[linux-block.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/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);


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