[mirror_ubuntu-artful-kernel.git] / arch / parisc / kernel / process.c

/*
 *    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) 2001-2002 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>

static int hlt_counter __read_mostly;

/*
 * Power off function, if any
 */ 
void (*pm_power_off)(void);

void disable_hlt(void)
{
	hlt_counter++;
}

EXPORT_SYMBOL(disable_hlt);

void enable_hlt(void)
{
	hlt_counter--;
}

EXPORT_SYMBOL(enable_hlt);

void default_idle(void)
{
	barrier();
}

/*
 * 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();
	}
}


#ifdef __LP64__
#define COMMAND_GLOBAL  0xfffffffffffe0030UL
#else
#define COMMAND_GLOBAL  0xfffe0030
#endif

#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.
	*/
}


/*
 * 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(pm_power_off)
		pm_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.");
}


/*
 * 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 __LP64__
		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 **) regs->gr[25],
		(char __user **) regs->gr[24], regs);
	if (error == 0) {
		task_lock(current);
		current->ptrace &= ~PT_DTRACE;
		task_unlock(current);
	}
	putname(filename);
out:

	return error;
}

unsigned long 
get_wchan(struct task_struct *p)
{
	struct unwind_frame_info info;
	unsigned long ip;
	int count = 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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* PARISC Architecture-dependent parts of process handling
	3	* based on the work for i386
	4	*
	5	* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
	6	* Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
	7	* Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
	8	* Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
	9	* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
	10	* Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
	11	* Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
b2450cc1	12	* Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
1da177e4 LT	13	* Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
	14	* Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
	15	* Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
	16	* Copyright (C) 2001-2002 Helge Deller <deller at parisc-linux.org>
	17	* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
	18	*
	19	*
	20	* This program is free software; you can redistribute it and/or modify
	21	* it under the terms of the GNU General Public License as published by
	22	* the Free Software Foundation; either version 2 of the License, or
	23	* (at your option) any later version.
	24	*
	25	* This program is distributed in the hope that it will be useful,
	26	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	27	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	28	* GNU General Public License for more details.
	29	*
	30	* You should have received a copy of the GNU General Public License
	31	* along with this program; if not, write to the Free Software
	32	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	33	*/
	34
	35	#include <stdarg.h>
	36
	37	#include <linux/elf.h>
	38	#include <linux/errno.h>
	39	#include <linux/kernel.h>
	40	#include <linux/mm.h>
	41	#include <linux/module.h>
	42	#include <linux/personality.h>
	43	#include <linux/ptrace.h>
	44	#include <linux/sched.h>
	45	#include <linux/stddef.h>
	46	#include <linux/unistd.h>
	47	#include <linux/kallsyms.h>
	48
	49	#include <asm/io.h>
0013a854	50	#include <asm/asm-offsets.h>
1da177e4 LT	51	#include <asm/pdc.h>
	52	#include <asm/pdc_chassis.h>
	53	#include <asm/pgalloc.h>
	54	#include <asm/uaccess.h>
	55	#include <asm/unwind.h>
	56
8039de10	57	static int hlt_counter __read_mostly;
1da177e4 LT	58
	59	/*
	60	* Power off function, if any
	61	*/
	62	void (*pm_power_off)(void);
	63
	64	void disable_hlt(void)
	65	{
	66	hlt_counter++;
	67	}
	68
	69	EXPORT_SYMBOL(disable_hlt);
	70
	71	void enable_hlt(void)
	72	{
	73	hlt_counter--;
	74	}
	75
	76	EXPORT_SYMBOL(enable_hlt);
	77
	78	void default_idle(void)
	79	{
	80	barrier();
	81	}
	82
	83	/*
	84	* The idle thread. There's no useful work to be
	85	* done, so just try to conserve power and have a
	86	* low exit latency (ie sit in a loop waiting for
	87	* somebody to say that they'd like to reschedule)
	88	*/
	89	void cpu_idle(void)
	90	{
64c7c8f8 NP	91	set_thread_flag(TIF_POLLING_NRFLAG);
64c7c8f8 NP	92
1da177e4 LT	93	/* endless idle loop with no priority at all */
	94	while (1) {
	95	while (!need_resched())
	96	barrier();
5bfb5d69	97	preempt_enable_no_resched();
1da177e4	98	schedule();
5bfb5d69	99	preempt_disable();
