[linux-block.git] / arch / s390 / kernel / process.c

/*
 * This file handles the architecture dependent parts of process handling.
 *
 *    Copyright IBM Corp. 1999,2009
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
 *		 Hartmut Penner <hp@de.ibm.com>,
 *		 Denis Joseph Barrow,
 */

#include <linux/compiler.h>
#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/user.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/utsname.h>
#include <linux/tick.h>
#include <linux/elfcore.h>
#include <linux/kernel_stat.h>
#include <linux/syscalls.h>
#include <asm/compat.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/irq.h>
#include <asm/timer.h>
#include <asm/nmi.h>
#include "entry.h"

asmlinkage void ret_from_fork(void) asm ("ret_from_fork");

/*
 * Return saved PC of a blocked thread. used in kernel/sched.
 * resume in entry.S does not create a new stack frame, it
 * just stores the registers %r6-%r15 to the frame given by
 * schedule. We want to return the address of the caller of
 * schedule, so we have to walk the backchain one time to
 * find the frame schedule() store its return address.
 */
unsigned long thread_saved_pc(struct task_struct *tsk)
{
	struct stack_frame *sf, *low, *high;

	if (!tsk || !task_stack_page(tsk))
		return 0;
	low = task_stack_page(tsk);
	high = (struct stack_frame *) task_pt_regs(tsk);
	sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
	if (sf <= low || sf > high)
		return 0;
	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	if (sf <= low || sf > high)
		return 0;
	return sf->gprs[8];
}

/*
 * The idle loop on a S390...
 */
static void default_idle(void)
{
	/* CPU is going idle. */
	local_irq_disable();
	if (need_resched()) {
		local_irq_enable();
		return;
	}
#ifdef CONFIG_HOTPLUG_CPU
	if (cpu_is_offline(smp_processor_id())) {
		preempt_enable_no_resched();
		cpu_die();
	}
#endif
	local_mcck_disable();
	if (test_thread_flag(TIF_MCCK_PENDING)) {
		local_mcck_enable();
		local_irq_enable();
		s390_handle_mcck();
		return;
	}
	trace_hardirqs_on();
	/* Don't trace preempt off for idle. */
	stop_critical_timings();
	/* Stop virtual timer and halt the cpu. */
	vtime_stop_cpu();
	/* Reenable preemption tracer. */
	start_critical_timings();
}

void cpu_idle(void)
{
	for (;;) {
		tick_nohz_stop_sched_tick(1);
		while (!need_resched())
			default_idle();
		tick_nohz_restart_sched_tick();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

extern void kernel_thread_starter(void);

asm(
	".align 4\n"
	"kernel_thread_starter:\n"
	"    la    2,0(10)\n"
	"    basr  14,9\n"
	"    la    2,0\n"
	"    br    11\n");

int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	struct pt_regs regs;

	memset(&regs, 0, sizeof(regs));
	regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
	regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
	regs.gprs[9] = (unsigned long) fn;
	regs.gprs[10] = (unsigned long) arg;
	regs.gprs[11] = (unsigned long) do_exit;
	regs.orig_gpr2 = -1;

	/* Ok, create the new process.. */
	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
		       0, &regs, 0, NULL, NULL);
}
EXPORT_SYMBOL(kernel_thread);

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
}

void flush_thread(void)
{
	clear_used_math();
	clear_tsk_thread_flag(current, TIF_USEDFPU);
}

void release_thread(struct task_struct *dead_task)
{
}

int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
		unsigned long unused,
		struct task_struct *p, struct pt_regs *regs)
{
	struct thread_info *ti;
	struct fake_frame
	{
		struct stack_frame sf;
		struct pt_regs childregs;
	} *frame;

	frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
	p->thread.ksp = (unsigned long) frame;
	/* Store access registers to kernel stack of new process. */
	frame->childregs = *regs;
	frame->childregs.gprs[2] = 0;	/* child returns 0 on fork. */
	frame->childregs.gprs[15] = new_stackp;
	frame->sf.back_chain = 0;

