[thirdparty/kernel/linux.git] / arch / xtensa / kernel / process.c

/*
 * arch/xtensa/kernel/process.c
 *
 * Xtensa Processor version.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2001 - 2005 Tensilica Inc.
 *
 * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
 * Chris Zankel <chris@zankel.net>
 * Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca>
 * Kevin Chea
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.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/elf.h>
#include <linux/hw_breakpoint.h>
#include <linux/init.h>
#include <linux/prctl.h>
#include <linux/init_task.h>
#include <linux/module.h>
#include <linux/mqueue.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>

#include <asm/pgtable.h>
#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/platform.h>
#include <asm/mmu.h>
#include <asm/irq.h>
#include <linux/atomic.h>
#include <asm/asm-offsets.h>
#include <asm/regs.h>
#include <asm/hw_breakpoint.h>

extern void ret_from_fork(void);
extern void ret_from_kernel_thread(void);

struct task_struct *current_set[NR_CPUS] = {&init_task, };

void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);


#ifdef CONFIG_STACKPROTECTOR
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif

#if XTENSA_HAVE_COPROCESSORS

void coprocessor_release_all(struct thread_info *ti)
{
	unsigned long cpenable;
	int i;

	/* Make sure we don't switch tasks during this operation. */

	preempt_disable();

	/* Walk through all cp owners and release it for the requested one. */

	cpenable = ti->cpenable;

	for (i = 0; i < XCHAL_CP_MAX; i++) {
		if (coprocessor_owner[i] == ti) {
			coprocessor_owner[i] = 0;
			cpenable &= ~(1 << i);
		}
	}

	ti->cpenable = cpenable;
	coprocessor_clear_cpenable();

	preempt_enable();
}

void coprocessor_flush_all(struct thread_info *ti)
{
	unsigned long cpenable, old_cpenable;
	int i;

	preempt_disable();

	RSR_CPENABLE(old_cpenable);
	cpenable = ti->cpenable;
	WSR_CPENABLE(cpenable);

	for (i = 0; i < XCHAL_CP_MAX; i++) {
		if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti)
			coprocessor_flush(ti, i);
		cpenable >>= 1;
	}
	WSR_CPENABLE(old_cpenable);

	preempt_enable();
}

#endif


/*
 * Powermanagement idle function, if any is provided by the platform.
 */
void arch_cpu_idle(void)
{
	platform_idle();
}

/*
 * This is called when the thread calls exit().
 */
void exit_thread(struct task_struct *tsk)
{
#if XTENSA_HAVE_COPROCESSORS
	coprocessor_release_all(task_thread_info(tsk));
#endif
}

/*
 * Flush thread state. This is called when a thread does an execve()
 * Note that we flush coprocessor registers for the case execve fails.
 */
void flush_thread(void)
{
#if XTENSA_HAVE_COPROCESSORS
	struct thread_info *ti = current_thread_info();
	coprocessor_flush_all(ti);
	coprocessor_release_all(ti);
#endif
	flush_ptrace_hw_breakpoint(current);
}

/*
 * this gets called so that we can store coprocessor state into memory and
 * copy the current task into the new thread.
 */
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
#if XTENSA_HAVE_COPROCESSORS
	coprocessor_flush_all(task_thread_info(src));
#endif
	*dst = *src;
	return 0;
}

/*
 * Copy thread.
 *
 * There are two modes in which this function is called:
 * 1) Userspace thread creation,
 *    regs != NULL, usp_thread_fn is userspace stack pointer.
 *    It is expected to copy parent regs (in case CLONE_VM is not set
 *    in the clone_flags) and set up passed usp in the childregs.
 * 2) Kernel thread creation,
 *    regs == NULL, usp_thread_fn is the function to run in the new thread
 *    and thread_fn_arg is its parameter.
 *    childregs are not used for the kernel threads.
 *
 * The stack layout for the new thread looks like this:
 *
 *	+------------------------+
 *	|       childregs        |
 *	+------------------------+ <- thread.sp = sp in dummy-frame
 *	|      dummy-frame       |    (saved in dummy-frame spill-area)
 *	+------------------------+
 *
 * We create a dummy frame to return to either ret_from_fork or
 *   ret_from_kernel_thread:
 *   a0 points to ret_from_fork/ret_from_kernel_thread (simulating a call4)
 *   sp points to itself (thread.sp)
 *   a2, a3 are unused for userspace threads,
 *   a2 points to thread_fn, a3 holds thread_fn arg for kernel threads.
 *
 * Note: This is a pristine frame, so we don't need any spill region on top of
 *       childregs.
 *
 * The fun part:  if we're keeping the same VM (i.e. cloning a thread,
 * not an entire process), we're normally given a new usp, and we CANNOT share
 * any live address register windows.  If we just copy those live frames over,
 * the two threads (parent and child) will overflow the same frames onto the
 * parent stack at different times, likely corrupting the parent stack (esp.
 * if the parent returns from functions that called clone() and calls new
 * ones, before the child overflows its now old copies of its parent windows).
 * One solution is to spill windows to the parent stack, but that's fairly
 * involved.  Much simpler to just not copy those live frames across.
 */

