[mirror_ubuntu-zesty-kernel.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/config.h>
#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/smp.h>
#include <linux/smp_lock.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/a.out.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 <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>

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;

	sf = (struct stack_frame *) tsk->thread.ksp;
	sf = (struct stack_frame *) sf->back_chain;
	return sf->gprs[8];
}

/*
 * Need to know about CPUs going idle?
 */
static struct notifier_block *idle_chain;

int register_idle_notifier(struct notifier_block *nb)
{
	return notifier_chain_register(&idle_chain, nb);
}
EXPORT_SYMBOL(register_idle_notifier);

int unregister_idle_notifier(struct notifier_block *nb)
{
	return notifier_chain_unregister(&idle_chain, nb);
}
EXPORT_SYMBOL(unregister_idle_notifier);

void do_monitor_call(struct pt_regs *regs, long interruption_code)
{
	/* disable monitor call class 0 */
	__ctl_clear_bit(8, 15);

	notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
			    (void *)(long) smp_processor_id());
}

extern void s390_handle_mcck(void);
/*
 * The idle loop on a S390...
 */
void default_idle(void)
{
	int cpu, rc;

	/* CPU is going idle. */
	cpu = smp_processor_id();

	local_irq_disable();
	if (need_resched()) {
		local_irq_enable();
		return;
	}

	rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu);
	if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
		BUG();
	if (rc != NOTIFY_OK) {
		local_irq_enable();
		return;
	}

	/* enable monitor call class 0 */
	__ctl_set_bit(8, 15);

#ifdef CONFIG_HOTPLUG_CPU
	if (cpu_is_offline(cpu))
		cpu_die();
#endif

	local_mcck_disable();
	if (test_thread_flag(TIF_MCCK_PENDING)) {
		local_mcck_enable();
		local_irq_enable();
		s390_handle_mcck();
		return;
	}

	/* 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 (;;) {
		while (!need_resched())
			default_idle();

		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

void show_regs(struct pt_regs *regs)
{
	struct task_struct *tsk = current;

        printk("CPU:    %d    %s\n", tsk->thread_info->cpu, print_tainted());
        printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
	       current->comm, current->pid, (void *) tsk,
	       (void *) tsk->thread.ksp);

	show_registers(regs);
	/* Show stack backtrace if pt_regs is from kernel mode */
	if (!(regs->psw.mask & PSW_MASK_PSTATE))
		show_trace(0,(unsigned long *) regs->gprs[15]);
}

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 = ((struct fake_frame *)
		 (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
        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));
        p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
	/* 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);
        p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
	/* 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(struct pt_regs regs)
{
	return do_fork(SIGCHLD, regs.gprs[15], &regs, 0, NULL, NULL);
}

asmlinkage long sys_clone(struct pt_regs regs)
{
        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(struct pt_regs regs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
		       regs.gprs[15], &regs, 0, NULL, NULL);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage long sys_execve(struct pt_regs regs)
{
        int error;
        char * filename;

        filename = getname((char __user *) regs.orig_gpr2);
        error = PTR_ERR(filename);
        if (IS_ERR(filename))
                goto out;
        error = do_execve(filename, (char __user * __user *) regs.gprs[3],
			  (char __user * __user *) regs.gprs[4], &regs);
	if (error == 0) {
		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));
	}
        putname(filename);
out:
        return error;
}


/*
 * 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;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{

/* changed the size calculations - should hopefully work better. lbt */
	dump->magic = CMAGIC;
	dump->start_code = 0;
	dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
	dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
	dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
	dump->u_dsize -= dump->u_tsize;
	dump->u_ssize = 0;
	if (dump->start_stack < TASK_SIZE)
		dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
	memcpy(&dump->regs, regs, sizeof(s390_regs));
	dump_fpu (regs, &dump->regs.fp_regs);
	dump->regs.per_info = current->thread.per_info;
}

