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>
30 #include <asm/system.h>
32 #include <asm/processor.h>
33 #include <asm/mmu_context.h>
35 #include <asm/reset-regs.h>
36 #include <asm/gdb-stub.h>
40 * power management idle function, if any..
42 void (*pm_idle)(void);
43 EXPORT_SYMBOL(pm_idle);
46 * return saved PC of a blocked thread.
48 unsigned long thread_saved_pc(struct task_struct *tsk)
50 return ((unsigned long *) tsk->thread.sp)[3];
54 * power off function, if any
56 void (*pm_power_off)(void);
57 EXPORT_SYMBOL(pm_power_off);
59 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
61 * we use this if we don't have any better idle routine
63 static void default_idle(void)
72 #else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
74 * On SMP it's slightly faster (but much more power-consuming!)
75 * to poll the ->work.need_resched flag instead of waiting for the
76 * cross-CPU IPI to arrive. Use this option with caution.
78 static inline void poll_idle(void)
85 * Deal with another CPU just having chosen a thread to
88 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
91 set_thread_flag(TIF_POLLING_NRFLAG);
92 while (!need_resched())
94 clear_thread_flag(TIF_POLLING_NRFLAG);
99 #endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
103 * - there's no useful work to be done, so just try to conserve power and have
104 * a low exit latency (ie sit in a loop waiting for somebody to say that
105 * they'd like to reschedule)
109 /* endless idle loop with no priority at all */
111 while (!need_resched()) {
117 #if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
119 #else /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
121 #endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
126 schedule_preempt_disabled();
130 void release_segments(struct mm_struct *mm)
134 void machine_restart(char *cmd)
136 #ifdef CONFIG_KERNEL_DEBUGGER
140 #ifdef mn10300_unit_hard_reset
141 mn10300_unit_hard_reset();
143 mn10300_proc_hard_reset();
147 void machine_halt(void)
149 #ifdef CONFIG_KERNEL_DEBUGGER
154 void machine_power_off(void)
156 #ifdef CONFIG_KERNEL_DEBUGGER
161 void show_regs(struct pt_regs *regs)
166 * create a kernel thread
168 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
172 memset(®s, 0, sizeof(regs));
174 regs.a2 = (unsigned long) fn;
175 regs.d2 = (unsigned long) arg;
176 regs.pc = (unsigned long) kernel_thread_helper;
177 local_save_flags(regs.epsw);
178 regs.epsw |= EPSW_IE | EPSW_IM_7;
180 /* Ok, create the new process.. */
181 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0,
184 EXPORT_SYMBOL(kernel_thread);
187 * free current thread data structures etc..
189 void exit_thread(void)
194 void flush_thread(void)
199 void release_thread(struct task_struct *dead_task)
204 * we do not have to muck with descriptors here, that is
205 * done in switch_mm() as needed.
207 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
212 * this gets called before we allocate a new thread and copy the current task
213 * into it so that we can store lazy state into memory
215 void prepare_to_copy(struct task_struct *tsk)
221 * set up the kernel stack for a new thread and copy arch-specific thread
222 * control information
224 int copy_thread(unsigned long clone_flags,
225 unsigned long c_usp, unsigned long ustk_size,
226 struct task_struct *p, struct pt_regs *kregs)
228 struct thread_info *ti = task_thread_info(p);
229 struct pt_regs *c_uregs, *c_kregs, *uregs;
232 uregs = current->thread.uregs;
234 c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
236 /* allocate the userspace exception frame and set it up */
237 c_ksp -= sizeof(struct pt_regs);
238 c_uregs = (struct pt_regs *) c_ksp;
240 p->thread.uregs = c_uregs;
243 c_uregs->epsw &= ~EPSW_FE; /* my FPU */
245 c_ksp -= 12; /* allocate function call ABI slack */
247 /* the new TLS pointer is passed in as arg #5 to sys_clone() */
248 if (clone_flags & CLONE_SETTLS)
249 c_uregs->e2 = current_frame()->d3;
251 /* set up the return kernel frame if called from kernel_thread() */
253 if (kregs != uregs) {
254 c_ksp -= sizeof(struct pt_regs);
255 c_kregs = (struct pt_regs *) c_ksp;
258 c_kregs->next = c_uregs;
259 #ifdef CONFIG_MN10300_CURRENT_IN_E2
260 c_kregs->e2 = (unsigned long) p; /* current */
263 c_ksp -= 12; /* allocate function call ABI slack */
266 /* set up things up so the scheduler can start the new task */
268 p->thread.a3 = (unsigned long) c_kregs;
269 p->thread.sp = c_ksp;
270 p->thread.pc = (unsigned long) ret_from_fork;
271 p->thread.wchan = (unsigned long) ret_from_fork;
272 p->thread.usp = c_usp;
279 * - tlsptr is retrieved by copy_thread() from current_frame()->d3
281 asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp,
282 int __user *parent_tidptr, int __user *child_tidptr,
285 return do_fork(clone_flags, newsp ?: current_frame()->sp,
286 current_frame(), 0, parent_tidptr, child_tidptr);
289 asmlinkage long sys_fork(void)
291 return do_fork(SIGCHLD, current_frame()->sp,
292 current_frame(), 0, NULL, NULL);
295 asmlinkage long sys_vfork(void)
297 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, current_frame()->sp,
298 current_frame(), 0, NULL, NULL);
301 asmlinkage long sys_execve(const char __user *name,
302 const char __user *const __user *argv,
303 const char __user *const __user *envp)
308 filename = getname(name);
309 error = PTR_ERR(filename);
310 if (IS_ERR(filename))
312 error = do_execve(filename, argv, envp, current_frame());
317 unsigned long get_wchan(struct task_struct *p)
319 return p->thread.wchan;