int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
		unsigned long thread_fn_arg, struct task_struct *p)
{
	struct pt_regs *childregs = task_pt_regs(p);

#if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS)
	struct thread_info *ti;
#endif

	/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */
	SPILL_SLOT(childregs, 1) = (unsigned long)childregs;
	SPILL_SLOT(childregs, 0) = 0;

	p->thread.sp = (unsigned long)childregs;

	if (!(p->flags & PF_KTHREAD)) {
		struct pt_regs *regs = current_pt_regs();
		unsigned long usp = usp_thread_fn ?
			usp_thread_fn : regs->areg[1];

		p->thread.ra = MAKE_RA_FOR_CALL(
				(unsigned long)ret_from_fork, 0x1);

		/* This does not copy all the regs.
		 * In a bout of brilliance or madness,
		 * ARs beyond a0-a15 exist past the end of the struct.
		 */
		*childregs = *regs;
		childregs->areg[1] = usp;
		childregs->areg[2] = 0;

		/* When sharing memory with the parent thread, the child
		   usually starts on a pristine stack, so we have to reset
		   windowbase, windowstart and wmask.
		   (Note that such a new thread is required to always create
		   an initial call4 frame)
		   The exception is vfork, where the new thread continues to
		   run on the parent's stack until it calls execve. This could
		   be a call8 or call12, which requires a legal stack frame
		   of the previous caller for the overflow handlers to work.
		   (Note that it's always legal to overflow live registers).
		   In this case, ensure to spill at least the stack pointer
		   of that frame. */

		if (clone_flags & CLONE_VM) {
			/* check that caller window is live and same stack */
			int len = childregs->wmask & ~0xf;
			if (regs->areg[1] == usp && len != 0) {
				int callinc = (regs->areg[0] >> 30) & 3;
				int caller_ars = XCHAL_NUM_AREGS - callinc * 4;
				put_user(regs->areg[caller_ars+1],
					 (unsigned __user*)(usp - 12));
			}
			childregs->wmask = 1;
			childregs->windowstart = 1;
			childregs->windowbase = 0;
		} else {
			int len = childregs->wmask & ~0xf;
			memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4],
			       &regs->areg[XCHAL_NUM_AREGS - len/4], len);
		}

		/* The thread pointer is passed in the '4th argument' (= a5) */
		if (clone_flags & CLONE_SETTLS)
			childregs->threadptr = childregs->areg[5];
	} else {
		p->thread.ra = MAKE_RA_FOR_CALL(
				(unsigned long)ret_from_kernel_thread, 1);

		/* pass parameters to ret_from_kernel_thread:
		 * a2 = thread_fn, a3 = thread_fn arg
		 */
		SPILL_SLOT(childregs, 3) = thread_fn_arg;
		SPILL_SLOT(childregs, 2) = usp_thread_fn;

		/* Childregs are only used when we're going to userspace
		 * in which case start_thread will set them up.
		 */
	}

#if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS)
	ti = task_thread_info(p);
	ti->cpenable = 0;
#endif

	clear_ptrace_hw_breakpoint(p);

	return 0;
}


/*
 * These bracket the sleeping functions..
 */

unsigned long get_wchan(struct task_struct *p)
{
	unsigned long sp, pc;
	unsigned long stack_page = (unsigned long) task_stack_page(p);
	int count = 0;

	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;

	sp = p->thread.sp;
	pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);

	do {
		if (sp < stack_page + sizeof(struct task_struct) ||
		    sp >= (stack_page + THREAD_SIZE) ||
		    pc == 0)
			return 0;
		if (!in_sched_functions(pc))
			return pc;

		/* Stack layout: sp-4: ra, sp-3: sp' */

		pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp);
		sp = *(unsigned long *)sp - 3;
	} while (count++ < 16);
	return 0;
}

