[net-next-2.6.git] / arch / alpha / kernel / process.c

/*
 *  linux/arch/alpha/kernel/process.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 */

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

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/time.h>
#include <linux/major.h>
#include <linux/stat.h>
#include <linux/vt.h>
#include <linux/mman.h>
#include <linux/elfcore.h>
#include <linux/reboot.h>
#include <linux/tty.h>
#include <linux/console.h>
#include <linux/slab.h>

#include <asm/reg.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/hwrpb.h>
#include <asm/fpu.h>

#include "proto.h"
#include "pci_impl.h"

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

void
cpu_idle(void)
{
	set_thread_flag(TIF_POLLING_NRFLAG);

	while (1) {
		/* FIXME -- EV6 and LCA45 know how to power down
		   the CPU.  */

		while (!need_resched())
			cpu_relax();
		schedule();
	}
}


struct halt_info {
	int mode;
	char *restart_cmd;
};

static void
common_shutdown_1(void *generic_ptr)
{
	struct halt_info *how = (struct halt_info *)generic_ptr;
	struct percpu_struct *cpup;
	unsigned long *pflags, flags;
	int cpuid = smp_processor_id();

	/* No point in taking interrupts anymore. */
	local_irq_disable();

	cpup = (struct percpu_struct *)
			((unsigned long)hwrpb + hwrpb->processor_offset
			 + hwrpb->processor_size * cpuid);
	pflags = &cpup->flags;
	flags = *pflags;

	/* Clear reason to "default"; clear "bootstrap in progress". */
	flags &= ~0x00ff0001UL;

#ifdef CONFIG_SMP
	/* Secondaries halt here. */
	if (cpuid != boot_cpuid) {
		flags |= 0x00040000UL; /* "remain halted" */
		*pflags = flags;
		set_cpu_present(cpuid, false);
		set_cpu_possible(cpuid, false);
		halt();
	}
#endif

	if (how->mode == LINUX_REBOOT_CMD_RESTART) {
		if (!how->restart_cmd) {
			flags |= 0x00020000UL; /* "cold bootstrap" */
		} else {
			/* For SRM, we could probably set environment
			   variables to get this to work.  We'd have to
			   delay this until after srm_paging_stop unless
			   we ever got srm_fixup working.

			   At the moment, SRM will use the last boot device,
			   but the file and flags will be the defaults, when
			   doing a "warm" bootstrap.  */
			flags |= 0x00030000UL; /* "warm bootstrap" */
		}
	} else {
		flags |= 0x00040000UL; /* "remain halted" */
	}
	*pflags = flags;

#ifdef CONFIG_SMP
	/* Wait for the secondaries to halt. */
	set_cpu_present(boot_cpuid, false);
	set_cpu_possible(boot_cpuid, false);
	while (cpus_weight(cpu_present_map))
		barrier();
#endif

	/* If booted from SRM, reset some of the original environment. */
	if (alpha_using_srm) {
#ifdef CONFIG_DUMMY_CONSOLE
		/* If we've gotten here after SysRq-b, leave interrupt
		   context before taking over the console. */
		if (in_interrupt())
			irq_exit();
		/* This has the effect of resetting the VGA video origin.  */
		take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1);
#endif
		pci_restore_srm_config();
		set_hae(srm_hae);
	}

	if (alpha_mv.kill_arch)
		alpha_mv.kill_arch(how->mode);

	if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) {
		/* Unfortunately, since MILO doesn't currently understand
		   the hwrpb bits above, we can't reliably halt the 
		   processor and keep it halted.  So just loop.  */
		return;
	}

	if (alpha_using_srm)
		srm_paging_stop();

	halt();
}

static void
common_shutdown(int mode, char *restart_cmd)
{
	struct halt_info args;
	args.mode = mode;
	args.restart_cmd = restart_cmd;
	on_each_cpu(common_shutdown_1, &args, 0);
}

void
machine_restart(char *restart_cmd)
{
	common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);
}


void
machine_halt(void)
{
	common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);
}


void
machine_power_off(void)
{
	common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL);
}