1da177e4 LT	100	check_pgt_cache();
	101	}
	102	}
	103
	104
	105	#ifdef __LP64__
	106	#define COMMAND_GLOBAL 0xfffffffffffe0030UL
	107	#else
	108	#define COMMAND_GLOBAL 0xfffe0030
	109	#endif
	110
	111	#define CMD_RESET 5 /* reset any module */
	112
	113	/*
	114	** The Wright Brothers and Gecko systems have a H/W problem
	115	** (Lasi...'nuf said) may cause a broadcast reset to lockup
	116	** the system. An HVERSION dependent PDC call was developed
	117	** to perform a "safe", platform specific broadcast reset instead
	118	** of kludging up all the code.
	119	**
	120	** Older machines which do not implement PDC_BROADCAST_RESET will
	121	** return (with an error) and the regular broadcast reset can be
	122	** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
	123	** the PDC call will not return (the system will be reset).
	124	*/
	125	void machine_restart(char *cmd)
	126	{
	127	#ifdef FASTBOOT_SELFTEST_SUPPORT
	128	/*
	129	** If user has modified the Firmware Selftest Bitmap,
	130	** run the tests specified in the bitmap after the
	131	** system is rebooted w/PDC_DO_RESET.
	132	**
	133	** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
	134	**
	135	** Using "directed resets" at each processor with the MEM_TOC
	136	** vector cleared will also avoid running destructive
	137	** memory self tests. (Not implemented yet)
	138	*/
	139	if (ftc_bitmap) {
	140	pdc_do_firm_test_reset(ftc_bitmap);
	141	}
	142	#endif
	143	/* set up a new led state on systems shipped with a LED State panel */
	144	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
	145
	146	/* "Normal" system reset */
	147	pdc_do_reset();
	148
	149	/* Nope...box should reset with just CMD_RESET now */
	150	gsc_writel(CMD_RESET, COMMAND_GLOBAL);
	151
	152	/* Wait for RESET to lay us to rest. */
	153	while (1) ;
	154
	155	}
	156
1da177e4 LT	157	void machine_halt(void)
	158	{
	159	/*
	160	** The LED/ChassisCodes are updated by the led_halt()
	161	** function, called by the reboot notifier chain.
	162	*/
	163	}
	164
1da177e4 LT	165
	166	/*
	167	* This routine is called from sys_reboot to actually turn off the
	168	* machine
	169	*/
	170	void machine_power_off(void)
	171	{
	172	/* If there is a registered power off handler, call it. */
	173	if(pm_power_off)
	174	pm_power_off();
	175
	176	/* Put the soft power button back under hardware control.
	177	* If the user had already pressed the power button, the
	178	* following call will immediately power off. */
	179	pdc_soft_power_button(0);
	180
	181	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
	182
	183	/* It seems we have no way to power the system off via
	184	* software. The user has to press the button himself. */
	185
	186	printk(KERN_EMERG "System shut down completed.\n"
	187	KERN_EMERG "Please power this system off now.");
	188	}
	189
1da177e4 LT	190
	191	/*
	192	* Create a kernel thread
	193	*/
	194
	195	extern pid_t __kernel_thread(int (fn)(void ), void *arg, unsigned long flags);
	196	pid_t kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	197	{
	198
	199	/*
	200	* FIXME: Once we are sure we don't need any debug here,
	201	* kernel_thread can become a #define.
	202	*/
	203
	204	return __kernel_thread(fn, arg, flags);
	205	}
	206	EXPORT_SYMBOL(kernel_thread);
	207
	208	/*
	209	* Free current thread data structures etc..
	210	*/
	211	void exit_thread(void)
	212	{
	213	}
	214
	215	void flush_thread(void)
	216	{
	217	/* Only needs to handle fpu stuff or perf monitors.
	218	** REVISIT: several arches implement a "lazy fpu state".
	219	*/
	220	set_fs(USER_DS);
	221	}
	222
	223	void release_thread(struct task_struct *dead_task)
	224	{
	225	}
	226
	227	/*
	228	* Fill in the FPU structure for a core dump.
	229	*/
	230
	231	int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
	232	{
	233	if (regs == NULL)
	234	return 0;
	235
	236	memcpy(r, regs->fr, sizeof *r);
	237	return 1;
	238	}
	239
	240	int dump_task_fpu (struct task_struct tsk, elf_fpregset_t r)
	241	{
	242	memcpy(r, tsk->thread.regs.fr, sizeof(*r));
	243	return 1;
	244	}
	245
	246	/* Note that "fork()" is implemented in terms of clone, with
	247	parameters (SIGCHLD, regs->gr[30], regs). */
	248	int
	249	sys_clone(unsigned long clone_flags, unsigned long usp,
	250	struct pt_regs *regs)
	251	{
b2450cc1 CD	252	/* Arugments from userspace are:
	253	r26 = Clone flags.
	254	r25 = Child stack.
	255	r24 = parent_tidptr.
	256	r23 = Is the TLS storage descriptor
	257	r22 = child_tidptr
	258
	259	However, these last 3 args are only examined
	260	if the proper flags are set. */
