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
  46 void (*pm_power_off)(void) = NULL;
  47 EXPORT_SYMBOL(pm_power_off);
  48
  49 asmlinkage void ret_from_fork(void);
  50 asmlinkage 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)
  56 static 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
  67 static void default_idle(void)
  68 {
  69         cpu_relax();
  70 }
  71 #endif
  72 void (*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  */
  80 void 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
  91 void machine_restart(char * __unused)
  92 {
  93         local_irq_disable();
  94         __asm__("jmp @@0");
  95 }
  96
  97 void machine_halt(void)
  98 {
  99         local_irq_disable();
 100         __asm__("sleep");
 101         for (;;);
 102 }
 103
 104 void machine_power_off(void)
 105 {
 106         local_irq_disable();
 107         __asm__("sleep");
 108         for (;;);
 109 }
 110
 111 void 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
 126 void flush_thread(void)
 127 {
 128 }
 129
 130 int 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
 154 unsigned long thread_saved_pc(struct task_struct *tsk)
 155 {
 156         return ((struct pt_regs *)tsk->thread.esp0)->pc;
 157 }
 158
 159 unsigned 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 }