xref: /freebsd/sys/arm/arm/machdep.c (revision 5d3e7166)
1 /*	$NetBSD: arm32_machdep.c,v 1.44 2004/03/24 15:34:47 atatat Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-4-Clause
5  *
6  * Copyright (c) 2004 Olivier Houchard
7  * Copyright (c) 1994-1998 Mark Brinicombe.
8  * Copyright (c) 1994 Brini.
9  * All rights reserved.
10  *
11  * This code is derived from software written for Brini by Mark Brinicombe
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgement:
23  *	This product includes software developed by Mark Brinicombe
24  *	for the NetBSD Project.
25  * 4. The name of the company nor the name of the author may be used to
26  *    endorse or promote products derived from this software without specific
27  *    prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
30  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
31  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32  * IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  * Machine dependent functions for kernel setup
42  *
43  * Created      : 17/09/94
44  * Updated	: 18/04/01 updated for new wscons
45  */
46 
47 #include "opt_ddb.h"
48 #include "opt_kstack_pages.h"
49 #include "opt_platform.h"
50 #include "opt_sched.h"
51 
52 #include <sys/cdefs.h>
53 __FBSDID("$FreeBSD$");
54 
55 #include <sys/param.h>
56 #include <sys/buf.h>
57 #include <sys/bus.h>
58 #include <sys/cons.h>
59 #include <sys/cpu.h>
60 #include <sys/devmap.h>
61 #include <sys/efi.h>
62 #include <sys/imgact.h>
63 #include <sys/kdb.h>
64 #include <sys/kernel.h>
65 #include <sys/ktr.h>
66 #include <sys/linker.h>
67 #include <sys/msgbuf.h>
68 #include <sys/physmem.h>
69 #include <sys/reboot.h>
70 #include <sys/rwlock.h>
71 #include <sys/sched.h>
72 #include <sys/syscallsubr.h>
73 #include <sys/sysent.h>
74 #include <sys/sysproto.h>
75 #include <sys/vmmeter.h>
76 
77 #include <vm/vm_object.h>
78 #include <vm/vm_page.h>
79 #include <vm/vm_pager.h>
80 
81 #include <machine/asm.h>
82 #include <machine/debug_monitor.h>
83 #include <machine/machdep.h>
84 #include <machine/metadata.h>
85 #include <machine/pcb.h>
86 #include <machine/platform.h>
87 #include <machine/sysarch.h>
88 #include <machine/undefined.h>
89 #include <machine/vfp.h>
90 #include <machine/vmparam.h>
91 
92 #ifdef FDT
93 #include <dev/fdt/fdt_common.h>
94 #include <machine/ofw_machdep.h>
95 #endif
96 
97 #ifdef DEBUG
98 #define	debugf(fmt, args...) printf(fmt, ##args)
99 #else
100 #define	debugf(fmt, args...)
101 #endif
102 
103 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
104     defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) || \
105     defined(COMPAT_FREEBSD9)
106 #error FreeBSD/arm doesn't provide compatibility with releases prior to 10
107 #endif
108 
109 
110 #if __ARM_ARCH < 6
111 #error FreeBSD requires ARMv6 or later
112 #endif
113 
114 struct pcpu __pcpu[MAXCPU];
115 struct pcpu *pcpup = &__pcpu[0];
116 
117 static struct trapframe proc0_tf;
118 uint32_t cpu_reset_address = 0;
119 int cold = 1;
120 vm_offset_t vector_page;
121 
122 /* The address at which the kernel was loaded.  Set early in initarm(). */
123 vm_paddr_t arm_physmem_kernaddr;
124 
125 extern int *end;
126 
127 #ifdef FDT
128 vm_paddr_t pmap_pa;
129 vm_offset_t systempage;
130 vm_offset_t irqstack;
131 vm_offset_t undstack;
132 vm_offset_t abtstack;
133 #endif /* FDT */
134 
135 #ifdef PLATFORM
136 static delay_func *delay_impl;
137 static void *delay_arg;
138 #endif
139 
140 struct kva_md_info kmi;
141 /*
142  * arm32_vector_init:
143  *
144  *	Initialize the vector page, and select whether or not to
145  *	relocate the vectors.