/* Used by sysrq-p, among others.  I don't believe r9-r15 are ever
   saved in the context it's used.  */

void
show_regs(struct pt_regs *regs)
{
	dik_show_regs(regs, NULL);
}

/*
 * Re-start a thread when doing execve()
 */
void
start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
{
	set_fs(USER_DS);
	regs->pc = pc;
	regs->ps = 8;
	wrusp(sp);
}
EXPORT_SYMBOL(start_thread);

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

void
flush_thread(void)
{
	/* Arrange for each exec'ed process to start off with a clean slate
	   with respect to the FPU.  This is all exceptions disabled.  */
	current_thread_info()->ieee_state = 0;
	wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0));

	/* Clean slate for TLS.  */
	current_thread_info()->pcb.unique = 0;
}

void
release_thread(struct task_struct *dead_task)
{
}

/*
 * "alpha_clone()".. By the time we get here, the
 * non-volatile registers have also been saved on the
 * stack. We do some ugly pointer stuff here.. (see
 * also copy_thread)
 *
 * Notice that "fork()" is implemented in terms of clone,
 * with parameters (SIGCHLD, 0).
 */
int
alpha_clone(unsigned long clone_flags, unsigned long usp,
	    int __user *parent_tid, int __user *child_tid,
	    unsigned long tls_value, struct pt_regs *regs)
{
	if (!usp)
		usp = rdusp();

	return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid);
}

int
alpha_vfork(struct pt_regs *regs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(),
		       regs, 0, NULL, NULL);
}

/*
 * Copy an alpha thread..
 *
 * Note the "stack_offset" stuff: when returning to kernel mode, we need
 * to have some extra stack-space for the kernel stack that still exists
 * after the "ret_from_fork".  When returning to user mode, we only want
 * the space needed by the syscall stack frame (ie "struct pt_regs").
 * Use the passed "regs" pointer to determine how much space we need
 * for a kernel fork().
 */

int
copy_thread(unsigned long clone_flags, unsigned long usp,
	    unsigned long unused,
	    struct task_struct * p, struct pt_regs * regs)
{
	extern void ret_from_fork(void);

	struct thread_info *childti = task_thread_info(p);
	struct pt_regs * childregs;
	struct switch_stack * childstack, *stack;
	unsigned long stack_offset, settls;

	stack_offset = PAGE_SIZE - sizeof(struct pt_regs);
	if (!(regs->ps & 8))
		stack_offset = (PAGE_SIZE-1) & (unsigned long) regs;
	childregs = (struct pt_regs *)
	  (stack_offset + PAGE_SIZE + task_stack_page(p));
		
	*childregs = *regs;
	settls = regs->r20;
	childregs->r0 = 0;
	childregs->r19 = 0;
	childregs->r20 = 1;	/* OSF/1 has some strange fork() semantics.  */
	regs->r20 = 0;
	stack = ((struct switch_stack *) regs) - 1;
	childstack = ((struct switch_stack *) childregs) - 1;
	*childstack = *stack;
	childstack->r26 = (unsigned long) ret_from_fork;
	childti->pcb.usp = usp;
	childti->pcb.ksp = (unsigned long) childstack;
	childti->pcb.flags = 1;	/* set FEN, clear everything else */

	/* Set a new TLS for the child thread?  Peek back into the
	   syscall arguments that we saved on syscall entry.  Oops,
	   except we'd have clobbered it with the parent/child set
	   of r20.  Read the saved copy.  */
	/* Note: if CLONE_SETTLS is not set, then we must inherit the
	   value from the parent, which will have been set by the block
	   copy in dup_task_struct.  This is non-intuitive, but is
	   required for proper operation in the case of a threaded
	   application calling fork.  */
	if (clone_flags & CLONE_SETTLS)
		childti->pcb.unique = settls;

	return 0;
}

/*
 * Fill in the user structure for a ELF core dump.
 */
void
dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti)
{
	/* switch stack follows right below pt_regs: */
	struct switch_stack * sw = ((struct switch_stack *) pt) - 1;

