machdep.c revision 225617
1/*	$NetBSD: arm32_machdep.c,v 1.44 2004/03/24 15:34:47 atatat Exp $	*/
2
3/*-
4 * Copyright (c) 2004 Olivier Houchard
5 * Copyright (c) 1994-1998 Mark Brinicombe.
6 * Copyright (c) 1994 Brini.
7 * All rights reserved.
8 *
9 * This code is derived from software written for Brini by Mark Brinicombe
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by Mark Brinicombe
22 *	for the NetBSD Project.
23 * 4. The name of the company nor the name of the author may be used to
24 *    endorse or promote products derived from this software without specific
25 *    prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
28 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
29 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30 * IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
31 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
32 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
33 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * Machine dependant functions for kernel setup
40 *
41 * Created      : 17/09/94
42 * Updated	: 18/04/01 updated for new wscons
43 */
44
45#include "opt_compat.h"
46#include "opt_ddb.h"
47
48#include <sys/cdefs.h>
49__FBSDID("$FreeBSD: head/sys/arm/arm/machdep.c 225617 2011-09-16 13:58:51Z kmacy $");
50
51#include <sys/param.h>
52#include <sys/proc.h>
53#include <sys/systm.h>
54#include <sys/bio.h>
55#include <sys/buf.h>
56#include <sys/bus.h>
57#include <sys/cons.h>
58#include <sys/cpu.h>
59#include <sys/exec.h>
60#include <sys/imgact.h>
61#include <sys/kernel.h>
62#include <sys/ktr.h>
63#include <sys/linker.h>
64#include <sys/lock.h>
65#include <sys/malloc.h>
66#include <sys/mutex.h>
67#include <sys/pcpu.h>
68#include <sys/ptrace.h>
69#include <sys/signalvar.h>
70#include <sys/syscallsubr.h>
71#include <sys/sysent.h>
72#include <sys/sysproto.h>
73#include <sys/uio.h>
74
75#include <vm/vm.h>
76#include <vm/pmap.h>
77#include <vm/vm_map.h>
78#include <vm/vm_object.h>
79#include <vm/vm_page.h>
80#include <vm/vm_pager.h>
81
82#include <machine/armreg.h>
83#include <machine/cpu.h>
84#include <machine/machdep.h>
85#include <machine/md_var.h>
86#include <machine/metadata.h>
87#include <machine/pcb.h>
88#include <machine/pmap.h>
89#include <machine/reg.h>
90#include <machine/trap.h>
91#include <machine/undefined.h>
92#include <machine/vmparam.h>
93#include <machine/sysarch.h>
94
95uint32_t cpu_reset_address = 0;
96int cold = 1;
97vm_offset_t vector_page;
98
99long realmem = 0;
100
101int (*_arm_memcpy)(void *, void *, int, int) = NULL;
102int (*_arm_bzero)(void *, int, int) = NULL;
103int _min_memcpy_size = 0;
104int _min_bzero_size = 0;
105
106extern int *end;
107#ifdef DDB
108extern vm_offset_t ksym_start, ksym_end;
109#endif
110
111void
112sendsig(catcher, ksi, mask)
113	sig_t catcher;
114	ksiginfo_t *ksi;
115	sigset_t *mask;
116{
117	struct thread *td;
118	struct proc *p;
119	struct trapframe *tf;
120	struct sigframe *fp, frame;
121	struct sigacts *psp;
122	int onstack;
123	int sig;
124	int code;
125
126	td = curthread;
127	p = td->td_proc;
128	PROC_LOCK_ASSERT(p, MA_OWNED);
129	sig = ksi->ksi_signo;
130	code = ksi->ksi_code;
131	psp = p->p_sigacts;
132	mtx_assert(&psp->ps_mtx, MA_OWNED);
133	tf = td->td_frame;
134	onstack = sigonstack(tf->tf_usr_sp);
135
136	CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
137	    catcher, sig);
138
139	/* Allocate and validate space for the signal handler context. */
140	if ((td->td_flags & TDP_ALTSTACK) != 0 && !(onstack) &&
141	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