146  *
147  *	NOTE: We expect the vector page to be mapped at its expected
148  *	destination.
149  */
150 
151 extern unsigned int page0[], page0_data[];
152 void
153 arm_vector_init(vm_offset_t va, int which)
154 {
155 	unsigned int *vectors = (int *) va;
156 	unsigned int *vectors_data = vectors + (page0_data - page0);
157 	int vec;
158 
159 	/*
160 	 * Loop through the vectors we're taking over, and copy the
161 	 * vector's insn and data word.
162 	 */
163 	for (vec = 0; vec < ARM_NVEC; vec++) {
164 		if ((which & (1 << vec)) == 0) {
165 			/* Don't want to take over this vector. */
166 			continue;
167 		}
168 		vectors[vec] = page0[vec];
169 		vectors_data[vec] = page0_data[vec];
170 	}
171 
172 	/* Now sync the vectors. */
173 	icache_sync(va, (ARM_NVEC * 2) * sizeof(u_int));
174 
175 	vector_page = va;
176 }
177 
178 static void
179 cpu_startup(void *dummy)
180 {
181 	struct pcb *pcb = thread0.td_pcb;
182 	const unsigned int mbyte = 1024 * 1024;
183 
184 	identify_arm_cpu();
185 
186 	vm_ksubmap_init(&kmi);
187 
188 	/*
189 	 * Display the RAM layout.
190 	 */
191 	printf("real memory  = %ju (%ju MB)\n",
192 	    (uintmax_t)arm32_ptob(realmem),
193 	    (uintmax_t)arm32_ptob(realmem) / mbyte);
194 	printf("avail memory = %ju (%ju MB)\n",
195 	    (uintmax_t)arm32_ptob(vm_free_count()),
196 	    (uintmax_t)arm32_ptob(vm_free_count()) / mbyte);
197 	if (bootverbose) {
198 		physmem_print_tables();
199 		devmap_print_table();
200 	}
201 
202 	bufinit();
203 	vm_pager_bufferinit();
204 	pcb->pcb_regs.sf_sp = (u_int)thread0.td_kstack +
205 	    USPACE_SVC_STACK_TOP;
206 	pmap_set_pcb_pagedir(kernel_pmap, pcb);
207 }
208 
209 SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL);
210 
211 /*
212  * Flush the D-cache for non-DMA I/O so that the I-cache can
213  * be made coherent later.
214  */
215 void
216 cpu_flush_dcache(void *ptr, size_t len)
217 {
218 
219 	dcache_wb_poc((vm_offset_t)ptr, (vm_paddr_t)vtophys(ptr), len);
220 }
221 
222 /* Get current clock frequency for the given cpu id. */
223 int
224 cpu_est_clockrate(int cpu_id, uint64_t *rate)
225 {
226 	struct pcpu *pc;
227 
228 	pc = pcpu_find(cpu_id);
229 	if (pc == NULL || rate == NULL)
230 		return (EINVAL);
231 
232 	if (pc->pc_clock == 0)
233 		return (EOPNOTSUPP);
234 
235 	*rate = pc->pc_clock;
236 
237 	return (0);
238 }
239 
240 void
241 cpu_idle(int busy)
242 {
243 
244 	CTR2(KTR_SPARE2, "cpu_idle(%d) at %d", busy, curcpu);
245 	spinlock_enter();
246 	if (!busy)
247 		cpu_idleclock();
248 	if (!sched_runnable())
249 		cpu_sleep(0);
250 	if (!busy)
251 		cpu_activeclock();
252 	spinlock_exit();
253 	CTR2(KTR_SPARE2, "cpu_idle(%d) at %d done", busy, curcpu);
254 }
255 
256 int
257 cpu_idle_wakeup(int cpu)
258 {
259 
260 	return (0);
261 }
262 
263 void
264 cpu_initclocks(void)
265 {
266 
267 #ifdef SMP
268 	if (PCPU_GET(cpuid) == 0)
