[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/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 <linux/rcupdate.h>

#include <asm/reg.h>
#include <asm/uaccess.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)
{
	current_thread_info()->status |= TS_POLLING;

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

		rcu_idle_enter();
		while (!need_resched())
			cpu_relax();

		rcu_idle_exit();
		schedule_preempt_disabled();
	}
}


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 (cpumask_weight(cpu_present_mask))
		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)
{
	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)
{
}

/*
 * Copy an alpha thread..
 */

int
copy_thread(unsigned long clone_flags, unsigned long usp,
	    unsigned long arg,
	    struct task_struct *p)
{
	extern void ret_from_fork(void);
	extern void ret_from_kernel_thread(void);

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

	childstack = ((struct switch_stack *) childregs) - 1;
	childti->pcb.ksp = (unsigned long) childstack;
	childti->pcb.flags = 1;	/* set FEN, clear everything else */

	if (unlikely(p->flags & PF_KTHREAD)) {
		/* kernel thread */
		memset(childstack, 0,
			sizeof(struct switch_stack) + sizeof(struct pt_regs));
		childstack->r26 = (unsigned long) ret_from_kernel_thread;
		childstack->r9 = usp;	/* function */
		childstack->r10 = arg;
		childregs->hae = alpha_mv.hae_cache,
		childti->pcb.usp = 0;
		return 0;
	}
	/* 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 = regs->r20;
	childti->pcb.usp = usp ?: rdusp();
	*childregs = *regs;
	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 = *stack;
	childstack->r26 = (unsigned long) ret_from_fork;
	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] = ti == current_thread_info() ? rdusp() : ti->pcb.usp;
	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);

