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