142		fp = (struct sigframe *)(td->td_sigstk.ss_sp +
143		    td->td_sigstk.ss_size);
144#if defined(COMPAT_43)
145		td->td_sigstk.ss_flags |= SS_ONSTACK;
146#endif
147	} else
148		fp = (struct sigframe *)td->td_frame->tf_usr_sp;
149
150	/* make room on the stack */
151	fp--;
152
153	/* make the stack aligned */
154	fp = (struct sigframe *)STACKALIGN(fp);
155	/* Populate the siginfo frame. */
156	get_mcontext(td, &frame.sf_uc.uc_mcontext, 0);
157	frame.sf_si = ksi->ksi_info;
158	frame.sf_uc.uc_sigmask = *mask;
159	frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK )
160	    ? ((onstack) ? SS_ONSTACK : 0) : SS_DISABLE;
161	frame.sf_uc.uc_stack = td->td_sigstk;
162	mtx_unlock(&psp->ps_mtx);
163	PROC_UNLOCK(td->td_proc);
164
165	/* Copy the sigframe out to the user's stack. */
166	if (copyout(&frame, fp, sizeof(*fp)) != 0) {
167		/* Process has trashed its stack. Kill it. */
168		CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
169		PROC_LOCK(p);
170		sigexit(td, SIGILL);
171	}
172
173	/* Translate the signal if appropriate. */
174	if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize)
175		sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
176
177	/*
178	 * Build context to run handler in.  We invoke the handler
179	 * directly, only returning via the trampoline.  Note the
180	 * trampoline version numbers are coordinated with machine-
181	 * dependent code in libc.
182	 */
183
184	tf->tf_r0 = sig;
185	tf->tf_r1 = (register_t)&fp->sf_si;
186	tf->tf_r2 = (register_t)&fp->sf_uc;
187
188	/* the trampoline uses r5 as the uc address */
189	tf->tf_r5 = (register_t)&fp->sf_uc;
190	tf->tf_pc = (register_t)catcher;
191	tf->tf_usr_sp = (register_t)fp;
192	tf->tf_usr_lr = (register_t)(PS_STRINGS - *(p->p_sysent->sv_szsigcode));
193
194	CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_usr_lr,
195	    tf->tf_usr_sp);
196
197	PROC_LOCK(p);
198	mtx_lock(&psp->ps_mtx);
199}
200
201struct kva_md_info kmi;
202
203/*
204 * arm32_vector_init:
205 *
206 *	Initialize the vector page, and select whether or not to
207 *	relocate the vectors.
208 *
209 *	NOTE: We expect the vector page to be mapped at its expected
210 *	destination.
211 */
212
213extern unsigned int page0[], page0_data[];
214void
215arm_vector_init(vm_offset_t va, int which)
216{
217	unsigned int *vectors = (int *) va;
218	unsigned int *vectors_data = vectors + (page0_data - page0);
219	int vec;
220
221	/*
222	 * Loop through the vectors we're taking over, and copy the
223	 * vector's insn and data word.
224	 */
225	for (vec = 0; vec < ARM_NVEC; vec++) {
226		if ((which & (1 << vec)) == 0) {
227			/* Don't want to take over this vector. */
228			continue;
229		}
230		vectors[vec] = page0[vec];
231		vectors_data[vec] = page0_data[vec];
232	}
233
234	/* Now sync the vectors. */
235	cpu_icache_sync_range(va, (ARM_NVEC * 2) * sizeof(u_int));
236
237	vector_page = va;
238
239	if (va == ARM_VECTORS_HIGH) {
240		/*
241		 * Assume the MD caller knows what it's doing here, and
242		 * really does want the vector page relocated.
243		 *
244		 * Note: This has to be done here (and not just in
245		 * cpu_setup()) because the vector page needs to be
246		 * accessible *before* cpu_startup() is called.
247		 * Think ddb(9) ...
248		 *
249		 * NOTE: If the CPU control register is not readable,
250		 * this will totally fail!  We'll just assume that
251		 * any system that has high vector support has a
252		 * readable CPU control register, for now.  If we
253		 * ever encounter one that does not, we'll have to
254		 * rethink this.
