[deliverable/linux.git] / arch / s390 / kernel / process.c

/*
 *  arch/s390/kernel/process.c
 *
 *  S390 version
 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *               Hartmut Penner (hp@de.ibm.com),
 *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
 *
 *  Derived from "arch/i386/kernel/process.c"
 *    Copyright (C) 1995, Linus Torvalds
 */

/*
 * This file handles the architecture-dependent parts of process handling..
 */

#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 <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/cpu.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];
}

DEFINE_PER_CPU(struct s390_idle_data, s390_idle);

static int s390_idle_enter(void)
{
	struct s390_idle_data *idle;

	idle = &__get_cpu_var(s390_idle);
	spin_lock(&idle->lock);
	idle->idle_count++;
	idle->in_idle = 1;
	idle->idle_enter = get_clock();
	spin_unlock(&idle->lock);
	vtime_stop_cpu_timer();
	return NOTIFY_OK;
}

void s390_idle_leave(void)
{
	struct s390_idle_data *idle;

	vtime_start_cpu_timer();
	idle = &__get_cpu_var(s390_idle);
	spin_lock(&idle->lock);
	idle->idle_time += get_clock() - idle->idle_enter;
	idle->in_idle = 0;
	spin_unlock(&idle->lock);
}

extern void s390_handle_mcck(void);
/*
 * 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;
	}
	if (s390_idle_enter() == NOTIFY_BAD) {
		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();
		s390_idle_leave();
		local_irq_enable();
		s390_handle_mcck();
		return;
	}
	trace_hardirqs_on();
	/* Wait for external, I/O or machine check interrupt. */
	__load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
			PSW_MASK_IO | PSW_MASK_EXT);
}

void cpu_idle(void)
{
	for (;;) {
		tick_nohz_stop_sched_tick();
		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);
}

/*
 * 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(int nr, unsigned long clone_flags, unsigned long new_stackp,
	unsigned long unused,
        struct task_struct * p, struct pt_regs * regs)
{
        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 (test_thread_flag(TIF_31BIT)) {
			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));

        return 0;
}

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

asmlinkage long sys_clone(void)
{
	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.
 */
asmlinkage long sys_vfork(void)
{
	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.
 */
asmlinkage long sys_execve(void)
{
	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;
}

