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process.c

/*
 *  linux/arch/m68knommu/kernel/process.c
 *
 *  Copyright (C) 1995  Hamish Macdonald
 *
 *  68060 fixes by Jesper Skov
 *
 *  uClinux changes
 *  Copyright (C) 2000-2002, David McCullough <davidm@snapgear.com>
 */

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

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/interrupt.h>
#include <linux/reboot.h>
#include <linux/fs.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/machdep.h>
#include <asm/setup.h>
#include <asm/pgtable.h>

asmlinkage void ret_from_fork(void);

/*
 * The following aren't currently used.
 */
void (*pm_idle)(void);
EXPORT_SYMBOL(pm_idle);

void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);

/*
 * The idle loop on an m68knommu..
 */
static void default_idle(void)
{
      local_irq_disable();
      while (!need_resched()) {
            /* This stop will re-enable interrupts */
            __asm__("stop #0x2000" : : : "cc");
            local_irq_disable();
      }
      local_irq_enable();
}

void (*idle)(void) = default_idle;

/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle(void)
{
      /* endless idle loop with no priority at all */
      while (1) {
            idle();
            preempt_enable_no_resched();
            schedule();
            preempt_disable();
      }
}

void machine_restart(char * __unused)
{
      if (mach_reset)
            mach_reset();
      for (;;);
}

void machine_halt(void)
{
      if (mach_halt)
            mach_halt();
      for (;;);
}

void machine_power_off(void)
{
      if (mach_power_off)
            mach_power_off();
      for (;;);
}

void show_regs(struct pt_regs * regs)
{
      printk(KERN_NOTICE "\n");
      printk(KERN_NOTICE "Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
             regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
      printk(KERN_NOTICE "ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
             regs->orig_d0, regs->d0, regs->a2, regs->a1);
      printk(KERN_NOTICE "A0: %08lx  D5: %08lx  D4: %08lx\n",
             regs->a0, regs->d5, regs->d4);
      printk(KERN_NOTICE "D3: %08lx  D2: %08lx  D1: %08lx\n",
             regs->d3, regs->d2, regs->d1);
      if (!(regs->sr & PS_S))
            printk(KERN_NOTICE "USP: %08lx\n", rdusp());
}

/*
 * Create a kernel thread
 */
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
      int retval;
      long clone_arg = flags | CLONE_VM;
      mm_segment_t fs;

      fs = get_fs();
      set_fs(KERNEL_DS);

      __asm__ __volatile__ (
                  "movel      %%sp, %%d2\n\t"
                  "movel      %5, %%d1\n\t"
                  "movel      %1, %%d0\n\t"
                  "trap #0\n\t"
                  "cmpl %%sp, %%d2\n\t"
                  "jeq  1f\n\t"
                  "movel      %3, %%sp@-\n\t"
                  "jsr  %4@\n\t"
                  "movel      %2, %%d0\n\t"
                  "trap #0\n"
                  "1:\n\t"
                  "movel      %%d0, %0\n"
            : "=d" (retval)
            : "i" (__NR_clone),
              "i" (__NR_exit),
              "a" (arg),
              "a" (fn),
              "a" (clone_arg)
            : "cc", "%d0", "%d1", "%d2");

      set_fs(fs);
      return retval;
}

void flush_thread(void)
{
#ifdef CONFIG_FPU
      unsigned long zero = 0;
#endif
      set_fs(USER_DS);
      current->thread.fs = __USER_DS;
#ifdef CONFIG_FPU
      if (!FPU_IS_EMU)
            asm volatile (".chip 68k/68881\n\t"
                        "frestore %0@\n\t"
                        ".chip 68k" : : "a" (&zero));
#endif
}

/*
 * "m68k_fork()".. By the time we get here, the
 * non-volatile registers have also been saved on the
 * stack. We do some ugly pointer stuff here.. (see
 * also copy_thread)
 */

asmlinkage int m68k_fork(struct pt_regs *regs)
{
      /* fork almost works, enough to trick you into looking elsewhere :-( */
      return(-EINVAL);
}

asmlinkage int m68k_vfork(struct pt_regs *regs)
{
      return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
}

asmlinkage int m68k_clone(struct pt_regs *regs)
{
      unsigned long clone_flags;
      unsigned long newsp;

      /* syscall2 puts clone_flags in d1 and usp in d2 */
      clone_flags = regs->d1;
      newsp = regs->d2;
      if (!newsp)
            newsp = rdusp();
        return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
}

int copy_thread(int nr, unsigned long clone_flags,
            unsigned long usp, unsigned long topstk,
            struct task_struct * p, struct pt_regs * regs)
{
      struct pt_regs * childregs;
      struct switch_stack * childstack, *stack;
      unsigned long *retp;

      childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;

      *childregs = *regs;
      childregs->d0 = 0;

      retp = ((unsigned long *) regs);
      stack = ((struct switch_stack *) retp) - 1;

      childstack = ((struct switch_stack *) childregs) - 1;
      *childstack = *stack;
      childstack->retpc = (unsigned long)ret_from_fork;

      p->thread.usp = usp;
      p->thread.ksp = (unsigned long)childstack;
      /*
       * Must save the current SFC/DFC value, NOT the value when
       * the parent was last descheduled - RGH  10-08-96
       */
      p->thread.fs = get_fs().seg;

