[deliverable/linux.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/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/elfcore.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/tick.h>
#include <linux/personality.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/kprobes.h>
#include <linux/random.h>
#include <linux/module.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 <asm/smp.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)
{
	if (cpu_is_offline(smp_processor_id()))
		cpu_die();
	local_irq_disable();
	if (need_resched()) {
		local_irq_enable();
		return;
	}
	local_mcck_disable();
	if (test_thread_flag(TIF_MCCK_PENDING)) {
		local_mcck_enable();
		local_irq_enable();
		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_idle_enter();
		rcu_idle_enter();
		while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING))
			default_idle();
		rcu_idle_exit();
		tick_nohz_idle_exit();
		if (test_thread_flag(TIF_MCCK_PENDING))
			s390_handle_mcck();
		schedule_preempt_disabled();
	}
}

extern void __kprobes kernel_thread_starter(void);

asm(
	".section .kprobes.text, \"ax\"\n"
	".global kernel_thread_starter\n"
	"kernel_thread_starter:\n"
	"    la    2,0(10)\n"
	"    basr  14,9\n"
	"    la    2,0\n"
	"    br    11\n"
	".previous\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_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
	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)
{
}

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_user, 0, sizeof(p->thread.per_user));
	memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
	clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
	clear_tsk_thread_flag(p, TIF_PER_TRAP);
	/* 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_DEFINE4(clone, unsigned long, newsp, unsigned long, clone_flags,
		int __user *, parent_tidptr, int __user *, child_tidptr)
{
	struct pt_regs *regs = task_pt_regs(current);

	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)
{
	current->thread.fp_regs.fpc = 0;
	if (MACHINE_HAS_IEEE)
		asm volatile("sfpc %0,%0" : : "d" (0));
}

/*
 * sys_execve() executes a new program.
 */
SYSCALL_DEFINE3(execve, const char __user *, name,
		const char __user *const __user *, argv,
		const char __user *const __user *, envp)
{
	struct pt_regs *regs = task_pt_regs(current);
	char *filename;
	long rc;

	filename = getname(name);
	rc = PTR_ERR(filename);
	if (IS_ERR(filename))
		return rc;
	rc = do_execve(filename, argv, envp, regs);
	if (rc)
		goto out;
	execve_tail();
	rc = regs->gprs[2];
out:
	putname(filename);
	return rc;
}

/*
 * 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;
}

unsigned long arch_align_stack(unsigned long sp)
{
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
		sp -= get_random_int() & ~PAGE_MASK;
	return sp & ~0xf;
}

static inline unsigned long brk_rnd(void)
{
	/* 8MB for 32bit, 1GB for 64bit */
	if (is_32bit_task())
		return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
	else
		return (get_random_int() & 0x3ffffUL) << 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;
}

unsigned long randomize_et_dyn(unsigned long base)
{
	unsigned long ret = PAGE_ALIGN(base + brk_rnd());

