[mirror_ubuntu-focal-kernel.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;
	int i;

	preempt_disable();

	cpenable = ti->cpenable;

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

	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	{
	97	unsigned long cpenable;
	98	int i;
	99
	100	preempt_disable();
	101
	102	cpenable = ti->cpenable;
	103
	104	for (i = 0; i < XCHAL_CP_MAX; i++) {
	105	if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti)
	106	coprocessor_flush(ti, i);
	107	cpenable >>= 1;
	108	}
	109
	110	preempt_enable();
	111	}
	112
	113	#endif
	114
	115
5a0015d6 CZ	116	/*
	117	* Powermanagement idle function, if any is provided by the platform.
	118	*/
f4e2e9a4	119	void arch_cpu_idle(void)
5a0015d6	120	{
f4e2e9a4	121	platform_idle();
5a0015d6 CZ	122	}
	123
	124	/*
c658eac6	125	* This is called when the thread calls exit().
5a0015d6	126	*/
e6464694	127	void exit_thread(struct task_struct *tsk)
5a0015d6	128	{
c658eac6	129	#if XTENSA_HAVE_COPROCESSORS
e6464694	130	coprocessor_release_all(task_thread_info(tsk));
c658eac6	131	#endif
5a0015d6 CZ	132	}
5a0015d6 CZ	133
c658eac6 CZ	134	/*
	135	* Flush thread state. This is called when a thread does an execve()
	136	* Note that we flush coprocessor registers for the case execve fails.
	137	*/
5a0015d6 CZ	138	void flush_thread(void)
5a0015d6 CZ	139	{
c658eac6 CZ	140	#if XTENSA_HAVE_COPROCESSORS
	141	struct thread_info *ti = current_thread_info();
	142	coprocessor_flush_all(ti);
	143	coprocessor_release_all(ti);
	144	#endif
c91e02bd	145	flush_ptrace_hw_breakpoint(current);
c658eac6 CZ	146	}
	147
	148	/*
55ccf3fe SS	149	* this gets called so that we can store coprocessor state into memory and
55ccf3fe SS	150	* copy the current task into the new thread.
c658eac6	151	*/
55ccf3fe	152	int arch_dup_task_struct(struct task_struct dst, struct task_struct src)
c658eac6 CZ	153	{
c658eac6 CZ	154	#if XTENSA_HAVE_COPROCESSORS
55ccf3fe	155	coprocessor_flush_all(task_thread_info(src));
c658eac6	156	#endif
55ccf3fe SS	157	dst = src;
55ccf3fe SS	158	return 0;
5a0015d6 CZ	159	}
	160
	161	/*
	162	* Copy thread.
	163	*
3306a726 MF	164	* There are two modes in which this function is called:
	165	* 1) Userspace thread creation,
	166	* regs != NULL, usp_thread_fn is userspace stack pointer.
	167	* It is expected to copy parent regs (in case CLONE_VM is not set
	168	* in the clone_flags) and set up passed usp in the childregs.
	169	* 2) Kernel thread creation,
	170	* regs == NULL, usp_thread_fn is the function to run in the new thread
	171	* and thread_fn_arg is its parameter.
	172	* childregs are not used for the kernel threads.
	173	*
5a0015d6 CZ	174	* The stack layout for the new thread looks like this:
5a0015d6 CZ	175	*
3306a726	176	* +------------------------+
5a0015d6 CZ	177	* \| childregs \|
	178	* +------------------------+ <- thread.sp = sp in dummy-frame
	179	* \| dummy-frame \| (saved in dummy-frame spill-area)
	180	* +------------------------+
	181	*
3306a726 MF	182	* We create a dummy frame to return to either ret_from_fork or
	183	* ret_from_kernel_thread:
	184	* a0 points to ret_from_fork/ret_from_kernel_thread (simulating a call4)
5a0015d6	185	* sp points to itself (thread.sp)
3306a726 MF	186	* a2, a3 are unused for userspace threads,
3306a726 MF	187	* a2 points to thread_fn, a3 holds thread_fn arg for kernel threads.