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 LT	1	/*
	2	* arch/s390/kernel/process.c
	3	*
	4	* S390 version
	5	* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
	6	* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
	7	* Hartmut Penner (hp@de.ibm.com),
	8	* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
	9	*
	10	* Derived from "arch/i386/kernel/process.c"
	11	* Copyright (C) 1995, Linus Torvalds
	12	*/
	13
	14	/*
	15	* This file handles the architecture-dependent parts of process handling..
	16	*/
	17
1da177e4 LT	18	#include <linux/compiler.h>
	19	#include <linux/cpu.h>
	20	#include <linux/errno.h>
	21	#include <linux/sched.h>
	22	#include <linux/kernel.h>
	23	#include <linux/mm.h>
4e950f6f	24	#include <linux/fs.h>
1da177e4	25	#include <linux/smp.h>
1da177e4 LT	26	#include <linux/stddef.h>
	27	#include <linux/unistd.h>
	28	#include <linux/ptrace.h>
	29	#include <linux/slab.h>
	30	#include <linux/vmalloc.h>
	31	#include <linux/user.h>
1da177e4 LT	32	#include <linux/interrupt.h>
	33	#include <linux/delay.h>
	34	#include <linux/reboot.h>
	35	#include <linux/init.h>
	36	#include <linux/module.h>
	37	#include <linux/notifier.h>
5c699714	38	#include <linux/utsname.h>
5a62b192	39	#include <linux/tick.h>
a806170e	40	#include <linux/elfcore.h>
1da177e4 LT	41	#include <asm/uaccess.h>
	42	#include <asm/pgtable.h>
	43	#include <asm/system.h>
	44	#include <asm/io.h>
	45	#include <asm/processor.h>
	46	#include <asm/irq.h>
	47	#include <asm/timer.h>
fae8b22d	48	#include <asm/cpu.h>
a806170e	49	#include "entry.h"
1da177e4	50
94c12cc7	51	asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
1da177e4 LT	52
	53	/*
	54	* Return saved PC of a blocked thread. used in kernel/sched.
	55	* resume in entry.S does not create a new stack frame, it
	56	* just stores the registers %r6-%r15 to the frame given by
	57	* schedule. We want to return the address of the caller of
	58	* schedule, so we have to walk the backchain one time to
	59	* find the frame schedule() store its return address.
	60	*/
	61	unsigned long thread_saved_pc(struct task_struct *tsk)
	62	{
eb33c190	63	struct stack_frame sf, low, *high;
1da177e4	64
eb33c190 HC	65	if (!tsk \|\| !task_stack_page(tsk))
	66	return 0;
	67	low = task_stack_page(tsk);
	68	high = (struct stack_frame *) task_pt_regs(tsk);
	69	sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
	70	if (sf <= low \|\| sf > high)
	71	return 0;
	72	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	73	if (sf <= low \|\| sf > high)
	74	return 0;
1da177e4 LT	75	return sf->gprs[8];
	76	}
	77
43ca5c3a	78	DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
1da177e4	79
43ca5c3a HC	80	static int s390_idle_enter(void)
	81	{
	82	struct s390_idle_data *idle;
43ca5c3a	83
43ca5c3a HC	84	idle = &__get_cpu_var(s390_idle);
	85	spin_lock(&idle->lock);
	86	idle->idle_count++;
	87	idle->in_idle = 1;
	88	idle->idle_enter = get_clock();
	89	spin_unlock(&idle->lock);
773922e1	90	vtime_stop_cpu_timer();
43ca5c3a HC	91	return NOTIFY_OK;
	92	}
	93
	94	void s390_idle_leave(void)
1da177e4	95	{
fae8b22d HC	96	struct s390_idle_data *idle;
fae8b22d HC	97
773922e1	98	vtime_start_cpu_timer();
fae8b22d HC	99	idle = &__get_cpu_var(s390_idle);
	100	spin_lock(&idle->lock);
	101	idle->idle_time += get_clock() - idle->idle_enter;
	102	idle->in_idle = 0;
	103	spin_unlock(&idle->lock);
1da177e4 LT	104	}
1da177e4 LT	105
77fa2245	106	extern void s390_handle_mcck(void);
1da177e4 LT	107	/*
	108	* The idle loop on a S390...
	109	*/
cdb04527	110	static void default_idle(void)
1da177e4	111	{
64c7c8f8	112	/* CPU is going idle. */
1da177e4	113	local_irq_disable();
64c7c8f8	114	if (need_resched()) {
1da177e4	115	local_irq_enable();
64c7c8f8 NP	116	return;
64c7c8f8 NP	117	}
43ca5c3a	118	if (s390_idle_enter() == NOTIFY_BAD) {
1da177e4 LT	119	local_irq_enable();
	120	return;
	121	}
1da177e4	122	#ifdef CONFIG_HOTPLUG_CPU
43ca5c3a	123	if (cpu_is_offline(smp_processor_id())) {
1fca251f	124	preempt_enable_no_resched();
1da177e4	125	cpu_die();
1fca251f	126	}
1da177e4	127	#endif