	dest[ 0] = pt->r0;
	dest[ 1] = pt->r1;
	dest[ 2] = pt->r2;
	dest[ 3] = pt->r3;
	dest[ 4] = pt->r4;
	dest[ 5] = pt->r5;
	dest[ 6] = pt->r6;
	dest[ 7] = pt->r7;
	dest[ 8] = pt->r8;
	dest[ 9] = sw->r9;
	dest[10] = sw->r10;
	dest[11] = sw->r11;
	dest[12] = sw->r12;
	dest[13] = sw->r13;
	dest[14] = sw->r14;
	dest[15] = sw->r15;
	dest[16] = pt->r16;
	dest[17] = pt->r17;
	dest[18] = pt->r18;
	dest[19] = pt->r19;
	dest[20] = pt->r20;
	dest[21] = pt->r21;
	dest[22] = pt->r22;
	dest[23] = pt->r23;
	dest[24] = pt->r24;
	dest[25] = pt->r25;
	dest[26] = pt->r26;
	dest[27] = pt->r27;
	dest[28] = pt->r28;
	dest[29] = pt->gp;
	dest[30] = rdusp();
	dest[31] = pt->pc;

	/* Once upon a time this was the PS value.  Which is stupid
	   since that is always 8 for usermode.  Usurped for the more
	   useful value of the thread's UNIQUE field.  */
	dest[32] = ti->pcb.unique;
}
EXPORT_SYMBOL(dump_elf_thread);

int
dump_elf_task(elf_greg_t *dest, struct task_struct *task)
{
	dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task));
	return 1;
}
EXPORT_SYMBOL(dump_elf_task);

int
dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task)
{
	struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1;
	memcpy(dest, sw->fp, 32 * 8);
	return 1;
}
EXPORT_SYMBOL(dump_elf_task_fp);

/*
 * sys_execve() executes a new program.
 */
asmlinkage int
do_sys_execve(const char __user *ufilename,
	      const char __user *const __user *argv,
	      const char __user *const __user *envp, struct pt_regs *regs)
{
	int error;
	char *filename;

	filename = getname(ufilename);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;
	error = do_execve(filename, argv, envp, regs);
	putname(filename);
out:
	return error;
}

/*
 * Return saved PC of a blocked thread.  This assumes the frame
 * pointer is the 6th saved long on the kernel stack and that the
 * saved return address is the first long in the frame.  This all
 * holds provided the thread blocked through a call to schedule() ($15
 * is the frame pointer in schedule() and $15 is saved at offset 48 by
 * entry.S:do_switch_stack).
 *
 * Under heavy swap load I've seen this lose in an ugly way.  So do
 * some extra sanity checking on the ranges we expect these pointers
 * to be in so that we can fail gracefully.  This is just for ps after
 * all.  -- r~
 */

unsigned long
thread_saved_pc(struct task_struct *t)
{
	unsigned long base = (unsigned long)task_stack_page(t);
	unsigned long fp, sp = task_thread_info(t)->pcb.ksp;

	if (sp > base && sp+6*8 < base + 16*1024) {
		fp = ((unsigned long*)sp)[6];
		if (fp > sp && fp < base + 16*1024)
			return *(unsigned long *)fp;
	}

	return 0;
}

unsigned long
get_wchan(struct task_struct *p)
{
	unsigned long schedule_frame;
	unsigned long pc;
	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;
	/*
	 * This one depends on the frame size of schedule().  Do a
	 * "disass schedule" in gdb to find the frame size.  Also, the
	 * code assumes that sleep_on() follows immediately after
	 * interruptible_sleep_on() and that add_timer() follows
	 * immediately after interruptible_sleep().  Ugly, isn't it?
	 * Maybe adding a wchan field to task_struct would be better,
	 * after all...
	 */