	if (!(current->flags & PF_RANDOMIZE))
		return base;
	if (ret < base)
		return base;
	return ret;
}
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>
1da177e4 LT	11	#include <linux/cpu.h>
1da177e4 LT	12	#include <linux/sched.h>
	13	#include <linux/kernel.h>
	14	#include <linux/mm.h>
638ad34a	15	#include <linux/elfcore.h>
1da177e4	16	#include <linux/smp.h>
5a0e3ad6	17	#include <linux/slab.h>
1da177e4	18	#include <linux/interrupt.h>
5a62b192	19	#include <linux/tick.h>
9887a1fc	20	#include <linux/personality.h>
26689452	21	#include <linux/syscalls.h>
3e86a8c6	22	#include <linux/compat.h>
860dba45	23	#include <linux/kprobes.h>
9887a1fc	24	#include <linux/random.h>
3af6fb68	25	#include <linux/module.h>
1da177e4 LT	26	#include <asm/system.h>
	27	#include <asm/io.h>
	28	#include <asm/processor.h>
	29	#include <asm/irq.h>
	30	#include <asm/timer.h>
f5daba1d	31	#include <asm/nmi.h>
da7f51c1	32	#include <asm/smp.h>
a806170e	33	#include "entry.h"
1da177e4	34
94c12cc7	35	asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
1da177e4 LT	36
	37	/*
	38	* Return saved PC of a blocked thread. used in kernel/sched.
	39	* resume in entry.S does not create a new stack frame, it
	40	* just stores the registers %r6-%r15 to the frame given by
	41	* schedule. We want to return the address of the caller of
	42	* schedule, so we have to walk the backchain one time to
	43	* find the frame schedule() store its return address.
	44	*/
	45	unsigned long thread_saved_pc(struct task_struct *tsk)
	46	{
eb33c190	47	struct stack_frame sf, low, *high;
1da177e4	48
eb33c190 HC	49	if (!tsk \|\| !task_stack_page(tsk))
	50	return 0;
	51	low = task_stack_page(tsk);
	52	high = (struct stack_frame *) task_pt_regs(tsk);
	53	sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
	54	if (sf <= low \|\| sf > high)
	55	return 0;
	56	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	57	if (sf <= low \|\| sf > high)
	58	return 0;
1da177e4 LT	59	return sf->gprs[8];
	60	}
	61
1da177e4 LT	62	/*
	63	* The idle loop on a S390...
	64	*/
cdb04527	65	static void default_idle(void)
1da177e4	66	{
da7f51c1	67	if (cpu_is_offline(smp_processor_id()))
1da177e4	68	cpu_die();
6931be08 HC	69	local_irq_disable();
	70	if (need_resched()) {
	71	local_irq_enable();
	72	return;
	73	}
77fa2245 HC	74	local_mcck_disable();
	75	if (test_thread_flag(TIF_MCCK_PENDING)) {
	76	local_mcck_enable();
	77	local_irq_enable();
77fa2245 HC	78	return;
77fa2245 HC	79	}
1f194a4c	80	trace_hardirqs_on();
632448f6 HC	81	/* Don't trace preempt off for idle. */
632448f6 HC	82	stop_critical_timings();
9cfb9b3c MS	83	/* Stop virtual timer and halt the cpu. */
	84	vtime_stop_cpu();
	85	/* Reenable preemption tracer. */
632448f6	86	start_critical_timings();
1da177e4 LT	87	}
	88
	89	void cpu_idle(void)
	90	{
5bfb5d69	91	for (;;) {
1268fbc7 FW	92	tick_nohz_idle_enter();
1268fbc7 FW	93	rcu_idle_enter();
f3612304	94	while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING))
5bfb5d69	95	default_idle();
1268fbc7 FW	96	rcu_idle_exit();
1268fbc7 FW	97	tick_nohz_idle_exit();
f3612304 HC	98	if (test_thread_flag(TIF_MCCK_PENDING))
f3612304 HC	99	s390_handle_mcck();
bd2f5536	100	schedule_preempt_disabled();
5bfb5d69	101	}
1da177e4 LT	102	}
1da177e4 LT	103
860dba45	104	extern void __kprobes kernel_thread_starter(void);
1da177e4	105
94c12cc7	106	asm(
860dba45 MS	107	".section .kprobes.text, \"ax\"\n"
860dba45 MS	108	".global kernel_thread_starter\n"
1da177e4 LT	109	"kernel_thread_starter:\n"
	110	" la 2,0(10)\n"
	111	" basr 14,9\n"
	112	" la 2,0\n"
860dba45 MS	113	" br 11\n"
860dba45 MS	114	".previous\n");
1da177e4 LT	115
	116	int kernel_thread(int (fn)(void ), void * arg, unsigned long flags)
	117	{
	118	struct pt_regs regs;
	119
	120	memset(&regs, 0, sizeof(regs));
b50511e4 MS	121	regs.psw.mask = psw_kernel_bits \|
b50511e4 MS	122	PSW_MASK_DAT \| PSW_MASK_IO \| PSW_MASK_EXT \| PSW_MASK_MCHECK;
1da177e4 LT	123	regs.psw.addr = (unsigned long) kernel_thread_starter \| PSW_ADDR_AMODE;
	124	regs.gprs[9] = (unsigned long) fn;