	261	int __user *child_tidptr;
	262	int __user *parent_tidptr;
1da177e4 LT	263
	264	/* usp must be word aligned. This also prevents users from
	265	* passing in the value 1 (which is the signal for a special
	266	* return for a kernel thread) */
	267	usp = ALIGN(usp, 4);
	268
	269	/* A zero value for usp means use the current stack */
b2450cc1 CD	270	if (usp == 0)
b2450cc1 CD	271	usp = regs->gr[30];
1da177e4	272
b2450cc1 CD	273	if (clone_flags & CLONE_PARENT_SETTID)
	274	parent_tidptr = (int __user *)regs->gr[24];
	275	else
	276	parent_tidptr = NULL;
	277
	278	if (clone_flags & (CLONE_CHILD_SETTID \| CLONE_CHILD_CLEARTID))
	279	child_tidptr = (int __user *)regs->gr[22];
	280	else
	281	child_tidptr = NULL;
	282
	283	return do_fork(clone_flags, usp, regs, 0, parent_tidptr, child_tidptr);
1da177e4 LT	284	}
	285
	286	int
	287	sys_vfork(struct pt_regs *regs)
	288	{
	289	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD, regs->gr[30], regs, 0, NULL, NULL);
	290	}
	291
	292	int
	293	copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	294	unsigned long unused, /* in ia64 this is "user_stack_size" */
	295	struct task_struct * p, struct pt_regs * pregs)
	296	{
	297	struct pt_regs * cregs = &(p->thread.regs);
40f1f0de	298	void *stack = task_stack_page(p);
1da177e4 LT	299
	300	/* We have to use void * instead of a function pointer, because
	301	* function pointers aren't a pointer to the function on 64-bit.
	302	* Make them const so the compiler knows they live in .text */
	303	extern void * const ret_from_kernel_thread;
	304	extern void * const child_return;
	305	#ifdef CONFIG_HPUX
	306	extern void * const hpux_child_return;
	307	#endif
	308
	309	cregs = pregs;
	310
	311	/* Set the return value for the child. Note that this is not
	312	actually restored by the syscall exit path, but we put it
	313	here for consistency in case of signals. */
	314	cregs->gr[28] = 0; /* child */
	315
	316	/*
	317	* We need to differentiate between a user fork and a
	318	* kernel fork. We can't use user_mode, because the
	319	* the syscall path doesn't save iaoq. Right now
	320	* We rely on the fact that kernel_thread passes
	321	* in zero for usp.
	322	*/
	323	if (usp == 1) {
	324	/* kernel thread */
40f1f0de	325	cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN;
1da177e4 LT	326	/* Must exit via ret_from_kernel_thread in order
	327	* to call schedule_tail()
	328	*/
	329	cregs->kpc = (unsigned long) &ret_from_kernel_thread;
	330	/*
	331	* Copy function and argument to be called from
	332	* ret_from_kernel_thread.
	333	*/
	334	#ifdef __LP64__
	335	cregs->gr[27] = pregs->gr[27];
	336	#endif
	337	cregs->gr[26] = pregs->gr[26];
	338	cregs->gr[25] = pregs->gr[25];
	339	} else {
	340	/* user thread */
	341	/*
	342	* Note that the fork wrappers are responsible
	343	* for setting gr[21].
	344	*/
	345
	346	/* Use same stack depth as parent */
40f1f0de	347	cregs->ksp = (unsigned long)stack
1da177e4 LT	348	+ (pregs->gr[21] & (THREAD_SIZE - 1));
	349	cregs->gr[30] = usp;
	350	if (p->personality == PER_HPUX) {
	351	#ifdef CONFIG_HPUX
	352	cregs->kpc = (unsigned long) &hpux_child_return;
	353	#else
	354	BUG();
	355	#endif
	356	} else {
	357	cregs->kpc = (unsigned long) &child_return;
	358	}
b2450cc1 CD	359	/* Setup thread TLS area from the 4th parameter in clone */
	360	if (clone_flags & CLONE_SETTLS)
	361	cregs->cr27 = pregs->gr[23];
	362
1da177e4 LT	363	}
	364
	365	return 0;
	366	}
	367
	368	unsigned long thread_saved_pc(struct task_struct *t)
	369	{
	370	return t->thread.regs.kpc;
	371	}
	372
	373	/*
	374	* sys_execve() executes a new program.
	375	*/
	376
	377	asmlinkage int sys_execve(struct pt_regs *regs)
	378	{
	379	int error;
	380	char *filename;
	381
	382	filename = getname((const char __user *) regs->gr[26]);
	383	error = PTR_ERR(filename);
	384	if (IS_ERR(filename))
	385	goto out;
	386	error = do_execve(filename, (char __user **) regs->gr[25],
	387	(char __user **) regs->gr[24], regs);
	388	if (error == 0) {
	389	task_lock(current);
	390	current->ptrace &= ~PT_DTRACE;
	391	task_unlock(current);
	392	}
	393	putname(filename);
	394	out:
	395
	396	return error;
	397	}
	398
	399	unsigned long
	400	get_wchan(struct task_struct *p)
	401	{
	402	struct unwind_frame_info info;
	403	unsigned long ip;
	404	int count = 0;
	405	/*
	406	* These bracket the sleeping functions..
	407	*/
	408
	409	unwind_frame_init_from_blocked_task(&info, p);
	410	do {
	411	if (unwind_once(&info) < 0)
	412	return 0;
	413	ip = info.ip;
	414	if (!in_sched_functions(ip))
	415	return ip;
	416	} while (count++ < 16);
	417	return 0;
	418	}