77fa2245 HC	128	local_mcck_disable();
	129	if (test_thread_flag(TIF_MCCK_PENDING)) {
	130	local_mcck_enable();
43ca5c3a	131	s390_idle_leave();
77fa2245 HC	132	local_irq_enable();
	133	s390_handle_mcck();
	134	return;
	135	}
1f194a4c	136	trace_hardirqs_on();
77fa2245	137	/* Wait for external, I/O or machine check interrupt. */
c1821c2e	138	__load_psw_mask(psw_kernel_bits \| PSW_MASK_WAIT \|
77fa2245	139	PSW_MASK_IO \| PSW_MASK_EXT);
1da177e4 LT	140	}
	141
	142	void cpu_idle(void)
	143	{
5bfb5d69	144	for (;;) {
5a62b192	145	tick_nohz_stop_sched_tick();
5bfb5d69 NP	146	while (!need_resched())
5bfb5d69 NP	147	default_idle();
5a62b192	148	tick_nohz_restart_sched_tick();
5bfb5d69 NP	149	preempt_enable_no_resched();
	150	schedule();
	151	preempt_disable();
	152	}
1da177e4 LT	153	}
1da177e4 LT	154
1da177e4 LT	155	extern void kernel_thread_starter(void);
1da177e4 LT	156
94c12cc7 MS	157	asm(
94c12cc7 MS	158	".align 4\n"
1da177e4 LT	159	"kernel_thread_starter:\n"
	160	" la 2,0(10)\n"
	161	" basr 14,9\n"
	162	" la 2,0\n"
	163	" br 11\n");
	164
	165	int kernel_thread(int (fn)(void ), void * arg, unsigned long flags)
	166	{
	167	struct pt_regs regs;
	168
	169	memset(&regs, 0, sizeof(regs));
c1821c2e	170	regs.psw.mask = psw_kernel_bits \| PSW_MASK_IO \| PSW_MASK_EXT;
1da177e4 LT	171	regs.psw.addr = (unsigned long) kernel_thread_starter \| PSW_ADDR_AMODE;
	172	regs.gprs[9] = (unsigned long) fn;
	173	regs.gprs[10] = (unsigned long) arg;
	174	regs.gprs[11] = (unsigned long) do_exit;
	175	regs.orig_gpr2 = -1;
	176
	177	/* Ok, create the new process.. */
	178	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED,
	179	0, &regs, 0, NULL, NULL);
	180	}
	181
	182	/*
	183	* Free current thread data structures etc..
	184	*/
	185	void exit_thread(void)
	186	{
	187	}
	188
	189	void flush_thread(void)
	190	{
	191	clear_used_math();
	192	clear_tsk_thread_flag(current, TIF_USEDFPU);
	193	}
	194
	195	void release_thread(struct task_struct *dead_task)
	196	{
	197	}
	198
	199	int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
	200	unsigned long unused,
	201	struct task_struct * p, struct pt_regs * regs)
	202	{
	203	struct fake_frame
	204	{
	205	struct stack_frame sf;
	206	struct pt_regs childregs;
	207	} *frame;
	208
c7584fb6	209	frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
1da177e4 LT	210	p->thread.ksp = (unsigned long) frame;
	211	/* Store access registers to kernel stack of new process. */
	212	frame->childregs = *regs;
	213	frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
	214	frame->childregs.gprs[15] = new_stackp;
	215	frame->sf.back_chain = 0;
	216
	217	/* new return point is ret_from_fork */
	218	frame->sf.gprs[8] = (unsigned long) ret_from_fork;
	219
	220	/* fake return stack for resume(), don't go back to schedule */
	221	frame->sf.gprs[9] = (unsigned long) frame;
	222
	223	/* Save access registers to new thread structure. */
	224	save_access_regs(&p->thread.acrs[0]);
	225
347a8dc3	226	#ifndef CONFIG_64BIT
1da177e4 LT	227	/*
	228	* save fprs to current->thread.fp_regs to merge them with
	229	* the emulated registers and then copy the result to the child.
	230	*/
	231	save_fp_regs(&current->thread.fp_regs);
	232	memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
	233	sizeof(s390_fp_regs));
1da177e4 LT	234	/* Set a new TLS ? */
	235	if (clone_flags & CLONE_SETTLS)
	236	p->thread.acrs[0] = regs->gprs[6];
347a8dc3	237	#else /* CONFIG_64BIT */
1da177e4 LT	238	/* Save the fpu registers to new thread structure. */
1da177e4 LT	239	save_fp_regs(&p->thread.fp_regs);
1da177e4 LT	240	/* Set a new TLS ? */
	241	if (clone_flags & CLONE_SETTLS) {
	242	if (test_thread_flag(TIF_31BIT)) {
	243	p->thread.acrs[0] = (unsigned int) regs->gprs[6];
	244	} else {
	245	p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
	246	p->thread.acrs[1] = (unsigned int) regs->gprs[6];
	247	}
	248	}
347a8dc3	249	#endif /* CONFIG_64BIT */
1da177e4 LT	250	/* start new process with ar4 pointing to the correct address space */
	251	p->thread.mm_segment = get_fs();
	252	/* Don't copy debug registers */