/*
 * 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>
4c94cada	31	#include <linux/rcupdate.h>
1da177e4 LT	32
	33	#include <asm/reg.h>
	34	#include <asm/uaccess.h>
1da177e4 LT	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	{
3185bd26	52	current_thread_info()->status \|= TS_POLLING;
64c7c8f8	53
1da177e4	54	while (1) {
1da177e4 LT	55	/* FIXME -- EV6 and LCA45 know how to power down
	56	the CPU. */
	57
4c94cada	58	rcu_idle_enter();
1da177e4	59	while (!need_resched())
64c7c8f8	60	cpu_relax();
6a6c0272	61
4c94cada	62	rcu_idle_exit();
6a6c0272	63	schedule_preempt_disabled();
1da177e4 LT	64	}
	65	}
	66
	67
	68	struct halt_info {
	69	int mode;
	70	char *restart_cmd;
	71	};
	72
	73	static void
	74	common_shutdown_1(void *generic_ptr)
	75	{
	76	struct halt_info how = (struct halt_info )generic_ptr;
	77	struct percpu_struct *cpup;
	78	unsigned long *pflags, flags;
	79	int cpuid = smp_processor_id();
	80
	81	/* No point in taking interrupts anymore. */
	82	local_irq_disable();
	83
	84	cpup = (struct percpu_struct *)
	85	((unsigned long)hwrpb + hwrpb->processor_offset
	86	+ hwrpb->processor_size * cpuid);
	87	pflags = &cpup->flags;
	88	flags = *pflags;
	89
	90	/* Clear reason to "default"; clear "bootstrap in progress". */
	91	flags &= ~0x00ff0001UL;
	92
	93	#ifdef CONFIG_SMP
	94	/* Secondaries halt here. */
	95	if (cpuid != boot_cpuid) {
	96	flags \|= 0x00040000UL; /* "remain halted" */
	97	*pflags = flags;
1371be0f RR	98	set_cpu_present(cpuid, false);
1371be0f RR	99	set_cpu_possible(cpuid, false);
1da177e4 LT	100	halt();
	101	}
	102	#endif
	103
	104	if (how->mode == LINUX_REBOOT_CMD_RESTART) {
	105	if (!how->restart_cmd) {
	106	flags \|= 0x00020000UL; /* "cold bootstrap" */
	107	} else {
	108	/* For SRM, we could probably set environment
	109	variables to get this to work. We'd have to
	110	delay this until after srm_paging_stop unless
	111	we ever got srm_fixup working.
	112
	113	At the moment, SRM will use the last boot device,
	114	but the file and flags will be the defaults, when
	115	doing a "warm" bootstrap. */
	116	flags \|= 0x00030000UL; /* "warm bootstrap" */
	117	}
	118	} else {
	119	flags \|= 0x00040000UL; /* "remain halted" */
	120	}
	121	*pflags = flags;
	122
	123	#ifdef CONFIG_SMP
	124	/* Wait for the secondaries to halt. */
1371be0f RR	125	set_cpu_present(boot_cpuid, false);
1371be0f RR	126	set_cpu_possible(boot_cpuid, false);
81740fc6	127	while (cpumask_weight(cpu_present_mask))
1da177e4 LT	128	barrier();
	129	#endif
	130
	131	/* If booted from SRM, reset some of the original environment. */
	132	if (alpha_using_srm) {
	133	#ifdef CONFIG_DUMMY_CONSOLE
4b3c86a7 IK	134	/* If we've gotten here after SysRq-b, leave interrupt
	135	context before taking over the console. */
	136	if (in_interrupt())
	137	irq_exit();
1da177e4 LT	138	/* This has the effect of resetting the VGA video origin. */
	139	take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1);
	140	#endif
	141	pci_restore_srm_config();
	142	set_hae(srm_hae);
	143	}
	144
	145	if (alpha_mv.kill_arch)
	146	alpha_mv.kill_arch(how->mode);
	147
	148	if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) {
	149	/* Unfortunately, since MILO doesn't currently understand
	150	the hwrpb bits above, we can't reliably halt the
	151	processor and keep it halted. So just loop. */
	152	return;
	153	}
	154
	155	if (alpha_using_srm)
	156	srm_paging_stop();
	157
	158	halt();
	159	}
	160
	161	static void
	162	common_shutdown(int mode, char *restart_cmd)
	163	{
	164	struct halt_info args;
	165	args.mode = mode;
	166	args.restart_cmd = restart_cmd;
15c8b6c1	167	on_each_cpu(common_shutdown_1, &args, 0);
1da177e4 LT	168	}
	169
	170	void
	171	machine_restart(char *restart_cmd)
