extable(__start_amode31_ex_table, num, addr);
+}
+
+static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+static bool ex_handler_uaccess(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	regs->gprs[ex->data] = -EFAULT;
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+bool fixup_exception(struct pt_regs *regs)
+{
+	const struct exception_table_entry *ex;
+
+	ex = s390_search_extables(instruction_pointer(regs));
+	if (!ex)
+		return false;
+	switch (ex->type) {
+	case EX_TYPE_FIXUP:
+		return ex_handler_fixup(ex, regs);
+	case EX_TYPE_BPF:
+		return ex_handler_bpf(ex, regs);
+	case EX_TYPE_UACCESS:
+		return ex_handler_uaccess(ex, regs);
+	}
+	panic("invalid exception table entry");
+}