	/* new return point is ret_from_fork */
	frame->sf.gprs[8] = (unsigned long) ret_from_fork;

	/* fake return stack for resume(), don't go back to schedule */
	frame->sf.gprs[9] = (unsigned long) frame;

	/* Save access registers to new thread structure. */
	save_access_regs(&p->thread.acrs[0]);

#ifndef CONFIG_64BIT
	/*
	 * save fprs to current->thread.fp_regs to merge them with
	 * the emulated registers and then copy the result to the child.
	 */
	save_fp_regs(&current->thread.fp_regs);
	memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
	       sizeof(s390_fp_regs));
	/* Set a new TLS ?  */
	if (clone_flags & CLONE_SETTLS)
		p->thread.acrs[0] = regs->gprs[6];
#else /* CONFIG_64BIT */
	/* Save the fpu registers to new thread structure. */
	save_fp_regs(&p->thread.fp_regs);
	/* Set a new TLS ?  */
	if (clone_flags & CLONE_SETTLS) {
		if (is_compat_task()) {
			p->thread.acrs[0] = (unsigned int) regs->gprs[6];
		} else {
			p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
			p->thread.acrs[1] = (unsigned int) regs->gprs[6];
		}
	}
#endif /* CONFIG_64BIT */
	/* start new process with ar4 pointing to the correct address space */
	p->thread.mm_segment = get_fs();
	/* Don't copy debug registers */
	memset(&p->thread.per_info, 0, sizeof(p->thread.per_info));
	/* Initialize per thread user and system timer values */
	ti = task_thread_info(p);
	ti->user_timer = 0;
	ti->system_timer = 0;
	return 0;
}

SYSCALL_DEFINE0(fork)
{
	struct pt_regs *regs = task_pt_regs(current);
	return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
}

SYSCALL_DEFINE0(clone)
{
	struct pt_regs *regs = task_pt_regs(current);
	unsigned long clone_flags;
	unsigned long newsp;
	int __user *parent_tidptr, *child_tidptr;

	clone_flags = regs->gprs[3];
	newsp = regs->orig_gpr2;
	parent_tidptr = (int __user *) regs->gprs[4];
	child_tidptr = (int __user *) regs->gprs[5];
	if (!newsp)
		newsp = regs->gprs[15];
	return do_fork(clone_flags, newsp, regs, 0,
		       parent_tidptr, child_tidptr);
}

/*
 * This is trivial, and on the face of it looks like it
 * could equally well be done in user mode.
 *
 * Not so, for quite unobvious reasons - register pressure.
 * In user mode vfork() cannot have a stack frame, and if
 * done by calling the "clone()" system call directly, you
 * do not have enough call-clobbered registers to hold all
 * the information you need.
 */
SYSCALL_DEFINE0(vfork)
{
	struct pt_regs *regs = task_pt_regs(current);
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
		       regs->gprs[15], regs, 0, NULL, NULL);
}

asmlinkage void execve_tail(void)
{
	task_lock(current);
	current->ptrace &= ~PT_DTRACE;
	task_unlock(current);
	current->thread.fp_regs.fpc = 0;
	if (MACHINE_HAS_IEEE)
		asm volatile("sfpc %0,%0" : : "d" (0));
}

/*
 * sys_execve() executes a new program.
 */
SYSCALL_DEFINE0(execve)
{
	struct pt_regs *regs = task_pt_regs(current);
	char *filename;
	unsigned long result;
	int rc;

	filename = getname((char __user *) regs->orig_gpr2);
	if (IS_ERR(filename)) {
		result = PTR_ERR(filename);
		goto out;
	}
	rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
		       (char __user * __user *) regs->gprs[4], regs);
	if (rc) {
		result = rc;
		goto out_putname;
	}
	execve_tail();
	result = regs->gprs[2];
out_putname:
	putname(filename);
out:
	return result;
}

