aboutsummaryrefslogtreecommitdiffstats
path: root/arch/score/kernel/process.c
blob: 79568466b5780d02c1876f2183ba1b801994ca71 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
/*
 * arch/score/kernel/process.c
 *
 * Score Processor version.
 *
 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
 *  Chen Liqin <liqin.chen@sunplusct.com>
 *  Lennox Wu <lennox.wu@sunplusct.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/elfcore.h>
#include <linux/pm.h>
#include <linux/rcupdate.h>

void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);

/* If or when software machine-restart is implemented, add code here. */
void machine_restart(char *command) {}

/* If or when software machine-halt is implemented, add code here. */
void machine_halt(void) {}

/* If or when software machine-power-off is implemented, add code here. */
void machine_power_off(void) {}

/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void __noreturn cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		rcu_idle_enter();
		while (!need_resched())
			barrier();
		rcu_idle_exit();
		schedule_preempt_disabled();
	}
}

void ret_from_fork(void);
void ret_from_kernel_thread(void);

void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
{
	unsigned long status;

	/* New thread loses kernel privileges. */
	status = regs->cp0_psr & ~(KU_MASK);
	status |= KU_USER;
	regs->cp0_psr = status;
	regs->cp0_epc = pc;
	regs->regs[0] = sp;
}

void exit_thread(void) {}

/*
 * When a process does an "exec", machine state like FPU and debug
 * registers need to be reset.  This is a hook function for that.
 * Currently we don't have any such state to reset, so this is empty.
 */
void flush_thread(void) {}

/*
 * set up the kernel stack and exception frames for a new process
 */
int copy_thread(unsigned long clone_flags, unsigned long usp,
		unsigned long arg, struct task_struct *p)
{
	struct thread_info *ti = task_thread_info(p);
	struct pt_regs *childregs = task_pt_regs(p);
	struct pt_regs *regs = current_pt_regs();

	p->thread.reg0 = (unsigned long) childregs;
	if (unlikely(p->flags & PF_KTHREAD)) {
		memset(childregs, 0, sizeof(struct pt_regs));
		p->thread->reg12 = usp;
		p->thread->reg13 = arg;
		p->thread.reg3 = (unsigned long) ret_from_kernel_thread;
	} else {
		*childregs = *current_pt_regs();
		childregs->regs[7] = 0;		/* Clear error flag */
		childregs->regs[4] = 0;		/* Child gets zero as return value */
		if (usp)
			childregs->regs[0] = usp;	/* user fork */
		p->thread.reg3 = (unsigned long) ret_from_fork;
	}

	p->thread.cp0_psr = 0;

	return 0;
}

/* Fill in the fpu structure for a core dump. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
{
	return 1;
}

unsigned long thread_saved_pc(struct task_struct *tsk)
{
	return task_pt_regs(tsk)->cp0_epc;
}

unsigned long get_wchan(struct task_struct *task)
{
	if (!task || task == current || task->state == TASK_RUNNING)
		return 0;

	if (!task_stack_page(task))
		return 0;

	return task_pt_regs(task)->cp0_epc;
}

unsigned long arch_align_stack(unsigned long sp)
{
	return sp;
}