aboutsummaryrefslogtreecommitdiffstats
path: root/arch/mn10300/include/asm/system.h
blob: 3c272a1a101575ea9218850f49e9a8b54617f104 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/* MN10300 System definitions
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#ifndef _ASM_SYSTEM_H
#define _ASM_SYSTEM_H

#include <asm/cpu-regs.h>

#ifdef __KERNEL__
#ifndef __ASSEMBLY__

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

#if !defined(CONFIG_LAZY_SAVE_FPU)
struct fpu_state_struct;
extern asmlinkage void fpu_save(struct fpu_state_struct *);
#define switch_fpu(prev, next)						\
	do {								\
		if ((prev)->thread.fpu_flags & THREAD_HAS_FPU) {	\
			(prev)->thread.fpu_flags &= ~THREAD_HAS_FPU;	\
			(prev)->thread.uregs->epsw &= ~EPSW_FE;		\
			fpu_save(&(prev)->thread.fpu_state);		\
		}							\
	} while (0)
#else
#define switch_fpu(prev, next) do {} while (0)
#endif

struct task_struct;
struct thread_struct;

extern asmlinkage
struct task_struct *__switch_to(struct thread_struct *prev,
				struct thread_struct *next,
				struct task_struct *prev_task);

/* context switching is now performed out-of-line in switch_to.S */
#define switch_to(prev, next, last)					\
do {									\
	switch_fpu(prev, next);						\
	current->thread.wchan = (u_long) __builtin_return_address(0);	\
	(last) = __switch_to(&(prev)->thread, &(next)->thread, (prev));	\
	mb();								\
	current->thread.wchan = 0;					\
} while (0)

#define arch_align_stack(x) (x)

#define nop() asm volatile ("nop")

#endif /* !__ASSEMBLY__ */

/*
 * Force strict CPU ordering.
 * And yes, this is required on UP too when we're talking
 * to devices.
 *
 * For now, "wmb()" doesn't actually do anything, as all
 * Intel CPU's follow what Intel calls a *Processor Order*,
 * in which all writes are seen in the program order even
 * outside the CPU.
 *
 * I expect future Intel CPU's to have a weaker ordering,
 * but I'd also expect them to finally get their act together
 * and add some real memory barriers if so.
 *
 * Some non intel clones support out of order store. wmb() ceases to be a
 * nop for these.
 */

#define mb()	asm volatile ("": : :"memory")
#define rmb()	mb()
#define wmb()	asm volatile ("": : :"memory")

#ifdef CONFIG_SMP
#define smp_mb()	mb()
#define smp_rmb()	rmb()
#define smp_wmb()	wmb()
#else
#define smp_mb()	barrier()
#define smp_rmb()	barrier()
#define smp_wmb()	barrier()
#endif

#define set_mb(var, value)  do { var = value;  mb(); } while (0)
#define set_wmb(var, value) do { var = value; wmb(); } while (0)

#define read_barrier_depends()		do {} while (0)
#define smp_read_barrier_depends()	do {} while (0)

/*****************************************************************************/
/*
 * MN10300 doesn't actually have an exchange instruction
 */
#ifndef __ASSEMBLY__

struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((struct __xchg_dummy *)(x))

static inline
unsigned long __xchg(volatile unsigned long *m, unsigned long val)
{
	unsigned long retval;
	unsigned long flags;

	local_irq_save(flags);
	retval = *m;
	*m = val;
	local_irq_restore(flags);
	return retval;
}

#define xchg(ptr, v)						\
	((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr),	\
				     (unsigned long)(v)))

static inline unsigned long __cmpxchg(volatile unsigned long *m,
				      unsigned long old, unsigned long new)
{
	unsigned long retval;
	unsigned long flags;

	local_irq_save(flags);
	retval = *m;
	if (retval == old)
		*m = new;
	local_irq_restore(flags);
	return retval;
}

#define cmpxchg(ptr, o, n)					\
	((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
					(unsigned long)(o),	\
					(unsigned long)(n)))

#endif /* !__ASSEMBLY__ */

#endif /* __KERNEL__ */
#endif /* _ASM_SYSTEM_H */