/* SPDX-License-Identifier: GPL-2.0 */
/*
 * include/asm-m68k/processor.h
 *
 * Copyright (C) 1995 Hamish Macdonald
 */

#ifndef __ASM_M68K_PROCESSOR_H
#define __ASM_M68K_PROCESSOR_H

#include <linux/preempt.h>
#include <linux/thread_info.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

/* Address spaces (or Function Codes in Motorola lingo) */
#define USER_DATA     1
#define USER_PROGRAM  2
#define SUPER_DATA    5
#define SUPER_PROGRAM 6
#define CPU_SPACE     7

#ifdef CONFIG_CPU_HAS_ADDRESS_SPACES
/*
 * Set the SFC/DFC registers for special MM operations.  For most normal
 * operation these remain set to USER_DATA for the uaccess routines.
 */
static inline void set_fc(unsigned long val)
{
        WARN_ON_ONCE(in_interrupt());

        __asm__ __volatile__ ("movec %0,%/sfc\n\t"
                              "movec %0,%/dfc\n\t"
                              : /* no outputs */ : "r" (val) : "memory");
}

static inline unsigned long get_fc(void)
{
        unsigned long val;

        __asm__ ("movec %/dfc,%0" : "=r" (val) : );

        return val;
}
#else
static inline void set_fc(unsigned long val)
{
}

static inline unsigned long get_fc(void)
{
        return USER_DATA;
}
#endif /* CONFIG_CPU_HAS_ADDRESS_SPACES */

struct thread_struct {
        unsigned long  ksp;             /* kernel stack pointer */
        unsigned long  usp;             /* user stack pointer */
        unsigned short sr;              /* saved status register */
        unsigned short fc;              /* saved fc (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,                                                 \
        .fc     = USER_DATA,                                            \
}

/*
 * 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

/*
 * 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);
}

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

unsigned long __get_wchan(struct task_struct *p);
void show_registers(struct pt_regs *regs);

#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