269 		cpu_initclocks_bsp();
270 	else
271 		cpu_initclocks_ap();
272 #else
273 	cpu_initclocks_bsp();
274 #endif
275 }
276 
277 #ifdef PLATFORM
278 void
279 arm_set_delay(delay_func *impl, void *arg)
280 {
281 
282 	KASSERT(impl != NULL, ("No DELAY implementation"));
283 	delay_impl = impl;
284 	delay_arg = arg;
285 }
286 
287 void
288 DELAY(int usec)
289 {
290 
291 	TSENTER();
292 	delay_impl(usec, delay_arg);
293 	TSEXIT();
294 }
295 #endif
296 
297 void
298 cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
299 {
300 
301 	pcpu->pc_mpidr = 0xffffffff;
302 }
303 
304 void
305 spinlock_enter(void)
306 {
307 	struct thread *td;
308 	register_t cspr;
309 
310 	td = curthread;
311 	if (td->td_md.md_spinlock_count == 0) {
312 		cspr = disable_interrupts(PSR_I | PSR_F);
313 		td->td_md.md_spinlock_count = 1;
314 		td->td_md.md_saved_cspr = cspr;
315 		critical_enter();
316 	} else
317 		td->td_md.md_spinlock_count++;
318 }
319 
320 void
321 spinlock_exit(void)
322 {
323 	struct thread *td;
324 	register_t cspr;
325 
326 	td = curthread;
327 	cspr = td->td_md.md_saved_cspr;
328 	td->td_md.md_spinlock_count--;
329 	if (td->td_md.md_spinlock_count == 0) {
330 		critical_exit();
331 		restore_interrupts(cspr);
332 	}
333 }
334 
335 /*
336  * Construct a PCB from a trapframe. This is called from kdb_trap() where
337  * we want to start a backtrace from the function that caused us to enter
338  * the debugger. We have the context in the trapframe, but base the trace
339  * on the PCB. The PCB doesn't have to be perfect, as long as it contains
340  * enough for a backtrace.
341  */
342 void
343 makectx(struct trapframe *tf, struct pcb *pcb)
344 {
345 	pcb->pcb_regs.sf_r4 = tf->tf_r4;
346 	pcb->pcb_regs.sf_r5 = tf->tf_r5;
347 	pcb->pcb_regs.sf_r6 = tf->tf_r6;
348 	pcb->pcb_regs.sf_r7 = tf->tf_r7;
349 	pcb->pcb_regs.sf_r8 = tf->tf_r8;
350 	pcb->pcb_regs.sf_r9 = tf->tf_r9;
351 	pcb->pcb_regs.sf_r10 = tf->tf_r10;
352 	pcb->pcb_regs.sf_r11 = tf->tf_r11;
353 	pcb->pcb_regs.sf_r12 = tf->tf_r12;
354 	pcb->pcb_regs.sf_pc = tf->tf_pc;
355 	pcb->pcb_regs.sf_lr = tf->tf_usr_lr;
356 	pcb->pcb_regs.sf_sp = tf->tf_usr_sp;
357 }
358 
359 void
360 pcpu0_init(void)
361 {
362 	set_curthread(&thread0);
363 	pcpu_init(pcpup, 0, sizeof(struct pcpu));
364 	pcpup->pc_mpidr = cp15_mpidr_get() & 0xFFFFFF;
365 	PCPU_SET(curthread, &thread0);
366 }
367 
368 /*
369  * Initialize proc0
370  */
371 void
372 init_proc0(vm_offset_t kstack)
373 {
374 	proc_linkup0(&proc0, &thread0);
375 	thread0.td_kstack = kstack;
376 	thread0.td_kstack_pages = kstack_pages;
377 	thread0.td_pcb = (struct pcb *)(thread0.td_kstack +
378 	    thread0.td_kstack_pages * PAGE_SIZE) - 1;
379 	thread0.td_pcb->pcb_flags = 0;
380 	thread0.td_pcb->pcb_fpflags = 0;
381 	thread0.td_pcb->pcb_vfpcpu = -1;
382 	thread0.td_pcb->pcb_vfpstate.fpscr = VFPSCR_DN;
