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/sched/debug.h>
  15 #include <linux/sched/task.h>
  16 #include <linux/sched/task_stack.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.h>
  19 #include <linux/smp.h>
  20 #include <linux/stddef.h>
  21 #include <linux/unistd.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/user.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/delay.h>
  26 #include <linux/reboot.h>
  27 #include <linux/percpu.h>
  28 #include <linux/err.h>
  29 #include <linux/fs.h>
  30 #include <linux/slab.h>
  31 #include <linux/rcupdate.h>
  32 #include <linux/uaccess.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/io.h>
  35 #include <asm/processor.h>
  36 #include <asm/mmu_context.h>
  37 #include <asm/fpu.h>
  38 #include <asm/reset-regs.h>
  39 #include <asm/gdb-stub.h>
  40 #include "internal.h"
  41
  42 /*
  43  * power off function, if any
  44  */
  45 void (*pm_power_off)(void);
  46 EXPORT_SYMBOL(pm_power_off);
  47
  48 /*
  49  * On SMP it's slightly faster (but much more power-consuming!)
  50  * to poll the ->work.need_resched flag instead of waiting for the
  51  * cross-CPU IPI to arrive. Use this option with caution.
  52  *
  53  * tglx: No idea why this depends on HOTPLUG_CPU !?!
  54  */
  55 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
  56 void arch_cpu_idle(void)
  57 {
  58         safe_halt();
  59 }
  60 #endif
  61
  62 void machine_restart(char *cmd)
  63 {
  64 #ifdef CONFIG_KERNEL_DEBUGGER
  65         gdbstub_exit(0);
  66 #endif
  67
  68 #ifdef mn10300_unit_hard_reset
  69         mn10300_unit_hard_reset();
  70 #else
  71         mn10300_proc_hard_reset();
  72 #endif
  73 }
  74
  75 void machine_halt(void)
  76 {
  77 #ifdef CONFIG_KERNEL_DEBUGGER
  78         gdbstub_exit(0);
  79 #endif
  80 }
  81
  82 void machine_power_off(void)
  83 {
  84 #ifdef CONFIG_KERNEL_DEBUGGER
  85         gdbstub_exit(0);
  86 #endif
  87 }
  88
  89 void show_regs(struct pt_regs *regs)
  90 {
  91         show_regs_print_info(KERN_DEFAULT);
  92 }
  93
  94 /*
  95  * free current thread data structures etc..
  96  */
  97 void exit_thread(struct task_struct *tsk)
  98 {
  99         exit_fpu(tsk);
 100 }
 101
 102 void flush_thread(void)
 103 {
 104         flush_fpu();
 105 }
 106
 107 void release_thread(struct task_struct *dead_task)
 108 {
 109 }
 110
 111 /*
 112  * this gets called so that we can store lazy state into memory and copy the
 113  * current task into the new thread.
 114  */
 115 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 116 {
 117         unlazy_fpu(src);
 118         *dst = *src;
 119         return 0;
 120 }
 121
 122 /*
 123  * set up the kernel stack for a new thread and copy arch-specific thread
 124  * control information
 125  */
 126 int copy_thread(unsigned long clone_flags,
 127                 unsigned long c_usp, unsigned long ustk_size,
 128                 struct task_struct *p)
 129 {
 130         struct thread_info *ti = task_thread_info(p);
 131         struct pt_regs *c_regs;
 132         unsigned long c_ksp;
 133
 134         c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
 135
 136         /* allocate the userspace exception frame and set it up */
 137         c_ksp -= sizeof(struct pt_regs);
 138         c_regs = (struct pt_regs *) c_ksp;
 139         c_ksp -= 12; /* allocate function call ABI slack */
 140
 141         /* set up things up so the scheduler can start the new task */
 142         p->thread.uregs = c_regs;
 143         ti->frame       = c_regs;
 144         p->thread.a3    = (unsigned long) c_regs;
 145         p->thread.sp    = c_ksp;
 146         p->thread.wchan = p->thread.pc;
 147         p->thread.usp   = c_usp;
 148
 149         if (unlikely(p->flags & PF_KTHREAD)) {
 150                 memset(c_regs, 0, sizeof(struct pt_regs));
 151                 c_regs->a0 = c_usp; /* function */
 152                 c_regs->d0 = ustk_size; /* argument */
 153                 local_save_flags(c_regs->epsw);
 154                 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
 155                 p->thread.pc    = (unsigned long) ret_from_kernel_thread;
 156                 return 0;
 157         }
 158         *c_regs = *current_pt_regs();
 159         if (c_usp)
 160                 c_regs->sp = c_usp;
 161         c_regs->epsw &= ~EPSW_FE; /* my FPU */
 162
 163         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 164         if (clone_flags & CLONE_SETTLS)
 165                 c_regs->e2 = current_frame()->d3;
 166
 167         p->thread.pc    = (unsigned long) ret_from_fork;
 168
 169         return 0;
 170 }
 171
 172 unsigned long get_wchan(struct task_struct *p)
 173 {
 174         return p->thread.wchan;
 175 }