LXR linux/arch/h8300/kernel/process.c

   1/*
   2 *  linux/arch/h8300/kernel/process.c
   3 *
   4 * Yoshinori Sato <ysato@users.sourceforge.jp>
   5 *
   6 *  Based on:
   7 *
   8 *  linux/arch/m68knommu/kernel/process.c
   9 *
  10 *  Copyright (C) 1998  D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>,
  11 *                      Kenneth Albanowski <kjahds@kjahds.com>,
  12 *                      The Silver Hammer Group, Ltd.
  13 *
  14 *  linux/arch/m68k/kernel/process.c
  15 *
  16 *  Copyright (C) 1995  Hamish Macdonald
  17 *
  18 *  68060 fixes by Jesper Skov
  19 */
  20
  21/*
  22 * This file handles the architecture-dependent parts of process handling..
  23 */
  24
  25#include <linux/errno.h>
  26#include <linux/module.h>
  27#include <linux/sched.h>
  28#include <linux/kernel.h>
  29#include <linux/mm.h>
  30#include <linux/smp.h>
  31#include <linux/stddef.h>
  32#include <linux/unistd.h>
  33#include <linux/ptrace.h>
  34#include <linux/user.h>
  35#include <linux/interrupt.h>
  36#include <linux/reboot.h>
  37#include <linux/fs.h>
  38#include <linux/slab.h>
  39#include <linux/rcupdate.h>
  40
  41#include <asm/uaccess.h>
  42#include <asm/traps.h>
  43#include <asm/setup.h>
  44#include <asm/pgtable.h>
  45
  46void (*pm_power_off)(void) = NULL;
  47EXPORT_SYMBOL(pm_power_off);
  48
  49asmlinkage void ret_from_fork(void);
  50asmlinkage void ret_from_kernel_thread(void);
  51
  52/*
  53 * The idle loop on an H8/300..
  54 */
  55#if !defined(CONFIG_H8300H_SIM) && !defined(CONFIG_H8S_SIM)
  56static void default_idle(void)
  57{
  58        local_irq_disable();
  59        if (!need_resched()) {
  60                local_irq_enable();
  61                /* XXX: race here! What if need_resched() gets set now? */
  62                __asm__("sleep");
  63        } else
  64                local_irq_enable();
  65}
  66#else
  67static void default_idle(void)
  68{
  69        cpu_relax();
  70}
  71#endif
  72void (*idle)(void) = default_idle;
  73
  74/*
  75 * The idle thread. There's no useful work to be
  76 * done, so just try to conserve power and have a
  77 * low exit latency (ie sit in a loop waiting for
  78 * somebody to say that they'd like to reschedule)
  79 */
  80void cpu_idle(void)
  81{
  82        while (1) {
  83                rcu_idle_enter();
  84                while (!need_resched())
  85                        idle();
  86                rcu_idle_exit();
  87                schedule_preempt_disabled();
  88        }
  89}
  90
  91void machine_restart(char * __unused)
  92{
  93        local_irq_disable();
  94        __asm__("jmp @@0"); 
  95}
  96
  97void machine_halt(void)
  98{
  99        local_irq_disable();
 100        __asm__("sleep");
 101        for (;;);
 102}
 103
 104void machine_power_off(void)
 105{
 106        local_irq_disable();
 107        __asm__("sleep");
 108        for (;;);
 109}
 110
 111void show_regs(struct pt_regs * regs)
 112{
 113        printk("\nPC: %08lx  Status: %02x",
 114               regs->pc, regs->ccr);
 115        printk("\nORIG_ER0: %08lx ER0: %08lx ER1: %08lx",
 116               regs->orig_er0, regs->er0, regs->er1);
 117        printk("\nER2: %08lx ER3: %08lx ER4: %08lx ER5: %08lx",
 118               regs->er2, regs->er3, regs->er4, regs->er5);
 119        printk("\nER6' %08lx ",regs->er6);
 120        if (user_mode(regs))
 121                printk("USP: %08lx\n", rdusp());
 122        else
 123                printk("\n");
 124}
 125
 126void flush_thread(void)
 127{
 128}
 129
 130int copy_thread(unsigned long clone_flags,
 131                unsigned long usp, unsigned long topstk,
 132                 struct task_struct * p)
 133{
 134        struct pt_regs * childregs;
 135
 136        childregs = (struct pt_regs *) (THREAD_SIZE + task_stack_page(p)) - 1;
 137
 138        if (unlikely(p->flags & PF_KTHREAD)) {
 139                memset(childregs, 0, sizeof(struct pt_regs));
 140                childregs->retpc = (unsigned long) ret_from_kernel_thread;
 141                childregs->er4 = topstk; /* arg */
 142                childregs->er5 = usp; /* fn */
 143                p->thread.ksp = (unsigned long)childregs;
 144        }
 145        *childregs = *current_pt_regs();
 146        childregs->retpc = (unsigned long) ret_from_fork;
 147        childregs->er0 = 0;
 148        p->thread.usp = usp ?: rdusp();
 149        p->thread.ksp = (unsigned long)childregs;
 150
 151        return 0;
 152}
 153
 154unsigned long thread_saved_pc(struct task_struct *tsk)
 155{
 156        return ((struct pt_regs *)tsk->thread.esp0)->pc;
 157}
 158
 159unsigned long get_wchan(struct task_struct *p)
 160{
 161        unsigned long fp, pc;
 162        unsigned long stack_page;
 163        int count = 0;
 164        if (!p || p == current || p->state == TASK_RUNNING)
 165                return 0;
 166
 167        stack_page = (unsigned long)p;
 168        fp = ((struct pt_regs *)p->thread.ksp)->er6;
 169        do {
 170                if (fp < stack_page+sizeof(struct thread_info) ||
 171                    fp >= 8184+stack_page)
 172                        return 0;
 173                pc = ((unsigned long *)fp)[1];
 174                if (!in_sched_functions(pc))
 175                        return pc;
 176                fp = *(unsigned long *) fp;
 177        } while (count++ < 16);
 178        return 0;
 179}
 180