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Initial Import 2.6.0

/*
 *  include/asm-s390/hardirq.h
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
 *
 *  Derived from "include/asm-i386/hardirq.h"
 */

#ifndef __ASM_HARDIRQ_H
#define __ASM_HARDIRQ_H

#include <linux/config.h>
#include <linux/threads.h>
#include <linux/sched.h>
#include <linux/cache.h>
#include <asm/lowcore.h>

/* irq_cpustat_t is unused currently, but could be converted
 * into a percpu variable instead of storing softirq_pending
 * on the lowcore */
typedef struct {
	unsigned int __softirq_pending;
} irq_cpustat_t;

#define softirq_pending(cpu) (lowcore_ptr[(cpu)]->softirq_pending)
#define local_softirq_pending() (S390_lowcore.softirq_pending)

#define __ARCH_IRQ_STAT

/*
 * We put the hardirq and softirq counter into the preemption
 * counter. The bitmask has the following meaning:
 *
 * - bits 0-7 are the preemption count (max preemption depth: 256)
 * - bits 8-15 are the softirq count (max # of softirqs: 256)
 * - bits 16-23 are the hardirq count (max # of hardirqs: 256)
 *
 * - ( bit 26 is the PREEMPT_ACTIVE flag. )
 *
 * PREEMPT_MASK: 0x000000ff
 * SOFTIRQ_MASK: 0x0000ff00
 * HARDIRQ_MASK: 0x00010000
 */

#define PREEMPT_BITS	8
#define SOFTIRQ_BITS	8
#define HARDIRQ_BITS	1

#define PREEMPT_SHIFT	0
#define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)
#define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)

#define __MASK(x)	((1UL << (x))-1)

#define PREEMPT_MASK	(__MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
#define SOFTIRQ_MASK	(__MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
#define HARDIRQ_MASK	(__MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)

#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))

#define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)
#define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)
#define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)

/*
 * Are we doing bottom half or hardware interrupt processing?
 * Are we in a softirq context? Interrupt context?
 */
#define in_irq()		(hardirq_count())
#define in_softirq()		(softirq_count())
#define in_interrupt()		(irq_count())


#define hardirq_trylock()	(!in_interrupt())
#define hardirq_endlock()	do { } while (0)

#define irq_enter()							\
do {									\
	BUG_ON( hardirq_count() );					\
	(preempt_count() += HARDIRQ_OFFSET);				\
} while(0)
	

extern void do_call_softirq(void);
extern void account_ticks(struct pt_regs *);

#define invoke_softirq() do_call_softirq()

#ifdef CONFIG_PREEMPT
# define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked())
# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
#else
# define in_atomic()	(preempt_count() != 0)
# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
#endif

#define irq_exit()							\
do {									\
	preempt_count() -= IRQ_EXIT_OFFSET;				\
	if (!in_interrupt() && local_softirq_pending())			\
		/* Use the async. stack for softirq */			\
		do_call_softirq();					\
	preempt_enable_no_resched();					\
} while (0)

#endif /* __ASM_HARDIRQ_H */