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 || !p->thread_info)
		return 0;
	low = (struct stack_frame *) p->thread_info;
	high = (struct stack_frame *)
		((unsigned long) p->thread_info + THREAD_SIZE) - 1;
	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
	18	#include <linux/config.h>
	19	#include <linux/compiler.h>
	20	#include <linux/cpu.h>
	21	#include <linux/errno.h>
	22	#include <linux/sched.h>
	23	#include <linux/kernel.h>
	24	#include <linux/mm.h>
	25	#include <linux/smp.h>
	26	#include <linux/smp_lock.h>
	27	#include <linux/stddef.h>
	28	#include <linux/unistd.h>
	29	#include <linux/ptrace.h>
	30	#include <linux/slab.h>
	31	#include <linux/vmalloc.h>
	32	#include <linux/user.h>
	33	#include <linux/a.out.h>
	34	#include <linux/interrupt.h>
	35	#include <linux/delay.h>
	36	#include <linux/reboot.h>
	37	#include <linux/init.h>
	38	#include <linux/module.h>
	39	#include <linux/notifier.h>
	40
	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>
	48
	49	asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
	50
	51	/*
	52	* Return saved PC of a blocked thread. used in kernel/sched.
	53	* resume in entry.S does not create a new stack frame, it
	54	* just stores the registers %r6-%r15 to the frame given by
	55	* schedule. We want to return the address of the caller of
	56	* schedule, so we have to walk the backchain one time to
	57	* find the frame schedule() store its return address.
	58	*/
	59	unsigned long thread_saved_pc(struct task_struct *tsk)
	60	{
	61	struct stack_frame *sf;
	62
	63	sf = (struct stack_frame *) tsk->thread.ksp;
	64	sf = (struct stack_frame *) sf->back_chain;
65	return sf->gprs[8];
66	}
67
68	/*
69	* Need to know about CPUs going idle?
70	*/
71	static struct notifier_block *idle_chain;
72
73	int register_idle_notifier(struct notifier_block *nb)
74	{
75	return notifier_chain_register(&idle_chain, nb);
76	}
77	EXPORT_SYMBOL(register_idle_notifier);
78
79	int unregister_idle_notifier(struct notifier_block *nb)
80	{
81	return notifier_chain_unregister(&idle_chain, nb);
82	}
83	EXPORT_SYMBOL(unregister_idle_notifier);
84
85	void do_monitor_call(struct pt_regs *regs, long interruption_code)
86	{
87	/* disable monitor call class 0 */
88	__ctl_clear_bit(8, 15);
89
90	notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
91	(void *)(long) smp_processor_id());
92	}
93
77fa2245	94	extern void s390_handle_mcck(void);
1da177e4 LT	95	/*
	96	* The idle loop on a S390...
	97	*/
	98	void default_idle(void)
	99	{
1da177e4 LT	100	int cpu, rc;
1da177e4 LT	101
64c7c8f8 NP	102	/* CPU is going idle. */
	103	cpu = smp_processor_id();
	104
1da177e4	105	local_irq_disable();
64c7c8f8	106	if (need_resched()) {
1da177e4	107	local_irq_enable();
64c7c8f8 NP	108	return;
64c7c8f8 NP	109	}
1da177e4	110
1da177e4 LT	111	rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu);
	112	if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
	113	BUG();
	114	if (rc != NOTIFY_OK) {
	115	local_irq_enable();
	116	return;
	117	}
	118
	119	/* enable monitor call class 0 */
	120	__ctl_set_bit(8, 15);
	121
	122	#ifdef CONFIG_HOTPLUG_CPU
64c7c8f8	123	if (cpu_is_offline(cpu))
1da177e4 LT	124	cpu_die();
	125	#endif
	126
77fa2245 HC	127	local_mcck_disable();
	128	if (test_thread_flag(TIF_MCCK_PENDING)) {
	129	local_mcck_enable();
	130	local_irq_enable();
	131	s390_handle_mcck();
	132	return;
	133	}
	134
	135	/* Wait for external, I/O or machine check interrupt. */
	136	__load_psw_mask(PSW_KERNEL_BITS \| PSW_MASK_WAIT \|
	137	PSW_MASK_IO \| PSW_MASK_EXT);
1da177e4 LT	138	}
	139
	140	void cpu_idle(void)
	141	{
5bfb5d69 NP	142	for (;;) {
	143	while (!need_resched())
	144	default_idle();
	145
	146	preempt_enable_no_resched();
	147	schedule();
	148	preempt_disable();
	149	}
