arch/score/kernel/process.c

   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
  32 void (*pm_power_off)(void);
  33 EXPORT_SYMBOL(pm_power_off);
  34
  35 /* If or when software machine-restart is implemented, add code here. */
  36 void machine_restart(char *command) {}
  37
  38 /* If or when software machine-halt is implemented, add code here. */
  39 void machine_halt(void) {}
  40
  41 /* If or when software machine-power-off is implemented, add code here. */
  42 void machine_power_off(void) {}
  43
  44 void ret_from_fork(void);
  45 void ret_from_kernel_thread(void);
  46
  47 void 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
  59 /*
  60  * When a process does an "exec", machine state like FPU and debug
  61  * registers need to be reset.  This is a hook function for that.
  62  * Currently we don't have any such state to reset, so this is empty.
  63  */
  64 void flush_thread(void) {}
  65
  66 /*
  67  * set up the kernel stack and exception frames for a new process
  68  */
  69 int copy_thread(unsigned long clone_flags, unsigned long usp,
  70                 unsigned long arg, struct task_struct *p)
  71 {
  72         struct thread_info *ti = task_thread_info(p);
  73         struct pt_regs *childregs = task_pt_regs(p);
  74         struct pt_regs *regs = current_pt_regs();
  75
  76         p->thread.reg0 = (unsigned long) childregs;
  77         if (unlikely(p->flags & PF_KTHREAD)) {
  78                 memset(childregs, 0, sizeof(struct pt_regs));
  79                 p->thread.reg12 = usp;
  80                 p->thread.reg13 = arg;
  81                 p->thread.reg3 = (unsigned long) ret_from_kernel_thread;
  82         } else {
  83                 *childregs = *current_pt_regs();
  84                 childregs->regs[7] = 0;         /* Clear error flag */
  85                 childregs->regs[4] = 0;         /* Child gets zero as return value */
  86                 if (usp)
  87                         childregs->regs[0] = usp;       /* user fork */
  88                 p->thread.reg3 = (unsigned long) ret_from_fork;
  89         }
  90
  91         p->thread.cp0_psr = 0;
  92
  93         return 0;
  94 }
  95
  96 /* Fill in the fpu structure for a core dump. */
  97 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
  98 {
  99         return 1;
 100 }
 101
 102 unsigned long thread_saved_pc(struct task_struct *tsk)
 103 {
 104         return task_pt_regs(tsk)->cp0_epc;
 105 }
 106
 107 unsigned long get_wchan(struct task_struct *task)
 108 {
 109         if (!task || task == current || task->state == TASK_RUNNING)
 110                 return 0;
 111
 112         if (!task_stack_page(task))
 113                 return 0;
 114
 115         return task_pt_regs(task)->cp0_epc;
 116 }
 117
 118 unsigned long arch_align_stack(unsigned long sp)
 119 {
 120         return sp;
 121 }