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/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/smp.h>
  19 #include <linux/stddef.h>
  20 #include <linux/unistd.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/user.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/delay.h>
  25 #include <linux/reboot.h>
  26 #include <linux/percpu.h>
  27 #include <linux/err.h>
  28 #include <linux/fs.h>
  29 #include <linux/slab.h>
  30 #include <linux/rcupdate.h>
  31 #include <linux/uaccess.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/io.h>
  34 #include <asm/processor.h>
  35 #include <asm/mmu_context.h>
  36 #include <asm/fpu.h>
  37 #include <asm/reset-regs.h>
  38 #include <asm/gdb-stub.h>
  39 #include "internal.h"
  40
  41 /*
  42  * return saved PC of a blocked thread.
  43  */
  44 unsigned long thread_saved_pc(struct task_struct *tsk)
  45 {
  46         return ((unsigned long *) tsk->thread.sp)[3];
  47 }
  48
  49 /*
  50  * power off function, if any
  51  */
  52 void (*pm_power_off)(void);
  53 EXPORT_SYMBOL(pm_power_off);
  54
  55 /*
  56  * On SMP it's slightly faster (but much more power-consuming!)
  57  * to poll the ->work.need_resched flag instead of waiting for the
  58  * cross-CPU IPI to arrive. Use this option with caution.
  59  *
  60  * tglx: No idea why this depends on HOTPLUG_CPU !?!
  61  */
  62 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
  63 void arch_cpu_idle(void)
  64 {
  65         safe_halt();
  66 }
  67 #endif
  68
  69 void release_segments(struct mm_struct *mm)
  70 {
  71 }
  72
  73 void machine_restart(char *cmd)
  74 {
  75 #ifdef CONFIG_KERNEL_DEBUGGER
  76         gdbstub_exit(0);
  77 #endif
  78
  79 #ifdef mn10300_unit_hard_reset
  80         mn10300_unit_hard_reset();
  81 #else
  82         mn10300_proc_hard_reset();
  83 #endif
  84 }
  85
  86 void machine_halt(void)
  87 {
  88 #ifdef CONFIG_KERNEL_DEBUGGER
  89         gdbstub_exit(0);
  90 #endif
  91 }
  92
  93 void machine_power_off(void)
  94 {
  95 #ifdef CONFIG_KERNEL_DEBUGGER
  96         gdbstub_exit(0);
  97 #endif
  98 }
  99
 100 void show_regs(struct pt_regs *regs)
 101 {
 102         show_regs_print_info(KERN_DEFAULT);
 103 }
 104
 105 /*
 106  * free current thread data structures etc..
 107  */
 108 void exit_thread(struct task_struct *tsk)
 109 {
 110         exit_fpu(tsk);
 111 }
 112
 113 void flush_thread(void)
 114 {
 115         flush_fpu();
 116 }
 117
 118 void release_thread(struct task_struct *dead_task)
 119 {
 120 }
 121
 122 /*
 123  * we do not have to muck with descriptors here, that is
 124  * done in switch_mm() as needed.
 125  */
 126 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
 127 {
 128 }
 129
 130 /*
 131  * this gets called so that we can store lazy state into memory and copy the
 132  * current task into the new thread.
 133  */
 134 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 135 {
 136         unlazy_fpu(src);
 137         *dst = *src;
 138         return 0;
 139 }
 140
 141 /*
 142  * set up the kernel stack for a new thread and copy arch-specific thread
 143  * control information
 144  */
 145 int copy_thread(unsigned long clone_flags,
 146                 unsigned long c_usp, unsigned long ustk_size,
 147                 struct task_struct *p)
 148 {
 149         struct thread_info *ti = task_thread_info(p);
 150         struct pt_regs *c_regs;
 151         unsigned long c_ksp;
 152
 153         c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
 154
 155         /* allocate the userspace exception frame and set it up */
 156         c_ksp -= sizeof(struct pt_regs);
 157         c_regs = (struct pt_regs *) c_ksp;
 158         c_ksp -= 12; /* allocate function call ABI slack */
 159
 160         /* set up things up so the scheduler can start the new task */
 161         p->thread.uregs = c_regs;
 162         ti->frame       = c_regs;
 163         p->thread.a3    = (unsigned long) c_regs;
 164         p->thread.sp    = c_ksp;
 165         p->thread.wchan = p->thread.pc;
 166         p->thread.usp   = c_usp;
 167
 168         if (unlikely(p->flags & PF_KTHREAD)) {
 169                 memset(c_regs, 0, sizeof(struct pt_regs));
 170                 c_regs->a0 = c_usp; /* function */
 171                 c_regs->d0 = ustk_size; /* argument */
 172                 local_save_flags(c_regs->epsw);
 173                 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
 174                 p->thread.pc    = (unsigned long) ret_from_kernel_thread;
 175                 return 0;
 176         }
 177         *c_regs = *current_pt_regs();
 178         if (c_usp)
 179                 c_regs->sp = c_usp;
 180         c_regs->epsw &= ~EPSW_FE; /* my FPU */
 181
 182         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 183         if (clone_flags & CLONE_SETTLS)
 184                 c_regs->e2 = current_frame()->d3;
 185
 186         p->thread.pc    = (unsigned long) ret_from_fork;
 187
 188         return 0;
 189 }
 190
 191 unsigned long get_wchan(struct task_struct *p)
 192 {
 193         return p->thread.wchan;
 194 }