system.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
 * Copyright (C) 1996 by Paul M. Antoine
 * Copyright (C) 1999 Silicon Graphics
 * Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 2000 MIPS Technologies, Inc.
 */
#ifndef _ASM_SYSTEM_H
#define _ASM_SYSTEM_H

#include <linux/types.h>
#include <linux/irqflags.h>

#include <asm/addrspace.h>
#include <asm/barrier.h>
#include <asm/cpu-features.h>
#include <asm/dsp.h>
#include <asm/war.h>


/*
 * switch_to(n) should switch tasks to task nr n, first
 * checking that n isn't the current task, in which case it does nothing.
 */
extern asmlinkage void *resume(void *last, void *next, void *next_ti);

struct task_struct;

#ifdef CONFIG_MIPS_MT_FPAFF

/*
 * Handle the scheduler resume end of FPU affinity management.  We do this
 * inline to try to keep the overhead down. If we have been forced to run on
 * a "CPU" with an FPU because of a previous high level of FP computation,
 * but did not actually use the FPU during the most recent time-slice (CU1
 * isn't set), we undo the restriction on cpus_allowed.
 *
 * We're not calling set_cpus_allowed() here, because we have no need to
 * force prompt migration - we're already switching the current CPU to a
 * different thread.
 */

#define switch_to(prev,next,last)					\
do {									\
	if (cpu_has_fpu &&						\
	    (prev->thread.mflags & MF_FPUBOUND) &&			\
	     (!(KSTK_STATUS(prev) & ST0_CU1))) {			\
		prev->thread.mflags &= ~MF_FPUBOUND;			\
		prev->cpus_allowed = prev->thread.user_cpus_allowed;	\
	}								\
	if (cpu_has_dsp)						\
		__save_dsp(prev);					\
	next->thread.emulated_fp = 0;					\
	(last) = resume(prev, next, next->thread_info);			\
	if (cpu_has_dsp)						\
		__restore_dsp(current);					\
} while(0)

#else
#define switch_to(prev,next,last)					\
do {									\
	if (cpu_has_dsp)						\
		__save_dsp(prev);					\
	(last) = resume(prev, next, task_thread_info(next));		\
	if (cpu_has_dsp)						\
		__restore_dsp(current);					\
} while(0)
#endif

/*
 * On SMP systems, when the scheduler does migration-cost autodetection,
 * it needs a way to flush as much of the CPU's caches as possible.
 *
 * TODO: fill this in!
 */
static inline void sched_cacheflush(void)
{
}

static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
{
	__u32 retval;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long dummy;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	ll	%0, %3			# xchg_u32	\n"
		"	.set	mips0					\n"
		"	move	%2, %z4					\n"
		"	.set	mips3					\n"
		"	sc	%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
		: "R" (*m), "Jr" (val)
		: "memory");
	} else if (cpu_has_llsc) {
		unsigned long dummy;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	ll	%0, %3			# xchg_u32	\n"
		"	.set	mips0					\n"
		"	move	%2, %z4					\n"
		"	.set	mips3					\n"
		"	sc	%2, %1					\n"
		"	beqz	%2, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
		: "R" (*m), "Jr" (val)
		: "memory");
	} else {
		unsigned long flags;

		local_irq_save(flags);
		retval = *m;
		*m = val;
		local_irq_restore(flags);	/* implies memory barrier  */
	}

	smp_mb();

	return retval;
}

#ifdef CONFIG_64BIT
static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
{
	__u64 retval;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long dummy;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	lld	%0, %3			# xchg_u64	\n"
		"	move	%2, %z4					\n"
		"	scd	%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
		: "R" (*m), "Jr" (val)
		: "memory");
	} else if (cpu_has_llsc) {
		unsigned long dummy;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	lld	%0, %3			# xchg_u64	\n"
		"	move	%2, %z4					\n"
		"	scd	%2, %1					\n"
		"	beqz	%2, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
		: "R" (*m), "Jr" (val)
		: "memory");
	} else {
		unsigned long flags;

		local_irq_save(flags);
		retval = *m;
		*m = val;
		local_irq_restore(flags);	/* implies memory barrier  */
	}

	smp_mb();

	return retval;
}
#else
extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
#endif

/* This function doesn't exist, so you'll get a linker error
   if something tries to do an invalid xchg().  */
extern void __xchg_called_with_bad_pointer(void);

static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
{
	switch (size) {
	case 4:
		return __xchg_u32(ptr, x);
	case 8:
		return __xchg_u64(ptr, x);
	}
	__xchg_called_with_bad_pointer();
	return x;
}