#ifdef CONFIG_FPU
      if (!FPU_IS_EMU) {
            /* Copy the current fpu state */
            asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");

            if (p->thread.fpstate[0])
              asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
                        "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
                        : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
                        : "memory");
            /* Restore the state in case the fpu was busy */
            asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
      }
#endif

      return 0;
}

/* Fill in the fpu structure for a core dump.  */

int dump_fpu(struct pt_regs *regs, struct user_m68kfp_struct *fpu)
{
#ifdef CONFIG_FPU
      char fpustate[216];

      if (FPU_IS_EMU) {
            int i;

            memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
            memcpy(fpu->fpregs, current->thread.fp, 96);
            /* Convert internal fpu reg representation
             * into long double format
             */
            for (i = 0; i < 24; i += 3)
                  fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
                                   ((fpu->fpregs[i] & 0x0000ffff) << 16);
            return 1;
      }

      /* First dump the fpu context to avoid protocol violation.  */
      asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
      if (!fpustate[0])
            return 0;

      asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
            :: "m" (fpu->fpcntl[0])
            : "memory");
      asm volatile ("fmovemx %/fp0-%/fp7,%0"
            :: "m" (fpu->fpregs[0])
            : "memory");
#endif
      return 1;
}

/*
 *    Generic dumping code. Used for panic and debug.
 */
void dump(struct pt_regs *fp)
{
      unsigned long     *sp;
      unsigned char     *tp;
      int         i;

      printk(KERN_EMERG "\n" KERN_EMERG "CURRENT PROCESS:\n" KERN_EMERG "\n");
      printk(KERN_EMERG "COMM=%s PID=%d\n", current->comm, current->pid);

      if (current->mm) {
            printk(KERN_EMERG "TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n",
                  (int) current->mm->start_code,
                  (int) current->mm->end_code,
                  (int) current->mm->start_data,
                  (int) current->mm->end_data,
                  (int) current->mm->end_data,
                  (int) current->mm->brk);
            printk(KERN_EMERG "USER-STACK=%08x KERNEL-STACK=%08x\n"
                  KERN_EMERG "\n",
                  (int) current->mm->start_stack,
                  (int)(((unsigned long) current) + THREAD_SIZE));
      }

      printk(KERN_EMERG "PC: %08lx\n", fp->pc);
      printk(KERN_EMERG "SR: %08lx    SP: %08lx\n", (long) fp->sr, (long) fp);
      printk(KERN_EMERG "d0: %08lx    d1: %08lx    d2: %08lx    d3: %08lx\n",
            fp->d0, fp->d1, fp->d2, fp->d3);
      printk(KERN_EMERG "d4: %08lx    d5: %08lx    a0: %08lx    a1: %08lx\n",
            fp->d4, fp->d5, fp->a0, fp->a1);
      printk(KERN_EMERG "\n" KERN_EMERG "USP: %08x   TRAPFRAME: %08x\n",
            (unsigned int) rdusp(), (unsigned int) fp);

      printk(KERN_EMERG "\n" KERN_EMERG "CODE:");
      tp = ((unsigned char *) fp->pc) - 0x20;
      for (sp = (unsigned long *) tp, i = 0; (i < 0x40);  i += 4) {
            if ((i % 0x10) == 0)
                  printk("\n" KERN_EMERG "%08x: ", (int) (tp + i));
            printk("%08x ", (int) *sp++);
      }
      printk("\n" KERN_EMERG "\n");

      printk(KERN_EMERG "KERNEL STACK:");
      tp = ((unsigned char *) fp) - 0x40;
      for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) {
            if ((i % 0x10) == 0)
                  printk("\n" KERN_EMERG "%08x: ", (int) (tp + i));
            printk("%08x ", (int) *sp++);
      }
      printk("\n" KERN_EMERG "\n");

      printk(KERN_EMERG "USER STACK:");
      tp = (unsigned char *) (rdusp() - 0x10);
      for (sp = (unsigned long *) tp, i = 0; (i < 0x80); i += 4) {
            if ((i % 0x10) == 0)
                  printk("\n" KERN_EMERG "%08x: ", (int) (tp + i));
            printk("%08x ", (int) *sp++);
      }
      printk("\n" KERN_EMERG "\n");
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(char *name, char **argv, char **envp)
{
      int error;
      char * filename;
      struct pt_regs *regs = (struct pt_regs *) &name;

      lock_kernel();
      filename = getname(name);
      error = PTR_ERR(filename);
      if (IS_ERR(filename))
            goto out;
      error = do_execve(filename, argv, envp, regs);
      putname(filename);
out:
      unlock_kernel();
      return error;
}

unsigned long get_wchan(struct task_struct *p)
{
      unsigned long fp, pc;
      unsigned long stack_page;
      int count = 0;
      if (!p || p == current || p->state == TASK_RUNNING)
            return 0;

      stack_page = (unsigned long)p;
      fp = ((struct switch_stack *)p->thread.ksp)->a6;
      do {
            if (fp < stack_page+sizeof(struct thread_info) ||
                fp >= THREAD_SIZE-8+stack_page)
                  return 0;
            pc = ((unsigned long *)fp)[1];
            if (!in_sched_functions(pc))
                  return pc;
            fp = *(unsigned long *) fp;
      } while (count++ < 16);
      return 0;
}

/*
 * Return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *tsk)
{
      struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;

      /* Check whether the thread is blocked in resume() */
      if (in_sched_functions(sw->retpc))
            return ((unsigned long *)sw->a6)[1];
      else
            return sw->retpc;
}


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