	172	{
	173	common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);
	174	}
	175
1da177e4 LT	176
	177	void
	178	machine_halt(void)
	179	{
	180	common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);
	181	}
	182
1da177e4 LT	183
	184	void
	185	machine_power_off(void)
	186	{
	187	common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL);
	188	}
	189
1da177e4 LT	190
	191	/* Used by sysrq-p, among others. I don't believe r9-r15 are ever
	192	saved in the context it's used. */
	193
	194	void
	195	show_regs(struct pt_regs *regs)
	196	{
	197	dik_show_regs(regs, NULL);
	198	}
	199
	200	/*
	201	* Re-start a thread when doing execve()
	202	*/
	203	void
	204	start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	205	{
1da177e4 LT	206	regs->pc = pc;
	207	regs->ps = 8;
	208	wrusp(sp);
	209	}
cff52daf	210	EXPORT_SYMBOL(start_thread);
1da177e4 LT	211
	212	/*
	213	* Free current thread data structures etc..
	214	*/
	215	void
	216	exit_thread(void)
	217	{
	218	}
	219
	220	void
	221	flush_thread(void)
	222	{
	223	/* Arrange for each exec'ed process to start off with a clean slate
	224	with respect to the FPU. This is all exceptions disabled. */
	225	current_thread_info()->ieee_state = 0;
	226	wrfpcr(FPCR_DYN_NORMAL \| ieee_swcr_to_fpcr(0));
	227
	228	/* Clean slate for TLS. */
	229	current_thread_info()->pcb.unique = 0;
	230	}
	231
	232	void
	233	release_thread(struct task_struct *dead_task)
	234	{
	235	}
	236
1da177e4 LT	237	/*
1da177e4 LT	238	* Copy an alpha thread..
1da177e4 LT	239	*/
	240
	241	int
6f2c55b8	242	copy_thread(unsigned long clone_flags, unsigned long usp,
cba1ec7e	243	unsigned long arg,
afa86fc4	244	struct task_struct *p)
1da177e4 LT	245	{
1da177e4 LT	246	extern void ret_from_fork(void);
cba1ec7e	247	extern void ret_from_kernel_thread(void);
1da177e4	248
27f45130	249	struct thread_info *childti = task_thread_info(p);
cba1ec7e	250	struct pt_regs *childregs = task_pt_regs(p);
25906730	251	struct pt_regs *regs = current_pt_regs();
cba1ec7e AV	252	struct switch_stack childstack, stack;
	253	unsigned long settls;
	254
	255	childstack = ((struct switch_stack *) childregs) - 1;
25906730 AV	256	childti->pcb.ksp = (unsigned long) childstack;
	257	childti->pcb.flags = 1; /* set FEN, clear everything else */
	258
	259	if (unlikely(p->flags & PF_KTHREAD)) {
cba1ec7e AV	260	/* kernel thread */
	261	memset(childstack, 0,
	262	sizeof(struct switch_stack) + sizeof(struct pt_regs));
	263	childstack->r26 = (unsigned long) ret_from_kernel_thread;
	264	childstack->r9 = usp; /* function */
	265	childstack->r10 = arg;
	266	childregs->hae = alpha_mv.hae_cache,
	267	childti->pcb.usp = 0;
cba1ec7e AV	268	return 0;
cba1ec7e AV	269	}
25906730 AV	270	/* Note: if CLONE_SETTLS is not set, then we must inherit the
	271	value from the parent, which will have been set by the block
	272	copy in dup_task_struct. This is non-intuitive, but is
	273	required for proper operation in the case of a threaded
	274	application calling fork. */
	275	if (clone_flags & CLONE_SETTLS)
	276	childti->pcb.unique = regs->r20;
	277	childti->pcb.usp = usp ?: rdusp();
1da177e4	278	childregs = regs;
1da177e4 LT	279	childregs->r0 = 0;
	280	childregs->r19 = 0;
	281	childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */
	282	regs->r20 = 0;
	283	stack = ((struct switch_stack *) regs) - 1;
1da177e4 LT	284	childstack = stack;
1da177e4 LT	285	childstack->r26 = (unsigned long) ret_from_fork;
1da177e4 LT	286	return 0;
	287	}
	288
1da177e4 LT	289	/*
	290	* Fill in the user structure for a ELF core dump.
	291	*/
	292	void
	293	dump_elf_thread(elf_greg_t dest, struct pt_regs pt, struct thread_info *ti)
	294	{
	295	/* switch stack follows right below pt_regs: */