383 	thread0.td_pcb->pcb_vfpsaved = &thread0.td_pcb->pcb_vfpstate;
384 	thread0.td_frame = &proc0_tf;
385 	pcpup->pc_curpcb = thread0.td_pcb;
386 }
387 
388 void
389 set_stackptrs(int cpu)
390 {
391 
392 	set_stackptr(PSR_IRQ32_MODE,
393 	    irqstack + ((IRQ_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
394 	set_stackptr(PSR_ABT32_MODE,
395 	    abtstack + ((ABT_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
396 	set_stackptr(PSR_UND32_MODE,
397 	    undstack + ((UND_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
398 }
399 
400 static void
401 arm_kdb_init(void)
402 {
403 
404 	kdb_init();
405 #ifdef KDB
406 	if (boothowto & RB_KDB)
407 		kdb_enter(KDB_WHY_BOOTFLAGS, "Boot flags requested debugger");
408 #endif
409 }
410 
411 #ifdef FDT
412 void *
413 initarm(struct arm_boot_params *abp)
414 {
415 	struct mem_region mem_regions[FDT_MEM_REGIONS];
416 	vm_paddr_t lastaddr;
417 	vm_offset_t dtbp, kernelstack, dpcpu;
418 	char *env;
419 	void *kmdp;
420 	int err_devmap, mem_regions_sz;
421 	phandle_t root;
422 	char dts_version[255];
423 #ifdef EFI
424 	struct efi_map_header *efihdr;
425 #endif
426 
427 	/* get last allocated physical address */
428 	arm_physmem_kernaddr = abp->abp_physaddr;
429 	lastaddr = parse_boot_param(abp) - KERNVIRTADDR + arm_physmem_kernaddr;
430 
431 	set_cpufuncs();
432 	cpuinfo_init();
433 
434 	/*
435 	 * Find the dtb passed in by the boot loader.
436 	 */
437 	kmdp = preload_search_by_type("elf kernel");
438 	dtbp = MD_FETCH(kmdp, MODINFOMD_DTBP, vm_offset_t);
439 #if defined(FDT_DTB_STATIC)
440 	/*
441 	 * In case the device tree blob was not retrieved (from metadata) try
442 	 * to use the statically embedded one.
443 	 */
444 	if (dtbp == (vm_offset_t)NULL)
445 		dtbp = (vm_offset_t)&fdt_static_dtb;
446 #endif
447 
448 	if (OF_install(OFW_FDT, 0) == FALSE)
449 		panic("Cannot install FDT");
450 
451 	if (OF_init((void *)dtbp) != 0)
452 		panic("OF_init failed with the found device tree");
453 
454 #if defined(LINUX_BOOT_ABI)
455 	arm_parse_fdt_bootargs();
456 #endif
457 
458 #ifdef EFI
459 	efihdr = (struct efi_map_header *)preload_search_info(kmdp,
460 	    MODINFO_METADATA | MODINFOMD_EFI_MAP);
461 	if (efihdr != NULL) {
462 		arm_add_efi_map_entries(efihdr, mem_regions, &mem_regions_sz);
463 	} else
464 #endif
465 	{
466 		/* Grab physical memory regions information from device tree. */
467 		if (fdt_get_mem_regions(mem_regions, &mem_regions_sz,NULL) != 0)
468 			panic("Cannot get physical memory regions");
469 	}
470 	physmem_hardware_regions(mem_regions, mem_regions_sz);
471 
472 	/* Grab reserved memory regions information from device tree. */
473 	if (fdt_get_reserved_regions(mem_regions, &mem_regions_sz) == 0)
474 		physmem_exclude_regions(mem_regions, mem_regions_sz,
475 		    EXFLAG_NODUMP | EXFLAG_NOALLOC);
476 
477 	/*
478 	 * Set TEX remapping registers.