	pc = thread_saved_pc(p);
	if (in_sched_functions(pc)) {
		schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6];
		return ((unsigned long *)schedule_frame)[12];
	}
	return pc;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/alpha/kernel/process.c
	3	*
	4	* Copyright (C) 1995 Linus Torvalds
	5	*/
	6
	7	/*
	8	* This file handles the architecture-dependent parts of process handling.
	9	*/
	10
1da177e4 LT	11	#include <linux/errno.h>
	12	#include <linux/module.h>
	13	#include <linux/sched.h>
	14	#include <linux/kernel.h>
	15	#include <linux/mm.h>
	16	#include <linux/smp.h>
1da177e4 LT	17	#include <linux/stddef.h>
	18	#include <linux/unistd.h>
	19	#include <linux/ptrace.h>
1da177e4	20	#include <linux/user.h>
1da177e4 LT	21	#include <linux/time.h>
	22	#include <linux/major.h>
	23	#include <linux/stat.h>
a8f340e3	24	#include <linux/vt.h>
1da177e4 LT	25	#include <linux/mman.h>
	26	#include <linux/elfcore.h>
	27	#include <linux/reboot.h>
	28	#include <linux/tty.h>
	29	#include <linux/console.h>
5a0e3ad6	30	#include <linux/slab.h>
1da177e4 LT	31
	32	#include <asm/reg.h>
	33	#include <asm/uaccess.h>
	34	#include <asm/system.h>
	35	#include <asm/io.h>
	36	#include <asm/pgtable.h>
	37	#include <asm/hwrpb.h>
	38	#include <asm/fpu.h>
	39
	40	#include "proto.h"
	41	#include "pci_impl.h"
	42
5e38291d EB	43	/*
	44	* Power off function, if any
	45	*/
	46	void (*pm_power_off)(void) = machine_power_off;
89eb1693	47	EXPORT_SYMBOL(pm_power_off);
5e38291d	48
1da177e4 LT	49	void
	50	cpu_idle(void)
	51	{
64c7c8f8 NP	52	set_thread_flag(TIF_POLLING_NRFLAG);
64c7c8f8 NP	53
1da177e4	54	while (1) {
1da177e4 LT	55	/* FIXME -- EV6 and LCA45 know how to power down
	56	the CPU. */
	57
	58	while (!need_resched())
64c7c8f8	59	cpu_relax();
1da177e4 LT	60	schedule();
	61	}
	62	}
	63
	64
	65	struct halt_info {
	66	int mode;
	67	char *restart_cmd;
	68	};
	69
	70	static void
	71	common_shutdown_1(void *generic_ptr)
	72	{
	73	struct halt_info how = (struct halt_info )generic_ptr;
	74	struct percpu_struct *cpup;
	75	unsigned long *pflags, flags;
	76	int cpuid = smp_processor_id();
	77
	78	/* No point in taking interrupts anymore. */
	79	local_irq_disable();
	80
	81	cpup = (struct percpu_struct *)
	82	((unsigned long)hwrpb + hwrpb->processor_offset
	83	+ hwrpb->processor_size * cpuid);
	84	pflags = &cpup->flags;
	85	flags = *pflags;
	86
	87	/* Clear reason to "default"; clear "bootstrap in progress". */
	88	flags &= ~0x00ff0001UL;
	89
	90	#ifdef CONFIG_SMP
	91	/* Secondaries halt here. */
	92	if (cpuid != boot_cpuid) {
	93	flags \|= 0x00040000UL; /* "remain halted" */
	94	*pflags = flags;
1371be0f RR	95	set_cpu_present(cpuid, false);
1371be0f RR	96	set_cpu_possible(cpuid, false);
1da177e4 LT	97	halt();
	98	}
	99	#endif
	100
	101	if (how->mode == LINUX_REBOOT_CMD_RESTART) {
	102	if (!how->restart_cmd) {
	103	flags \|= 0x00020000UL; /* "cold bootstrap" */
	104	} else {
	105	/* For SRM, we could probably set environment
	106	variables to get this to work. We'd have to
	107	delay this until after srm_paging_stop unless
	108	we ever got srm_fixup working.
	109
	110	At the moment, SRM will use the last boot device,
	111	but the file and flags will be the defaults, when
	112	doing a "warm" bootstrap. */
	113	flags \|= 0x00030000UL; /* "warm bootstrap" */
	114	}
	115	} else {
	116	flags \|= 0x00040000UL; /* "remain halted" */
	117	}
	118	*pflags = flags;
	119
	120	#ifdef CONFIG_SMP
	121	/* Wait for the secondaries to halt. */