/*
 * fill in the FPU structure for a core dump.
 */
int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
{
#ifndef CONFIG_64BIT
	/*
	 * save fprs to current->thread.fp_regs to merge them with
	 * the emulated registers and then copy the result to the dump.
	 */
	save_fp_regs(&current->thread.fp_regs);
	memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
#else /* CONFIG_64BIT */
	save_fp_regs(fpregs);
#endif /* CONFIG_64BIT */
	return 1;
}
EXPORT_SYMBOL(dump_fpu);

unsigned long get_wchan(struct task_struct *p)
{
	struct stack_frame *sf, *low, *high;
	unsigned long return_address;
	int count;

	if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
		return 0;
	low = task_stack_page(p);
	high = (struct stack_frame *) task_pt_regs(p);
	sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
	if (sf <= low || sf > high)
		return 0;
	for (count = 0; count < 16; count++) {
		sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
		if (sf <= low || sf > high)
			return 0;
		return_address = sf->gprs[8] & PSW_ADDR_INSN;
		if (!in_sched_functions(return_address))
			return return_address;
	}
	return 0;
}
Commit	Line	Data
1da177e4	1	/*
cbdc2292	2	* This file handles the architecture dependent parts of process handling.
1da177e4	3	*
cbdc2292 HC	4	* Copyright IBM Corp. 1999,2009
	5	* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
	6	* Hartmut Penner <hp@de.ibm.com>,
	7	* Denis Joseph Barrow,
1da177e4 LT	8	*/
1da177e4 LT	9
1da177e4 LT	10	#include <linux/compiler.h>
	11	#include <linux/cpu.h>
	12	#include <linux/errno.h>
	13	#include <linux/sched.h>
	14	#include <linux/kernel.h>
	15	#include <linux/mm.h>
4e950f6f	16	#include <linux/fs.h>
1da177e4	17	#include <linux/smp.h>
1da177e4 LT	18	#include <linux/stddef.h>
	19	#include <linux/unistd.h>
	20	#include <linux/ptrace.h>
	21	#include <linux/slab.h>
	22	#include <linux/vmalloc.h>
	23	#include <linux/user.h>
1da177e4 LT	24	#include <linux/interrupt.h>
	25	#include <linux/delay.h>
	26	#include <linux/reboot.h>
	27	#include <linux/init.h>
	28	#include <linux/module.h>
	29	#include <linux/notifier.h>
5c699714	30	#include <linux/utsname.h>
5a62b192	31	#include <linux/tick.h>
a806170e	32	#include <linux/elfcore.h>
6f430924	33	#include <linux/kernel_stat.h>
26689452	34	#include <linux/syscalls.h>
7757591a	35	#include <asm/compat.h>
1da177e4 LT	36	#include <asm/uaccess.h>
	37	#include <asm/pgtable.h>
	38	#include <asm/system.h>
	39	#include <asm/io.h>
	40	#include <asm/processor.h>
	41	#include <asm/irq.h>
	42	#include <asm/timer.h>
f5daba1d	43	#include <asm/nmi.h>
a806170e	44	#include "entry.h"
1da177e4	45
94c12cc7	46	asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
1da177e4 LT	47
	48	/*
	49	* Return saved PC of a blocked thread. used in kernel/sched.
	50	* resume in entry.S does not create a new stack frame, it
	51	* just stores the registers %r6-%r15 to the frame given by
	52	* schedule. We want to return the address of the caller of
	53	* schedule, so we have to walk the backchain one time to
	54	* find the frame schedule() store its return address.
	55	*/
	56	unsigned long thread_saved_pc(struct task_struct *tsk)
	57	{
eb33c190	58	struct stack_frame sf, low, *high;
