/* $Id: process.c,v 1.1.1.1.2.4 2003/05/29 04:21:33 lethal Exp $
 *
 *  linux/arch/sh/kernel/process.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
 */

/*
 * This file handles the architecture-dependent parts of process handling..
 */

#include <linux/unistd.h>
#include <linux/slab.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/elf.h>

static int hlt_counter=0;

int ubc_usercnt = 0;

#define HARD_IDLE_TIMEOUT (HZ / 3)

void disable_hlt(void)
{
        hlt_counter++;
}

void enable_hlt(void)
{
        hlt_counter--;
}

/*
 * The idle loop on a uniprocessor i386..
 */ 
void cpu_idle(void *unused)
{
        /* endless idle loop with no priority at all */
        init_idle();
        current->nice = 20;
        current->counter = -100;

        while (1) {
                if (hlt_counter) {
                        while (1)
                                if (current->need_resched)
                                        break;
                } else {
                        __cli();
                        while (!current->need_resched) {
                                __sti();
                                asm volatile("sleep" : : : "memory");
                                __cli();
                        }
                        __sti();
                }
                schedule();
                check_pgt_cache();
        }
}

void machine_restart(char * __unused)
{
        /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
        asm volatile("ldc %0, sr\n\t"
                     "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
}

void machine_halt(void)
{
        while (1)
                asm volatile("sleep" : : : "memory");
}

void machine_power_off(void)
{
}

void show_regs(struct pt_regs * regs)
{
        printk("\n");
        printk("PC  : %08lx SP  : %08lx SR  : %08lx TEA : %08x    %s\n",
               regs->pc, regs->regs[15], regs->sr, ctrl_inl(MMU_TEA), print_tainted());
        printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
               regs->regs[0],regs->regs[1],
               regs->regs[2],regs->regs[3]);
        printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
               regs->regs[4],regs->regs[5],
               regs->regs[6],regs->regs[7]);
        printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
               regs->regs[8],regs->regs[9],
               regs->regs[10],regs->regs[11]);
        printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
               regs->regs[12],regs->regs[13],
               regs->regs[14]);
        printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
               regs->mach, regs->macl, regs->gbr, regs->pr);
}

struct task_struct * alloc_task_struct(void)
{
        /* Get two pages */
        return (struct task_struct *) __get_free_pages(GFP_KERNEL,1);
}

void free_task_struct(struct task_struct *p)
{
        free_pages((unsigned long) p, 1);
}

/*
 * Create a kernel thread
 */

/*
 * This is the mechanism for creating a new kernel thread.
 *
 */
int arch_kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{       /* Don't use this in BL=1(cli).  Or else, CPU resets! */
        register unsigned long __sc0 __asm__ ("r0");
        register unsigned long __sc3 __asm__ ("r3") = __NR_clone;
        register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM;
        register unsigned long __sc5 __asm__ ("r5") = 0;
        register unsigned long __sc8 __asm__ ("r8") = (long) arg;
        register unsigned long __sc9 __asm__ ("r9") = (long) fn;

        __asm__("trapa  #0x12\n\t"      /* Linux/SH system call */
                "tst    r0, r0\n\t"     /* child or parent? */
                "bf     1f\n\t"         /* parent - jump */
                "jsr    @r9\n\t"        /* call fn */
                " mov   r8, r4\n\t"     /* push argument */
                "mov    r0, r4\n\t"     /* return value to arg of exit */
                "mov    %1, r3\n\t"     /* exit */
                "trapa  #0x11\n"
                "1:"
                : "=z" (__sc0)
                : "i" (__NR_exit), "r" (__sc3), "r" (__sc4), "r" (__sc5), 
                  "r" (__sc8), "r" (__sc9)
                : "memory", "t");
        return __sc0;
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
        if (current->thread.ubc_pc1) {
                current->thread.ubc_pc1 = 0;
                ubc_usercnt -= 1;
        }
}

void flush_thread(void)
{
#if defined(__sh3__)
        /* do nothing */
        /* Possibly, set clear debug registers */
#elif defined(__SH4__)
        struct task_struct *tsk = current;

        /* Forget lazy FPU state */
        clear_fpu(tsk);
        tsk->used_math = 0;
#endif
}

void release_thread(struct task_struct *dead_task)
{
        /* do nothing */
}

/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
#if defined(__SH4__)
        int fpvalid;
        struct task_struct *tsk = current;

        fpvalid = tsk->used_math;
        if (fpvalid) {
                unlazy_fpu(tsk);
                memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
        }

        return fpvalid;
#else
        return 0; /* Task didn't use the fpu at all. */
#endif
}

asmlinkage void ret_from_fork(void);

int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
                unsigned long unused,
                struct task_struct *p, struct pt_regs *regs)
{
        struct pt_regs *childregs;
#if defined(__SH4__)
        struct task_struct *tsk = current;

        unlazy_fpu(tsk);
        p->thread.fpu = current->thread.fpu;
        p->used_math = tsk->used_math;
#endif
        childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long) p)) - 1;
        *childregs = *regs;

        if (user_mode(regs)) {
                childregs->regs[15] = usp;
        } else {
                childregs->regs[15] = (unsigned long)p+2*PAGE_SIZE;
        }
        childregs->regs[0] = 0; /* Set return value for child */
        childregs->sr |= SR_FD; /* Invalidate FPU flag */

        p->thread.sp = (unsigned long) childregs;
        p->thread.pc = (unsigned long) ret_from_fork;

        p->thread.ubc_pc1 = 0;
        p->thread.ubc_pc2 = 0;