1371be0f RR	122	set_cpu_present(boot_cpuid, false);
1371be0f RR	123	set_cpu_possible(boot_cpuid, false);
c7d2d28b	124	while (cpus_weight(cpu_present_map))
1da177e4 LT	125	barrier();
	126	#endif
	127
	128	/* If booted from SRM, reset some of the original environment. */
	129	if (alpha_using_srm) {
	130	#ifdef CONFIG_DUMMY_CONSOLE
4b3c86a7 IK	131	/* If we've gotten here after SysRq-b, leave interrupt
	132	context before taking over the console. */
	133	if (in_interrupt())
	134	irq_exit();
1da177e4 LT	135	/* This has the effect of resetting the VGA video origin. */
	136	take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1);
	137	#endif
	138	pci_restore_srm_config();
	139	set_hae(srm_hae);
	140	}
	141
	142	if (alpha_mv.kill_arch)
	143	alpha_mv.kill_arch(how->mode);
	144
	145	if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) {
	146	/* Unfortunately, since MILO doesn't currently understand
	147	the hwrpb bits above, we can't reliably halt the
	148	processor and keep it halted. So just loop. */
	149	return;
	150	}
	151
	152	if (alpha_using_srm)
	153	srm_paging_stop();
	154
	155	halt();
	156	}
	157
	158	static void
	159	common_shutdown(int mode, char *restart_cmd)
	160	{
	161	struct halt_info args;
	162	args.mode = mode;
	163	args.restart_cmd = restart_cmd;
15c8b6c1	164	on_each_cpu(common_shutdown_1, &args, 0);
1da177e4 LT	165	}
	166
	167	void
	168	machine_restart(char *restart_cmd)
	169	{
	170	common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);
	171	}
	172
1da177e4 LT	173
	174	void
	175	machine_halt(void)
	176	{
	177	common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);
	178	}
	179
1da177e4 LT	180
	181	void
	182	machine_power_off(void)
	183	{
	184	common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL);
	185	}
	186
1da177e4 LT	187
	188	/* Used by sysrq-p, among others. I don't believe r9-r15 are ever
	189	saved in the context it's used. */
	190
	191	void
	192	show_regs(struct pt_regs *regs)
	193	{
	194	dik_show_regs(regs, NULL);
	195	}
	196
	197	/*
	198	* Re-start a thread when doing execve()
	199	*/
	200	void
	201	start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	202	{
	203	set_fs(USER_DS);
	204	regs->pc = pc;
	205	regs->ps = 8;
	206	wrusp(sp);
	207	}
cff52daf	208	EXPORT_SYMBOL(start_thread);
1da177e4 LT	209
	210	/*
	211	* Free current thread data structures etc..
	212	*/
	213	void
	214	exit_thread(void)
	215	{
	216	}
	217
	218	void
	219	flush_thread(void)
	220	{
	221	/* Arrange for each exec'ed process to start off with a clean slate
	222	with respect to the FPU. This is all exceptions disabled. */
	223	current_thread_info()->ieee_state = 0;
	224	wrfpcr(FPCR_DYN_NORMAL \| ieee_swcr_to_fpcr(0));
	225
	226	/* Clean slate for TLS. */
	227	current_thread_info()->pcb.unique = 0;
	228	}
	229
	230	void
	231	release_thread(struct task_struct *dead_task)
	232	{
	233	}
	234
	235	/*
	236	* "alpha_clone()".. By the time we get here, the
	237	* non-volatile registers have also been saved on the
	238	* stack. We do some ugly pointer stuff here.. (see
	239	* also copy_thread)
	240	*
	241	* Notice that "fork()" is implemented in terms of clone,
	242	* with parameters (SIGCHLD, 0).
	243	*/
	244	int
	245	alpha_clone(unsigned long clone_flags, unsigned long usp,
	246	int __user parent_tid, int __user child_tid,
	247	unsigned long tls_value, struct pt_regs *regs)
	248	{
	249	if (!usp)
	250	usp = rdusp();
	251
	252	return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid);
