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1a29ef8e97
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@19815 3c298f89-4303-0410-b956-a3cf2f4a3e73
102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
/*
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* arch/ubicom32/include/asm/system.h
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* Low level switching definitions.
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*
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* (C) Copyright 2009, Ubicom, Inc.
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*
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* This file is part of the Ubicom32 Linux Kernel Port.
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*
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* The Ubicom32 Linux Kernel Port is free software: you can redistribute
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* it and/or modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, either version 2 of the
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* License, or (at your option) any later version.
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*
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* The Ubicom32 Linux Kernel Port is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with the Ubicom32 Linux Kernel Port. If not,
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* see <http://www.gnu.org/licenses/>.
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*
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* Ubicom32 implementation derived from (with many thanks):
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* arch/m68knommu
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* arch/blackfin
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* arch/parisc
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*/
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#ifndef _ASM_UBICOM32_SYSTEM_H
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#define _ASM_UBICOM32_SYSTEM_H
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#include <linux/irqflags.h>
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#include <linux/linkage.h>
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#include <asm/segment.h>
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#include <asm/entry.h>
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#include <asm/ldsr.h>
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#include <asm/irq.h>
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#include <asm/percpu.h>
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#include <asm/ubicom32-common.h>
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#include <asm/processor.h>
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/*
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* switch_to(n) should switch tasks to task ptr, first checking that
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* ptr isn't the current task, in which case it does nothing.
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*/
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asmlinkage void resume(void);
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extern void *__switch_to(struct task_struct *prev,
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struct thread_struct *prev_switch,
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struct thread_struct *next_switch);
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/*
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* We will need a per linux thread sw_ksp for the switch_to macro to
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* track the kernel stack pointer for the current thread on that linux thread.
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*/
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#define switch_to(prev,next,last) \
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({ \
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void *_last; \
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_last = (void *) \
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__switch_to(prev, &prev->thread, &next->thread); \
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(last) = _last; \
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})
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/*
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* Force strict CPU ordering.
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* Not really required on ubicom32...
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*/
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#define nop() asm volatile ("nop"::)
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#define mb() asm volatile ("" : : :"memory")
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#define rmb() asm volatile ("" : : :"memory")
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#define wmb() asm volatile ("" : : :"memory")
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#define set_mb(var, value) ({ (var) = (value); wmb(); })
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#ifdef CONFIG_SMP
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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#define smp_read_barrier_depends() read_barrier_depends()
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#else
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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#define smp_read_barrier_depends() do { } while(0)
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#endif
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#define read_barrier_depends() ((void)0)
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/*
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* The following defines change how the scheduler calls the switch_to()
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* macro.
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*
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* 1) The first causes the runqueue to be unlocked on entry to
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* switch_to(). Since our ctx code does not play with the runqueue
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* we do not need it unlocked.
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*
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* 2) The later turns interrupts on during a ctxsw to reduce the latency of
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* interrupts during ctx. At this point in the port, we believe that this
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* latency is not a problem since we have very little code to perform a ctxsw.
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*/
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// #define __ARCH_WANT_UNLOCKED_CTXSW
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// #define __ARCH_WANT_INTERRUPTS_ON_CTXSW
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#endif /* _ASM_UBICOM32_SYSTEM_H */
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