1da177e4	59
eb33c190 HC	60	if (!tsk \|\| !task_stack_page(tsk))
	61	return 0;
	62	low = task_stack_page(tsk);
	63	high = (struct stack_frame *) task_pt_regs(tsk);
	64	sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
	65	if (sf <= low \|\| sf > high)
	66	return 0;
	67	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	68	if (sf <= low \|\| sf > high)
	69	return 0;
1da177e4 LT	70	return sf->gprs[8];
	71	}
	72
1da177e4 LT	73	/*
	74	* The idle loop on a S390...
	75	*/
cdb04527	76	static void default_idle(void)
1da177e4	77	{
64c7c8f8	78	/* CPU is going idle. */
1da177e4	79	local_irq_disable();
64c7c8f8	80	if (need_resched()) {
1da177e4	81	local_irq_enable();
64c7c8f8 NP	82	return;
64c7c8f8 NP	83	}
1da177e4	84	#ifdef CONFIG_HOTPLUG_CPU
43ca5c3a	85	if (cpu_is_offline(smp_processor_id())) {
1fca251f	86	preempt_enable_no_resched();
1da177e4	87	cpu_die();
1fca251f	88	}
1da177e4	89	#endif
77fa2245 HC	90	local_mcck_disable();
	91	if (test_thread_flag(TIF_MCCK_PENDING)) {
	92	local_mcck_enable();
	93	local_irq_enable();
	94	s390_handle_mcck();
	95	return;
	96	}
1f194a4c	97	trace_hardirqs_on();
632448f6 HC	98	/* Don't trace preempt off for idle. */
632448f6 HC	99	stop_critical_timings();
9cfb9b3c MS	100	/* Stop virtual timer and halt the cpu. */
	101	vtime_stop_cpu();
	102	/* Reenable preemption tracer. */
632448f6	103	start_critical_timings();
1da177e4 LT	104	}
	105
	106	void cpu_idle(void)
	107	{
5bfb5d69	108	for (;;) {
e338125b	109	tick_nohz_stop_sched_tick(1);
5bfb5d69 NP	110	while (!need_resched())
5bfb5d69 NP	111	default_idle();
5a62b192	112	tick_nohz_restart_sched_tick();
5bfb5d69 NP	113	preempt_enable_no_resched();
	114	schedule();
	115	preempt_disable();
	116	}
1da177e4 LT	117	}
1da177e4 LT	118
1da177e4 LT	119	extern void kernel_thread_starter(void);
1da177e4 LT	120
94c12cc7 MS	121	asm(
94c12cc7 MS	122	".align 4\n"
1da177e4 LT	123	"kernel_thread_starter:\n"
	124	" la 2,0(10)\n"
	125	" basr 14,9\n"
	126	" la 2,0\n"
	127	" br 11\n");
	128
	129	int kernel_thread(int (fn)(void ), void * arg, unsigned long flags)
	130	{
	131	struct pt_regs regs;
	132
	133	memset(&regs, 0, sizeof(regs));
c1821c2e	134	regs.psw.mask = psw_kernel_bits \| PSW_MASK_IO \| PSW_MASK_EXT;
1da177e4 LT	135	regs.psw.addr = (unsigned long) kernel_thread_starter \| PSW_ADDR_AMODE;
	136	regs.gprs[9] = (unsigned long) fn;
	137	regs.gprs[10] = (unsigned long) arg;
	138	regs.gprs[11] = (unsigned long) do_exit;
	139	regs.orig_gpr2 = -1;
	140
	141	/* Ok, create the new process.. */
	142	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED,
	143	0, &regs, 0, NULL, NULL);
	144	}
1485c5c8	145	EXPORT_SYMBOL(kernel_thread);
1da177e4 LT	146
	147	/*
	148	* Free current thread data structures etc..
	149	*/
	150	void exit_thread(void)
	151	{
	152	}
	153
	154	void flush_thread(void)
	155	{
	156	clear_used_math();
	157	clear_tsk_thread_flag(current, TIF_USEDFPU);
	158	}
	159
	160	void release_thread(struct task_struct *dead_task)
	161	{
	162	}
	163
6f2c55b8	164	int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
cbdc2292 HC	165	unsigned long unused,
cbdc2292 HC	166	struct task_struct p, struct pt_regs regs)
1da177e4	167	{
