1 /*-
2 * Copyright (c) 1982, 1986 The Regents of the University of California.
3 * Copyright (c) 1989, 1990 William Jolitz
4 * Copyright (c) 1994 John Dyson
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * the Systems Programming Group of the University of Utah Computer
9 * Science Department, and William Jolitz.
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 the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR 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 * from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
40 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
41 */
42
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45
46 #include "opt_isa.h"
47 #include "opt_cpu.h"
48 #include "opt_compat.h"
49
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/bio.h>
53 #include <sys/buf.h>
54 #include <sys/kernel.h>
55 #include <sys/ktr.h>
56 #include <sys/lock.h>
57 #include <sys/malloc.h>
58 #include <sys/mbuf.h>
59 #include <sys/mutex.h>
60 #include <sys/pioctl.h>
61 #include <sys/proc.h>
62 #include <sys/smp.h>
63 #include <sys/sysctl.h>
64 #include <sys/sysent.h>
65 #include <sys/unistd.h>
66 #include <sys/vnode.h>
67 #include <sys/vmmeter.h>
68
69 #include <machine/cpu.h>
70 #include <machine/md_var.h>
71 #include <machine/pcb.h>
72 #include <machine/smp.h>
73 #include <machine/specialreg.h>
74 #include <machine/tss.h>
75
76 #include <vm/vm.h>
77 #include <vm/vm_extern.h>
78 #include <vm/vm_kern.h>
79 #include <vm/vm_page.h>
80 #include <vm/vm_map.h>
81 #include <vm/vm_param.h>
82
83 #include <x86/isa/isa.h>
84
85 static void cpu_reset_real(void);
86 #ifdef SMP
87 static void cpu_reset_proxy(void);
88 static u_int cpu_reset_proxyid;
89 static volatile u_int cpu_reset_proxy_active;
90 #endif
91
92 _Static_assert(OFFSETOF_CURTHREAD == offsetof(struct pcpu, pc_curthread),
93 "OFFSETOF_CURTHREAD does not correspond with offset of pc_curthread.");
94 _Static_assert(OFFSETOF_CURPCB == offsetof(struct pcpu, pc_curpcb),
95 "OFFSETOF_CURPCB does not correspond with offset of pc_curpcb.");
96
97 struct savefpu *
98 get_pcb_user_save_td(struct thread *td)
99 {
100 vm_offset_t p;
101
102 p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
103 roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN);
104 KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area"));
105 return ((struct savefpu *)p);
106 }
107
108 struct savefpu *
109 get_pcb_user_save_pcb(struct pcb *pcb)
110 {
111 vm_offset_t p;
112
113 p = (vm_offset_t)(pcb + 1);
114 return ((struct savefpu *)p);
115 }
116
117 struct pcb *
118 get_pcb_td(struct thread *td)
119 {
120 vm_offset_t p;
121
122 p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
123 roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) -
124 sizeof(struct pcb);
125 return ((struct pcb *)p);
126 }
127
128 void *
129 alloc_fpusave(int flags)
130 {
131 void *res;
132 struct savefpu_ymm *sf;
133
134 res = malloc(cpu_max_ext_state_size, M_DEVBUF, flags);
135 if (use_xsave) {
136 sf = (struct savefpu_ymm *)res;
137 bzero(&sf->sv_xstate.sx_hd, sizeof(sf->sv_xstate.sx_hd));
138 sf->sv_xstate.sx_hd.xstate_bv = xsave_mask;
139 }
140 return (res);
141 }
142
143 /*
144 * Finish a fork operation, with process p2 nearly set up.
145 * Copy and update the pcb, set up the stack so that the child
146 * ready to run and return to user mode.
147 */
148 void
149 cpu_fork(td1, p2, td2, flags)
150 register struct thread *td1;
151 register struct proc *p2;
152 struct thread *td2;
153 int flags;
154 {
155 register struct proc *p1;
156 struct pcb *pcb2;
157 struct mdproc *mdp1, *mdp2;
158 struct proc_ldt *pldt;
159 pmap_t pmap2;
160
161 p1 = td1->td_proc;
162 if ((flags & RFPROC) == 0) {
163 if ((flags & RFMEM) == 0) {
164 /* unshare user LDT */
165 mdp1 = &p1->p_md;
166 mtx_lock(&dt_lock);
167 if ((pldt = mdp1->md_ldt) != NULL &&
168 pldt->ldt_refcnt > 1 &&
169 user_ldt_alloc(p1, 1) == NULL)
170 panic("could not copy LDT");
171 mtx_unlock(&dt_lock);
172 }
173 return;
174 }
175
176 /* Ensure that td1's pcb is up to date. */
177 fpuexit(td1);
178
179 /* Point the pcb to the top of the stack */
180 pcb2 = get_pcb_td(td2);
181 td2->td_pcb = pcb2;
182
183 /* Copy td1's pcb */
184 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
185
186 /* Properly initialize pcb_save */
187 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
188 bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2),
189 cpu_max_ext_state_size);
190
191 /* Point mdproc and then copy over td1's contents */
192 mdp2 = &p2->p_md;
193 bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
194
195 /*
196 * Create a new fresh stack for the new process.
