text: /*
   *    PARISC Architecture-dependent parts of process handling
   *    based on the work for i386
   *
   *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
   *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
   *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
   *    Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
   *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
   *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
   *    Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
   *    Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
   *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
   *    Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
   *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
   *    Copyright (C) 2001-2007 Helge Deller <deller at parisc-linux.org>
   *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
   *
   *
   *    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, write to the Free Software
   *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  #include <stdarg.h>
  
  #include <linux/elf.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/module.h>
  #include <linux/personality.h>
  #include <linux/ptrace.h>
  #include <linux/sched.h>
  #include <linux/stddef.h>
  #include <linux/unistd.h>
  #include <linux/kallsyms.h>
  
  #include <asm/io.h>
  #include <asm/asm-offsets.h>
  #include <asm/pdc.h>
  #include <asm/pdc_chassis.h>
  #include <asm/pgalloc.h>
  #include <asm/uaccess.h>
  #include <asm/unwind.h>
  
  /*
   * 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 cpu_idle(void)
  {
  	set_thread_flag(TIF_POLLING_NRFLAG);
  
  	/* endless idle loop with no priority at all */
  	while (1) {
  		while (!need_resched())
  			barrier();
  		preempt_enable_no_resched();
  		schedule();
  		preempt_disable();
  		check_pgt_cache();
  	}
  }
  
  
  #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
  #define CMD_RESET       5       /* reset any module */
  
  /*
  ** The Wright Brothers and Gecko systems have a H/W problem
  ** (Lasi...'nuf said) may cause a broadcast reset to lockup
  ** the system. An HVERSION dependent PDC call was developed
  ** to perform a "safe", platform specific broadcast reset instead
  ** of kludging up all the code.
  **
  ** Older machines which do not implement PDC_BROADCAST_RESET will
  ** return (with an error) and the regular broadcast reset can be
  ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
  ** the PDC call will not return (the system will be reset).
  */
  void machine_restart(char *cmd)
  {
  #ifdef FASTBOOT_SELFTEST_SUPPORT
  	/*
  	 ** If user has modified the Firmware Selftest Bitmap,
  	 ** run the tests specified in the bitmap after the
  	 ** system is rebooted w/PDC_DO_RESET.
  	 **
  	 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
  	 **
  	 ** Using "directed resets" at each processor with the MEM_TOC
  	 ** vector cleared will also avoid running destructive
  	 ** memory self tests. (Not implemented yet)
  	 */
  	if (ftc_bitmap) {
  		pdc_do_firm_test_reset(ftc_bitmap);
  	}
  #endif
  	/* set up a new led state on systems shipped with a LED State panel */
  	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
  	
  	/* "Normal" system reset */
  	pdc_do_reset();
  
  	/* Nope...box should reset with just CMD_RESET now */
  	gsc_writel(CMD_RESET, COMMAND_GLOBAL);
  
  	/* Wait for RESET to lay us to rest. */
  	while (1) ;
  
  }
  
  void machine_halt(void)
  {
  	/*
  	** The LED/ChassisCodes are updated by the led_halt()
  	** function, called by the reboot notifier chain.
  	*/
  }
  
  void (*chassis_power_off)(void);
  
  /*
   * This routine is called from sys_reboot to actually turn off the
   * machine 
   */
  void machine_power_off(void)
  {
  	/* If there is a registered power off handler, call it. */
  	if (chassis_power_off)
  		chassis_power_off();
  
  	/* Put the soft power button back under hardware control.
  	 * If the user had already pressed the power button, the
  	 * following call will immediately power off. */
  	pdc_soft_power_button(0);
  	
  	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
  		
  	/* It seems we have no way to power the system off via
  	 * software. The user has to press the button himself. */
  
  	printk(KERN_EMERG "System shut down completed.\n"
  	       KERN_EMERG "Please power this system off now.");
  }
  
  void (*pm_power_off)(void) = machine_power_off;
  EXPORT_SYMBOL(pm_power_off);
  
  /*
   * Create a kernel thread
   */
  
  extern pid_t __kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
  pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
  {
  
  	/*
  	 * FIXME: Once we are sure we don't need any debug here,
  	 *	  kernel_thread can become a #define.
  	 */
  
  	return __kernel_thread(fn, arg, flags);
  }
  EXPORT_SYMBOL(kernel_thread);
  
  /*
   * Free current thread data structures etc..
   */
  void exit_thread(void)
  {
  }
  
  void flush_thread(void)
  {
  	/* Only needs to handle fpu stuff or perf monitors.
  	** REVISIT: several arches implement a "lazy fpu state".
  	*/
  	set_fs(USER_DS);
  }
  
  void release_thread(struct task_struct *dead_task)
  {
  }
  
  /*
   * Fill in the FPU structure for a core dump.
   */
  
  int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
  {
  	if (regs == NULL)
  		return 0;
  
  	memcpy(r, regs->fr, sizeof *r);
  	return 1;
  }
  
  int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
  {
  	memcpy(r, tsk->thread.regs.fr, sizeof(*r));
  	return 1;
  }
  
  /* Note that "fork()" is implemented in terms of clone, with
     parameters (SIGCHLD, regs->gr[30], regs). */
  int
  sys_clone(unsigned long clone_flags, unsigned long usp,
  	  struct pt_regs *regs)
  {
    	/* Arugments from userspace are:
  	   r26 = Clone flags.
  	   r25 = Child stack.
  	   r24 = parent_tidptr.
  	   r23 = Is the TLS storage descriptor 
  	   r22 = child_tidptr 
  	   
