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system.h

#ifndef __PARISC_SYSTEM_H
#define __PARISC_SYSTEM_H

#include <asm/psw.h>

/* The program status word as bitfields.  */
00007 struct pa_psw {
      unsigned int y:1;
      unsigned int z:1;
      unsigned int rv:2;
      unsigned int w:1;
      unsigned int e:1;
      unsigned int s:1;
      unsigned int t:1;

      unsigned int h:1;
      unsigned int l:1;
      unsigned int n:1;
      unsigned int x:1;
      unsigned int b:1;
      unsigned int c:1;
      unsigned int v:1;
      unsigned int m:1;

      unsigned int cb:8;

      unsigned int o:1;
      unsigned int g:1;
      unsigned int f:1;
      unsigned int r:1;
      unsigned int q:1;
      unsigned int p:1;
      unsigned int d:1;
      unsigned int i:1;
};

#ifdef CONFIG_64BIT
#define pa_psw(task) ((struct pa_psw *) ((char *) (task) + TASK_PT_PSW + 4))
#else
#define pa_psw(task) ((struct pa_psw *) ((char *) (task) + TASK_PT_PSW))
#endif

struct task_struct;

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)

/* interrupt control */
#define local_save_flags(x)   __asm__ __volatile__("ssm 0, %0" : "=r" (x) : : "memory")
#define local_irq_disable()   __asm__ __volatile__("rsm %0,%%r0\n" : : "i" (PSW_I) : "memory" )
#define local_irq_enable()    __asm__ __volatile__("ssm %0,%%r0\n" : : "i" (PSW_I) : "memory" )

#define local_irq_save(x) \
      __asm__ __volatile__("rsm %1,%0" : "=r" (x) :"i" (PSW_I) : "memory" )
#define local_irq_restore(x) \
      __asm__ __volatile__("mtsm %0" : : "r" (x) : "memory" )

#define irqs_disabled()             \
({                            \
      unsigned long flags;          \
      local_save_flags(flags);      \
      (flags & PSW_I) == 0;         \
})

#define mfctl(reg)      ({          \
      unsigned long cr;       \
      __asm__ __volatile__(         \
            "mfctl " #reg ",%0" :   \
             "=r" (cr)        \
      );                      \
      cr;                     \
})

#define mtctl(gr, cr) \
      __asm__ __volatile__("mtctl %0,%1" \
            : /* no outputs */ \
            : "r" (gr), "i" (cr) : "memory")

/* these are here to de-mystefy the calling code, and to provide hooks */
/* which I needed for debugging EIEM problems -PB */
#define get_eiem() mfctl(15)
static inline void set_eiem(unsigned long val)
{
      mtctl(val, 15);
}

#define mfsp(reg) ({          \
      unsigned long cr;       \
      __asm__ __volatile__(         \
            "mfsp " #reg ",%0" :    \
             "=r" (cr)        \
      );                      \
      cr;                     \
})

#define mtsp(gr, cr) \
      __asm__ __volatile__("mtsp %0,%1" \
            : /* no outputs */ \
            : "r" (gr), "i" (cr) : "memory")


/*
** This is simply the barrier() macro from linux/kernel.h but when serial.c
** uses tqueue.h uses smp_mb() defined using barrier(), linux/kernel.h
** hasn't yet been included yet so it fails, thus repeating the macro here.
**
** PA-RISC architecture allows for weakly ordered memory accesses although
** none of the processors use it. There is a strong ordered bit that is
** set in the O-bit of the page directory entry. Operating systems that
** can not tolerate out of order accesses should set this bit when mapping
** pages. The O-bit of the PSW should also be set to 1 (I don't believe any
** of the processor implemented the PSW O-bit). The PCX-W ERS states that
** the TLB O-bit is not implemented so the page directory does not need to
** have the O-bit set when mapping pages (section 3.1). This section also
** states that the PSW Y, Z, G, and O bits are not implemented.
** So it looks like nothing needs to be done for parisc-linux (yet).
** (thanks to chada for the above comment -ggg)
**
** The __asm__ op below simple prevents gcc/ld from reordering
** instructions across the mb() "call".
*/
#define mb()            __asm__ __volatile__("":::"memory") /* barrier() */
#define rmb()           mb()
#define wmb()           mb()
#define smp_mb()  mb()
#define smp_rmb() mb()
#define smp_wmb() mb()
#define smp_read_barrier_depends()  do { } while(0)
#define read_barrier_depends()            do { } while(0)

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

#ifndef CONFIG_PA20
/* Because kmalloc only guarantees 8-byte alignment for kmalloc'd data,
   and GCC only guarantees 8-byte alignment for stack locals, we can't
   be assured of 16-byte alignment for atomic lock data even if we
   specify "__attribute ((aligned(16)))" in the type declaration.  So,
   we use a struct containing an array of four ints for the atomic lock
   type and dynamically select the 16-byte aligned int from the array
   for the semaphore.  */

#define __PA_LDCW_ALIGNMENT   16
#define __ldcw_align(a) ({                            \
      unsigned long __ret = (unsigned long) &(a)->lock[0];  \
      __ret = (__ret + __PA_LDCW_ALIGNMENT - 1)       \
            & ~(__PA_LDCW_ALIGNMENT - 1);             \
      (volatile unsigned int *) __ret;                \
})
#define __LDCW    "ldcw"

#else /*CONFIG_PA20*/
/* From: "Jim Hull" <jim.hull of hp.com>
   I've attached a summary of the change, but basically, for PA 2.0, as
   long as the ",CO" (coherent operation) completer is specified, then the
   16-byte alignment requirement for ldcw and ldcd is relaxed, and instead
   they only require "natural" alignment (4-byte for ldcw, 8-byte for
   ldcd). */

#define __PA_LDCW_ALIGNMENT   4
#define __ldcw_align(a) ((volatile unsigned int *)a)
#define __LDCW    "ldcw,co"

#endif /*!CONFIG_PA20*/

/* LDCW, the only atomic read-write operation PA-RISC has. *sigh*.  */
#define __ldcw(a) ({                                  \
      unsigned __ret;                                 \
      __asm__ __volatile__(__LDCW " 0(%1),%0"               \
            : "=r" (__ret) : "r" (a));                \
      __ret;                                          \
})

#ifdef CONFIG_SMP
# define __lock_aligned __attribute__((__section__(".data.lock_aligned")))
#endif

#define arch_align_stack(x) (x)

#endif

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