	125	regs.gprs[10] = (unsigned long) arg;
	126	regs.gprs[11] = (unsigned long) do_exit;
	127	regs.orig_gpr2 = -1;
	128
	129	/* Ok, create the new process.. */
	130	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED,
	131	0, &regs, 0, NULL, NULL);
	132	}
1485c5c8	133	EXPORT_SYMBOL(kernel_thread);
1da177e4 LT	134
	135	/*
	136	* Free current thread data structures etc..
	137	*/
	138	void exit_thread(void)
	139	{
	140	}
	141
	142	void flush_thread(void)
	143	{
1da177e4 LT	144	}
	145
	146	void release_thread(struct task_struct *dead_task)
	147	{
	148	}
	149
6f2c55b8	150	int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
cbdc2292 HC	151	unsigned long unused,
cbdc2292 HC	152	struct task_struct p, struct pt_regs regs)
1da177e4	153	{
5168ce2c	154	struct thread_info *ti;
cbdc2292 HC	155	struct fake_frame
	156	{
	157	struct stack_frame sf;
	158	struct pt_regs childregs;
	159	} *frame;
	160
	161	frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
	162	p->thread.ksp = (unsigned long) frame;
1da177e4	163	/* Store access registers to kernel stack of new process. */
cbdc2292	164	frame->childregs = *regs;
1da177e4	165	frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
cbdc2292 HC	166	frame->childregs.gprs[15] = new_stackp;
cbdc2292 HC	167	frame->sf.back_chain = 0;
1da177e4	168
cbdc2292 HC	169	/* new return point is ret_from_fork */
cbdc2292 HC	170	frame->sf.gprs[8] = (unsigned long) ret_from_fork;
1da177e4	171
cbdc2292 HC	172	/* fake return stack for resume(), don't go back to schedule */
cbdc2292 HC	173	frame->sf.gprs[9] = (unsigned long) frame;
1da177e4 LT	174
	175	/* Save access registers to new thread structure. */
	176	save_access_regs(&p->thread.acrs[0]);
	177
347a8dc3	178	#ifndef CONFIG_64BIT
cbdc2292	179	/*
1da177e4 LT	180	* save fprs to current->thread.fp_regs to merge them with
	181	* the emulated registers and then copy the result to the child.
	182	*/
	183	save_fp_regs(&current->thread.fp_regs);
	184	memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
	185	sizeof(s390_fp_regs));
1da177e4 LT	186	/* Set a new TLS ? */
	187	if (clone_flags & CLONE_SETTLS)
	188	p->thread.acrs[0] = regs->gprs[6];
347a8dc3	189	#else /* CONFIG_64BIT */
1da177e4 LT	190	/* Save the fpu registers to new thread structure. */
1da177e4 LT	191	save_fp_regs(&p->thread.fp_regs);
1da177e4 LT	192	/* Set a new TLS ? */
1da177e4 LT	193	if (clone_flags & CLONE_SETTLS) {
7757591a	194	if (is_compat_task()) {
1da177e4 LT	195	p->thread.acrs[0] = (unsigned int) regs->gprs[6];
	196	} else {
	197	p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
	198	p->thread.acrs[1] = (unsigned int) regs->gprs[6];
	199	}
	200	}
347a8dc3	201	#endif /* CONFIG_64BIT */
1da177e4 LT	202	/* start new process with ar4 pointing to the correct address space */
1da177e4 LT	203	p->thread.mm_segment = get_fs();
cbdc2292	204	/* Don't copy debug registers */
5e9a2692 MS	205	memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
5e9a2692 MS	206	memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
f8d5faf7	207	clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
5e9a2692	208	clear_tsk_thread_flag(p, TIF_PER_TRAP);
5168ce2c HC	209	/* Initialize per thread user and system timer values */
	210	ti = task_thread_info(p);
	211	ti->user_timer = 0;
	212	ti->system_timer = 0;
cbdc2292	213	return 0;
1da177e4 LT	214	}
1da177e4 LT	215
26689452	216	SYSCALL_DEFINE0(fork)
1da177e4	217	{
03ff9a23 MS	218	struct pt_regs *regs = task_pt_regs(current);
03ff9a23 MS	219	return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
1da177e4 LT	220	}
1da177e4 LT	221
2d70ca23 HC	222	SYSCALL_DEFINE4(clone, unsigned long, newsp, unsigned long, clone_flags,
2d70ca23 HC	223	int __user , parent_tidptr, int __user , child_tidptr)
1da177e4	224	{
03ff9a23	225	struct pt_regs *regs = task_pt_regs(current);
1da177e4	226
03ff9a23 MS	227	if (!newsp)
	228	newsp = regs->gprs[15];
	229	return do_fork(clone_flags, newsp, regs, 0,
1da177e4 LT	230	parent_tidptr, child_tidptr);
	231	}
	232
	233	/*