/*
 * xtensa_gregset_t and 'struct pt_regs' are vastly different formats
 * of processor registers.  Besides different ordering,
 * xtensa_gregset_t contains non-live register information that
 * 'struct pt_regs' does not.  Exception handling (primarily) uses
 * 'struct pt_regs'.  Core files and ptrace use xtensa_gregset_t.
 *
 */

void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs)
{
	unsigned long wb, ws, wm;
	int live, last;

	wb = regs->windowbase;
	ws = regs->windowstart;
	wm = regs->wmask;
	ws = ((ws >> wb) | (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1);

	/* Don't leak any random bits. */

	memset(elfregs, 0, sizeof(*elfregs));

	/* Note:  PS.EXCM is not set while user task is running; its
	 * being set in regs->ps is for exception handling convenience.
	 */

	elfregs->pc		= regs->pc;
	elfregs->ps		= (regs->ps & ~(1 << PS_EXCM_BIT));
	elfregs->lbeg		= regs->lbeg;
	elfregs->lend		= regs->lend;
	elfregs->lcount		= regs->lcount;
	elfregs->sar		= regs->sar;
	elfregs->windowstart	= ws;

	live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
	last = XCHAL_NUM_AREGS - (wm >> 4) * 4;
	memcpy(elfregs->a, regs->areg, live * 4);
	memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16);
}