197 * Copy the trap frame for the return to user mode as if from a
198 * syscall. This copies most of the user mode register values.
199 */
200 td2->td_frame = (struct trapframe *)td2->td_pcb - 1;
201 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
202
203 td2->td_frame->tf_rax = 0; /* Child returns zero */
204 td2->td_frame->tf_rflags &= ~PSL_C; /* success */
205 td2->td_frame->tf_rdx = 1;
206
207 /*
208 * If the parent process has the trap bit set (i.e. a debugger had
209 * single stepped the process to the system call), we need to clear
210 * the trap flag from the new frame unless the debugger had set PF_FORK
211 * on the parent. Otherwise, the child will receive a (likely
212 * unexpected) SIGTRAP when it executes the first instruction after
213 * returning to userland.
214 */
215 if ((p1->p_pfsflags & PF_FORK) == 0)
216 td2->td_frame->tf_rflags &= ~PSL_T;
217
218 /*
219 * Set registers for trampoline to user mode. Leave space for the
220 * return address on stack. These are the kernel mode register values.
221 */
222 pmap2 = vmspace_pmap(p2->p_vmspace);
223 pcb2->pcb_cr3 = pmap2->pm_cr3;
224 pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */
225 pcb2->pcb_rbp = 0;
226 pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *);
227 pcb2->pcb_rbx = (register_t)td2; /* fork_trampoline argument */
228 pcb2->pcb_rip = (register_t)fork_trampoline;
229 /*-
230 * pcb2->pcb_dr*: cloned above.
231 * pcb2->pcb_savefpu: cloned above.
232 * pcb2->pcb_flags: cloned above.
233 * pcb2->pcb_onfault: cloned above (always NULL here?).
234 * pcb2->pcb_[fg]sbase: cloned above
235 */
236
237 /* Setup to release spin count in fork_exit(). */
238 td2->td_md.md_spinlock_count = 1;
239 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
240
241 /* As an i386, do not copy io permission bitmap. */
242 pcb2->pcb_tssp = NULL;
243
244 /* New segment registers. */
245 set_pcb_flags(pcb2, PCB_FULL_IRET);
246
247 /* Copy the LDT, if necessary. */
248 mdp1 = &td1->td_proc->p_md;
249 mdp2 = &p2->p_md;
250 mtx_lock(&dt_lock);
251 if (mdp1->md_ldt != NULL) {
252 if (flags & RFMEM) {
253 mdp1->md_ldt->ldt_refcnt++;
254 mdp2->md_ldt = mdp1->md_ldt;
255 bcopy(&mdp1->md_ldt_sd, &mdp2->md_ldt_sd, sizeof(struct
256 system_segment_descriptor));
257 } else {
258 mdp2->md_ldt = NULL;
259 mdp2->md_ldt = user_ldt_alloc(p2, 0);
260 if (mdp2->md_ldt == NULL)
261 panic("could not copy LDT");
262 amd64_set_ldt_data(td2, 0, max_ldt_segment,
263 (struct user_segment_descriptor *)
264 mdp1->md_ldt->ldt_base);
265 }
266 } else
267 mdp2->md_ldt = NULL;
268 mtx_unlock(&dt_lock);
269
270 /*
271 * Now, cpu_switch() can schedule the new process.
272 * pcb_rsp is loaded pointing to the cpu_switch() stack frame
273 * containing the return address when exiting cpu_switch.
274 * This will normally be to fork_trampoline(), which will have
275 * %ebx loaded with the new proc's pointer. fork_trampoline()
276 * will set up a stack to call fork_return(p, frame); to complete
277 * the return to user-mode.
278 */
279 }
280
281 /*
282 * Intercept the return address from a freshly forked process that has NOT
283 * been scheduled yet.
284 *
285 * This is needed to make kernel threads stay in kernel mode.
