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Diffstat (limited to 'include/asm-generic/system.h')
| -rw-r--r-- | include/asm-generic/system.h | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/include/asm-generic/system.h b/include/asm-generic/system.h new file mode 100644 index 000000000000..efa403b5e121 --- /dev/null +++ b/include/asm-generic/system.h @@ -0,0 +1,161 @@ +/* Generic system definitions, based on MN10300 definitions. + * + * It should be possible to use these on really simple architectures, + * but it serves more as a starting point for new ports. + * + * 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_GENERIC_SYSTEM_H +#define __ASM_GENERIC_SYSTEM_H + +#ifdef __KERNEL__ +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <linux/irqflags.h> + +#include <asm/cmpxchg-local.h> + +struct task_struct; + +/* context switching is now performed out-of-line in switch_to.S */ +extern struct task_struct *__switch_to(struct task_struct *, + struct task_struct *); +#define switch_to(prev, next, last) \ + do { \ + ((last) = __switch_to((prev), (next))); \ + } 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. + * + * This implementation only contains a compiler barrier. + */ + +#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) + +/* + * we make sure local_irq_enable() doesn't cause priority inversion + */ +#ifndef __ASSEMBLY__ + +/* 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) +{ + unsigned long ret, flags; + + switch (size) { + case 1: +#ifdef __xchg_u8 + return __xchg_u8(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u8 *)ptr; + *(volatile u8 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u8 */ + + case 2: +#ifdef __xchg_u16 + return __xchg_u16(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u16 *)ptr; + *(volatile u16 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u16 */ + + case 4: +#ifdef __xchg_u32 + return __xchg_u32(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u32 *)ptr; + *(volatile u32 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u32 */ + +#ifdef CONFIG_64BIT + case 8: +#ifdef __xchg_u64 + return __xchg_u64(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u64 *)ptr; + *(volatile u64 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u64 */ +#endif /* CONFIG_64BIT */ + + default: + __xchg_called_with_bad_pointer(); + return x; + } +} + +#define xchg(ptr, x) \ + ((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))) + +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_GENERIC_SYSTEM_H */ |