255		 */
256		cpu_control(CPU_CONTROL_VECRELOC, CPU_CONTROL_VECRELOC);
257	}
258}
259
260static void
261cpu_startup(void *dummy)
262{
263	struct pcb *pcb = thread0.td_pcb;
264#ifndef ARM_CACHE_LOCK_ENABLE
265	vm_page_t m;
266#endif
267
268	cpu_setup("");
269	identify_arm_cpu();
270
271	printf("real memory  = %ju (%ju MB)\n", (uintmax_t)ptoa(physmem),
272	    (uintmax_t)ptoa(physmem) / 1048576);
273	realmem = physmem;
274
275	/*
276	 * Display the RAM layout.
277	 */
278	if (bootverbose) {
279		int indx;
280
281		printf("Physical memory chunk(s):\n");
282		for (indx = 0; phys_avail[indx + 1] != 0; indx += 2) {
283			vm_paddr_t size;
284
285			size = phys_avail[indx + 1] - phys_avail[indx];
286			printf("%#08jx - %#08jx, %ju bytes (%ju pages)\n",
287			    (uintmax_t)phys_avail[indx],
288			    (uintmax_t)phys_avail[indx + 1] - 1,
289			    (uintmax_t)size, (uintmax_t)size / PAGE_SIZE);
290		}
291	}
292
293	vm_ksubmap_init(&kmi);
294
295	printf("avail memory = %ju (%ju MB)\n",
296	    (uintmax_t)ptoa(cnt.v_free_count),
297	    (uintmax_t)ptoa(cnt.v_free_count) / 1048576);
298
299	bufinit();
300	vm_pager_bufferinit();
301	pcb->un_32.pcb32_und_sp = (u_int)thread0.td_kstack +
302	    USPACE_UNDEF_STACK_TOP;
303	pcb->un_32.pcb32_sp = (u_int)thread0.td_kstack +
304	    USPACE_SVC_STACK_TOP;
305	vector_page_setprot(VM_PROT_READ);
306	pmap_set_pcb_pagedir(pmap_kernel(), pcb);
307	pmap_postinit();
308#ifdef ARM_CACHE_LOCK_ENABLE
309	pmap_kenter_user(ARM_TP_ADDRESS, ARM_TP_ADDRESS);
310	arm_lock_cache_line(ARM_TP_ADDRESS);
311#else
312	m = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ | VM_ALLOC_ZERO);
313	pmap_kenter_user(ARM_TP_ADDRESS, VM_PAGE_TO_PHYS(m));
314#endif
315}
316
317SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL);
318
319/*
320 * Flush the D-cache for non-DMA I/O so that the I-cache can
321 * be made coherent later.
322 */
323void
324cpu_flush_dcache(void *ptr, size_t len)
325{
326
327	cpu_dcache_wb_range((uintptr_t)ptr, len);
328	cpu_l2cache_wb_range((uintptr_t)ptr, len);
329}
330
331/* Get current clock frequency for the given cpu id. */
332int
333cpu_est_clockrate(int cpu_id, uint64_t *rate)
334{
335
336	return (ENXIO);
337}
338
339void
340cpu_idle(int busy)
341{
342	cpu_sleep(0);
343}
344
345int
346cpu_idle_wakeup(int cpu)
347{
348
349	return (0);
350}
351
352int
353fill_regs(struct thread *td, struct reg *regs)
354{
355	struct trapframe *tf = td->td_frame;
356	bcopy(&tf->tf_r0, regs->r, sizeof(regs->r));
357	regs->r_sp = tf->tf_usr_sp;
358	regs->r_lr = tf->tf_usr_lr;
359	regs->r_pc = tf->tf_pc;
360	regs->r_cpsr = tf->tf_spsr;
361	return (0);
362}
363int
364fill_fpregs(struct thread *td, struct fpreg *regs)
365{
366	bzero(regs, sizeof(*regs));
367	return (0);
368}
369
370int
371set_regs(struct thread *td, struct reg *regs)
372{
373	struct trapframe *tf = td->td_frame;
374
375	bcopy(regs->r, &tf->tf_r0, sizeof(regs->r));
376	tf->tf_usr_sp = regs->r_sp;
377	tf->tf_usr_lr = regs->r_lr;
378	tf->tf_pc = regs->r_pc;
379	tf->tf_spsr &=  ~PSR_FLAGS;
380	tf->tf_spsr |= regs->r_cpsr & PSR_FLAGS;
381	return (0);
382}
383
384int
385set_fpregs(struct thread *td, struct fpreg *regs)
386{
387	return (0);
388}
389
390int
391fill_dbregs(struct thread *td, struct dbreg *regs)
392{
393	return (0);
394}
395int