5a0015d6 CZ	188	*
	189	* Note: This is a pristine frame, so we don't need any spill region on top of
	190	* childregs.
84ed3053 MG	191	*
	192	* The fun part: if we're keeping the same VM (i.e. cloning a thread,
	193	* not an entire process), we're normally given a new usp, and we CANNOT share
	194	* any live address register windows. If we just copy those live frames over,
	195	* the two threads (parent and child) will overflow the same frames onto the
	196	* parent stack at different times, likely corrupting the parent stack (esp.
	197	* if the parent returns from functions that called clone() and calls new
	198	* ones, before the child overflows its now old copies of its parent windows).
	199	* One solution is to spill windows to the parent stack, but that's fairly
	200	* involved. Much simpler to just not copy those live frames across.
5a0015d6 CZ	201	*/
5a0015d6 CZ	202
3306a726	203	int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
afa86fc4	204	unsigned long thread_fn_arg, struct task_struct *p)
5a0015d6	205	{
3306a726	206	struct pt_regs *childregs = task_pt_regs(p);
5a0015d6	207
39070cb8 CZ	208	#if (XTENSA_HAVE_COPROCESSORS \|\| XTENSA_HAVE_IO_PORTS)
	209	struct thread_info *ti;
	210	#endif
	211
5a0015d6	212	/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */
062b1c19 MF	213	SPILL_SLOT(childregs, 1) = (unsigned long)childregs;
062b1c19 MF	214	SPILL_SLOT(childregs, 0) = 0;
5a0015d6	215
5a0015d6	216	p->thread.sp = (unsigned long)childregs;
c658eac6	217
3306a726 MF	218	if (!(p->flags & PF_KTHREAD)) {
	219	struct pt_regs *regs = current_pt_regs();
	220	unsigned long usp = usp_thread_fn ?
	221	usp_thread_fn : regs->areg[1];
	222
	223	p->thread.ra = MAKE_RA_FOR_CALL(
	224	(unsigned long)ret_from_fork, 0x1);
5a0015d6	225
3306a726 MF	226	/* This does not copy all the regs.
	227	* In a bout of brilliance or madness,
	228	* ARs beyond a0-a15 exist past the end of the struct.
	229	*/
	230	childregs = regs;
5a0015d6	231	childregs->areg[1] = usp;
3306a726	232	childregs->areg[2] = 0;
6ebe7da2 CZ	233
	234	/* When sharing memory with the parent thread, the child
	235	usually starts on a pristine stack, so we have to reset
	236	windowbase, windowstart and wmask.
	237	(Note that such a new thread is required to always create
	238	an initial call4 frame)
	239	The exception is vfork, where the new thread continues to
	240	run on the parent's stack until it calls execve. This could
	241	be a call8 or call12, which requires a legal stack frame
	242	of the previous caller for the overflow handlers to work.
	243	(Note that it's always legal to overflow live registers).
	244	In this case, ensure to spill at least the stack pointer
	245	of that frame. */
	246
84ed3053	247	if (clone_flags & CLONE_VM) {
6ebe7da2 CZ	248	/* check that caller window is live and same stack */
	249	int len = childregs->wmask & ~0xf;
	250	if (regs->areg[1] == usp && len != 0) {
	251	int callinc = (regs->areg[0] >> 30) & 3;
	252	int caller_ars = XCHAL_NUM_AREGS - callinc * 4;
	253	put_user(regs->areg[caller_ars+1],
	254	(unsigned __user*)(usp - 12));
	255	}
	256	childregs->wmask = 1;
	257	childregs->windowstart = 1;
	258	childregs->windowbase = 0;
84ed3053 MG	259	} else {
	260	int len = childregs->wmask & ~0xf;
	261	memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4],
	262	&regs->areg[XCHAL_NUM_AREGS - len/4], len);
	263	}
c50842df CZ	264
c50842df CZ	265	/* The thread pointer is passed in the '4th argument' (= a5) */
5a0015d6	266	if (clone_flags & CLONE_SETTLS)
c50842df	267	childregs->threadptr = childregs->areg[5];
5a0015d6	268	} else {
3306a726 MF	269	p->thread.ra = MAKE_RA_FOR_CALL(
	270	(unsigned long)ret_from_kernel_thread, 1);
	271
	272	/* pass parameters to ret_from_kernel_thread:
	273	* a2 = thread_fn, a3 = thread_fn arg
	274	*/
062b1c19 MF	275	SPILL_SLOT(childregs, 3) = thread_fn_arg;
062b1c19 MF	276	SPILL_SLOT(childregs, 2) = usp_thread_fn;
3306a726 MF	277
	278	/* Childregs are only used when we're going to userspace
	279	* in which case start_thread will set them up.
