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process.c

/* process.c: FRV specific parts of process handling
 *
 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * - Derived from arch/m68k/kernel/process.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#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/elf.h>
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>

#include <asm/asm-offsets.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/setup.h>
#include <asm/pgtable.h>
#include <asm/tlb.h>
#include <asm/gdb-stub.h>
#include <asm/mb-regs.h>

#include "local.h"

asmlinkage void ret_from_fork(void);

#include <asm/pgalloc.h>

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

struct task_struct *alloc_task_struct(void)
{
      struct task_struct *p = kmalloc(THREAD_SIZE, GFP_KERNEL);
      if (p)
            atomic_set((atomic_t *)(p+1), 1);
      return p;
}

void free_task_struct(struct task_struct *p)
{
      if (atomic_dec_and_test((atomic_t *)(p+1)))
            kfree(p);
}

static void core_sleep_idle(void)
{
#ifdef LED_DEBUG_SLEEP
      /* Show that we're sleeping... */
      __set_LEDS(0x55aa);
#endif
      frv_cpu_core_sleep();
#ifdef LED_DEBUG_SLEEP
      /* ... and that we woke up */
      __set_LEDS(0);
#endif
      mb();
}

void (*idle)(void) = core_sleep_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)
{
      int cpu = smp_processor_id();

      /* endless idle loop with no priority at all */
      while (1) {
            while (!need_resched()) {
                  irq_stat[cpu].idle_timestamp = jiffies;

                  check_pgt_cache();

                  if (!frv_dma_inprogress && idle)
                        idle();
            }

            preempt_enable_no_resched();
            schedule();
            preempt_disable();
      }
}

void machine_restart(char * __unused)
{
      unsigned long reset_addr;
#ifdef CONFIG_GDBSTUB
      gdbstub_exit(0);
#endif

      if (PSR_IMPLE(__get_PSR()) == PSR_IMPLE_FR551)
            reset_addr = 0xfefff500;
      else
            reset_addr = 0xfeff0500;

      /* Software reset. */
      asm volatile("      dcef @(gr0,gr0),1 ! membar !"
                 "      sti     %1,@(%0,0) !"
                 "      nop ! nop ! nop ! nop ! nop ! "
                 "      nop ! nop ! nop ! nop ! nop ! "
                 "      nop ! nop ! nop ! nop ! nop ! "
                 "      nop ! nop ! nop ! nop ! nop ! "
                 : : "r" (reset_addr), "r" (1) );

      for (;;)
            ;
}

void machine_halt(void)
{
#ifdef CONFIG_GDBSTUB
      gdbstub_exit(0);
#endif

      for (;;);
}

void machine_power_off(void)
{
#ifdef CONFIG_GDBSTUB
      gdbstub_exit(0);
#endif

      for (;;);
}

void flush_thread(void)
{
#if 0 //ndef NO_FPU
      unsigned long zero = 0;
#endif
      set_fs(USER_DS);
}

inline unsigned long user_stack(const struct pt_regs *regs)
{
      while (regs->next_frame)
            regs = regs->next_frame;
      return user_mode(regs) ? regs->sp : 0;
}

asmlinkage int sys_fork(void)
{
#ifndef CONFIG_MMU
      /* fork almost works, enough to trick you into looking elsewhere:-( */
      return -EINVAL;
#else
      return do_fork(SIGCHLD, user_stack(__frame), __frame, 0, NULL, NULL);
#endif
}

asmlinkage int sys_vfork(void)
{
      return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, user_stack(__frame), __frame, 0,
                   NULL, NULL);
}

/*****************************************************************************/
/*
 * clone a process
 * - tlsptr is retrieved by copy_thread()
 */
asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
                   int __user *parent_tidptr, int __user *child_tidptr,
                   int __user *tlsptr)
{
      if (!newsp)
            newsp = user_stack(__frame);
      return do_fork(clone_flags, newsp, __frame, 0, parent_tidptr, child_tidptr);
} /* end sys_clone() */

/*****************************************************************************/
/*
 * This gets called before we allocate a new thread and copy
 * the current task into it.
 */
void prepare_to_copy(struct task_struct *tsk)
{
      //unlazy_fpu(tsk);
} /* end prepare_to_copy() */