396set_dbregs(struct thread *td, struct dbreg *regs)
397{
398	return (0);
399}
400
401
402static int
403ptrace_read_int(struct thread *td, vm_offset_t addr, u_int32_t *v)
404{
405	struct iovec iov;
406	struct uio uio;
407
408	PROC_LOCK_ASSERT(td->td_proc, MA_NOTOWNED);
409	iov.iov_base = (caddr_t) v;
410	iov.iov_len = sizeof(u_int32_t);
411	uio.uio_iov = &iov;
412	uio.uio_iovcnt = 1;
413	uio.uio_offset = (off_t)addr;
414	uio.uio_resid = sizeof(u_int32_t);
415	uio.uio_segflg = UIO_SYSSPACE;
416	uio.uio_rw = UIO_READ;
417	uio.uio_td = td;
418	return proc_rwmem(td->td_proc, &uio);
419}
420
421static int
422ptrace_write_int(struct thread *td, vm_offset_t addr, u_int32_t v)
423{
424	struct iovec iov;
425	struct uio uio;
426
427	PROC_LOCK_ASSERT(td->td_proc, MA_NOTOWNED);
428	iov.iov_base = (caddr_t) &v;
429	iov.iov_len = sizeof(u_int32_t);
430	uio.uio_iov = &iov;
431	uio.uio_iovcnt = 1;
432	uio.uio_offset = (off_t)addr;
433	uio.uio_resid = sizeof(u_int32_t);
434	uio.uio_segflg = UIO_SYSSPACE;
435	uio.uio_rw = UIO_WRITE;
436	uio.uio_td = td;
437	return proc_rwmem(td->td_proc, &uio);
438}
439
440int
441ptrace_single_step(struct thread *td)
442{
443	struct proc *p;
444	int error;
445
446	KASSERT(td->td_md.md_ptrace_instr == 0,
447	 ("Didn't clear single step"));
448	p = td->td_proc;
449	PROC_UNLOCK(p);
450	error = ptrace_read_int(td, td->td_frame->tf_pc + 4,
451	    &td->td_md.md_ptrace_instr);
452	if (error)
453		goto out;
454	error = ptrace_write_int(td, td->td_frame->tf_pc + 4,
455	    PTRACE_BREAKPOINT);
456	if (error)
457		td->td_md.md_ptrace_instr = 0;
458	td->td_md.md_ptrace_addr = td->td_frame->tf_pc + 4;
459out:
460	PROC_LOCK(p);
461	return (error);
462}
463
464int
465ptrace_clear_single_step(struct thread *td)
466{
467	struct proc *p;
468
469	if (td->td_md.md_ptrace_instr) {
470		p = td->td_proc;
471		PROC_UNLOCK(p);
472		ptrace_write_int(td, td->td_md.md_ptrace_addr,
473		    td->td_md.md_ptrace_instr);
474		PROC_LOCK(p);
475		td->td_md.md_ptrace_instr = 0;
476	}
477	return (0);
478}
479
480int
481ptrace_set_pc(struct thread *td, unsigned long addr)
482{
483	td->td_frame->tf_pc = addr;
484	return (0);
485}
486
487void
488cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
489{
490}
491
492void
493spinlock_enter(void)
494{
495	struct thread *td;
496	register_t cspr;
497
498	td = curthread;
499	if (td->td_md.md_spinlock_count == 0) {
500		cspr = disable_interrupts(I32_bit | F32_bit);
501		td->td_md.md_spinlock_count = 1;
502		td->td_md.md_saved_cspr = cspr;
503	} else
504		td->td_md.md_spinlock_count++;
505	critical_enter();
506}
507
508void
509spinlock_exit(void)
510{
511	struct thread *td;
512	register_t cspr;
513
514	td = curthread;
515	critical_exit();
516	cspr = td->td_md.md_saved_cspr;
517	td->td_md.md_spinlock_count--;
518	if (td->td_md.md_spinlock_count == 0)
519		restore_interrupts(cspr);
520}
521
522/*
523 * Clear registers on exec
524 */
525void
526exec_setregs(struct thread *td, struct image_params *imgp, u_long stack)
527{
528	struct trapframe *tf = td->td_frame;
529
530	memset(tf, 0, sizeof(*tf));
531	tf->tf_usr_sp = stack;
532	tf->tf_usr_lr = imgp->entry_addr;
533	tf->tf_svc_lr = 0x77777777;
534	tf->tf_pc = imgp->entry_addr;
535	tf->tf_spsr = PSR_USR32_MODE;
536}
537
538/*
539 * Get machine context.
