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  * return saved PC of a blocked thread.
  44  */
  45 unsigned long thread_saved_pc(struct task_struct *tsk)
  46 {
  47         return ((unsigned long *) tsk->thread.sp)[3];
  48 }
  49
  50 /*
  51  * power off function, if any
  52  */
  53 void (*pm_power_off)(void);
  54 EXPORT_SYMBOL(pm_power_off);
  55
  56 /*
  57  * On SMP it's slightly faster (but much more power-consuming!)
  58  * to poll the ->work.need_resched flag instead of waiting for the
  59  * cross-CPU IPI to arrive. Use this option with caution.
  60  *
  61  * tglx: No idea why this depends on HOTPLUG_CPU !?!
  62  */
  63 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
  64 void arch_cpu_idle(void)
  65 {
  66         safe_halt();
  67 }
  68 #endif
  69
  70 void release_segments(struct mm_struct *mm)
  71 {
  72 }
  73
  74 void machine_restart(char *cmd)
  75 {
  76 #ifdef CONFIG_KERNEL_DEBUGGER
  77         gdbstub_exit(0);
  78 #endif
  79
  80 #ifdef mn10300_unit_hard_reset
  81         mn10300_unit_hard_reset();
  82 #else
  83         mn10300_proc_hard_reset();
  84 #endif
  85 }
  86
  87 void machine_halt(void)
  88 {
  89 #ifdef CONFIG_KERNEL_DEBUGGER
  90         gdbstub_exit(0);
  91 #endif
  92 }
  93
  94 void machine_power_off(void)
  95 {
  96 #ifdef CONFIG_KERNEL_DEBUGGER
  97         gdbstub_exit(0);
  98 #endif
  99 }
 100
 101 void show_regs(struct pt_regs *regs)
 102 {
 103         show_regs_print_info(KERN_DEFAULT);
 104 }
 105
 106 /*
 107  * free current thread data structures etc..
 108  */
 109 void exit_thread(struct task_struct *tsk)
 110 {
 111         exit_fpu(tsk);
 112 }
 113
 114 void flush_thread(void)
 115 {
 116         flush_fpu();
 117 }
 118
 119 void release_thread(struct task_struct *dead_task)
 120 {
 121 }
 122
 123 /*
 124  * we do not have to muck with descriptors here, that is
 125  * done in switch_mm() as needed.
 126  */
 127 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
 128 {
 129 }
 130
 131 /*
 132  * this gets called so that we can store lazy state into memory and copy the
 133  * current task into the new thread.
 134  */
 135 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 136 {
 137         unlazy_fpu(src);
 138         *dst = *src;
 139         return 0;
 140 }
 141
 142 /*
 143  * set up the kernel stack for a new thread and copy arch-specific thread
 144  * control information
 145  */
 146 int copy_thread(unsigned long clone_flags,
 147                 unsigned long c_usp, unsigned long ustk_size,
 148                 struct task_struct *p)
 149 {
 150         struct thread_info *ti = task_thread_info(p);
 151         struct pt_regs *c_regs;
 152         unsigned long c_ksp;
 153
 154         c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
 155
 156         /* allocate the userspace exception frame and set it up */
 157         c_ksp -= sizeof(struct pt_regs);
 158         c_regs = (struct pt_regs *) c_ksp;
 159         c_ksp -= 12; /* allocate function call ABI slack */
 160
 161         /* set up things up so the scheduler can start the new task */
 162         p->thread.uregs = c_regs;
 163         ti->frame       = c_regs;
 164         p->thread.a3    = (unsigned long) c_regs;
 165         p->thread.sp    = c_ksp;
 166         p->thread.wchan = p->thread.pc;
 167         p->thread.usp   = c_usp;
 168
 169         if (unlikely(p->flags & PF_KTHREAD)) {
 170                 memset(c_regs, 0, sizeof(struct pt_regs));
 171                 c_regs->a0 = c_usp; /* function */
 172                 c_regs->d0 = ustk_size; /* argument */
 173                 local_save_flags(c_regs->epsw);
 174                 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
 175                 p->thread.pc    = (unsigned long) ret_from_kernel_thread;
 176                 return 0;
 177         }
 178         *c_regs = *current_pt_regs();
 179         if (c_usp)
 180                 c_regs->sp = c_usp;
 181         c_regs->epsw &= ~EPSW_FE; /* my FPU */
 182
 183         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 184         if (clone_flags & CLONE_SETTLS)
 185                 c_regs->e2 = current_frame()->d3;
 186
 187         p->thread.pc    = (unsigned long) ret_from_fork;
 188
 189         return 0;
 190 }
 191
 192 unsigned long get_wchan(struct task_struct *p)
 193 {
 194         return p->thread.wchan;
 195 }