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/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/smp.h>
  18 #include <linux/stddef.h>
  19 #include <linux/unistd.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/user.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/delay.h>
  24 #include <linux/reboot.h>
  25 #include <linux/percpu.h>
  26 #include <linux/err.h>
  27 #include <linux/fs.h>
  28 #include <linux/slab.h>
  29 #include <linux/rcupdate.h>
  30 #include <linux/uaccess.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/io.h>
  33 #include <asm/processor.h>
  34 #include <asm/mmu_context.h>
  35 #include <asm/fpu.h>
  36 #include <asm/reset-regs.h>
  37 #include <asm/gdb-stub.h>
  38 #include "internal.h"
  39
  40 /*
  41  * return saved PC of a blocked thread.
  42  */
  43 unsigned long thread_saved_pc(struct task_struct *tsk)
  44 {
  45         return ((unsigned long *) tsk->thread.sp)[3];
  46 }
  47
  48 /*
  49  * power off function, if any
  50  */
  51 void (*pm_power_off)(void);
  52 EXPORT_SYMBOL(pm_power_off);
  53
  54 /*
  55  * On SMP it's slightly faster (but much more power-consuming!)
  56  * to poll the ->work.need_resched flag instead of waiting for the
  57  * cross-CPU IPI to arrive. Use this option with caution.
  58  *
  59  * tglx: No idea why this depends on HOTPLUG_CPU !?!
  60  */
  61 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
  62 void arch_cpu_idle(void)
  63 {
  64         safe_halt();
  65 }
  66 #endif
  67
  68 void release_segments(struct mm_struct *mm)
  69 {
  70 }
  71
  72 void machine_restart(char *cmd)
  73 {
  74 #ifdef CONFIG_KERNEL_DEBUGGER
  75         gdbstub_exit(0);
  76 #endif
  77
  78 #ifdef mn10300_unit_hard_reset
  79         mn10300_unit_hard_reset();
  80 #else
  81         mn10300_proc_hard_reset();
  82 #endif
  83 }
  84
  85 void machine_halt(void)
  86 {
  87 #ifdef CONFIG_KERNEL_DEBUGGER
  88         gdbstub_exit(0);
  89 #endif
  90 }
  91
  92 void machine_power_off(void)
  93 {
  94 #ifdef CONFIG_KERNEL_DEBUGGER
  95         gdbstub_exit(0);
  96 #endif
  97 }
  98
  99 void show_regs(struct pt_regs *regs)
 100 {
 101         show_regs_print_info(KERN_DEFAULT);
 102 }
 103
 104 /*
 105  * free current thread data structures etc..
 106  */
 107 void exit_thread(struct task_struct *tsk)
 108 {
 109         exit_fpu(tsk);
 110 }
 111
 112 void flush_thread(void)
 113 {
 114         flush_fpu();
 115 }
 116
 117 void release_thread(struct task_struct *dead_task)
 118 {
 119 }
 120
 121 /*
 122  * we do not have to muck with descriptors here, that is
 123  * done in switch_mm() as needed.
 124  */
 125 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
 126 {
 127 }
 128
 129 /*
 130  * this gets called so that we can store lazy state into memory and copy the
 131  * current task into the new thread.
 132  */
 133 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 134 {
 135         unlazy_fpu(src);
 136         *dst = *src;
 137         return 0;
 138 }
 139
 140 /*
 141  * set up the kernel stack for a new thread and copy arch-specific thread
 142  * control information
 143  */
 144 int copy_thread(unsigned long clone_flags,
 145                 unsigned long c_usp, unsigned long ustk_size,
 146                 struct task_struct *p)
 147 {
 148         struct thread_info *ti = task_thread_info(p);
 149         struct pt_regs *c_regs;
 150         unsigned long c_ksp;
 151
 152         c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
 153
 154         /* allocate the userspace exception frame and set it up */
 155         c_ksp -= sizeof(struct pt_regs);
 156         c_regs = (struct pt_regs *) c_ksp;
 157         c_ksp -= 12; /* allocate function call ABI slack */
 158
 159         /* set up things up so the scheduler can start the new task */
 160         p->thread.uregs = c_regs;
 161         ti->frame       = c_regs;
 162         p->thread.a3    = (unsigned long) c_regs;
 163         p->thread.sp    = c_ksp;
 164         p->thread.wchan = p->thread.pc;
 165         p->thread.usp   = c_usp;
 166
 167         if (unlikely(p->flags & PF_KTHREAD)) {
 168                 memset(c_regs, 0, sizeof(struct pt_regs));
 169                 c_regs->a0 = c_usp; /* function */
 170                 c_regs->d0 = ustk_size; /* argument */
 171                 local_save_flags(c_regs->epsw);
 172                 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
 173                 p->thread.pc    = (unsigned long) ret_from_kernel_thread;
 174                 return 0;
 175         }
 176         *c_regs = *current_pt_regs();
 177         if (c_usp)
 178                 c_regs->sp = c_usp;
 179         c_regs->epsw &= ~EPSW_FE; /* my FPU */
 180
 181         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 182         if (clone_flags & CLONE_SETTLS)
 183                 c_regs->e2 = current_frame()->d3;
 184
 185         p->thread.pc    = (unsigned long) ret_from_fork;
 186
 187         return 0;
 188 }
 189
 190 unsigned long get_wchan(struct task_struct *p)
 191 {
 192         return p->thread.wchan;
 193 }