linux/arch/arc/include/asm/syscalls.h
Vineet Gupta 91e040a79d 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>
2016-10-24 09:24:26 -07:00

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C

/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _ASM_ARC_SYSCALLS_H
#define _ASM_ARC_SYSCALLS_H 1
#include <linux/compiler.h>
#include <linux/linkage.h>
#include <linux/types.h>
int sys_clone_wrapper(int, int, int, int, int);
int sys_cacheflush(uint32_t, uint32_t uint32_t);
int sys_arc_settls(void *);
int sys_arc_gettls(void);
int sys_arc_usr_cmpxchg(int *, int, int);
#include <asm-generic/syscalls.h>
#endif