2 * arch/score/kernel/process.c
4 * Score Processor version.
6 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
7 * Chen Liqin <liqin.chen@sunplusct.com>
8 * Lennox Wu <lennox.wu@sunplusct.com>
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.
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.
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
26 #include <linux/module.h>
28 void (*pm_power_off)(void);
29 EXPORT_SYMBOL(pm_power_off);
31 /* If or when software machine-restart is implemented, add code here. */
32 void machine_restart(char *command) {}
34 /* If or when software machine-halt is implemented, add code here. */
35 void machine_halt(void) {}
37 /* If or when software machine-power-off is implemented, add code here. */
38 void machine_power_off(void) {}
41 * The idle thread. There's no useful work to be
42 * done, so just try to conserve power and have a
43 * low exit latency (ie sit in a loop waiting for
44 * somebody to say that they'd like to reschedule)
46 void __noreturn cpu_idle(void)
48 /* endless idle loop with no priority at all */
50 while (!need_resched())
53 preempt_enable_no_resched();
59 void ret_from_fork(void);
61 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
65 /* New thread loses kernel privileges. */
66 status = regs->cp0_psr & ~(KU_MASK);
68 regs->cp0_psr = status;
73 void exit_thread(void) {}
76 * When a process does an "exec", machine state like FPU and debug
77 * registers need to be reset. This is a hook function for that.
78 * Currently we don't have any such state to reset, so this is empty.
80 void flush_thread(void) {}
83 * set up the kernel stack and exception frames for a new process
85 int copy_thread(unsigned long clone_flags, unsigned long usp,
87 struct task_struct *p, struct pt_regs *regs)
89 struct thread_info *ti = task_thread_info(p);
90 struct pt_regs *childregs = task_pt_regs(p);
92 p->set_child_tid = NULL;
93 p->clear_child_tid = NULL;
96 childregs->regs[7] = 0; /* Clear error flag */
97 childregs->regs[4] = 0; /* Child gets zero as return value */
98 regs->regs[4] = p->pid;
100 if (childregs->cp0_psr & 0x8) { /* test kernel fork or user fork */
101 childregs->regs[0] = usp; /* user fork */
103 childregs->regs[28] = (unsigned long) ti; /* kernel fork */
104 childregs->regs[0] = (unsigned long) childregs;
107 p->thread.reg0 = (unsigned long) childregs;
108 p->thread.reg3 = (unsigned long) ret_from_fork;
109 p->thread.cp0_psr = 0;
114 /* Fill in the fpu structure for a core dump. */
115 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
120 static void __noreturn
121 kernel_thread_helper(void *unused0, int (*fn)(void *),
122 void *arg, void *unused1)
128 * Create a kernel thread.
130 long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
134 memset(®s, 0, sizeof(regs));
136 regs.regs[6] = (unsigned long) arg;
137 regs.regs[5] = (unsigned long) fn;
138 regs.cp0_epc = (unsigned long) kernel_thread_helper;
139 regs.cp0_psr = (regs.cp0_psr & ~(0x1|0x4|0x8)) | \
140 ((regs.cp0_psr & 0x3) << 2);
142 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, \
143 0, ®s, 0, NULL, NULL);
146 unsigned long thread_saved_pc(struct task_struct *tsk)
148 return task_pt_regs(tsk)->cp0_epc;
151 unsigned long get_wchan(struct task_struct *task)
153 if (!task || task == current || task->state == TASK_RUNNING)
156 if (!task_stack_page(task))
159 return task_pt_regs(task)->cp0_epc;
162 unsigned long arch_align_stack(unsigned long sp)