int dump_fpu(void)
{
	return 0;
}
Commit	Line	Data
5a0015d6 CZ	1	/*
	2	* arch/xtensa/kernel/process.c
	3	*
	4	* Xtensa Processor version.
	5	*
	6	* This file is subject to the terms and conditions of the GNU General Public
	7	* License. See the file "COPYING" in the main directory of this archive
	8	* for more details.
	9	*
	10	* Copyright (C) 2001 - 2005 Tensilica Inc.
	11	*
	12	* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
	13	* Chris Zankel <chris@zankel.net>
	14	* Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca>
	15	* Kevin Chea
	16	*/
	17
5a0015d6 CZ	18	#include <linux/errno.h>
5a0015d6 CZ	19	#include <linux/sched.h>
b17b0153	20	#include <linux/sched/debug.h>
29930025	21	#include <linux/sched/task.h>
68db0cf1	22	#include <linux/sched/task_stack.h>
5a0015d6 CZ	23	#include <linux/kernel.h>
	24	#include <linux/mm.h>
	25	#include <linux/smp.h>
5a0015d6 CZ	26	#include <linux/stddef.h>
	27	#include <linux/unistd.h>
	28	#include <linux/ptrace.h>
5a0015d6	29	#include <linux/elf.h>
c91e02bd	30	#include <linux/hw_breakpoint.h>
5a0015d6 CZ	31	#include <linux/init.h>
	32	#include <linux/prctl.h>
	33	#include <linux/init_task.h>
	34	#include <linux/module.h>
	35	#include <linux/mqueue.h>
73089cbf	36	#include <linux/fs.h>
5a0e3ad6	37	#include <linux/slab.h>
11ad47a0	38	#include <linux/rcupdate.h>
5a0015d6 CZ	39
5a0015d6 CZ	40	#include <asm/pgtable.h>
7c0f6ba6	41	#include <linux/uaccess.h>
5a0015d6 CZ	42	#include <asm/io.h>
	43	#include <asm/processor.h>
	44	#include <asm/platform.h>
	45	#include <asm/mmu.h>
	46	#include <asm/irq.h>
60063497	47	#include <linux/atomic.h>
0013a854	48	#include <asm/asm-offsets.h>
173d6681	49	#include <asm/regs.h>
c91e02bd	50	#include <asm/hw_breakpoint.h>
5a0015d6 CZ	51
5a0015d6 CZ	52	extern void ret_from_fork(void);
3306a726	53	extern void ret_from_kernel_thread(void);
5a0015d6	54
5a0015d6 CZ	55	struct task_struct *current_set[NR_CPUS] = {&init_task, };
5a0015d6 CZ	56
47f3fc94 AB	57	void (*pm_power_off)(void) = NULL;
	58	EXPORT_SYMBOL(pm_power_off);
	59
5a0015d6	60
050e9baa	61	#ifdef CONFIG_STACKPROTECTOR
40d1a07b MF	62	#include <linux/stackprotector.h>
	63	unsigned long __stack_chk_guard __read_mostly;
	64	EXPORT_SYMBOL(__stack_chk_guard);
	65	#endif
	66
c658eac6 CZ	67	#if XTENSA_HAVE_COPROCESSORS
	68
	69	void coprocessor_release_all(struct thread_info *ti)
	70	{
	71	unsigned long cpenable;
	72	int i;
	73
	74	/* Make sure we don't switch tasks during this operation. */
	75
	76	preempt_disable();
	77
	78	/* Walk through all cp owners and release it for the requested one. */
	79
	80	cpenable = ti->cpenable;
	81
	82	for (i = 0; i < XCHAL_CP_MAX; i++) {
	83	if (coprocessor_owner[i] == ti) {
	84	coprocessor_owner[i] = 0;
	85	cpenable &= ~(1 << i);
	86	}
	87	}
	88
	89	ti->cpenable = cpenable;
	90	coprocessor_clear_cpenable();
	91
	92	preempt_enable();
	93	}
	94
	95	void coprocessor_flush_all(struct thread_info *ti)
	96	{
2958b666	97	unsigned long cpenable, old_cpenable;
c658eac6 CZ	98	int i;
	99
	100	preempt_disable();
	101
2958b666	102	RSR_CPENABLE(old_cpenable);
c658eac6	103	cpenable = ti->cpenable;
2958b666	104	WSR_CPENABLE(cpenable);
c658eac6 CZ	105
	106	for (i = 0; i < XCHAL_CP_MAX; i++) {
	107	if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti)
	108	coprocessor_flush(ti, i);
	109	cpenable >>= 1;
	110	}
2958b666	111	WSR_CPENABLE(old_cpenable);
c658eac6 CZ	112
	113	preempt_enable();
	114	}
	115
	116	#endif
	117
	118
5a0015d6 CZ	119	/*
	120	* Powermanagement idle function, if any is provided by the platform.
	121	*/
f4e2e9a4	122	void arch_cpu_idle(void)
5a0015d6	123	{
f4e2e9a4	124	platform_idle();
5a0015d6 CZ	125	}
	126
	127	/*
c658eac6	128	* This is called when the thread calls exit().
5a0015d6	129	*/
e6464694	130	void exit_thread(struct task_struct *tsk)
5a0015d6	131	{
c658eac6	132	#if XTENSA_HAVE_COPROCESSORS
e6464694	133	coprocessor_release_all(task_thread_info(tsk));
c658eac6	134	#endif
5a0015d6 CZ	135	}
5a0015d6 CZ	136
c658eac6 CZ	137	/*
	138	* Flush thread state. This is called when a thread does an execve()
	139	* Note that we flush coprocessor registers for the case execve fails.
	140	*/
5a0015d6 CZ	141	void flush_thread(void)
5a0015d6 CZ	142	{
c658eac6 CZ	143	#if XTENSA_HAVE_COPROCESSORS
	144	struct thread_info *ti = current_thread_info();
	145	coprocessor_flush_all(ti);
