ARC: syscall for userspace cmpxchg assist

Older ARC700 cores (ARC750 specifically) lack instructions to implement
atomic r-w-w. This is problematic for userspace libraries such as NPTL
which need atomic primitives. So enable them by providing kernel assist.
This is costly but really the only sane soluton (othern than tight
spinning using the otherwise availiable atomic exchange EX instruciton).

Good thing is there are only a few of these cores running Linux out in
the wild.

This only works on UP systems.

Reviewed-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

path: root/include/dt-bindings/spmi/spmi.h

/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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.
 */
#ifndef __DT_BINDINGS_SPMI_H
#define __DT_BINDINGS_SPMI_H

#define SPMI_USID	0
#define SPMI_GSID	1

#endif