540 */
541int
542get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
543{
544	struct trapframe *tf = td->td_frame;
545	__greg_t *gr = mcp->__gregs;
546
547	if (clear_ret & GET_MC_CLEAR_RET)
548		gr[_REG_R0] = 0;
549	else
550		gr[_REG_R0]   = tf->tf_r0;
551	gr[_REG_R1]   = tf->tf_r1;
552	gr[_REG_R2]   = tf->tf_r2;
553	gr[_REG_R3]   = tf->tf_r3;
554	gr[_REG_R4]   = tf->tf_r4;
555	gr[_REG_R5]   = tf->tf_r5;
556	gr[_REG_R6]   = tf->tf_r6;
557	gr[_REG_R7]   = tf->tf_r7;
558	gr[_REG_R8]   = tf->tf_r8;
559	gr[_REG_R9]   = tf->tf_r9;
560	gr[_REG_R10]  = tf->tf_r10;
561	gr[_REG_R11]  = tf->tf_r11;
562	gr[_REG_R12]  = tf->tf_r12;
563	gr[_REG_SP]   = tf->tf_usr_sp;
564	gr[_REG_LR]   = tf->tf_usr_lr;
565	gr[_REG_PC]   = tf->tf_pc;
566	gr[_REG_CPSR] = tf->tf_spsr;
567
568	return (0);
569}
570
571/*
572 * Set machine context.
573 *
574 * However, we don't set any but the user modifiable flags, and we won't
575 * touch the cs selector.
576 */
577int
578set_mcontext(struct thread *td, const mcontext_t *mcp)
579{
580	struct trapframe *tf = td->td_frame;
581	const __greg_t *gr = mcp->__gregs;
582
583	tf->tf_r0 = gr[_REG_R0];
584	tf->tf_r1 = gr[_REG_R1];
585	tf->tf_r2 = gr[_REG_R2];
586	tf->tf_r3 = gr[_REG_R3];
587	tf->tf_r4 = gr[_REG_R4];
588	tf->tf_r5 = gr[_REG_R5];
589	tf->tf_r6 = gr[_REG_R6];
590	tf->tf_r7 = gr[_REG_R7];
591	tf->tf_r8 = gr[_REG_R8];
592	tf->tf_r9 = gr[_REG_R9];
593	tf->tf_r10 = gr[_REG_R10];
594	tf->tf_r11 = gr[_REG_R11];
595	tf->tf_r12 = gr[_REG_R12];
596	tf->tf_usr_sp = gr[_REG_SP];
597	tf->tf_usr_lr = gr[_REG_LR];
598	tf->tf_pc = gr[_REG_PC];
599	tf->tf_spsr = gr[_REG_CPSR];
600
601	return (0);
602}
603
604/*
605 * MPSAFE
606 */
607int
608sys_sigreturn(td, uap)
609	struct thread *td;
610	struct sigreturn_args /* {
611		const struct __ucontext *sigcntxp;
612	} */ *uap;
613{
614	struct sigframe sf;
615	struct trapframe *tf;
616	int spsr;
617
618	if (uap == NULL)
619		return (EFAULT);
620	if (copyin(uap->sigcntxp, &sf, sizeof(sf)))
621		return (EFAULT);
622	/*
623	 * Make sure the processor mode has not been tampered with and
624	 * interrupts have not been disabled.