479 	 * Setup kernel page tables and switch to kernel L1 page table.
480 	 */
481 	pmap_set_tex();
482 	pmap_bootstrap_prepare(lastaddr);
483 
484 	/*
485 	 * If EARLY_PRINTF support is enabled, we need to re-establish the
486 	 * mapping after pmap_bootstrap_prepare() switches to new page tables.
487 	 * Note that we can only do the remapping if the VA is outside the
488 	 * kernel, now that we have real virtual (not VA=PA) mappings in effect.
489 	 * Early printf does not work between the time pmap_set_tex() does
490 	 * cp15_prrr_set() and this code remaps the VA.
491 	 */
492 #if defined(EARLY_PRINTF) && defined(SOCDEV_PA) && defined(SOCDEV_VA) && SOCDEV_VA < KERNBASE
493 	pmap_preboot_map_attr(SOCDEV_PA, SOCDEV_VA, 1024 * 1024,
494 	    VM_PROT_READ | VM_PROT_WRITE, VM_MEMATTR_DEVICE);
495 #endif
496 
497 	/*
498 	 * Now that proper page tables are installed, call cpu_setup() to enable
499 	 * instruction and data caches and other chip-specific features.
500 	 */
501 	cpu_setup();
502 
503 	/* Platform-specific initialisation */
504 	platform_probe_and_attach();
505 	pcpu0_init();
506 
507 	/* Do basic tuning, hz etc */
508 	init_param1();
509 
510 	/*
511 	 * Allocate a page for the system page mapped to 0xffff0000
512 	 * This page will just contain the system vectors and can be
513 	 * shared by all processes.
514 	 */
515 	systempage = pmap_preboot_get_pages(1);
516 
517 	/* Map the vector page. */
518 	pmap_preboot_map_pages(systempage, ARM_VECTORS_HIGH,  1);
519 	if (virtual_end >= ARM_VECTORS_HIGH)
520 		virtual_end = ARM_VECTORS_HIGH - 1;
521 
522 	/* Allocate dynamic per-cpu area. */
523 	dpcpu = pmap_preboot_get_vpages(DPCPU_SIZE / PAGE_SIZE);
524 	dpcpu_init((void *)dpcpu, 0);
525 
526 	/* Allocate stacks for all modes */
527 	irqstack    = pmap_preboot_get_vpages(IRQ_STACK_SIZE * MAXCPU);
528 	abtstack    = pmap_preboot_get_vpages(ABT_STACK_SIZE * MAXCPU);
529 	undstack    = pmap_preboot_get_vpages(UND_STACK_SIZE * MAXCPU );
530 	kernelstack = pmap_preboot_get_vpages(kstack_pages);
531 
532 	/* Allocate message buffer. */
533 	msgbufp = (void *)pmap_preboot_get_vpages(
534 	    round_page(msgbufsize) / PAGE_SIZE);
535 
536 	/*
537 	 * Pages were allocated during the secondary bootstrap for the
538 	 * stacks for different CPU modes.
539 	 * We must now set the r13 registers in the different CPU modes to
540 	 * point to these stacks.
541 	 * Since the ARM stacks use STMFD etc. we must set r13 to the top end
542 	 * of the stack memory.