	146	coprocessor_release_all(ti);
	147	#endif
c91e02bd	148	flush_ptrace_hw_breakpoint(current);
c658eac6 CZ	149	}
	150
	151	/*
55ccf3fe SS	152	* this gets called so that we can store coprocessor state into memory and
55ccf3fe SS	153	* copy the current task into the new thread.
c658eac6	154	*/
55ccf3fe	155	int arch_dup_task_struct(struct task_struct dst, struct task_struct src)
c658eac6 CZ	156	{
c658eac6 CZ	157	#if XTENSA_HAVE_COPROCESSORS
55ccf3fe	158	coprocessor_flush_all(task_thread_info(src));
c658eac6	159	#endif
55ccf3fe SS	160	dst = src;
55ccf3fe SS	161	return 0;
5a0015d6 CZ	162	}
	163
	164	/*
	165	* Copy thread.
	166	*
3306a726 MF	167	* There are two modes in which this function is called:
	168	* 1) Userspace thread creation,
	169	* regs != NULL, usp_thread_fn is userspace stack pointer.
	170	* It is expected to copy parent regs (in case CLONE_VM is not set
	171	* in the clone_flags) and set up passed usp in the childregs.
	172	* 2) Kernel thread creation,
	173	* regs == NULL, usp_thread_fn is the function to run in the new thread
	174	* and thread_fn_arg is its parameter.
	175	* childregs are not used for the kernel threads.
	176	*
5a0015d6 CZ	177	* The stack layout for the new thread looks like this:
5a0015d6 CZ	178	*
3306a726	179	* +------------------------+
5a0015d6 CZ	180	* \| childregs \|
	181	* +------------------------+ <- thread.sp = sp in dummy-frame
	182	* \| dummy-frame \| (saved in dummy-frame spill-area)
	183	* +------------------------+
	184	*
3306a726 MF	185	* We create a dummy frame to return to either ret_from_fork or
	186	* ret_from_kernel_thread:
	187	* a0 points to ret_from_fork/ret_from_kernel_thread (simulating a call4)
5a0015d6	188	* sp points to itself (thread.sp)
3306a726 MF	189	* a2, a3 are unused for userspace threads,
3306a726 MF	190	* a2 points to thread_fn, a3 holds thread_fn arg for kernel threads.
5a0015d6 CZ	191	*
	192	* Note: This is a pristine frame, so we don't need any spill region on top of
	193	* childregs.
84ed3053 MG	194	*
	195	* The fun part: if we're keeping the same VM (i.e. cloning a thread,
	196	* not an entire process), we're normally given a new usp, and we CANNOT share
	197	* any live address register windows. If we just copy those live frames over,
	198	* the two threads (parent and child) will overflow the same frames onto the
	199	* parent stack at different times, likely corrupting the parent stack (esp.
	200	* if the parent returns from functions that called clone() and calls new
	201	* ones, before the child overflows its now old copies of its parent windows).
	202	* One solution is to spill windows to the parent stack, but that's fairly
	203	* involved. Much simpler to just not copy those live frames across.
5a0015d6 CZ	204	*/
5a0015d6 CZ	205
3306a726	206	int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
afa86fc4	207	unsigned long thread_fn_arg, struct task_struct *p)
5a0015d6	208	{
3306a726	209	struct pt_regs *childregs = task_pt_regs(p);
5a0015d6	210
39070cb8 CZ	211	#if (XTENSA_HAVE_COPROCESSORS \|\| XTENSA_HAVE_IO_PORTS)
	212	struct thread_info *ti;
	213	#endif
	214
5a0015d6	215	/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */
062b1c19 MF	216	SPILL_SLOT(childregs, 1) = (unsigned long)childregs;
062b1c19 MF	217	SPILL_SLOT(childregs, 0) = 0;
5a0015d6	218
5a0015d6	219	p->thread.sp = (unsigned long)childregs;
c658eac6	220
3306a726 MF	221	if (!(p->flags & PF_KTHREAD)) {
	222	struct pt_regs *regs = current_pt_regs();
	223	unsigned long usp = usp_thread_fn ?
	224	usp_thread_fn : regs->areg[1];
	225
	226	p->thread.ra = MAKE_RA_FOR_CALL(
	227	(unsigned long)ret_from_fork, 0x1);
5a0015d6	228
3306a726 MF	229	/* This does not copy all the regs.
	230	* In a bout of brilliance or madness,
	231	* ARs beyond a0-a15 exist past the end of the struct.
	232	*/
	233	childregs = regs;
5a0015d6	234	childregs->areg[1] = usp;
3306a726	235	childregs->areg[2] = 0;
6ebe7da2 CZ	236
	237	/* When sharing memory with the parent thread, the child
	238	usually starts on a pristine stack, so we have to reset
	239	windowbase, windowstart and wmask.
	240	(Note that such a new thread is required to always create
	241	an initial call4 frame)
	242	The exception is vfork, where the new thread continues to
	243	run on the parent's stack until it calls execve. This could
	244	be a call8 or call12, which requires a legal stack frame
