arch/mn10300/kernel/process.c

   1 /* MN10300  Process handling code
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11 #include <linux/module.h>
  12 #include <linux/errno.h>
  13 #include <linux/sched.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mm.h>
  16 #include <linux/smp.h>
  17 #include <linux/stddef.h>
  18 #include <linux/unistd.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/user.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/delay.h>
  23 #include <linux/reboot.h>
  24 #include <linux/percpu.h>
  25 #include <linux/err.h>
  26 #include <linux/fs.h>
  27 #include <linux/slab.h>
  28 #include <linux/rcupdate.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/io.h>
  32 #include <asm/processor.h>
  33 #include <asm/mmu_context.h>
  34 #include <asm/fpu.h>
  35 #include <asm/reset-regs.h>
  36 #include <asm/gdb-stub.h>
  37 #include "internal.h"
  38
  39 /*
  40  * return saved PC of a blocked thread.
  41  */
  42 unsigned long thread_saved_pc(struct task_struct *tsk)
  43 {
  44         return ((unsigned long *) tsk->thread.sp)[3];
  45 }
  46
  47 /*
  48  * power off function, if any
  49  */
  50 void (*pm_power_off)(void);
  51 EXPORT_SYMBOL(pm_power_off);
  52
  53 /*
  54  * On SMP it's slightly faster (but much more power-consuming!)
  55  * to poll the ->work.need_resched flag instead of waiting for the
  56  * cross-CPU IPI to arrive. Use this option with caution.
  57  *
  58  * tglx: No idea why this depends on HOTPLUG_CPU !?!
  59  */
  60 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
  61 void arch_cpu_idle(void)
  62 {
  63         safe_halt();
  64 }
  65 #endif
  66
  67 void release_segments(struct mm_struct *mm)
  68 {
  69 }
  70
  71 void machine_restart(char *cmd)
  72 {
  73 #ifdef CONFIG_KERNEL_DEBUGGER
  74         gdbstub_exit(0);
  75 #endif
  76
  77 #ifdef mn10300_unit_hard_reset
  78         mn10300_unit_hard_reset();
  79 #else
  80         mn10300_proc_hard_reset();
  81 #endif
  82 }
  83
  84 void machine_halt(void)
  85 {
  86 #ifdef CONFIG_KERNEL_DEBUGGER
  87         gdbstub_exit(0);
  88 #endif
  89 }
  90
  91 void machine_power_off(void)
  92 {
  93 #ifdef CONFIG_KERNEL_DEBUGGER
  94         gdbstub_exit(0);
  95 #endif
  96 }
  97
  98 void show_regs(struct pt_regs *regs)
  99 {
 100 }
 101
 102 /*
 103  * free current thread data structures etc..
 104  */
 105 void exit_thread(void)
 106 {
 107         exit_fpu();
 108 }
 109
 110 void flush_thread(void)
 111 {
 112         flush_fpu();
 113 }
 114
 115 void release_thread(struct task_struct *dead_task)
 116 {
 117 }
 118
 119 /*
 120  * we do not have to muck with descriptors here, that is
 121  * done in switch_mm() as needed.
 122  */
 123 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
 124 {
 125 }
 126
 127 /*
 128  * this gets called so that we can store lazy state into memory and copy the
 129  * current task into the new thread.
 130  */
 131 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 132 {
 133         unlazy_fpu(src);
 134         *dst = *src;
 135         return 0;
 136 }
 137
 138 /*
 139  * set up the kernel stack for a new thread and copy arch-specific thread
 140  * control information
 141  */
 142 int copy_thread(unsigned long clone_flags,
 143                 unsigned long c_usp, unsigned long ustk_size,
 144                 struct task_struct *p)
 145 {
 146         struct thread_info *ti = task_thread_info(p);
 147         struct pt_regs *c_regs;
 148         unsigned long c_ksp;
 149
 150         c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
 151
 152         /* allocate the userspace exception frame and set it up */
 153         c_ksp -= sizeof(struct pt_regs);
 154         c_regs = (struct pt_regs *) c_ksp;
 155         c_ksp -= 12; /* allocate function call ABI slack */
 156
 157         /* set up things up so the scheduler can start the new task */
 158         p->thread.uregs = c_regs;
 159         ti->frame       = c_regs;
 160         p->thread.a3    = (unsigned long) c_regs;
 161         p->thread.sp    = c_ksp;
 162         p->thread.wchan = p->thread.pc;
 163         p->thread.usp   = c_usp;
 164
 165         if (unlikely(p->flags & PF_KTHREAD)) {
 166                 memset(c_regs, 0, sizeof(struct pt_regs));
 167                 c_regs->a0 = c_usp; /* function */
 168                 c_regs->d0 = ustk_size; /* argument */
 169                 local_save_flags(c_regs->epsw);
 170                 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
 171                 p->thread.pc    = (unsigned long) ret_from_kernel_thread;
 172                 return 0;
 173         }
 174         *c_regs = *current_pt_regs();
 175         if (c_usp)
 176                 c_regs->sp = c_usp;
 177         c_regs->epsw &= ~EPSW_FE; /* my FPU */
 178
 179         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 180         if (clone_flags & CLONE_SETTLS)
 181                 c_regs->e2 = current_frame()->d3;
 182
 183         p->thread.pc    = (unsigned long) ret_from_fork;
 184
 185         return 0;
 186 }
 187
 188 unsigned long get_wchan(struct task_struct *p)
 189 {
 190         return p->thread.wchan;
 191 }