	253	}
	254
	255	int
	256	alpha_vfork(struct pt_regs *regs)
	257	{
	258	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD, rdusp(),
	259	regs, 0, NULL, NULL);
	260	}
	261
	262	/*
	263	* Copy an alpha thread..
	264	*
	265	* Note the "stack_offset" stuff: when returning to kernel mode, we need
	266	* to have some extra stack-space for the kernel stack that still exists
	267	* after the "ret_from_fork". When returning to user mode, we only want
	268	* the space needed by the syscall stack frame (ie "struct pt_regs").
	269	* Use the passed "regs" pointer to determine how much space we need
	270	* for a kernel fork().
	271	*/
	272
273	int
6f2c55b8	274	copy_thread(unsigned long clone_flags, unsigned long usp,
1da177e4 LT	275	unsigned long unused,
	276	struct task_struct * p, struct pt_regs * regs)
	277	{
	278	extern void ret_from_fork(void);
	279
27f45130	280	struct thread_info *childti = task_thread_info(p);
1da177e4 LT	281	struct pt_regs * childregs;
	282	struct switch_stack * childstack, *stack;
	283	unsigned long stack_offset, settls;
	284
	285	stack_offset = PAGE_SIZE - sizeof(struct pt_regs);
	286	if (!(regs->ps & 8))
	287	stack_offset = (PAGE_SIZE-1) & (unsigned long) regs;
	288	childregs = (struct pt_regs *)
27f45130	289	(stack_offset + PAGE_SIZE + task_stack_page(p));
1da177e4 LT	290
	291	childregs = regs;
	292	settls = regs->r20;
	293	childregs->r0 = 0;
	294	childregs->r19 = 0;
	295	childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */
	296	regs->r20 = 0;
	297	stack = ((struct switch_stack *) regs) - 1;
	298	childstack = ((struct switch_stack *) childregs) - 1;
	299	childstack = stack;
	300	childstack->r26 = (unsigned long) ret_from_fork;
	301	childti->pcb.usp = usp;
	302	childti->pcb.ksp = (unsigned long) childstack;
	303	childti->pcb.flags = 1; /* set FEN, clear everything else */
	304
	305	/* Set a new TLS for the child thread? Peek back into the
	306	syscall arguments that we saved on syscall entry. Oops,
	307	except we'd have clobbered it with the parent/child set
	308	of r20. Read the saved copy. */
	309	/* Note: if CLONE_SETTLS is not set, then we must inherit the
	310	value from the parent, which will have been set by the block
	311	copy in dup_task_struct. This is non-intuitive, but is
	312	required for proper operation in the case of a threaded
	313	application calling fork. */
	314	if (clone_flags & CLONE_SETTLS)
	315	childti->pcb.unique = settls;
	316
	317	return 0;
	318	}
	319
1da177e4 LT	320	/*
	321	* Fill in the user structure for a ELF core dump.
	322	*/
	323	void
	324	dump_elf_thread(elf_greg_t dest, struct pt_regs pt, struct thread_info *ti)
	325	{
	326	/* switch stack follows right below pt_regs: */
	327	struct switch_stack * sw = ((struct switch_stack *) pt) - 1;
	328
	329	dest[ 0] = pt->r0;
	330	dest[ 1] = pt->r1;
	331	dest[ 2] = pt->r2;
	332	dest[ 3] = pt->r3;
	333	dest[ 4] = pt->r4;
	334	dest[ 5] = pt->r5;
	335	dest[ 6] = pt->r6;
	336	dest[ 7] = pt->r7;
	337	dest[ 8] = pt->r8;
	338	dest[ 9] = sw->r9;
	339	dest[10] = sw->r10;
	340	dest[11] = sw->r11;
	341	dest[12] = sw->r12;
	342	dest[13] = sw->r13;
	343	dest[14] = sw->r14;
	344	dest[15] = sw->r15;
	345	dest[16] = pt->r16;
	346	dest[17] = pt->r17;
	347	dest[18] = pt->r18;
	348	dest[19] = pt->r19;
	349	dest[20] = pt->r20;
	350	dest[21] = pt->r21;
	351	dest[22] = pt->r22;
	352	dest[23] = pt->r23;
	353	dest[24] = pt->r24;
	354	dest[25] = pt->r25;
	355	dest[26] = pt->r26;