625	 */
626	spsr = sf.sf_uc.uc_mcontext.__gregs[_REG_CPSR];
627	if ((spsr & PSR_MODE) != PSR_USR32_MODE ||
628	    (spsr & (I32_bit | F32_bit)) != 0)
629		return (EINVAL);
630		/* Restore register context. */
631	tf = td->td_frame;
632	set_mcontext(td, &sf.sf_uc.uc_mcontext);
633
634	/* Restore signal mask. */
635	kern_sigprocmask(td, SIG_SETMASK, &sf.sf_uc.uc_sigmask, NULL, 0);
636
637	return (EJUSTRETURN);
638}
639
640
641/*
642 * Construct a PCB from a trapframe. This is called from kdb_trap() where
643 * we want to start a backtrace from the function that caused us to enter
644 * the debugger. We have the context in the trapframe, but base the trace
645 * on the PCB. The PCB doesn't have to be perfect, as long as it contains
646 * enough for a backtrace.
647 */
648void
649makectx(struct trapframe *tf, struct pcb *pcb)
650{
651	pcb->un_32.pcb32_r8 = tf->tf_r8;
652	pcb->un_32.pcb32_r9 = tf->tf_r9;
653	pcb->un_32.pcb32_r10 = tf->tf_r10;
654	pcb->un_32.pcb32_r11 = tf->tf_r11;
655	pcb->un_32.pcb32_r12 = tf->tf_r12;
656	pcb->un_32.pcb32_pc = tf->tf_pc;
657	pcb->un_32.pcb32_lr = tf->tf_usr_lr;
658	pcb->un_32.pcb32_sp = tf->tf_usr_sp;
659}
660
661/*
662 * Fake up a boot descriptor table
663 */
664vm_offset_t
665fake_preload_metadata(void)
666{
667#ifdef DDB
668	vm_offset_t zstart = 0, zend = 0;
669#endif
670	vm_offset_t lastaddr;
671	int i = 0;
672	static uint32_t fake_preload[35];
673
674	fake_preload[i++] = MODINFO_NAME;
675	fake_preload[i++] = strlen("elf kernel") + 1;
676	strcpy((char*)&fake_preload[i++], "elf kernel");
677	i += 2;
678	fake_preload[i++] = MODINFO_TYPE;
679	fake_preload[i++] = strlen("elf kernel") + 1;
680	strcpy((char*)&fake_preload[i++], "elf kernel");
681	i += 2;
682	fake_preload[i++] = MODINFO_ADDR;
683	fake_preload[i++] = sizeof(vm_offset_t);
684	fake_preload[i++] = KERNVIRTADDR;
685	fake_preload[i++] = MODINFO_SIZE;
686	fake_preload[i++] = sizeof(uint32_t);
687	fake_preload[i++] = (uint32_t)&end - KERNVIRTADDR;
688#ifdef DDB
689	if (*(uint32_t *)KERNVIRTADDR == MAGIC_TRAMP_NUMBER) {
690		fake_preload[i++] = MODINFO_METADATA|MODINFOMD_SSYM;
691		fake_preload[i++] = sizeof(vm_offset_t);
692		fake_preload[i++] = *(uint32_t *)(KERNVIRTADDR + 4);
693		fake_preload[i++] = MODINFO_METADATA|MODINFOMD_ESYM;
694		fake_preload[i++] = sizeof(vm_offset_t);
695		fake_preload[i++] = *(uint32_t *)(KERNVIRTADDR + 8);
696		lastaddr = *(uint32_t *)(KERNVIRTADDR + 8);
697		zend = lastaddr;
698		zstart = *(uint32_t *)(KERNVIRTADDR + 4);
699		ksym_start = zstart;
700		ksym_end = zend;
701	} else
702#endif
703		lastaddr = (vm_offset_t)&end;
704	fake_preload[i++] = 0;
705	fake_preload[i] = 0;
706	preload_metadata = (void *)fake_preload;
707
708	return (lastaddr);
709}
710