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}
124