1/*
  2 * arch/score/kernel/process.c
  3 *
  4 * Score Processor version.
  5 *
  6 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
  7 *  Chen Liqin <liqin.chen@sunplusct.com>
  8 *  Lennox Wu <lennox.wu@sunplusct.com>
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of the GNU General Public License as published by
 12 * the Free Software Foundation; either version 2 of the License, or
 13 * (at your option) any later version.
 14 *
 15 * This program is distributed in the hope that it will be useful,
 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 18 * GNU General Public License for more details.
 19 *
 20 * You should have received a copy of the GNU General Public License
 21 * along with this program; if not, see the file COPYING, or write
 22 * to the Free Software Foundation, Inc.,
 23 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 24 */
 25
 26#include <linux/module.h>
 27#include <linux/reboot.h>
 28#include <linux/elfcore.h>
 29#include <linux/pm.h>
 30#include <linux/rcupdate.h>
 31
 32void (*pm_power_off)(void);
 33EXPORT_SYMBOL(pm_power_off);
 34
 35/* If or when software machine-restart is implemented, add code here. */
 36void machine_restart(char *command) {}
 37
 38/* If or when software machine-halt is implemented, add code here. */
 39void machine_halt(void) {}
 40
 41/* If or when software machine-power-off is implemented, add code here. */
 42void machine_power_off(void) {}
 43
 44void ret_from_fork(void);
 45void ret_from_kernel_thread(void);
 46
 47void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
 48{
 49	unsigned long status;
 50
 51	/* New thread loses kernel privileges. */
 52	status = regs->cp0_psr & ~(KU_MASK);
 53	status |= KU_USER;
 54	regs->cp0_psr = status;
 55	regs->cp0_epc = pc;
 56	regs->regs[0] = sp;
 57}
 58
 59void exit_thread(void) {}
 60
 61/*
 62 * When a process does an "exec", machine state like FPU and debug
 63 * registers need to be reset.  This is a hook function for that.
 64 * Currently we don't have any such state to reset, so this is empty.
 65 */
 66void flush_thread(void) {}
 67
 68/*
 69 * set up the kernel stack and exception frames for a new process
 70 */
 71int copy_thread(unsigned long clone_flags, unsigned long usp,
 72		unsigned long arg, struct task_struct *p)
 73{
 74	struct thread_info *ti = task_thread_info(p);
 75	struct pt_regs *childregs = task_pt_regs(p);
 76	struct pt_regs *regs = current_pt_regs();
 77
 78	p->thread.reg0 = (unsigned long) childregs;
 79	if (unlikely(p->flags & PF_KTHREAD)) {
 80		memset(childregs, 0, sizeof(struct pt_regs));
 81		p->thread.reg12 = usp;
 82		p->thread.reg13 = arg;
 83		p->thread.reg3 = (unsigned long) ret_from_kernel_thread;
 84	} else {
 85		*childregs = *current_pt_regs();
 86		childregs->regs[7] = 0;		/* Clear error flag */
 87		childregs->regs[4] = 0;		/* Child gets zero as return value */
 88		if (usp)
 89			childregs->regs[0] = usp;	/* user fork */
 90		p->thread.reg3 = (unsigned long) ret_from_fork;
 91	}
 92
 93	p->thread.cp0_psr = 0;
 94
 95	return 0;
 96}
 97
 98/* Fill in the fpu structure for a core dump. */
 99int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
100{
101	return 1;
102}
103
104unsigned long thread_saved_pc(struct task_struct *tsk)
105{
106	return task_pt_regs(tsk)->cp0_epc;
107}
108
109unsigned long get_wchan(struct task_struct *task)
110{
111	if (!task || task == current || task->state == TASK_RUNNING)
112		return 0;
113
114	if (!task_stack_page(task))
115		return 0;
116
117	return task_pt_regs(task)->cp0_epc;
118}
119
120unsigned long arch_align_stack(unsigned long sp)
121{
122	return sp;
123}