processor.h

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/*
 * include/asm-m68k/processor.h
 *
 * Copyright (C) 1995 Hamish Macdonald
 */

#ifndef __ASM_M68K_PROCESSOR_H
#define __ASM_M68K_PROCESSOR_H

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

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

static inline unsigned long rdusp(void)
{
#ifdef CONFIG_COLDFIRE_SW_A7
    extern unsigned int sw_usp;
    return sw_usp;
#else
    register unsigned long usp __asm__("a0");
    /* move %usp,%a0 */
    __asm__ __volatile__(".word 0x4e68" : "=a" (usp));
    return usp;
#endif
}

static inline void wrusp(unsigned long usp)
{
#ifdef CONFIG_COLDFIRE_SW_A7
    extern unsigned int sw_usp;
    sw_usp = usp;
#else
    register unsigned long a0 __asm__("a0") = usp;
    /* move %a0,%usp */
    __asm__ __volatile__(".word 0x4e60" : : "a" (a0) );
#endif
}

/*
 * 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.
 */
#ifdef CONFIG_MMU
#if defined(CONFIG_COLDFIRE)
#define TASK_SIZE   (0xC0000000UL)
#elif defined(CONFIG_SUN3)
#define TASK_SIZE   (0x0E000000UL)
#else
#define TASK_SIZE   (0xF0000000UL)
#endif
#else
#define TASK_SIZE   (0xFFFFFFFFUL)
#endif

#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.
 */
#ifdef CONFIG_MMU
#if defined(CONFIG_COLDFIRE)
#define TASK_UNMAPPED_BASE  0x60000000UL
#elif defined(CONFIG_SUN3)
#define TASK_UNMAPPED_BASE  0x0A000000UL
#else
#define TASK_UNMAPPED_BASE  0xC0000000UL
#endif
#define TASK_UNMAPPED_ALIGN(addr, off)  PAGE_ALIGN(addr)
#else
#define TASK_UNMAPPED_BASE  0
#endif

struct thread_struct {
    unsigned long  ksp;     /* kernel stack pointer */
    unsigned long  usp;     /* user stack pointer */
    unsigned short sr;      /* saved status register */
    unsigned short fs;      /* saved fs (sfc, dfc) */
    unsigned long  crp[2];      /* cpu root pointer */
    unsigned long  esp0;        /* points to SR of stack frame */
    unsigned long  faddr;       /* info about last fault */
    int            signo, code;
    unsigned long  fp[8*3];
    unsigned long  fpcntl[3];   /* fp control regs */
    unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
};

#define INIT_THREAD  {                          \
    .ksp    = sizeof(init_stack) + (unsigned long) init_stack,  \
    .sr = PS_S,                         \
    .fs = __KERNEL_DS,                      \
}

/*
 * ColdFire stack format sbould be 0x4 for an aligned usp (will always be
 * true on thread creation). We need to set this explicitly.
 */
#ifdef CONFIG_COLDFIRE
#define setframeformat(_regs)   do { (_regs)->format = 0x4; } while(0)
#else
#define setframeformat(_regs)   do { } while (0)
#endif

#ifdef CONFIG_MMU
/*
 * Do necessary setup to start up a newly executed thread.
 */
static inline void start_thread(struct pt_regs * regs, unsigned long pc,
                unsigned long usp)
{
    regs->pc = pc;
    regs->sr &= ~0x2000;
    setframeformat(regs);
    wrusp(usp);
}

extern int handle_kernel_fault(struct pt_regs *regs);

#else

#define start_thread(_regs, _pc, _usp)                  \
do {                                                    \
    (_regs)->pc = (_pc);                            \
    ((struct switch_stack *)(_regs))[-1].a6 = 0;    \
    setframeformat(_regs);                          \
    if (current->mm)                                \
        (_regs)->d5 = current->mm->start_data;  \
    (_regs)->sr &= ~0x2000;                         \
    wrusp(_usp);                                    \
} while(0)

static inline  int handle_kernel_fault(struct pt_regs *regs)
{
    /* Any fault in kernel is fatal on non-mmu */
    return 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)
{
}

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

extern 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 && \
        (virt_addr_valid((tsk)->thread.esp0))) \
          eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
    eip; })
#define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)

#define task_pt_regs(tsk)   ((struct pt_regs *) ((tsk)->thread.esp0))

#define cpu_relax() barrier()

#endif