        return 0;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{
        dump->magic = CMAGIC;
        dump->start_code = current->mm->start_code;
        dump->start_data  = current->mm->start_data;
        dump->start_stack = regs->regs[15] & ~(PAGE_SIZE - 1);
        dump->u_tsize = (current->mm->end_code - dump->start_code) >> PAGE_SHIFT;
        dump->u_dsize = (current->mm->brk + (PAGE_SIZE-1) - dump->start_data) >> PAGE_SHIFT;
        dump->u_ssize = (current->mm->start_stack - dump->start_stack +
                         PAGE_SIZE - 1) >> PAGE_SHIFT;
        /* Debug registers will come here. */

        dump->regs = *regs;

        dump->u_fpvalid = dump_fpu(regs, &dump->fpu);
}

/* Tracing by user break controller.  */
static inline void
ubc_set_tracing(int asid, unsigned long nextpc1, unsigned nextpc2)
{
        ctrl_outl(nextpc1, UBC_BARA);
        ctrl_outb(asid, UBC_BASRA);
        if(UBC_TYPE_SH7729){
                ctrl_outl(0, UBC_BAMRA);
                ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
        }else{
                ctrl_outb(0, UBC_BAMRA);
                ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
        }

        if (nextpc2 != (unsigned long) -1) {
                ctrl_outl(nextpc2, UBC_BARB);
                ctrl_outb(asid, UBC_BASRB);
                if(UBC_TYPE_SH7729){
                        ctrl_outl(0, UBC_BAMRB);
                        ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRB);
                }else{
                        ctrl_outb(0, UBC_BAMRB);
                        ctrl_outw(BBR_INST | BBR_READ, UBC_BBRB);
                }
        }
        if(UBC_TYPE_SH7729)
                ctrl_outl(BRCR_PCTE, UBC_BRCR);
        else
                ctrl_outw(0, UBC_BRCR);
}

/*
 *      switch_to(x,y) should switch tasks from x to y.
 *
 */
void __switch_to(struct task_struct *prev, struct task_struct *next)
{
#if defined(__SH4__)
        unlazy_fpu(prev);
#endif

        /*
         * Restore the kernel mode register
         *      k7 (r7_bank1)
         */
        asm volatile("ldc       %0, r7_bank"
                     : /* no output */
                     :"r" (next));

        /* If no tasks are using the UBC, we're done */
        if (ubc_usercnt == 0)
                return;

        /* Otherwise, set or clear UBC as appropriate */
        if (next->thread.ubc_pc1) {
                ubc_set_tracing(next->mm->context & MMU_CONTEXT_ASID_MASK,
                                next->thread.ubc_pc1, next->thread.ubc_pc2);
        } else {
                ctrl_outw(0, UBC_BBRA);
                ctrl_outw(0, UBC_BBRB);
        }
}

asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
                        unsigned long r6, unsigned long r7,
                        struct pt_regs regs)
{
        return do_fork(SIGCHLD, regs.regs[15], &regs, 0);
}

asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
                         unsigned long r6, unsigned long r7,
                         struct pt_regs regs)
{
        if (!newsp)
                newsp = regs.regs[15];
        return do_fork(clone_flags, newsp, &regs, 0);
}

/*
 * This is trivial, and on the face of it looks like it
 * could equally well be done in user mode.
 *
 * Not so, for quite unobvious reasons - register pressure.
 * In user mode vfork() cannot have a stack frame, and if
 * done by calling the "clone()" system call directly, you
 * do not have enough call-clobbered registers to hold all
 * the information you need.
 */
asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
                         unsigned long r6, unsigned long r7,
                         struct pt_regs regs)
{
        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.regs[15], &regs, 0);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(char *ufilename, char **uargv,
                          char **uenvp, unsigned long r7,
                          struct pt_regs regs)
{
        int error;
        char *filename;

        filename = getname(ufilename);
        error = PTR_ERR(filename);
        if (IS_ERR(filename))
                goto out;

        error = do_execve(filename, uargv, uenvp, &regs);
        if (error == 0)
                current->ptrace &= ~PT_DTRACE;
        putname(filename);
out:
        return error;
}

/*
 * These bracket the sleeping functions..
 */
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
#define first_sched     ((unsigned long) scheduling_functions_start_here)
#define last_sched      ((unsigned long) scheduling_functions_end_here)

unsigned long get_wchan(struct task_struct *p)
{
        unsigned long schedule_frame;
        unsigned long pc;

        if (!p || p == current || p->state == TASK_RUNNING)
                return 0;

        /*
         * The same comment as on the Alpha applies here, too ...
         */
        pc = thread_saved_pc(&p->thread);
        if (pc >= (unsigned long) interruptible_sleep_on && pc < (unsigned long) add_timer) {
                schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
                return (unsigned long)((unsigned long *)schedule_frame)[1];
        }
        return pc;
}

asmlinkage void print_syscall(int x)
{
        unsigned long flags, sr;
        asm("stc        sr, %0": "=r" (sr));
        save_and_cli(flags);
        printk("%c: %c %c, %c: SYSCALL\n", (x&63)+32,
               (current->flags&PF_USEDFPU)?'C':' ',
               (init_task.flags&PF_USEDFPU)?'K':' ', (sr&SR_FD)?' ':'F');
        restore_flags(flags);
}

asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
                                 unsigned long r6, unsigned long r7,
                                 struct pt_regs regs)
{
        /* Clear tracing.  */
        ctrl_outw(0, UBC_BBRA);
        ctrl_outw(0, UBC_BBRB);
        current->thread.ubc_pc1 = 0;
        current->thread.ubc_pc2 = (unsigned long) -1;
        ubc_usercnt -= 1;

        force_sig(SIGTRAP, current);
}

asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
                                          unsigned long r6, unsigned long r7,
                                          struct pt_regs regs)
{
        regs.pc -= 2;
        force_sig(SIGTRAP, current);
}