	245	of the previous caller for the overflow handlers to work.
	246	(Note that it's always legal to overflow live registers).
	247	In this case, ensure to spill at least the stack pointer
	248	of that frame. */
	249
84ed3053	250	if (clone_flags & CLONE_VM) {
6ebe7da2 CZ	251	/* check that caller window is live and same stack */
	252	int len = childregs->wmask & ~0xf;
	253	if (regs->areg[1] == usp && len != 0) {
	254	int callinc = (regs->areg[0] >> 30) & 3;
	255	int caller_ars = XCHAL_NUM_AREGS - callinc * 4;
	256	put_user(regs->areg[caller_ars+1],
	257	(unsigned __user*)(usp - 12));
	258	}
	259	childregs->wmask = 1;
	260	childregs->windowstart = 1;
	261	childregs->windowbase = 0;
84ed3053 MG	262	} else {
	263	int len = childregs->wmask & ~0xf;
	264	memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4],
	265	&regs->areg[XCHAL_NUM_AREGS - len/4], len);
	266	}
c50842df CZ	267
c50842df CZ	268	/* The thread pointer is passed in the '4th argument' (= a5) */
5a0015d6	269	if (clone_flags & CLONE_SETTLS)
c50842df	270	childregs->threadptr = childregs->areg[5];
5a0015d6	271	} else {
3306a726 MF	272	p->thread.ra = MAKE_RA_FOR_CALL(
	273	(unsigned long)ret_from_kernel_thread, 1);
	274
	275	/* pass parameters to ret_from_kernel_thread:
	276	* a2 = thread_fn, a3 = thread_fn arg
	277	*/
062b1c19 MF	278	SPILL_SLOT(childregs, 3) = thread_fn_arg;
062b1c19 MF	279	SPILL_SLOT(childregs, 2) = usp_thread_fn;
3306a726 MF	280
	281	/* Childregs are only used when we're going to userspace
	282	* in which case start_thread will set them up.
	283	*/
5a0015d6	284	}
c658eac6 CZ	285
	286	#if (XTENSA_HAVE_COPROCESSORS \|\| XTENSA_HAVE_IO_PORTS)
	287	ti = task_thread_info(p);
	288	ti->cpenable = 0;
	289	#endif
	290
c91e02bd MF	291	clear_ptrace_hw_breakpoint(p);
c91e02bd MF	292
5a0015d6 CZ	293	return 0;
	294	}
	295
	296
5a0015d6 CZ	297	/*
	298	* These bracket the sleeping functions..
	299	*/
	300
	301	unsigned long get_wchan(struct task_struct *p)
	302	{
	303	unsigned long sp, pc;
04fe6faf	304	unsigned long stack_page = (unsigned long) task_stack_page(p);
5a0015d6 CZ	305	int count = 0;
	306
	307	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	308	return 0;
	309
	310	sp = p->thread.sp;
	311	pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);
	312
	313	do {
	314	if (sp < stack_page + sizeof(struct task_struct) \|\|
	315	sp >= (stack_page + THREAD_SIZE) \|\|
	316	pc == 0)
	317	return 0;
	318	if (!in_sched_functions(pc))
	319	return pc;
	320
	321	/* Stack layout: sp-4: ra, sp-3: sp' */
	322
	323	pc = MAKE_PC_FROM_RA((unsigned long)sp - 4, sp);
	324	sp = (unsigned long )sp - 3;
	325	} while (count++ < 16);
	326	return 0;
	327	}
	328
	329	/*
5a0015d6 CZ	330	* xtensa_gregset_t and 'struct pt_regs' are vastly different formats
	331	* of processor registers. Besides different ordering,
	332	* xtensa_gregset_t contains non-live register information that
	333	* 'struct pt_regs' does not. Exception handling (primarily) uses
	334	* 'struct pt_regs'. Core files and ptrace use xtensa_gregset_t.
	335	*
	336	*/
	337
c658eac6	338	void xtensa_elf_core_copy_regs (xtensa_gregset_t elfregs, struct pt_regs regs)
5a0015d6	339	{
c658eac6 CZ	340	unsigned long wb, ws, wm;
	341	int live, last;
	342
	343	wb = regs->windowbase;
	344	ws = regs->windowstart;
	345	wm = regs->wmask;
	346	ws = ((ws >> wb) \| (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1);
	347
	348	/* Don't leak any random bits. */
	349
688bb415	350	memset(elfregs, 0, sizeof(*elfregs));
c658eac6	351
5a0015d6 CZ	352	/* Note: PS.EXCM is not set while user task is running; its
	353	* being set in regs->ps is for exception handling convenience.
	354	*/
	355
	356	elfregs->pc = regs->pc;
173d6681	357	elfregs->ps = (regs->ps & ~(1 << PS_EXCM_BIT));
5a0015d6 CZ	358	elfregs->lbeg = regs->lbeg;
	359	elfregs->lend = regs->lend;
	360	elfregs->lcount = regs->lcount;
	361	elfregs->sar = regs->sar;
c658eac6	362	elfregs->windowstart = ws;
5a0015d6	363
c658eac6 CZ	364	live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
	365	last = XCHAL_NUM_AREGS - (wm >> 4) * 4;
	366	memcpy(elfregs->a, regs->areg, live * 4);
	367	memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16);
5a0015d6 CZ	368	}
5a0015d6 CZ	369
c658eac6	370	int dump_fpu(void)
5a0015d6	371	{
5a0015d6 CZ	372	return 0;
5a0015d6 CZ	373	}