	356	dest[27] = pt->r27;
	357	dest[28] = pt->r28;
	358	dest[29] = pt->gp;
	359	dest[30] = rdusp();
	360	dest[31] = pt->pc;
	361
	362	/* Once upon a time this was the PS value. Which is stupid
	363	since that is always 8 for usermode. Usurped for the more
	364	useful value of the thread's UNIQUE field. */
	365	dest[32] = ti->pcb.unique;
	366	}
cff52daf	367	EXPORT_SYMBOL(dump_elf_thread);
1da177e4 LT	368
	369	int
	370	dump_elf_task(elf_greg_t dest, struct task_struct task)
	371	{
e52f4ca2	372	dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task));
1da177e4 LT	373	return 1;
1da177e4 LT	374	}
cff52daf	375	EXPORT_SYMBOL(dump_elf_task);
1da177e4 LT	376
	377	int
	378	dump_elf_task_fp(elf_fpreg_t dest, struct task_struct task)
	379	{
e52f4ca2	380	struct switch_stack sw = (struct switch_stack )task_pt_regs(task) - 1;
1da177e4	381	memcpy(dest, sw->fp, 32 * 8);
1da177e4 LT	382	return 1;
1da177e4 LT	383	}
cff52daf	384	EXPORT_SYMBOL(dump_elf_task_fp);
1da177e4 LT	385
	386	/*
	387	* sys_execve() executes a new program.
	388	*/
	389	asmlinkage int
d7627467 DH	390	do_sys_execve(const char __user *ufilename,
	391	const char __user const __user argv,
	392	const char __user const __user envp, struct pt_regs *regs)
1da177e4 LT	393	{
	394	int error;
	395	char *filename;
	396
	397	filename = getname(ufilename);
	398	error = PTR_ERR(filename);
	399	if (IS_ERR(filename))
	400	goto out;
	401	error = do_execve(filename, argv, envp, regs);
	402	putname(filename);
	403	out:
	404	return error;
	405	}
	406
	407	/*
	408	* Return saved PC of a blocked thread. This assumes the frame
	409	* pointer is the 6th saved long on the kernel stack and that the
	410	* saved return address is the first long in the frame. This all
	411	* holds provided the thread blocked through a call to schedule() ($15
	412	* is the frame pointer in schedule() and $15 is saved at offset 48 by
	413	* entry.S:do_switch_stack).
	414	*
	415	* Under heavy swap load I've seen this lose in an ugly way. So do
	416	* some extra sanity checking on the ranges we expect these pointers
	417	* to be in so that we can fail gracefully. This is just for ps after
	418	* all. -- r~
	419	*/
	420
	421	unsigned long
36c8b586	422	thread_saved_pc(struct task_struct *t)
1da177e4	423	{
27f45130	424	unsigned long base = (unsigned long)task_stack_page(t);
37bfbaf9	425	unsigned long fp, sp = task_thread_info(t)->pcb.ksp;
1da177e4 LT	426
	427	if (sp > base && sp+68 < base + 161024) {
	428	fp = ((unsigned long*)sp)[6];
	429	if (fp > sp && fp < base + 16*1024)
	430	return (unsigned long )fp;
	431	}
	432
	433	return 0;
	434	}
	435
	436	unsigned long
	437	get_wchan(struct task_struct *p)
	438	{
	439	unsigned long schedule_frame;
	440	unsigned long pc;
	441	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	442	return 0;
	443	/*
	444	* This one depends on the frame size of schedule(). Do a
	445	* "disass schedule" in gdb to find the frame size. Also, the
	446	* code assumes that sleep_on() follows immediately after
	447	* interruptible_sleep_on() and that add_timer() follows
	448	* immediately after interruptible_sleep(). Ugly, isn't it?
	449	* Maybe adding a wchan field to task_struct would be better,
	450	* after all...
	451	*/
	452
	453	pc = thread_saved_pc(p);
	454	if (in_sched_functions(pc)) {
37bfbaf9	455	schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6];
1da177e4 LT	456	return ((unsigned long *)schedule_frame)[12];
	457	}
	458	return pc;
	459	}