1 /* MN10300 Process handling code
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
16 #include <linux/smp.h>
17 #include <linux/stddef.h>
18 #include <linux/unistd.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/interrupt.h>
22 #include <linux/delay.h>
23 #include <linux/reboot.h>
24 #include <linux/percpu.h>
25 #include <linux/err.h>
27 #include <linux/slab.h>
28 #include <asm/uaccess.h>
29 #include <asm/pgtable.h>
31 #include <asm/processor.h>
32 #include <asm/mmu_context.h>
34 #include <asm/reset-regs.h>
35 #include <asm/gdb-stub.h>
39 * power management idle function, if any..
41 void (*pm_idle)(void);
42 EXPORT_SYMBOL(pm_idle);
45 * return saved PC of a blocked thread.
47 unsigned long thread_saved_pc(struct task_struct *tsk)
49 return ((unsigned long *) tsk->thread.sp)[3];
53 * power off function, if any
55 void (*pm_power_off)(void);
56 EXPORT_SYMBOL(pm_power_off);
58 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
60 * we use this if we don't have any better idle routine
62 static void default_idle(void)
71 #else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
73 * On SMP it's slightly faster (but much more power-consuming!)
74 * to poll the ->work.need_resched flag instead of waiting for the
75 * cross-CPU IPI to arrive. Use this option with caution.
77 static inline void poll_idle(void)
84 * Deal with another CPU just having chosen a thread to
87 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
90 set_thread_flag(TIF_POLLING_NRFLAG);
91 while (!need_resched())
93 clear_thread_flag(TIF_POLLING_NRFLAG);
98 #endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
102 * - there's no useful work to be done, so just try to conserve power and have
103 * a low exit latency (ie sit in a loop waiting for somebody to say that
104 * they'd like to reschedule)
108 /* endless idle loop with no priority at all */
110 while (!need_resched()) {
116 #if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
118 #else /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
120 #endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
125 schedule_preempt_disabled();
129 void release_segments(struct mm_struct *mm)
133 void machine_restart(char *cmd)
135 #ifdef CONFIG_KERNEL_DEBUGGER
139 #ifdef mn10300_unit_hard_reset
140 mn10300_unit_hard_reset();
142 mn10300_proc_hard_reset();
146 void machine_halt(void)
148 #ifdef CONFIG_KERNEL_DEBUGGER
153 void machine_power_off(void)
155 #ifdef CONFIG_KERNEL_DEBUGGER
160 void show_regs(struct pt_regs *regs)
165 * create a kernel thread
167 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
171 memset(®s, 0, sizeof(regs));
173 regs.a2 = (unsigned long) fn;
174 regs.d2 = (unsigned long) arg;
175 regs.pc = (unsigned long) kernel_thread_helper;
176 local_save_flags(regs.epsw);
177 regs.epsw |= EPSW_IE | EPSW_IM_7;
179 /* Ok, create the new process.. */
180 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0,
183 EXPORT_SYMBOL(kernel_thread);
186 * free current thread data structures etc..
188 void exit_thread(void)
193 void flush_thread(void)
198 void release_thread(struct task_struct *dead_task)
203 * we do not have to muck with descriptors here, that is
204 * done in switch_mm() as needed.
206 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
211 * this gets called before we allocate a new thread and copy the current task
212 * into it so that we can store lazy state into memory
214 void prepare_to_copy(struct task_struct *tsk)
220 * set up the kernel stack for a new thread and copy arch-specific thread
221 * control information
223 int copy_thread(unsigned long clone_flags,
224 unsigned long c_usp, unsigned long ustk_size,
225 struct task_struct *p, struct pt_regs *kregs)
227 struct thread_info *ti = task_thread_info(p);
228 struct pt_regs *c_uregs, *c_kregs, *uregs;
231 uregs = current->thread.uregs;
233 c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
235 /* allocate the userspace exception frame and set it up */
236 c_ksp -= sizeof(struct pt_regs);
237 c_uregs = (struct pt_regs *) c_ksp;
239 p->thread.uregs = c_uregs;
242 c_uregs->epsw &= ~EPSW_FE; /* my FPU */
244 c_ksp -= 12; /* allocate function call ABI slack */
246 /* the new TLS pointer is passed in as arg #5 to sys_clone() */
247 if (clone_flags & CLONE_SETTLS)
248 c_uregs->e2 = current_frame()->d3;
250 /* set up the return kernel frame if called from kernel_thread() */
252 if (kregs != uregs) {
253 c_ksp -= sizeof(struct pt_regs);
254 c_kregs = (struct pt_regs *) c_ksp;
257 c_kregs->next = c_uregs;
258 #ifdef CONFIG_MN10300_CURRENT_IN_E2
259 c_kregs->e2 = (unsigned long) p; /* current */
262 c_ksp -= 12; /* allocate function call ABI slack */
265 /* set up things up so the scheduler can start the new task */
267 p->thread.a3 = (unsigned long) c_kregs;
268 p->thread.sp = c_ksp;
269 p->thread.pc = (unsigned long) ret_from_fork;
270 p->thread.wchan = (unsigned long) ret_from_fork;
271 p->thread.usp = c_usp;
278 * - tlsptr is retrieved by copy_thread() from current_frame()->d3
280 asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp,
281 int __user *parent_tidptr, int __user *child_tidptr,
284 return do_fork(clone_flags, newsp ?: current_frame()->sp,
285 current_frame(), 0, parent_tidptr, child_tidptr);
288 asmlinkage long sys_fork(void)
290 return do_fork(SIGCHLD, current_frame()->sp,
291 current_frame(), 0, NULL, NULL);
294 asmlinkage long sys_vfork(void)
296 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, current_frame()->sp,
297 current_frame(), 0, NULL, NULL);
300 asmlinkage long sys_execve(const char __user *name,
301 const char __user *const __user *argv,
302 const char __user *const __user *envp)
307 filename = getname(name);
308 error = PTR_ERR(filename);
309 if (IS_ERR(filename))
311 error = do_execve(filename, argv, envp, current_frame());
316 unsigned long get_wchan(struct task_struct *p)
318 return p->thread.wchan;