286 */
287 void
288 cpu_set_fork_handler(td, func, arg)
289 struct thread *td;
290 void (*func)(void *);
291 void *arg;
292 {
293 /*
294 * Note that the trap frame follows the args, so the function
295 * is really called like this: func(arg, frame);
296 */
297 td->td_pcb->pcb_r12 = (long) func; /* function */
298 td->td_pcb->pcb_rbx = (long) arg; /* first arg */
299 }
300
301 void
302 cpu_exit(struct thread *td)
303 {
304
305 /*
306 * If this process has a custom LDT, release it.
307 */
308 mtx_lock(&dt_lock);
309 if (td->td_proc->p_md.md_ldt != 0)
310 user_ldt_free(td);
311 else
312 mtx_unlock(&dt_lock);
313 }
314
315 void
316 cpu_thread_exit(struct thread *td)
317 {
318 struct pcb *pcb;
319
320 critical_enter();
321 if (td == PCPU_GET(fpcurthread))
322 fpudrop();
323 critical_exit();
324
325 pcb = td->td_pcb;
326
327 /* Disable any hardware breakpoints. */
328 if (pcb->pcb_flags & PCB_DBREGS) {
329 reset_dbregs();
330 clear_pcb_flags(pcb, PCB_DBREGS);
331 }
332 }
333
334 void
335 cpu_thread_clean(struct thread *td)
336 {
337 struct pcb *pcb;
338
339 pcb = td->td_pcb;
340
341 /*
342 * Clean TSS/iomap
343 */
344 if (pcb->pcb_tssp != NULL) {
345 kmem_free(kernel_arena, (vm_offset_t)pcb->pcb_tssp,
346 ctob(IOPAGES + 1));
347 pcb->pcb_tssp = NULL;
348 }
349 }
350
351 void
352 cpu_thread_swapin(struct thread *td)
353 {
354 }
355
356 void
357 cpu_thread_swapout(struct thread *td)
358 {
359 }
360
361 void
362 cpu_thread_alloc(struct thread *td)
363 {
364 struct pcb *pcb;
365 struct xstate_hdr *xhdr;
366
367 td->td_pcb = pcb = get_pcb_td(td);
368 td->td_frame = (struct trapframe *)pcb - 1;
369 pcb->pcb_save = get_pcb_user_save_pcb(pcb);
370 if (use_xsave) {
371 xhdr = (struct xstate_hdr *)(pcb->pcb_save + 1);
372 bzero(xhdr, sizeof(*xhdr));
373 xhdr->xstate_bv = xsave_mask;
374 }
375 }
376
377 void
378 cpu_thread_free(struct thread *td)
379 {
380
381 cpu_thread_clean(td);
382 }
383
384 void
385 cpu_set_syscall_retval(struct thread *td, int error)
386 {
387
388 switch (error) {
389 case 0:
390 td->td_frame->tf_rax = td->td_retval[0];
391 td->td_frame->tf_rdx = td->td_retval[1];
392 td->td_frame->tf_rflags &= ~PSL_C;
393 break;
394
395 case ERESTART:
396 /*
397 * Reconstruct pc, we know that 'syscall' is 2 bytes,
398 * lcall $X,y is 7 bytes, int 0x80 is 2 bytes.
399 * We saved this in tf_err.
400 * %r10 (which was holding the value of %rcx) is restored
401 * for the next iteration.
402 * %r10 restore is only required for freebsd/amd64 processes,
403 * but shall be innocent for any ia32 ABI.
404 *
405 * Require full context restore to get the arguments
406 * in the registers reloaded at return to usermode.
407 */
408 td->td_frame->tf_rip -= td->td_frame->tf_err;
409 td->td_frame->tf_r10 = td->td_frame->tf_rcx;
410 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
411 break;
412
413 case EJUSTRETURN:
414 break;
415
416 default:
417 td->td_frame->tf_rax = SV_ABI_ERRNO(td->td_proc, error);
418 td->td_frame->tf_rflags |= PSL_C;
419 break;
420 }
421 }
422
423 /*
424 * Initialize machine state (pcb and trap frame) for a new thread about to
425 * upcall. Put enough state in the new thread's PCB to get it to go back
426 * userret(), where we can intercept it again to set the return (upcall)
427 * Address and stack, along with those from upcals that are from other sources
428 * such as those generated in thread_userret() itself.
429 */
430 void
431 cpu_set_upcall(struct thread *td, struct thread *td0)
432 {
433 struct pcb *pcb2;
434
435 /* Point the pcb to the top of the stack. */
436 pcb2 = td->td_pcb;
437
438 /*
439 * Copy the upcall pcb. This loads kernel regs.
440 * Those not loaded individually below get their default
441 * values here.
