v4.19.13 snapshot.
diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
new file mode 100644
index 0000000..8d25f89
--- /dev/null
+++ b/arch/riscv/include/asm/syscall.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ * Copyright 2015 Regents of the University of California, Berkeley
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * See asm-generic/syscall.h for descriptions of what we must do here.
+ */
+
+#ifndef _ASM_RISCV_SYSCALL_H
+#define _ASM_RISCV_SYSCALL_H
+
+#include <linux/sched.h>
+#include <linux/err.h>
+
+/* The array of function pointers for syscalls. */
+extern void *sys_call_table[];
+
+/*
+ * Only the low 32 bits of orig_r0 are meaningful, so we return int.
+ * This importantly ignores the high bits on 64-bit, so comparisons
+ * sign-extend the low 32 bits.
+ */
+static inline int syscall_get_nr(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->a7;
+}
+
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int sysno)
+{
+ regs->a7 = sysno;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ regs->a0 = regs->orig_a0;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ unsigned long error = regs->a0;
+
+ return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->a0;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+ struct pt_regs *regs,
+ int error, long val)
+{
+ regs->a0 = (long) error ?: val;
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ unsigned long *args)
+{
+ BUG_ON(i + n > 6);
+ if (i == 0) {
+ args[0] = regs->orig_a0;
+ args++;
+ i++;
+ n--;
+ }
+ memcpy(args, ®s->a1 + i * sizeof(regs->a1), n * sizeof(args[0]));
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ const unsigned long *args)
+{
+ BUG_ON(i + n > 6);
+ if (i == 0) {
+ regs->orig_a0 = args[0];
+ args++;
+ i++;
+ n--;
+ }
+ memcpy(®s->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
+}
+
+#endif /* _ASM_RISCV_SYSCALL_H */