290 lines
6.2 KiB
C
290 lines
6.2 KiB
C
/* MN10300 Process handling code
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/percpu.h>
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#include <linux/err.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/mmu_context.h>
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#include <asm/fpu.h>
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#include <asm/reset-regs.h>
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#include <asm/gdb-stub.h>
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#include "internal.h"
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/*
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* power management idle function, if any..
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*/
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void (*pm_idle)(void);
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EXPORT_SYMBOL(pm_idle);
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/*
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* return saved PC of a blocked thread.
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*/
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unsigned long thread_saved_pc(struct task_struct *tsk)
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{
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return ((unsigned long *) tsk->thread.sp)[3];
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}
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/*
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* power off function, if any
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*/
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void (*pm_power_off)(void);
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EXPORT_SYMBOL(pm_power_off);
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#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
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/*
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* we use this if we don't have any better idle routine
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*/
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static void default_idle(void)
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{
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local_irq_disable();
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if (!need_resched())
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safe_halt();
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else
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local_irq_enable();
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}
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#else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
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/*
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* On SMP it's slightly faster (but much more power-consuming!)
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* to poll the ->work.need_resched flag instead of waiting for the
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* cross-CPU IPI to arrive. Use this option with caution.
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*/
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static inline void poll_idle(void)
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{
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int oldval;
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local_irq_enable();
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/*
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* Deal with another CPU just having chosen a thread to
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* run here:
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*/
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oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
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if (!oldval) {
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set_thread_flag(TIF_POLLING_NRFLAG);
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while (!need_resched())
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cpu_relax();
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clear_thread_flag(TIF_POLLING_NRFLAG);
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} else {
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set_need_resched();
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}
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}
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#endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
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/*
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* the idle thread
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* - there's no useful work to be done, so just try to conserve power and have
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* a low exit latency (ie sit in a loop waiting for somebody to say that
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* they'd like to reschedule)
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*/
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void cpu_idle(void)
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{
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/* endless idle loop with no priority at all */
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for (;;) {
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while (!need_resched()) {
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void (*idle)(void);
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smp_rmb();
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idle = pm_idle;
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if (!idle) {
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#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
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idle = poll_idle;
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#else /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
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idle = default_idle;
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#endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
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}
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idle();
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}
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schedule_preempt_disabled();
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}
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}
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void release_segments(struct mm_struct *mm)
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{
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}
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void machine_restart(char *cmd)
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{
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#ifdef CONFIG_KERNEL_DEBUGGER
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gdbstub_exit(0);
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#endif
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#ifdef mn10300_unit_hard_reset
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mn10300_unit_hard_reset();
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#else
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mn10300_proc_hard_reset();
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#endif
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}
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void machine_halt(void)
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{
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#ifdef CONFIG_KERNEL_DEBUGGER
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gdbstub_exit(0);
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#endif
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}
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void machine_power_off(void)
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{
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#ifdef CONFIG_KERNEL_DEBUGGER
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gdbstub_exit(0);
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#endif
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}
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void show_regs(struct pt_regs *regs)
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{
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}
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/*
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* create a kernel thread
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*/
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int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
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{
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struct pt_regs regs = {
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.a0 = (unsigned long) fn;
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.d0 = (unsigned long) arg;
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};
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local_save_flags(regs.epsw);
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regs.epsw |= EPSW_IE | EPSW_IM_7;
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/* Ok, create the new process.. */
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return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0,
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NULL, NULL);
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}
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/*
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* free current thread data structures etc..
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*/
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void exit_thread(void)
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{
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exit_fpu();
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}
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void flush_thread(void)
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{
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flush_fpu();
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}
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void release_thread(struct task_struct *dead_task)
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{
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}
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/*
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* we do not have to muck with descriptors here, that is
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* done in switch_mm() as needed.
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*/
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void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
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{
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}
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/*
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* this gets called so that we can store lazy state into memory and copy the
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* current task into the new thread.
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*/
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int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
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{
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unlazy_fpu(src);
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*dst = *src;
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return 0;
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}
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/*
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* set up the kernel stack for a new thread and copy arch-specific thread
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* control information
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*/
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int copy_thread(unsigned long clone_flags,
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unsigned long c_usp, unsigned long ustk_size,
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struct task_struct *p, struct pt_regs *kregs)
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{
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struct thread_info *ti = task_thread_info(p);
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struct pt_regs *c_regs;
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unsigned long c_ksp;
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c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
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/* allocate the userspace exception frame and set it up */
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c_ksp -= sizeof(struct pt_regs);
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c_regs = (struct pt_regs *) c_ksp;
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p->thread.uregs = c_regs;
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*c_regs = *kregs;
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c_regs->sp = c_usp;
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c_regs->epsw &= ~EPSW_FE; /* my FPU */
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c_ksp -= 12; /* allocate function call ABI slack */
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/* the new TLS pointer is passed in as arg #5 to sys_clone() */
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if (clone_flags & CLONE_SETTLS)
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c_regs->e2 = current_frame()->d3;
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if (unlikely(!user_mode(kregs)))
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p->thread.pc = (unsigned long) ret_from_kernel_thread;
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else
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p->thread.pc = (unsigned long) ret_from_fork;
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/* set up things up so the scheduler can start the new task */
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ti->frame = c_regs;
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p->thread.a3 = (unsigned long) c_regs;
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p->thread.sp = c_ksp;
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p->thread.wchan = p->thread.pc;
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p->thread.usp = c_usp;
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return 0;
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}
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/*
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* clone a process
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* - tlsptr is retrieved by copy_thread() from current_frame()->d3
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*/
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asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp,
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int __user *parent_tidptr, int __user *child_tidptr,
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int __user *tlsptr)
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{
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return do_fork(clone_flags, newsp ?: current_frame()->sp,
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current_frame(), 0, parent_tidptr, child_tidptr);
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}
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asmlinkage long sys_fork(void)
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{
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return do_fork(SIGCHLD, current_frame()->sp,
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current_frame(), 0, NULL, NULL);
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}
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asmlinkage long sys_vfork(void)
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{
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, current_frame()->sp,
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current_frame(), 0, NULL, NULL);
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}
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unsigned long get_wchan(struct task_struct *p)
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{
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return p->thread.wchan;
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}
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