442 */
443 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
444 clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE |
445 PCB_KERNFPU);
446 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
447 bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save,
448 cpu_max_ext_state_size);
449 set_pcb_flags(pcb2, PCB_FULL_IRET);
450
451 /*
452 * Create a new fresh stack for the new thread.
453 */
454 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
455
456 /* If the current thread has the trap bit set (i.e. a debugger had
457 * single stepped the process to the system call), we need to clear
458 * the trap flag from the new frame. Otherwise, the new thread will
459 * receive a (likely unexpected) SIGTRAP when it executes the first
460 * instruction after returning to userland.
461 */
462 td->td_frame->tf_rflags &= ~PSL_T;
463
464 /*
465 * Set registers for trampoline to user mode. Leave space for the
466 * return address on stack. These are the kernel mode register values.
467 */
468 pcb2->pcb_r12 = (register_t)fork_return; /* trampoline arg */
469 pcb2->pcb_rbp = 0;
470 pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *); /* trampoline arg */
471 pcb2->pcb_rbx = (register_t)td; /* trampoline arg */
472 pcb2->pcb_rip = (register_t)fork_trampoline;
473 /*
474 * If we didn't copy the pcb, we'd need to do the following registers:
475 * pcb2->pcb_cr3: cloned above.
476 * pcb2->pcb_dr*: cloned above.
477 * pcb2->pcb_savefpu: cloned above.
478 * pcb2->pcb_onfault: cloned above (always NULL here?).
479 * pcb2->pcb_[fg]sbase: cloned above
480 */
481
482 /* Setup to release spin count in fork_exit(). */
483 td->td_md.md_spinlock_count = 1;
484 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
485 }
486
487 /*
488 * Set that machine state for performing an upcall that has to
489 * be done in thread_userret() so that those upcalls generated
490 * in thread_userret() itself can be done as well.
491 */
492 void
493 cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg,
494 stack_t *stack)
495 {
496
497 /*
498 * Do any extra cleaning that needs to be done.
499 * The thread may have optional components
500 * that are not present in a fresh thread.
501 * This may be a recycled thread so make it look
502 * as though it's newly allocated.
503 */
504 cpu_thread_clean(td);
505
506 #ifdef COMPAT_FREEBSD32
507 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
508 /*
509 * Set the trap frame to point at the beginning of the uts
510 * function.
511 */
512 td->td_frame->tf_rbp = 0;
513 td->td_frame->tf_rsp =
514 (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
515 td->td_frame->tf_rip = (uintptr_t)entry;
516
517 /*
518 * Pass the address of the mailbox for this kse to the uts
519 * function as a parameter on the stack.
520 */
521 suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)),
522 (uint32_t)(uintptr_t)arg);
523
524 return;
525 }
526 #endif
527
528 /*
529 * Set the trap frame to point at the beginning of the uts
530 * function.
531 */
532 td->td_frame->tf_rbp = 0;
533 td->td_frame->tf_rsp =
534 ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f;
535 td->td_frame->tf_rsp -= 8;
536 td->td_frame->tf_rip = (register_t)entry;
537 td->td_frame->tf_ds = _udatasel;
538 td->td_frame->tf_es = _udatasel;
539 td->td_frame->tf_fs = _ufssel;
540 td->td_frame->tf_gs = _ugssel;
541 td->td_frame->tf_flags = TF_HASSEGS;
542
543 /*
544 * Pass the address of the mailbox for this kse to the uts
545 * function as a parameter on the stack.