1da177e4 LT	150	}
	151
	152	void show_regs(struct pt_regs *regs)
	153	{
	154	struct task_struct *tsk = current;
	155
	156	printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted());
	157	printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
	158	current->comm, current->pid, (void *) tsk,
	159	(void *) tsk->thread.ksp);
	160
	161	show_registers(regs);
	162	/* Show stack backtrace if pt_regs is from kernel mode */
	163	if (!(regs->psw.mask & PSW_MASK_PSTATE))
	164	show_trace(0,(unsigned long *) regs->gprs[15]);
	165	}
	166
	167	extern void kernel_thread_starter(void);
	168
	169	__asm__(".align 4\n"
	170	"kernel_thread_starter:\n"
	171	" la 2,0(10)\n"
	172	" basr 14,9\n"
	173	" la 2,0\n"
	174	" br 11\n");
	175
	176	int kernel_thread(int (fn)(void ), void * arg, unsigned long flags)
	177	{
	178	struct pt_regs regs;
	179
	180	memset(&regs, 0, sizeof(regs));
	181	regs.psw.mask = PSW_KERNEL_BITS \| PSW_MASK_IO \| PSW_MASK_EXT;
	182	regs.psw.addr = (unsigned long) kernel_thread_starter \| PSW_ADDR_AMODE;
	183	regs.gprs[9] = (unsigned long) fn;
	184	regs.gprs[10] = (unsigned long) arg;
	185	regs.gprs[11] = (unsigned long) do_exit;
	186	regs.orig_gpr2 = -1;
	187
	188	/* Ok, create the new process.. */
	189	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED,
	190	0, &regs, 0, NULL, NULL);
	191	}
	192
	193	/*
	194	* Free current thread data structures etc..
	195	*/
	196	void exit_thread(void)
	197	{
	198	}
	199
	200	void flush_thread(void)
	201	{
	202	clear_used_math();
	203	clear_tsk_thread_flag(current, TIF_USEDFPU);
	204	}
	205
	206	void release_thread(struct task_struct *dead_task)
	207	{
	208	}
	209
	210	int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
	211	unsigned long unused,
	212	struct task_struct * p, struct pt_regs * regs)
	213	{
214	struct fake_frame
215	{
216	struct stack_frame sf;
217	struct pt_regs childregs;
218	} *frame;
219
220	frame = ((struct fake_frame *)
221	(THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
222	p->thread.ksp = (unsigned long) frame;
223	/* Store access registers to kernel stack of new process. */
224	frame->childregs = *regs;
225	frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
226	frame->childregs.gprs[15] = new_stackp;
227	frame->sf.back_chain = 0;
228
229	/* new return point is ret_from_fork */
230	frame->sf.gprs[8] = (unsigned long) ret_from_fork;
231
232	/* fake return stack for resume(), don't go back to schedule */
233	frame->sf.gprs[9] = (unsigned long) frame;
234
235	/* Save access registers to new thread structure. */
236	save_access_regs(&p->thread.acrs[0]);
237
347a8dc3	238	#ifndef CONFIG_64BIT
1da177e4 LT	239	/*
	240	* save fprs to current->thread.fp_regs to merge them with
	241	* the emulated registers and then copy the result to the child.
	242	*/
	243	save_fp_regs(&current->thread.fp_regs);
	244	memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
	245	sizeof(s390_fp_regs));
	246	p->thread.user_seg = __pa((unsigned long) p->mm->pgd) \| _SEGMENT_TABLE;
	247	/* Set a new TLS ? */
	248	if (clone_flags & CLONE_SETTLS)
	249	p->thread.acrs[0] = regs->gprs[6];
347a8dc3	250	#else /* CONFIG_64BIT */
1da177e4 LT	251	/* Save the fpu registers to new thread structure. */
	252	save_fp_regs(&p->thread.fp_regs);
	253	p->thread.user_seg = __pa((unsigned long) p->mm->pgd) \| _REGION_TABLE;
	254	/* Set a new TLS ? */
	255	if (clone_flags & CLONE_SETTLS) {
	256	if (test_thread_flag(TIF_31BIT)) {
	257	p->thread.acrs[0] = (unsigned int) regs->gprs[6];
	258	} else {
	259	p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
	260	p->thread.acrs[1] = (unsigned int) regs->gprs[6];
	261	}
	262	}
347a8dc3	263	#endif /* CONFIG_64BIT */
1da177e4 LT	264	/* start new process with ar4 pointing to the correct address space */
