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/*
* 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>
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) {
while (!need_resched())
barrier();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
void ret_from_fork(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 unused,
struct task_struct *p, struct pt_regs *regs)
{
struct thread_info *ti = task_thread_info(p);
struct pt_regs *childregs = task_pt_regs(p);
p->set_child_tid = NULL;
p->clear_child_tid = NULL;
*childregs = *regs;
childregs->regs[7] = 0; /* Clear error flag */
childregs->regs[4] = 0; /* Child gets zero as return value */
regs->regs[4] = p->pid;
if (childregs->cp0_psr & 0x8) { /* test kernel fork or user fork */
childregs->regs[0] = usp; /* user fork */
} else {
childregs->regs[28] = (unsigned long) ti; /* kernel fork */
childregs->regs[0] = (unsigned long) childregs;
}
p->thread.reg0 = (unsigned long) childregs;
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;
}
static void __noreturn
kernel_thread_helper(void *unused0, int (*fn)(void *),
void *arg, void *unused1)
{
do_exit(fn(arg));
}
/*
* Create a kernel thread.
*/
long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(®s, 0, sizeof(regs));
regs.regs[6] = (unsigned long) arg;
regs.regs[5] = (unsigned long) fn;
regs.cp0_epc = (unsigned long) kernel_thread_helper;
regs.cp0_psr = (regs.cp0_psr & ~(0x1|0x4|0x8)) | \
((regs.cp0_psr & 0x3) << 2);
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, \
0, ®s, 0, NULL, NULL);
}
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;
}
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