546 */
547 td->td_frame->tf_rdi = (register_t)arg;
548 }
549
550 int
551 cpu_set_user_tls(struct thread *td, void *tls_base)
552 {
553 struct pcb *pcb;
554
555 if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS)
556 return (EINVAL);
557
558 pcb = td->td_pcb;
559 set_pcb_flags(pcb, PCB_FULL_IRET);
560 #ifdef COMPAT_FREEBSD32
561 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
562 pcb->pcb_gsbase = (register_t)tls_base;
563 return (0);
564 }
565 #endif
566 pcb->pcb_fsbase = (register_t)tls_base;
567 return (0);
568 }
569
570 #ifdef SMP
571 static void
572 cpu_reset_proxy()
573 {
574
575 cpu_reset_proxy_active = 1;
576 while (cpu_reset_proxy_active == 1)
577 ia32_pause(); /* Wait for other cpu to see that we've started */
578
579 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
580 DELAY(1000000);
581 cpu_reset_real();
582 }
583 #endif
584
585 void
586 cpu_reset()
587 {
588 #ifdef SMP
589 cpuset_t map;
590 u_int cnt;
591
592 if (smp_started) {
593 map = all_cpus;
594 CPU_CLR(PCPU_GET(cpuid), &map);
595 CPU_NAND(&map, &stopped_cpus);
596 if (!CPU_EMPTY(&map)) {
597 printf("cpu_reset: Stopping other CPUs\n");
598 stop_cpus(map);
599 }
600
601 if (PCPU_GET(cpuid) != 0) {
602 cpu_reset_proxyid = PCPU_GET(cpuid);
603 cpustop_restartfunc = cpu_reset_proxy;
604 cpu_reset_proxy_active = 0;
605 printf("cpu_reset: Restarting BSP\n");
606
607 /* Restart CPU #0. */
608 CPU_SETOF(0, &started_cpus);
609 wmb();
610
611 cnt = 0;
612 while (cpu_reset_proxy_active == 0 && cnt < 10000000) {
613 ia32_pause();
614 cnt++; /* Wait for BSP to announce restart */
615 }
616 if (cpu_reset_proxy_active == 0) {
617 printf("cpu_reset: Failed to restart BSP\n");
618 } else {
619 cpu_reset_proxy_active = 2;
620 while (1)
621 ia32_pause();
622 /* NOTREACHED */
623 }
624 }
625
626 DELAY(1000000);
627 }
628 #endif
629 cpu_reset_real();
630 /* NOTREACHED */
631 }
632
633 static void
634 cpu_reset_real()
635 {
636 struct region_descriptor null_idt;
637 int b;
638
639 disable_intr();
640
641 /*
642 * Attempt to do a CPU reset via the keyboard controller,
643 * do not turn off GateA20, as any machine that fails
644 * to do the reset here would then end up in no man's land.
645 */
646 outb(IO_KBD + 4, 0xFE);
647 DELAY(500000); /* wait 0.5 sec to see if that did it */
648
649 /*
650 * Attempt to force a reset via the Reset Control register at
651 * I/O port 0xcf9. Bit 2 forces a system reset when it
652 * transitions from 0 to 1. Bit 1 selects the type of reset
653 * to attempt: 0 selects a "soft" reset, and 1 selects a
654 * "hard" reset. We try a "hard" reset. The first write sets
655 * bit 1 to select a "hard" reset and clears bit 2. The
656 * second write forces a 0 -> 1 transition in bit 2 to trigger
657 * a reset.
658 */
659 outb(0xcf9, 0x2);
660 outb(0xcf9, 0x6);
661 DELAY(500000); /* wait 0.5 sec to see if that did it */
662
663 /*
664 * Attempt to force a reset via the Fast A20 and Init register
665 * at I/O port 0x92. Bit 1 serves as an alternate A20 gate.
666 * Bit 0 asserts INIT# when set to 1. We are careful to only
667 * preserve bit 1 while setting bit 0. We also must clear bit
668 * 0 before setting it if it isn't already clear.
669 */
670 b = inb(0x92);
671 if (b != 0xff) {
672 if ((b & 0x1) != 0)
673 outb(0x92, b & 0xfe);
674 outb(0x92, b | 0x1);
675 DELAY(500000); /* wait 0.5 sec to see if that did it */
676 }
677
678 printf("No known reset method worked, attempting CPU shutdown\n");
679 DELAY(1000000); /* wait 1 sec for printf to complete */
680
681 /* Wipe the IDT. */
682 null_idt.rd_limit = 0;
683 null_idt.rd_base = 0;
684 lidt(&null_idt);
685
686 /* "good night, sweet prince .... <THUNK!>" */
687 breakpoint();
688
689 /* NOTREACHED */
690 while(1);
691 }
692
693 /*
694 * Software interrupt handler for queued VM system processing.
695 */
696 void
697 swi_vm(void *dummy)
698 {
699 if (busdma_swi_pending != 0)
700 busdma_swi();
701 }
702
703 /*
704 * Tell whether this address is in some physical memory region.
705 * Currently used by the kernel coredump code in order to avoid
706 * dumping the ``ISA memory hole'' which could cause indefinite hangs,
707 * or other unpredictable behaviour.
708 */
709
710 int
711 is_physical_memory(vm_paddr_t addr)
712 {
713
714 #ifdef DEV_ISA
715 /* The ISA ``memory hole''. */
716 if (addr >= 0xa0000 && addr < 0x100000)
717 return 0;
718 #endif
719
720 /*
721 * stuff other tests for known memory-mapped devices (PCI?)
722 * here
723 */
724
725 return 1;
726 }
Cache object: 2d106105b2edd3c22143110df7a2deac
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