	253	memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
	254
	255	return 0;
	256	}
	257
03ff9a23	258	asmlinkage long sys_fork(void)
1da177e4	259	{
03ff9a23 MS	260	struct pt_regs *regs = task_pt_regs(current);
03ff9a23 MS	261	return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
1da177e4 LT	262	}
1da177e4 LT	263
03ff9a23	264	asmlinkage long sys_clone(void)
1da177e4	265	{
03ff9a23 MS	266	struct pt_regs *regs = task_pt_regs(current);
	267	unsigned long clone_flags;
	268	unsigned long newsp;
1da177e4 LT	269	int __user parent_tidptr, child_tidptr;
1da177e4 LT	270
03ff9a23 MS	271	clone_flags = regs->gprs[3];
	272	newsp = regs->orig_gpr2;
	273	parent_tidptr = (int __user *) regs->gprs[4];
	274	child_tidptr = (int __user *) regs->gprs[5];
	275	if (!newsp)
	276	newsp = regs->gprs[15];
	277	return do_fork(clone_flags, newsp, regs, 0,
1da177e4 LT	278	parent_tidptr, child_tidptr);
	279	}
	280
	281	/*
	282	* This is trivial, and on the face of it looks like it
	283	* could equally well be done in user mode.
	284	*
	285	* Not so, for quite unobvious reasons - register pressure.
	286	* In user mode vfork() cannot have a stack frame, and if
	287	* done by calling the "clone()" system call directly, you
	288	* do not have enough call-clobbered registers to hold all
	289	* the information you need.
	290	*/
03ff9a23	291	asmlinkage long sys_vfork(void)
1da177e4	292	{
03ff9a23	293	struct pt_regs *regs = task_pt_regs(current);
1da177e4	294	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD,
03ff9a23 MS	295	regs->gprs[15], regs, 0, NULL, NULL);
	296	}
	297
	298	asmlinkage void execve_tail(void)
	299	{
	300	task_lock(current);
	301	current->ptrace &= ~PT_DTRACE;
	302	task_unlock(current);
	303	current->thread.fp_regs.fpc = 0;
	304	if (MACHINE_HAS_IEEE)
	305	asm volatile("sfpc %0,%0" : : "d" (0));
1da177e4 LT	306	}
	307
	308	/*
	309	* sys_execve() executes a new program.
	310	*/
03ff9a23	311	asmlinkage long sys_execve(void)
1da177e4	312	{
03ff9a23 MS	313	struct pt_regs *regs = task_pt_regs(current);
	314	char *filename;
	315	unsigned long result;
	316	int rc;
	317
	318	filename = getname((char __user *) regs->orig_gpr2);
	319	if (IS_ERR(filename)) {
	320	result = PTR_ERR(filename);
	321	goto out;
1da177e4	322	}
03ff9a23 MS	323	rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
	324	(char __user * __user *) regs->gprs[4], regs);
	325	if (rc) {
	326	result = rc;
	327	goto out_putname;
	328	}
	329	execve_tail();
	330	result = regs->gprs[2];
	331	out_putname:
	332	putname(filename);
1da177e4	333	out:
03ff9a23	334	return result;
1da177e4 LT	335	}
1da177e4 LT	336
1da177e4 LT	337	/*
	338	* fill in the FPU structure for a core dump.
	339	*/
	340	int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
	341	{
347a8dc3	342	#ifndef CONFIG_64BIT
1da177e4 LT	343	/*
	344	* save fprs to current->thread.fp_regs to merge them with
	345	* the emulated registers and then copy the result to the dump.
	346	*/
	347	save_fp_regs(&current->thread.fp_regs);
	348	memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
347a8dc3	349	#else /* CONFIG_64BIT */
1da177e4	350	save_fp_regs(fpregs);
347a8dc3	351	#endif /* CONFIG_64BIT */
1da177e4 LT	352	return 1;
	353	}
	354
1da177e4 LT	355	unsigned long get_wchan(struct task_struct *p)
	356	{
	357	struct stack_frame sf, low, *high;
	358	unsigned long return_address;
	359	int count;
	360
30af7120	361	if (!p \|\| p == current \|\| p->state == TASK_RUNNING \|\| !task_stack_page(p))
1da177e4	362	return 0;
30af7120 AV	363	low = task_stack_page(p);
30af7120 AV	364	high = (struct stack_frame *) task_pt_regs(p);
1da177e4 LT	365	sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
	366	if (sf <= low \|\| sf > high)
	367	return 0;
	368	for (count = 0; count < 16; count++) {
	369	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	370	if (sf <= low \|\| sf > high)
	371	return 0;
	372	return_address = sf->gprs[8] & PSW_ADDR_INSN;
	373	if (!in_sched_functions(return_address))
	374	return return_address;
	375	}
	376	return 0;
	377	}
	378