5168ce2c	168	struct thread_info *ti;
cbdc2292 HC	169	struct fake_frame
	170	{
	171	struct stack_frame sf;
	172	struct pt_regs childregs;
	173	} *frame;
	174
	175	frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
	176	p->thread.ksp = (unsigned long) frame;
1da177e4	177	/* Store access registers to kernel stack of new process. */
cbdc2292	178	frame->childregs = *regs;
1da177e4	179	frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
cbdc2292 HC	180	frame->childregs.gprs[15] = new_stackp;
cbdc2292 HC	181	frame->sf.back_chain = 0;
1da177e4	182
cbdc2292 HC	183	/* new return point is ret_from_fork */
cbdc2292 HC	184	frame->sf.gprs[8] = (unsigned long) ret_from_fork;
1da177e4	185
cbdc2292 HC	186	/* fake return stack for resume(), don't go back to schedule */
cbdc2292 HC	187	frame->sf.gprs[9] = (unsigned long) frame;
1da177e4 LT	188
	189	/* Save access registers to new thread structure. */
	190	save_access_regs(&p->thread.acrs[0]);
	191
347a8dc3	192	#ifndef CONFIG_64BIT
cbdc2292	193	/*
1da177e4 LT	194	* save fprs to current->thread.fp_regs to merge them with
	195	* the emulated registers and then copy the result to the child.
	196	*/
	197	save_fp_regs(&current->thread.fp_regs);
	198	memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
	199	sizeof(s390_fp_regs));
1da177e4 LT	200	/* Set a new TLS ? */
	201	if (clone_flags & CLONE_SETTLS)
	202	p->thread.acrs[0] = regs->gprs[6];
347a8dc3	203	#else /* CONFIG_64BIT */
1da177e4 LT	204	/* Save the fpu registers to new thread structure. */
1da177e4 LT	205	save_fp_regs(&p->thread.fp_regs);
1da177e4 LT	206	/* Set a new TLS ? */
1da177e4 LT	207	if (clone_flags & CLONE_SETTLS) {
7757591a	208	if (is_compat_task()) {
1da177e4 LT	209	p->thread.acrs[0] = (unsigned int) regs->gprs[6];
	210	} else {
	211	p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
	212	p->thread.acrs[1] = (unsigned int) regs->gprs[6];
	213	}
	214	}
347a8dc3	215	#endif /* CONFIG_64BIT */
1da177e4 LT	216	/* start new process with ar4 pointing to the correct address space */
1da177e4 LT	217	p->thread.mm_segment = get_fs();
cbdc2292 HC	218	/* Don't copy debug registers */
cbdc2292 HC	219	memset(&p->thread.per_info, 0, sizeof(p->thread.per_info));
5168ce2c HC	220	/* Initialize per thread user and system timer values */
	221	ti = task_thread_info(p);
	222	ti->user_timer = 0;
	223	ti->system_timer = 0;
cbdc2292	224	return 0;
1da177e4 LT	225	}
1da177e4 LT	226
26689452	227	SYSCALL_DEFINE0(fork)
1da177e4	228	{
03ff9a23 MS	229	struct pt_regs *regs = task_pt_regs(current);
03ff9a23 MS	230	return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
1da177e4 LT	231	}
1da177e4 LT	232
26689452	233	SYSCALL_DEFINE0(clone)
1da177e4	234	{
03ff9a23 MS	235	struct pt_regs *regs = task_pt_regs(current);
	236	unsigned long clone_flags;
	237	unsigned long newsp;
1da177e4 LT	238	int __user parent_tidptr, child_tidptr;
1da177e4 LT	239
03ff9a23 MS	240	clone_flags = regs->gprs[3];
	241	newsp = regs->orig_gpr2;
	242	parent_tidptr = (int __user *) regs->gprs[4];
	243	child_tidptr = (int __user *) regs->gprs[5];
	244	if (!newsp)
	245	newsp = regs->gprs[15];
	246	return do_fork(clone_flags, newsp, regs, 0,
1da177e4 LT	247	parent_tidptr, child_tidptr);