543 	 */
544 	set_stackptrs(0);
545 	mutex_init();
546 
547 	/* Establish static device mappings. */
548 	err_devmap = platform_devmap_init();
549 	devmap_bootstrap(0, NULL);
550 	vm_max_kernel_address = platform_lastaddr();
551 
552 	/*
553 	 * Only after the SOC registers block is mapped we can perform device
554 	 * tree fixups, as they may attempt to read parameters from hardware.
555 	 */
556 	OF_interpret("perform-fixup", 0);
557 	platform_gpio_init();
558 	cninit();
559 
560 	/*
561 	 * If we made a mapping for EARLY_PRINTF after pmap_bootstrap_prepare(),
562 	 * undo it now that the normal console printf works.
563 	 */
564 #if defined(EARLY_PRINTF) && defined(SOCDEV_PA) && defined(SOCDEV_VA) && SOCDEV_VA < KERNBASE
565 	pmap_kremove(SOCDEV_VA);
566 #endif
567 
568 	debugf("initarm: console initialized\n");
569 	debugf(" arg1 kmdp = 0x%08x\n", (uint32_t)kmdp);
570 	debugf(" boothowto = 0x%08x\n", boothowto);
571 	debugf(" dtbp = 0x%08x\n", (uint32_t)dtbp);
572 	debugf(" lastaddr1: 0x%08x\n", lastaddr);
573 	arm_print_kenv();
574 
575 	env = kern_getenv("kernelname");
576 	if (env != NULL)
577 		strlcpy(kernelname, env, sizeof(kernelname));
578 
579 	if (err_devmap != 0)
580 		printf("WARNING: could not fully configure devmap, error=%d\n",
581 		    err_devmap);
582 
583 	platform_late_init();
584 
585 	root = OF_finddevice("/");
586 	if (OF_getprop(root, "freebsd,dts-version", dts_version, sizeof(dts_version)) > 0) {
587 		if (strcmp(LINUX_DTS_VERSION, dts_version) != 0)
588 			printf("WARNING: DTB version is %s while kernel expects %s, "
589 			    "please update the DTB in the ESP\n",
590 			    dts_version,
591 			    LINUX_DTS_VERSION);
592 	} else {
593 		printf("WARNING: Cannot find freebsd,dts-version property, "
594 		    "cannot check DTB compliance\n");
595 	}
596 
597 	/*
598 	 * We must now clean the cache again....
599 	 * Cleaning may be done by reading new data to displace any
600 	 * dirty data in the cache. This will have happened in cpu_setttb()
601 	 * but since we are boot strapping the addresses used for the read
602 	 * may have just been remapped and thus the cache could be out
603 	 * of sync. A re-clean after the switch will cure this.
604 	 * After booting there are no gross relocations of the kernel thus
605 	 * this problem will not occur after initarm().
606 	 */
607 	/* Set stack for exception handlers */
608 	undefined_init();
609 	init_proc0(kernelstack);
610 	arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
611 	enable_interrupts(PSR_A);
612 	pmap_bootstrap(0);
613 
614 	/* Exclude the kernel (and all the things we allocated which immediately
615 	 * follow the kernel) from the VM allocation pool but not from crash
616 	 * dumps.  virtual_avail is a global variable which tracks the kva we've
617 	 * "allocated" while setting up pmaps.
618 	 *
619 	 * Prepare the list of physical memory available to the vm subsystem.
620 	 */
621 	physmem_exclude_region(abp->abp_physaddr,
622 		pmap_preboot_get_pages(0) - abp->abp_physaddr, EXFLAG_NOALLOC);
623 	physmem_init_kernel_globals();
624 
625 	init_param2(physmem);
626 	/* Init message buffer. */
627 	msgbufinit(msgbufp, msgbufsize);
628 	dbg_monitor_init();
629 	arm_kdb_init();
630 	/* Apply possible BP hardening. */
631 	cpuinfo_init_bp_hardening();
632 	return ((void *)STACKALIGN(thread0.td_pcb));
633 
634 }
635 #endif /* FDT */
636