	280	*/
5a0015d6	281	}
c658eac6 CZ	282
	283	#if (XTENSA_HAVE_COPROCESSORS \|\| XTENSA_HAVE_IO_PORTS)
	284	ti = task_thread_info(p);
	285	ti->cpenable = 0;
	286	#endif
	287
c91e02bd MF	288	clear_ptrace_hw_breakpoint(p);
c91e02bd MF	289
5a0015d6 CZ	290	return 0;
	291	}
	292
	293
5a0015d6 CZ	294	/*
	295	* These bracket the sleeping functions..
	296	*/
	297
	298	unsigned long get_wchan(struct task_struct *p)
	299	{
	300	unsigned long sp, pc;
04fe6faf	301	unsigned long stack_page = (unsigned long) task_stack_page(p);
5a0015d6 CZ	302	int count = 0;
	303
	304	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	305	return 0;
	306
	307	sp = p->thread.sp;
	308	pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);
	309
	310	do {
	311	if (sp < stack_page + sizeof(struct task_struct) \|\|
	312	sp >= (stack_page + THREAD_SIZE) \|\|
	313	pc == 0)
	314	return 0;
	315	if (!in_sched_functions(pc))
	316	return pc;
	317
	318	/* Stack layout: sp-4: ra, sp-3: sp' */
	319
	320	pc = MAKE_PC_FROM_RA((unsigned long)sp - 4, sp);
	321	sp = (unsigned long )sp - 3;
	322	} while (count++ < 16);
	323	return 0;
	324	}
	325
	326	/*
5a0015d6 CZ	327	* xtensa_gregset_t and 'struct pt_regs' are vastly different formats
	328	* of processor registers. Besides different ordering,
	329	* xtensa_gregset_t contains non-live register information that
	330	* 'struct pt_regs' does not. Exception handling (primarily) uses
	331	* 'struct pt_regs'. Core files and ptrace use xtensa_gregset_t.
	332	*
	333	*/
	334
c658eac6	335	void xtensa_elf_core_copy_regs (xtensa_gregset_t elfregs, struct pt_regs regs)
5a0015d6	336	{
c658eac6 CZ	337	unsigned long wb, ws, wm;
	338	int live, last;
	339
	340	wb = regs->windowbase;
	341	ws = regs->windowstart;
	342	wm = regs->wmask;
	343	ws = ((ws >> wb) \| (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1);
	344
	345	/* Don't leak any random bits. */
	346
688bb415	347	memset(elfregs, 0, sizeof(*elfregs));
c658eac6	348
5a0015d6 CZ	349	/* Note: PS.EXCM is not set while user task is running; its
	350	* being set in regs->ps is for exception handling convenience.
	351	*/
	352
	353	elfregs->pc = regs->pc;
173d6681	354	elfregs->ps = (regs->ps & ~(1 << PS_EXCM_BIT));
5a0015d6 CZ	355	elfregs->lbeg = regs->lbeg;
	356	elfregs->lend = regs->lend;
	357	elfregs->lcount = regs->lcount;
	358	elfregs->sar = regs->sar;
c658eac6	359	elfregs->windowstart = ws;
5a0015d6	360
c658eac6 CZ	361	live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
	362	last = XCHAL_NUM_AREGS - (wm >> 4) * 4;
	363	memcpy(elfregs->a, regs->areg, live * 4);
	364	memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16);
5a0015d6 CZ	365	}
5a0015d6 CZ	366
c658eac6	367	int dump_fpu(void)
5a0015d6	368	{
5a0015d6 CZ	369	return 0;
5a0015d6 CZ	370	}