	248	}
	249
	250	/*
	251	* This is trivial, and on the face of it looks like it
	252	* could equally well be done in user mode.
	253	*
	254	* Not so, for quite unobvious reasons - register pressure.
	255	* In user mode vfork() cannot have a stack frame, and if
	256	* done by calling the "clone()" system call directly, you
	257	* do not have enough call-clobbered registers to hold all
	258	* the information you need.
	259	*/
26689452	260	SYSCALL_DEFINE0(vfork)
1da177e4	261	{
03ff9a23	262	struct pt_regs *regs = task_pt_regs(current);
1da177e4	263	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD,
03ff9a23 MS	264	regs->gprs[15], regs, 0, NULL, NULL);
	265	}
	266
	267	asmlinkage void execve_tail(void)
	268	{
	269	task_lock(current);
	270	current->ptrace &= ~PT_DTRACE;
	271	task_unlock(current);
	272	current->thread.fp_regs.fpc = 0;
	273	if (MACHINE_HAS_IEEE)
	274	asm volatile("sfpc %0,%0" : : "d" (0));
1da177e4 LT	275	}
	276
	277	/*
	278	* sys_execve() executes a new program.
	279	*/
26689452	280	SYSCALL_DEFINE0(execve)
1da177e4	281	{
03ff9a23 MS	282	struct pt_regs *regs = task_pt_regs(current);
	283	char *filename;
	284	unsigned long result;
	285	int rc;
	286
	287	filename = getname((char __user *) regs->orig_gpr2);
	288	if (IS_ERR(filename)) {
	289	result = PTR_ERR(filename);
	290	goto out;
1da177e4	291	}
03ff9a23 MS	292	rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
	293	(char __user * __user *) regs->gprs[4], regs);
	294	if (rc) {
	295	result = rc;
	296	goto out_putname;
	297	}
	298	execve_tail();
	299	result = regs->gprs[2];
	300	out_putname:
	301	putname(filename);
1da177e4	302	out:
03ff9a23	303	return result;
1da177e4 LT	304	}
1da177e4 LT	305
1da177e4 LT	306	/*
	307	* fill in the FPU structure for a core dump.
	308	*/
	309	int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
	310	{
347a8dc3	311	#ifndef CONFIG_64BIT
cbdc2292	312	/*
1da177e4 LT	313	* save fprs to current->thread.fp_regs to merge them with
	314	* the emulated registers and then copy the result to the dump.
	315	*/
	316	save_fp_regs(&current->thread.fp_regs);
	317	memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
347a8dc3	318	#else /* CONFIG_64BIT */
1da177e4	319	save_fp_regs(fpregs);
347a8dc3	320	#endif /* CONFIG_64BIT */
1da177e4 LT	321	return 1;
1da177e4 LT	322	}
1485c5c8	323	EXPORT_SYMBOL(dump_fpu);
1da177e4	324
1da177e4 LT	325	unsigned long get_wchan(struct task_struct *p)
	326	{
	327	struct stack_frame sf, low, *high;
	328	unsigned long return_address;
	329	int count;
	330
30af7120	331	if (!p \|\| p == current \|\| p->state == TASK_RUNNING \|\| !task_stack_page(p))
1da177e4	332	return 0;
30af7120 AV	333	low = task_stack_page(p);
30af7120 AV	334	high = (struct stack_frame *) task_pt_regs(p);
1da177e4 LT	335	sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
	336	if (sf <= low \|\| sf > high)
	337	return 0;
	338	for (count = 0; count < 16; count++) {
	339	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	340	if (sf <= low \|\| sf > high)
	341	return 0;
	342	return_address = sf->gprs[8] & PSW_ADDR_INSN;
	343	if (!in_sched_functions(return_address))
	344	return return_address;
	345	}
	346	return 0;
	347	}