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 release_segments(struct mm_struct *mm)
  63 {
  64 }
  65
  66 void machine_restart(char *cmd)
  67 {
  68 #ifdef CONFIG_KERNEL_DEBUGGER
  69         gdbstub_exit(0);
  70 #endif
  71
  72 #ifdef mn10300_unit_hard_reset
  73         mn10300_unit_hard_reset();
  74 #else
  75         mn10300_proc_hard_reset();
  76 #endif
  77 }
  78
  79 void machine_halt(void)
  80 {
  81 #ifdef CONFIG_KERNEL_DEBUGGER
  82         gdbstub_exit(0);
  83 #endif
  84 }
  85
  86 void machine_power_off(void)
  87 {
  88 #ifdef CONFIG_KERNEL_DEBUGGER
  89         gdbstub_exit(0);
  90 #endif
  91 }
  92
  93 void show_regs(struct pt_regs *regs)
  94 {
  95         show_regs_print_info(KERN_DEFAULT);
  96 }
  97
  98 /*
  99  * free current thread data structures etc..
 100  */
 101 void exit_thread(struct task_struct *tsk)
 102 {
 103         exit_fpu(tsk);
 104 }
 105
 106 void flush_thread(void)
 107 {
 108         flush_fpu();
 109 }
 110
 111 void release_thread(struct task_struct *dead_task)
 112 {
 113 }
 114
 115 /*
 116  * we do not have to muck with descriptors here, that is
 117  * done in switch_mm() as needed.
 118  */
 119 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
 120 {
 121 }
 122
 123 /*
 124  * this gets called so that we can store lazy state into memory and copy the
 125  * current task into the new thread.
 126  */
 127 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 128 {
 129         unlazy_fpu(src);
 130         *dst = *src;
 131         return 0;
 132 }
 133
 134 /*
 135  * set up the kernel stack for a new thread and copy arch-specific thread
 136  * control information
 137  */
 138 int copy_thread(unsigned long clone_flags,
 139                 unsigned long c_usp, unsigned long ustk_size,
 140                 struct task_struct *p)
 141 {
 142         struct thread_info *ti = task_thread_info(p);
 143         struct pt_regs *c_regs;
 144         unsigned long c_ksp;
 145
 146         c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
 147
 148         /* allocate the userspace exception frame and set it up */
 149         c_ksp -= sizeof(struct pt_regs);
 150         c_regs = (struct pt_regs *) c_ksp;
 151         c_ksp -= 12; /* allocate function call ABI slack */
 152
 153         /* set up things up so the scheduler can start the new task */
 154         p->thread.uregs = c_regs;
 155         ti->frame       = c_regs;
 156         p->thread.a3    = (unsigned long) c_regs;
 157         p->thread.sp    = c_ksp;
 158         p->thread.wchan = p->thread.pc;
 159         p->thread.usp   = c_usp;
 160
 161         if (unlikely(p->flags & PF_KTHREAD)) {
 162                 memset(c_regs, 0, sizeof(struct pt_regs));
 163                 c_regs->a0 = c_usp; /* function */
 164                 c_regs->d0 = ustk_size; /* argument */
 165                 local_save_flags(c_regs->epsw);
 166                 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
 167                 p->thread.pc    = (unsigned long) ret_from_kernel_thread;
 168                 return 0;
 169         }
 170         *c_regs = *current_pt_regs();
 171         if (c_usp)
 172                 c_regs->sp = c_usp;
 173         c_regs->epsw &= ~EPSW_FE; /* my FPU */
 174
 175         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 176         if (clone_flags & CLONE_SETTLS)
 177                 c_regs->e2 = current_frame()->d3;
 178
 179         p->thread.pc    = (unsigned long) ret_from_fork;
 180
 181         return 0;
 182 }
 183
 184 unsigned long get_wchan(struct task_struct *p)
 185 {
 186         return p->thread.wchan;
 187 }