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) 2001-2014 Helge Deller <deller@gmx.de>
   *    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/fs.h>
  #include <linux/module.h>
  #include <linux/personality.h>
  #include <linux/ptrace.h>
  #include <linux/sched.h>
  #include <linux/sched/debug.h>
  #include <linux/sched/task.h>
  #include <linux/sched/task_stack.h>
  #include <linux/slab.h>
  #include <linux/stddef.h>
  #include <linux/unistd.h>
  #include <linux/kallsyms.h>
  #include <linux/uaccess.h>
  #include <linux/rcupdate.h>
  #include <linux/random.h>
  
  #include <asm/io.h>
  #include <asm/asm-offsets.h>
  #include <asm/assembly.h>
  #include <asm/pdc.h>
  #include <asm/pdc_chassis.h>
  #include <asm/pgalloc.h>
  #include <asm/unwind.h>
  #include <asm/sections.h>
  
  #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"
  	       "Please power this system off now.");
  
  	for (;;);
  }
  
  void (*pm_power_off)(void) = machine_power_off;
  EXPORT_SYMBOL(pm_power_off);
  
  void flush_thread(void)
  {
  	/* Only needs to handle fpu stuff or perf monitors.
  	** REVISIT: several arches implement a "lazy fpu state".
  	*/
  }
  
  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;
  }
  
  /*
   * Copy architecture-specific thread state
   */
  int
  copy_thread(unsigned long clone_flags, unsigned long usp,
  	    unsigned long kthread_arg, struct task_struct *p)
  {
  	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;
  
  	if (unlikely(p->flags & PF_KTHREAD)) {
  		/* kernel thread */
  		memset(cregs, 0, sizeof(struct pt_regs));
  		if (!usp) /* idle thread */
  			return 0;
  		/* Must exit via ret_from_kernel_thread in order
  		 * to call schedule_tail()
  		 */
  		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
  		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] = ((unsigned long *)usp)[3];
  		cregs->gr[26] = ((unsigned long *)usp)[2];
  #else
  		cregs->gr[26] = usp;
  #endif
  		cregs->gr[25] = kthread_arg;
  	} else {
  		/* user thread */
  		/* 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) */
  		if (usp) {
  			usp = ALIGN(usp, 4);
  			if (likely(usp))
  				cregs->gr[30] = usp;
  		}
  		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
  		cregs->kpc = (unsigned long) &child_return;
  
  		/* Setup thread TLS area from the 4th parameter in clone */
  		if (clone_flags & CLONE_SETTLS)
  			cregs->cr27 = cregs->gr[23];
  	}
  
  	return 0;
  }
  
  unsigned long thread_saved_pc(struct task_struct *t)
  {
  	return t->thread.regs.kpc;
  }
  
  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;
  }
  
  #ifdef CONFIG_64BIT
  void *dereference_function_descriptor(void *ptr)
  {
  	Elf64_Fdesc *desc = ptr;
  	void *p;
  
  	if (!probe_kernel_address(&desc->addr, p))
  		ptr = p;
  	return ptr;
  }
  #endif
  
  static inline unsigned long brk_rnd(void)
  {
  	return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
  }
  
  unsigned long arch_randomize_brk(struct mm_struct *mm)
  {
  	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
  
  	if (ret < mm->brk)
  		return mm->brk;
  	return ret;
  }
  