	265	p->thread.mm_segment = get_fs();
	266	/* Don't copy debug registers */
	267	memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
	268
	269	return 0;
	270	}
	271
	272	asmlinkage long sys_fork(struct pt_regs regs)
	273	{
	274	return do_fork(SIGCHLD, regs.gprs[15], &regs, 0, NULL, NULL);
	275	}
	276
	277	asmlinkage long sys_clone(struct pt_regs regs)
	278	{
	279	unsigned long clone_flags;
	280	unsigned long newsp;
	281	int __user parent_tidptr, child_tidptr;
	282
	283	clone_flags = regs.gprs[3];
	284	newsp = regs.orig_gpr2;
	285	parent_tidptr = (int __user *) regs.gprs[4];
	286	child_tidptr = (int __user *) regs.gprs[5];
	287	if (!newsp)
	288	newsp = regs.gprs[15];
	289	return do_fork(clone_flags, newsp, &regs, 0,
	290	parent_tidptr, child_tidptr);
	291	}
	292
	293	/*
	294	* This is trivial, and on the face of it looks like it
	295	* could equally well be done in user mode.
	296	*
	297	* Not so, for quite unobvious reasons - register pressure.
	298	* In user mode vfork() cannot have a stack frame, and if
	299	* done by calling the "clone()" system call directly, you
	300	* do not have enough call-clobbered registers to hold all
	301	* the information you need.
	302	*/
	303	asmlinkage long sys_vfork(struct pt_regs regs)
	304	{
	305	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD,
	306	regs.gprs[15], &regs, 0, NULL, NULL);
	307	}
	308
	309	/*
	310	* sys_execve() executes a new program.
	311	*/
	312	asmlinkage long sys_execve(struct pt_regs regs)
	313	{
	314	int error;
	315	char * filename;
	316
	317	filename = getname((char __user *) regs.orig_gpr2);
	318	error = PTR_ERR(filename);
	319	if (IS_ERR(filename))
	320	goto out;
	321	error = do_execve(filename, (char __user * __user *) regs.gprs[3],
	322	(char __user * __user *) regs.gprs[4], &regs);
	323	if (error == 0) {
	324	task_lock(current);
	325	current->ptrace &= ~PT_DTRACE;
	326	task_unlock(current);
	327	current->thread.fp_regs.fpc = 0;
328	if (MACHINE_HAS_IEEE)
329	asm volatile("sfpc %0,%0" : : "d" (0));
330	}
331	putname(filename);
332	out:
333	return error;
334	}
335
336
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
	355	/*
	356	* fill in the user structure for a core dump..
	357	*/
	358	void dump_thread(struct pt_regs * regs, struct user * dump)
	359	{
	360
	361	/* changed the size calculations - should hopefully work better. lbt */
	362	dump->magic = CMAGIC;
	363	dump->start_code = 0;
	364	dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
	365	dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
	366	dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
	367	dump->u_dsize -= dump->u_tsize;
	368	dump->u_ssize = 0;
	369	if (dump->start_stack < TASK_SIZE)
	370	dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
	371	memcpy(&dump->regs, regs, sizeof(s390_regs));
	372	dump_fpu (regs, &dump->regs.fp_regs);
	373	dump->regs.per_info = current->thread.per_info;
	374	}
	375
	376	unsigned long get_wchan(struct task_struct *p)
	377	{
	378	struct stack_frame sf, low, *high;
	379	unsigned long return_address;
	380	int count;
	381
	382	if (!p \|\| p == current \|\| p->state == TASK_RUNNING \|\| !p->thread_info)
	383	return 0;
	384	low = (struct stack_frame *) p->thread_info;
	385	high = (struct stack_frame *)
	386	((unsigned long) p->thread_info + THREAD_SIZE) - 1;
	387	sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
	388	if (sf <= low \|\| sf > high)
	389	return 0;
	390	for (count = 0; count < 16; count++) {
	391	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	392	if (sf <= low \|\| sf > high)
	393	return 0;
	394	return_address = sf->gprs[8] & PSW_ADDR_INSN;
	395	if (!in_sched_functions(return_address))
	396	return return_address;
	397	}
	398	return 0;
	399	}
	400