  	   However, these last 3 args are only examined
  	   if the proper flags are set. */
  	int __user *child_tidptr;
  	int __user *parent_tidptr;
  
  	/* usp must be word aligned.  This also prevents users from
  	 * passing in the value 1 (which is the signal for a special
  	 * return for a kernel thread) */
  	usp = ALIGN(usp, 4);
  
  	/* A zero value for usp means use the current stack */
  	if (usp == 0)
  	  usp = regs->gr[30];
  
  	if (clone_flags & CLONE_PARENT_SETTID)
  	  parent_tidptr = (int __user *)regs->gr[24];
  	else
  	  parent_tidptr = NULL;
  	
  	if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID))
  	  child_tidptr = (int __user *)regs->gr[22];
  	else
  	  child_tidptr = NULL;
  
  	return do_fork(clone_flags, usp, regs, 0, parent_tidptr, child_tidptr);
  }
  
  int
  sys_vfork(struct pt_regs *regs)
  {
  	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gr[30], regs, 0, NULL, NULL);
  }
  
  int
  copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
  	    unsigned long unused,	/* in ia64 this is "user_stack_size" */
  	    struct task_struct * p, struct pt_regs * pregs)
  {
  	struct pt_regs * cregs = &(p->thread.regs);
  	void *stack = task_stack_page(p);
  	
  	/* We have to use void * instead of a function pointer, because
  	 * function pointers aren't a pointer to the function on 64-bit.
  	 * Make them const so the compiler knows they live in .text */
  	extern void * const ret_from_kernel_thread;
  	extern void * const child_return;
  #ifdef CONFIG_HPUX
  	extern void * const hpux_child_return;
  #endif
  
  	*cregs = *pregs;
  
  	/* Set the return value for the child.  Note that this is not
             actually restored by the syscall exit path, but we put it
             here for consistency in case of signals. */
  	cregs->gr[28] = 0; /* child */
  
  	/*
  	 * We need to differentiate between a user fork and a
  	 * kernel fork. We can't use user_mode, because the
  	 * the syscall path doesn't save iaoq. Right now
  	 * We rely on the fact that kernel_thread passes
  	 * in zero for usp.
  	 */
  	if (usp == 1) {
  		/* kernel thread */
  		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN;
  		/* Must exit via ret_from_kernel_thread in order
  		 * to call schedule_tail()
  		 */
  		cregs->kpc = (unsigned long) &ret_from_kernel_thread;
  		/*
  		 * Copy function and argument to be called from
  		 * ret_from_kernel_thread.
  		 */
  #ifdef CONFIG_64BIT
  		cregs->gr[27] = pregs->gr[27];
  #endif
  		cregs->gr[26] = pregs->gr[26];
  		cregs->gr[25] = pregs->gr[25];
  	} else {
  		/* user thread */
  		/*
  		 * Note that the fork wrappers are responsible
  		 * for setting gr[21].
  		 */
  
  		/* Use same stack depth as parent */
  		cregs->ksp = (unsigned long)stack
  			+ (pregs->gr[21] & (THREAD_SIZE - 1));
  		cregs->gr[30] = usp;
  		if (p->personality == PER_HPUX) {
  #ifdef CONFIG_HPUX
  			cregs->kpc = (unsigned long) &hpux_child_return;
  #else
  			BUG();
  #endif
  		} else {
  			cregs->kpc = (unsigned long) &child_return;
  		}
  		/* Setup thread TLS area from the 4th parameter in clone */
  		if (clone_flags & CLONE_SETTLS)
  		  cregs->cr27 = pregs->gr[23];
  	
  	}
  
  	return 0;
  }
  
  unsigned long thread_saved_pc(struct task_struct *t)
  {
  	return t->thread.regs.kpc;
  }
  
  /*
   * sys_execve() executes a new program.
   */
  
  asmlinkage int sys_execve(struct pt_regs *regs)
  {
  	int error;
  	char *filename;
  
  	filename = getname((const char __user *) regs->gr[26]);
  	error = PTR_ERR(filename);
  	if (IS_ERR(filename))
  		goto out;
  	error = do_execve(filename, (char __user * __user *) regs->gr[25],
  		(char __user * __user *) regs->gr[24], regs);
  	if (error == 0) {
  		task_lock(current);
  		current->ptrace &= ~PT_DTRACE;
  		task_unlock(current);
  	}
  	putname(filename);
  out:
  
  	return error;
  }
  
  extern int __execve(const char *filename, char *const argv[],
  		char *const envp[], struct task_struct *task);
  int kernel_execve(const char *filename, char *const argv[], char *const envp[])
  {
  	return __execve(filename, argv, envp, current);
  }
  
  unsigned long
  get_wchan(struct task_struct *p)
  {
  	struct unwind_frame_info info;
  	unsigned long ip;
  	int count = 0;
  
  	if (!p || p == current || p->state == TASK_RUNNING)
  		return 0;
  
  	/*
  	 * These bracket the sleeping functions..
  	 */
  
  	unwind_frame_init_from_blocked_task(&info, p);
  	do {
  		if (unwind_once(&info) < 0)
  			return 0;
  		ip = info.ip;
  		if (!in_sched_functions(ip))
  			return ip;
  	} while (count++ < 16);
  	return 0;
  }
  