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Diffstat (limited to 'target/linux/ubicom32/files/arch/ubicom32/include/asm/system.h')
| -rw-r--r-- | target/linux/ubicom32/files/arch/ubicom32/include/asm/system.h | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/target/linux/ubicom32/files/arch/ubicom32/include/asm/system.h b/target/linux/ubicom32/files/arch/ubicom32/include/asm/system.h new file mode 100644 index 000000000..c3ec6083e --- /dev/null +++ b/target/linux/ubicom32/files/arch/ubicom32/include/asm/system.h @@ -0,0 +1,101 @@ +/* + * 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 */ |