169 lines
4.3 KiB
C
169 lines
4.3 KiB
C
/*
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* arch/score/kernel/process.c
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*
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* Score Processor version.
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*
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* Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
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* Chen Liqin <liqin.chen@sunplusct.com>
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* Lennox Wu <lennox.wu@sunplusct.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see the file COPYING, or write
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* to the Free Software Foundation, Inc.,
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* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <linux/module.h>
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#include <linux/reboot.h>
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#include <linux/elfcore.h>
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#include <linux/pm.h>
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#include <linux/rcupdate.h>
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void (*pm_power_off)(void);
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EXPORT_SYMBOL(pm_power_off);
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/* If or when software machine-restart is implemented, add code here. */
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void machine_restart(char *command) {}
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/* If or when software machine-halt is implemented, add code here. */
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void machine_halt(void) {}
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/* If or when software machine-power-off is implemented, add code here. */
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void machine_power_off(void) {}
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/*
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* The idle thread. There's no useful work to be
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* done, so just try to conserve power and have a
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* low exit latency (ie sit in a loop waiting for
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* somebody to say that they'd like to reschedule)
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*/
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void __noreturn cpu_idle(void)
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{
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/* endless idle loop with no priority at all */
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while (1) {
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rcu_idle_enter();
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while (!need_resched())
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barrier();
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rcu_idle_exit();
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schedule_preempt_disabled();
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}
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}
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void ret_from_fork(void);
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void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
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{
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unsigned long status;
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/* New thread loses kernel privileges. */
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status = regs->cp0_psr & ~(KU_MASK);
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status |= KU_USER;
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regs->cp0_psr = status;
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regs->cp0_epc = pc;
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regs->regs[0] = sp;
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}
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void exit_thread(void) {}
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/*
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* When a process does an "exec", machine state like FPU and debug
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* registers need to be reset. This is a hook function for that.
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* Currently we don't have any such state to reset, so this is empty.
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*/
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void flush_thread(void) {}
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/*
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* set up the kernel stack and exception frames for a new process
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*/
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int copy_thread(unsigned long clone_flags, unsigned long usp,
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unsigned long unused,
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struct task_struct *p, struct pt_regs *regs)
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{
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struct thread_info *ti = task_thread_info(p);
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struct pt_regs *childregs = task_pt_regs(p);
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p->set_child_tid = NULL;
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p->clear_child_tid = NULL;
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*childregs = *regs;
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childregs->regs[7] = 0; /* Clear error flag */
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childregs->regs[4] = 0; /* Child gets zero as return value */
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regs->regs[4] = p->pid;
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if (childregs->cp0_psr & 0x8) { /* test kernel fork or user fork */
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childregs->regs[0] = usp; /* user fork */
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} else {
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childregs->regs[28] = (unsigned long) ti; /* kernel fork */
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childregs->regs[0] = (unsigned long) childregs;
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}
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p->thread.reg0 = (unsigned long) childregs;
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p->thread.reg3 = (unsigned long) ret_from_fork;
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p->thread.cp0_psr = 0;
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return 0;
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}
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/* Fill in the fpu structure for a core dump. */
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
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{
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return 1;
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}
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static void __noreturn
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kernel_thread_helper(void *unused0, int (*fn)(void *),
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void *arg, void *unused1)
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{
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do_exit(fn(arg));
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}
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/*
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* Create a kernel thread.
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*/
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long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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regs.regs[6] = (unsigned long) arg;
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regs.regs[5] = (unsigned long) fn;
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regs.cp0_epc = (unsigned long) kernel_thread_helper;
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regs.cp0_psr = (regs.cp0_psr & ~(0x1|0x4|0x8)) | \
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((regs.cp0_psr & 0x3) << 2);
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return do_fork(flags | CLONE_VM | CLONE_UNTRACED, \
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0, ®s, 0, NULL, NULL);
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}
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unsigned long thread_saved_pc(struct task_struct *tsk)
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{
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return task_pt_regs(tsk)->cp0_epc;
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}
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unsigned long get_wchan(struct task_struct *task)
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{
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if (!task || task == current || task->state == TASK_RUNNING)
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return 0;
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if (!task_stack_page(task))
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return 0;
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return task_pt_regs(task)->cp0_epc;
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}
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unsigned long arch_align_stack(unsigned long sp)
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{
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return sp;
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}
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