#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
#define tas(ptr) (xchg((ptr),1))

#define __HAVE_ARCH_CMPXCHG 1

static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
	unsigned long new)
{
	__u32 retval;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noat					\n"
		"	.set	mips3					\n"
		"1:	ll	%0, %2			# __cmpxchg_u32	\n"
		"	bne	%0, %z3, 2f				\n"
		"	.set	mips0					\n"
		"	move	$1, %z4					\n"
		"	.set	mips3					\n"
		"	sc	$1, %1					\n"
		"	beqzl	$1, 1b					\n"
		"2:							\n"
		"	.set	pop					\n"
		: "=&r" (retval), "=R" (*m)
		: "R" (*m), "Jr" (old), "Jr" (new)
		: "memory");
	} else if (cpu_has_llsc) {
		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noat					\n"
		"	.set	mips3					\n"
		"1:	ll	%0, %2			# __cmpxchg_u32	\n"
		"	bne	%0, %z3, 2f				\n"
		"	.set	mips0					\n"
		"	move	$1, %z4					\n"
		"	.set	mips3					\n"
		"	sc	$1, %1					\n"
		"	beqz	$1, 1b					\n"
		"2:							\n"
		"	.set	pop					\n"
		: "=&r" (retval), "=R" (*m)
		: "R" (*m), "Jr" (old), "Jr" (new)
		: "memory");
	} else {
		unsigned long flags;

		local_irq_save(flags);
		retval = *m;
		if (retval == old)
			*m = new;
		local_irq_restore(flags);	/* implies memory barrier  */
	}

	smp_mb();

	return retval;
}

#ifdef CONFIG_64BIT
static inline unsigned long __cmpxchg_u64(volatile int * m, unsigned long old,
	unsigned long new)
{
	__u64 retval;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noat					\n"
		"	.set	mips3					\n"
		"1:	lld	%0, %2			# __cmpxchg_u64	\n"
		"	bne	%0, %z3, 2f				\n"
		"	move	$1, %z4					\n"
		"	scd	$1, %1					\n"
		"	beqzl	$1, 1b					\n"
		"2:							\n"
		"	.set	pop					\n"
		: "=&r" (retval), "=R" (*m)
		: "R" (*m), "Jr" (old), "Jr" (new)
		: "memory");
	} else if (cpu_has_llsc) {
		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noat					\n"
		"	.set	mips3					\n"
		"1:	lld	%0, %2			# __cmpxchg_u64	\n"
		"	bne	%0, %z3, 2f				\n"
		"	move	$1, %z4					\n"
		"	scd	$1, %1					\n"
		"	beqz	$1, 1b					\n"
		"2:							\n"
		"	.set	pop					\n"
		: "=&r" (retval), "=R" (*m)
		: "R" (*m), "Jr" (old), "Jr" (new)
		: "memory");
	} else {
		unsigned long flags;

		local_irq_save(flags);
		retval = *m;
		if (retval == old)
			*m = new;
		local_irq_restore(flags);	/* implies memory barrier  */
	}

	smp_mb();

	return retval;
}
#else
extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
	volatile int * m, unsigned long old, unsigned long new);
#define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
#endif

/* This function doesn't exist, so you'll get a linker error
   if something tries to do an invalid cmpxchg().  */
extern void __cmpxchg_called_with_bad_pointer(void);

static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
	unsigned long new, int size)
{
	switch (size) {
	case 4:
		return __cmpxchg_u32(ptr, old, new);
	case 8:
		return __cmpxchg_u64(ptr, old, new);
	}
	__cmpxchg_called_with_bad_pointer();
	return old;
}

#define cmpxchg(ptr,old,new) ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))

extern void set_handler (unsigned long offset, void *addr, unsigned long len);
extern void set_uncached_handler (unsigned long offset, void *addr, unsigned long len);
extern void *set_vi_handler (int n, void *addr);
extern void *set_except_vector(int n, void *addr);
extern unsigned long ebase;
extern void per_cpu_trap_init(void);

extern int stop_a_enabled;

/*
 * See include/asm-ia64/system.h; prevents deadlock on SMP
 * systems.
 */
#define __ARCH_WANT_UNLOCKED_CTXSW

#define arch_align_stack(x) (x)

#endif /* _ASM_SYSTEM_H */