processor.h

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/*
 * include/asm-h8300/processor.h
 *
 * Copyright (C) 2002 Yoshinori Sato
 *
 * Based on: linux/asm-m68nommu/processor.h
 *
 * Copyright (C) 1995 Hamish Macdonald
 */

#ifndef __ASM_H8300_PROCESSOR_H
#define __ASM_H8300_PROCESSOR_H

/*
 * Default implementation of macro that returns current
 * instruction pointer ("program counter").
 */
#define current_text_addr() ({ __label__ _l; _l: &&_l;})

#include <linux/compiler.h>
#include <asm/segment.h>
#include <asm/fpu.h>
#include <asm/ptrace.h>
#include <asm/current.h>

static inline unsigned long rdusp(void) {
    extern unsigned int sw_usp;
    return(sw_usp);
}

static inline void wrusp(unsigned long usp) {
    extern unsigned int sw_usp;
    sw_usp = usp;
}

/*
 * User space process size: 3.75GB. This is hardcoded into a few places,
 * so don't change it unless you know what you are doing.
 */
#define TASK_SIZE   (0xFFFFFFFFUL)

#ifdef __KERNEL__
#define STACK_TOP   TASK_SIZE
#define STACK_TOP_MAX   STACK_TOP
#endif

/*
 * This decides where the kernel will search for a free chunk of vm
 * space during mmap's. We won't be using it
 */
#define TASK_UNMAPPED_BASE  0

struct thread_struct {
    unsigned long  ksp;     /* kernel stack pointer */
    unsigned long  usp;     /* user stack pointer */
    unsigned long  ccr;     /* saved status register */
    unsigned long  esp0;            /* points to SR of stack frame */
    struct {
        unsigned short *addr;
        unsigned short inst;
    } breakinfo;
};

#define INIT_THREAD  {                      \
    .ksp  = sizeof(init_stack) + (unsigned long)init_stack, \
    .usp  = 0,                      \
    .ccr  = PS_S,                       \
    .esp0 = 0,                      \
    .breakinfo = {                      \
        .addr = (unsigned short *)-1,           \
        .inst = 0                   \
    }                           \
}

/*
 * Do necessary setup to start up a newly executed thread.
 *
 * pass the data segment into user programs if it exists,
 * it can't hurt anything as far as I can tell
 */
#if defined(__H8300H__)
#define start_thread(_regs, _pc, _usp)                  \
do {                                    \
    (_regs)->pc = (_pc);                        \
    (_regs)->ccr = 0x00;       /* clear all flags */        \
    (_regs)->er5 = current->mm->start_data; /* GOT base */  \
    wrusp((unsigned long)(_usp) - sizeof(unsigned long)*3); \
} while(0)
#endif
#if defined(__H8300S__)
#define start_thread(_regs, _pc, _usp)                  \
do {                                    \
    (_regs)->pc = (_pc);                        \
    (_regs)->ccr = 0x00;       /* clear kernel flag */      \
    (_regs)->exr = 0x78;       /* enable all interrupts */  \
    (_regs)->er5 = current->mm->start_data; /* GOT base */  \
    /* 14 = space for retaddr(4), vector(4), er0(4) and ext(2) on stack */ \
    wrusp(((unsigned long)(_usp)) - 14);                    \
} while(0)
#endif

/* Forward declaration, a strange C thing */
struct task_struct;

/* Free all resources held by a thread. */
static inline void release_thread(struct task_struct *dead_task)
{
}

extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);

/*
 * Free current thread data structures etc..
 */
static inline void exit_thread(void)
{
}

/*
 * Return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *tsk);
unsigned long get_wchan(struct task_struct *p);

#define KSTK_EIP(tsk)   \
    ({          \
    unsigned long eip = 0;   \
    if ((tsk)->thread.esp0 > PAGE_SIZE && \
        MAP_NR((tsk)->thread.esp0) < max_mapnr) \
          eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
    eip; })
#define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)

#define cpu_relax()    barrier()

#define HARD_RESET_NOW() ({     \
        local_irq_disable();        \
        asm("jmp @@0");         \
})

#endif