	296	struct switch_stack * sw = ((struct switch_stack *) pt) - 1;
	297
	298	dest[ 0] = pt->r0;
	299	dest[ 1] = pt->r1;
	300	dest[ 2] = pt->r2;
	301	dest[ 3] = pt->r3;
	302	dest[ 4] = pt->r4;
	303	dest[ 5] = pt->r5;
	304	dest[ 6] = pt->r6;
	305	dest[ 7] = pt->r7;
	306	dest[ 8] = pt->r8;
	307	dest[ 9] = sw->r9;
	308	dest[10] = sw->r10;
	309	dest[11] = sw->r11;
	310	dest[12] = sw->r12;
	311	dest[13] = sw->r13;
	312	dest[14] = sw->r14;
	313	dest[15] = sw->r15;
	314	dest[16] = pt->r16;
	315	dest[17] = pt->r17;
	316	dest[18] = pt->r18;
	317	dest[19] = pt->r19;
	318	dest[20] = pt->r20;
	319	dest[21] = pt->r21;
	320	dest[22] = pt->r22;
	321	dest[23] = pt->r23;
	322	dest[24] = pt->r24;
	323	dest[25] = pt->r25;
	324	dest[26] = pt->r26;
	325	dest[27] = pt->r27;
	326	dest[28] = pt->r28;
	327	dest[29] = pt->gp;
32163f4b	328	dest[30] = ti == current_thread_info() ? rdusp() : ti->pcb.usp;
1da177e4 LT	329	dest[31] = pt->pc;
	330
	331	/* Once upon a time this was the PS value. Which is stupid
	332	since that is always 8 for usermode. Usurped for the more
	333	useful value of the thread's UNIQUE field. */
	334	dest[32] = ti->pcb.unique;
	335	}
cff52daf	336	EXPORT_SYMBOL(dump_elf_thread);
1da177e4 LT	337
	338	int
	339	dump_elf_task(elf_greg_t dest, struct task_struct task)
	340	{
e52f4ca2	341	dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task));
1da177e4 LT	342	return 1;
1da177e4 LT	343	}
cff52daf	344	EXPORT_SYMBOL(dump_elf_task);
1da177e4 LT	345
	346	int
	347	dump_elf_task_fp(elf_fpreg_t dest, struct task_struct task)
	348	{
e52f4ca2	349	struct switch_stack sw = (struct switch_stack )task_pt_regs(task) - 1;
1da177e4	350	memcpy(dest, sw->fp, 32 * 8);
1da177e4 LT	351	return 1;
1da177e4 LT	352	}
cff52daf	353	EXPORT_SYMBOL(dump_elf_task_fp);
1da177e4	354
1da177e4 LT	355	/*
	356	* Return saved PC of a blocked thread. This assumes the frame
	357	* pointer is the 6th saved long on the kernel stack and that the
	358	* saved return address is the first long in the frame. This all
	359	* holds provided the thread blocked through a call to schedule() ($15
	360	* is the frame pointer in schedule() and $15 is saved at offset 48 by
	361	* entry.S:do_switch_stack).
	362	*
	363	* Under heavy swap load I've seen this lose in an ugly way. So do
	364	* some extra sanity checking on the ranges we expect these pointers
	365	* to be in so that we can fail gracefully. This is just for ps after
	366	* all. -- r~
	367	*/
	368
	369	unsigned long
36c8b586	370	thread_saved_pc(struct task_struct *t)
1da177e4	371	{
27f45130	372	unsigned long base = (unsigned long)task_stack_page(t);
37bfbaf9	373	unsigned long fp, sp = task_thread_info(t)->pcb.ksp;
1da177e4 LT	374
	375	if (sp > base && sp+68 < base + 161024) {
	376	fp = ((unsigned long*)sp)[6];
	377	if (fp > sp && fp < base + 16*1024)
	378	return (unsigned long )fp;
	379	}
	380
	381	return 0;
	382	}
	383
	384	unsigned long
	385	get_wchan(struct task_struct *p)
	386	{
	387	unsigned long schedule_frame;
	388	unsigned long pc;
	389	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	390	return 0;
	391	/*
	392	* This one depends on the frame size of schedule(). Do a
	393	* "disass schedule" in gdb to find the frame size. Also, the
	394	* code assumes that sleep_on() follows immediately after
	395	* interruptible_sleep_on() and that add_timer() follows
	396	* immediately after interruptible_sleep(). Ugly, isn't it?
	397	* Maybe adding a wchan field to task_struct would be better,
	398	* after all...
	399	*/
	400
	401	pc = thread_saved_pc(p);
	402	if (in_sched_functions(pc)) {
37bfbaf9	403	schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6];
1da177e4 LT	404	return ((unsigned long *)schedule_frame)[12];
	405	}
	406	return pc;
	407	}