	234	* This is trivial, and on the face of it looks like it
	235	* could equally well be done in user mode.
	236	*
	237	* Not so, for quite unobvious reasons - register pressure.
	238	* In user mode vfork() cannot have a stack frame, and if
	239	* done by calling the "clone()" system call directly, you
	240	* do not have enough call-clobbered registers to hold all
	241	* the information you need.
	242	*/
26689452	243	SYSCALL_DEFINE0(vfork)
1da177e4	244	{
03ff9a23	245	struct pt_regs *regs = task_pt_regs(current);
1da177e4	246	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD,
03ff9a23 MS	247	regs->gprs[15], regs, 0, NULL, NULL);
	248	}
	249
	250	asmlinkage void execve_tail(void)
	251	{
03ff9a23 MS	252	current->thread.fp_regs.fpc = 0;
	253	if (MACHINE_HAS_IEEE)
	254	asm volatile("sfpc %0,%0" : : "d" (0));
1da177e4 LT	255	}
	256
	257	/*
	258	* sys_execve() executes a new program.
	259	*/
d7627467 DH	260	SYSCALL_DEFINE3(execve, const char __user *, name,
	261	const char __user const __user , argv,
	262	const char __user const __user , envp)
1da177e4	263	{
03ff9a23 MS	264	struct pt_regs *regs = task_pt_regs(current);
03ff9a23 MS	265	char *filename;
3e86a8c6	266	long rc;
03ff9a23	267
3e86a8c6 HC	268	filename = getname(name);
	269	rc = PTR_ERR(filename);
	270	if (IS_ERR(filename))
	271	return rc;
	272	rc = do_execve(filename, argv, envp, regs);
	273	if (rc)
03ff9a23	274	goto out;
03ff9a23	275	execve_tail();
3e86a8c6	276	rc = regs->gprs[2];
1da177e4	277	out:
3e86a8c6 HC	278	putname(filename);
3e86a8c6 HC	279	return rc;
1da177e4 LT	280	}
1da177e4 LT	281
1da177e4 LT	282	/*
	283	* fill in the FPU structure for a core dump.
	284	*/
	285	int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
	286	{
347a8dc3	287	#ifndef CONFIG_64BIT
cbdc2292	288	/*
1da177e4 LT	289	* save fprs to current->thread.fp_regs to merge them with
	290	* the emulated registers and then copy the result to the dump.
	291	*/
	292	save_fp_regs(&current->thread.fp_regs);
	293	memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
347a8dc3	294	#else /* CONFIG_64BIT */
1da177e4	295	save_fp_regs(fpregs);
347a8dc3	296	#endif /* CONFIG_64BIT */
1da177e4 LT	297	return 1;
1da177e4 LT	298	}
1485c5c8	299	EXPORT_SYMBOL(dump_fpu);
1da177e4	300
1da177e4 LT	301	unsigned long get_wchan(struct task_struct *p)
	302	{
	303	struct stack_frame sf, low, *high;
	304	unsigned long return_address;
	305	int count;
	306
30af7120	307	if (!p \|\| p == current \|\| p->state == TASK_RUNNING \|\| !task_stack_page(p))
1da177e4	308	return 0;
30af7120 AV	309	low = task_stack_page(p);
30af7120 AV	310	high = (struct stack_frame *) task_pt_regs(p);
1da177e4 LT	311	sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
	312	if (sf <= low \|\| sf > high)
	313	return 0;
	314	for (count = 0; count < 16; count++) {
	315	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
	316	if (sf <= low \|\| sf > high)
	317	return 0;
	318	return_address = sf->gprs[8] & PSW_ADDR_INSN;
	319	if (!in_sched_functions(return_address))
	320	return return_address;
	321	}
	322	return 0;
	323	}
9887a1fc HC	324
	325	unsigned long arch_align_stack(unsigned long sp)
	326	{
	327	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
	328	sp -= get_random_int() & ~PAGE_MASK;
	329	return sp & ~0xf;
	330	}
33519182 HC	331
	332	static inline unsigned long brk_rnd(void)
	333	{
	334	/* 8MB for 32bit, 1GB for 64bit */
	335	if (is_32bit_task())
	336	return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
	337	else
	338	return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
	339	}
	340
	341	unsigned long arch_randomize_brk(struct mm_struct *mm)
	342	{
	343	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
	344
	345	if (ret < mm->brk)
	346	return mm->brk;
	347	return ret;
	348	}
d2c9dfcc HC	349
	350	unsigned long randomize_et_dyn(unsigned long base)
	351	{
	352	unsigned long ret = PAGE_ALIGN(base + brk_rnd());
	353
	354	if (!(current->flags & PF_RANDOMIZE))
	355	return base;
	356	if (ret < base)
	357	return base;
	358	return ret;
	359	}