/*****************************************************************************/
/*
 * set up the kernel stack and exception frames for a new process
 */
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 *childregs0, *childregs, *regs0;

      regs0 = __kernel_frame0_ptr;
      childregs0 = (struct pt_regs *)
            (task_stack_page(p) + THREAD_SIZE - FRV_FRAME0_SIZE);
      childregs = childregs0;

      /* set up the userspace frame (the only place that the USP is stored) */
      *childregs0 = *regs0;

      childregs0->gr8         = 0;
      childregs0->sp          = usp;
      childregs0->next_frame  = NULL;

      /* set up the return kernel frame if called from kernel_thread() */
      if (regs != regs0) {
            childregs--;
            *childregs = *regs;
            childregs->sp = (unsigned long) childregs0;
            childregs->next_frame = childregs0;
            childregs->gr15 = (unsigned long) task_thread_info(p);
            childregs->gr29 = (unsigned long) p;
      }

      p->set_child_tid = p->clear_child_tid = NULL;

      p->thread.frame    = childregs;
      p->thread.curr     = p;
      p->thread.sp       = (unsigned long) childregs;
      p->thread.fp       = 0;
      p->thread.lr       = 0;
      p->thread.pc       = (unsigned long) ret_from_fork;
      p->thread.frame0 = childregs0;

      /* the new TLS pointer is passed in as arg #5 to sys_clone() */
      if (clone_flags & CLONE_SETTLS)
            childregs->gr29 = childregs->gr12;

      save_user_regs(p->thread.user);

      return 0;
} /* end copy_thread() */

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
{
      int error;
      char * filename;

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

unsigned long get_wchan(struct task_struct *p)
{
      struct pt_regs *regs0;
      unsigned long fp, pc;
      unsigned long stack_limit;
      int count = 0;
      if (!p || p == current || p->state == TASK_RUNNING)
            return 0;

      stack_limit = (unsigned long) (p + 1);
      fp = p->thread.fp;
      regs0 = p->thread.frame0;

      do {
            if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
                  return 0;

            pc = ((unsigned long *) fp)[2];

            /* FIXME: This depends on the order of these functions. */
            if (!in_sched_functions(pc))
                  return pc;

            fp = *(unsigned long *) fp;
      } while (count++ < 16);

      return 0;
}

unsigned long thread_saved_pc(struct task_struct *tsk)
{
      /* Check whether the thread is blocked in resume() */
      if (in_sched_functions(tsk->thread.pc))
            return ((unsigned long *)tsk->thread.fp)[2];
      else
            return tsk->thread.pc;
}

int elf_check_arch(const struct elf32_hdr *hdr)
{
      unsigned long hsr0 = __get_HSR(0);
      unsigned long psr = __get_PSR();

      if (hdr->e_machine != EM_FRV)
            return 0;

      switch (hdr->e_flags & EF_FRV_GPR_MASK) {
      case EF_FRV_GPR64:
            if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
                  return 0;
      case EF_FRV_GPR32:
      case 0:
            break;
      default:
            return 0;
      }

      switch (hdr->e_flags & EF_FRV_FPR_MASK) {
      case EF_FRV_FPR64:
            if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
                  return 0;
      case EF_FRV_FPR32:
      case EF_FRV_FPR_NONE:
      case 0:
            break;
      default:
            return 0;
      }

      if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
            if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
                PSR_IMPLE(psr) != PSR_IMPLE_FR451)
                  return 0;

      switch (hdr->e_flags & EF_FRV_CPU_MASK) {
      case EF_FRV_CPU_GENERIC:
            break;
      case EF_FRV_CPU_FR300:
      case EF_FRV_CPU_SIMPLE:
      case EF_FRV_CPU_TOMCAT:
      default:
            return 0;
      case EF_FRV_CPU_FR400:
            if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
                PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
                PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
                PSR_IMPLE(psr) != PSR_IMPLE_FR551)
                  return 0;
            break;
      case EF_FRV_CPU_FR450:
            if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
                  return 0;
            break;
      case EF_FRV_CPU_FR500:
            if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
                  return 0;
            break;
      case EF_FRV_CPU_FR550:
            if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
                  return 0;
            break;
      }

      return 1;
}

int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
{
      memcpy(fpregs,
             &current->thread.user->f,
             sizeof(current->thread.user->f));
      return 1;
}

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