1 files changed, 81 insertions, 0 deletions
diff --git a/arch/s390/include/asm/extable.h b/arch/s390/include/asm/extable.h
new file mode 100644
index 000000000..ce0db8172
--- /dev/null
+++ b/arch/s390/include/asm/extable.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __S390_EXTABLE_H
+#define __S390_EXTABLE_H
+
+#include <asm/ptrace.h>
+#include <linux/compiler.h>
+
+/*
+ * The exception table consists of three addresses:
+ *
+ * - Address of an instruction that is allowed to fault.
+ * - Address at which the program should continue.
+ * - Optional address of handler that takes pt_regs * argument and runs in
+ *   interrupt context.
+ *
+ * No registers are modified, so it is entirely up to the continuation code
+ * to figure out what to do.
+ *
+ * All the routines below use bits of fixup code that are out of line
+ * with the main instruction path.  This means when everything is well,
+ * we don't even have to jump over them.  Further, they do not intrude
+ * on our cache or tlb entries.
+ */
+
+struct exception_table_entry
+{
+	int insn, fixup;
+	long handler;
+};
+
+extern struct exception_table_entry *__start_dma_ex_table;
+extern struct exception_table_entry *__stop_dma_ex_table;
+
+const struct exception_table_entry *s390_search_extables(unsigned long addr);
+
+static inline unsigned long extable_fixup(const struct exception_table_entry *x)
+{
+	return (unsigned long)&x->fixup + x->fixup;
+}
+
+typedef bool (*ex_handler_t)(const struct exception_table_entry *,
+			     struct pt_regs *);
+
+static inline ex_handler_t
+ex_fixup_handler(const struct exception_table_entry *x)
+{
+	if (likely(!x->handler))
+		return NULL;
+	return (ex_handler_t)((unsigned long)&x->handler + x->handler);
+}
+
+static inline bool ex_handle(const struct exception_table_entry *x,
+			     struct pt_regs *regs)
+{
+	ex_handler_t handler = ex_fixup_handler(x);
+
+	if (unlikely(handler))
+		return handler(x, regs);
+	regs->psw.addr = extable_fixup(x);
+	return true;
+}
+
+#define ARCH_HAS_RELATIVE_EXTABLE
+
+static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
+				       struct exception_table_entry *b,
+				       struct exception_table_entry tmp,
+				       int delta)
+{
+	a->fixup = b->fixup + delta;
+	b->fixup = tmp.fixup - delta;
+	a->handler = b->handler;
+	if (a->handler)
+		a->handler += delta;
+	b->handler = tmp.handler;
+	if (b->handler)
+		b->handler -= delta;
+}
+#define swap_ex_entry_fixup swap_ex_entry_fixup
+
+#endif