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/*
* arch/ubicom32/include/asm/system.h
* Low level switching definitions.
*
* (C) Copyright 2009, Ubicom, Inc.
*
* This file is part of the Ubicom32 Linux Kernel Port.
*
* The Ubicom32 Linux Kernel Port 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, either version 2 of the
* License, or (at your option) any later version.
*
* The Ubicom32 Linux Kernel Port 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.
*
* You should have received a copy of the GNU General Public License
* along with the Ubicom32 Linux Kernel Port. If not,
* see <http://www.gnu.org/licenses/>.
*
* Ubicom32 implementation derived from (with many thanks):
* arch/m68knommu
* arch/blackfin
* arch/parisc
*/
#ifndef _ASM_UBICOM32_SYSTEM_H
#define _ASM_UBICOM32_SYSTEM_H
#include <linux/irqflags.h>
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/entry.h>
#include <asm/ldsr.h>
#include <asm/irq.h>
#include <asm/percpu.h>
#include <asm/ubicom32-common.h>
#include <asm/processor.h>
/*
* switch_to(n) should switch tasks to task ptr, first checking that
* ptr isn't the current task, in which case it does nothing.
*/
asmlinkage void resume(void);
extern void *__switch_to(struct task_struct *prev,
struct thread_struct *prev_switch,
struct thread_struct *next_switch);
/*
* We will need a per linux thread sw_ksp for the switch_to macro to
* track the kernel stack pointer for the current thread on that linux thread.
*/
#define switch_to(prev,next,last) \
({ \
void *_last; \
_last = (void *) \
__switch_to(prev, &prev->thread, &next->thread); \
(last) = _last; \
})
/*
* Force strict CPU ordering.
* Not really required on ubicom32...
*/
#define nop() asm volatile ("nop"::)
#define mb() asm volatile ("" : : :"memory")
#define rmb() asm volatile ("" : : :"memory")
#define wmb() asm volatile ("" : : :"memory")
#define set_mb(var, value) ({ (var) = (value); wmb(); })
#ifdef CONFIG_SMP
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
#else
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() do { } while(0)
#endif
#define read_barrier_depends() ((void)0)
/*
* The following defines change how the scheduler calls the switch_to()
* macro.
*
* 1) The first causes the runqueue to be unlocked on entry to
* switch_to(). Since our ctx code does not play with the runqueue
* we do not need it unlocked.
*
* 2) The later turns interrupts on during a ctxsw to reduce the latency of
* interrupts during ctx. At this point in the port, we believe that this
* latency is not a problem since we have very little code to perform a ctxsw.
*/
// #define __ARCH_WANT_UNLOCKED_CTXSW
// #define __ARCH_WANT_INTERRUPTS_ON_CTXSW
#endif /* _ASM_UBICOM32_SYSTEM_H */
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