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: releng/6.2/sys/i386/i386/vm_machdep.c 161534 2006-08-22 16:52:42Z rink $");
45
46 #include "opt_isa.h"
47 #include "opt_npx.h"
48 #include "opt_reset.h"
49 #include "opt_cpu.h"
50 #include "opt_xbox.h"
51
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/bio.h>
55 #include <sys/buf.h>
56 #include <sys/kse.h>
57 #include <sys/kernel.h>
58 #include <sys/ktr.h>
59 #include <sys/lock.h>
60 #include <sys/malloc.h>
61 #include <sys/mbuf.h>
62 #include <sys/mutex.h>
63 #include <sys/pioctl.h>
64 #include <sys/proc.h>
65 #include <sys/sf_buf.h>
66 #include <sys/smp.h>
67 #include <sys/sched.h>
68 #include <sys/sysctl.h>
69 #include <sys/unistd.h>
70 #include <sys/vnode.h>
71 #include <sys/vmmeter.h>
72
73 #include <machine/cpu.h>
74 #include <machine/cputypes.h>
75 #include <machine/md_var.h>
76 #include <machine/pcb.h>
77 #include <machine/pcb_ext.h>
78 #include <machine/smp.h>
79 #include <machine/vm86.h>
80
81 #ifdef CPU_ELAN
82 #include <machine/elan_mmcr.h>
83 #endif
84
85 #include <vm/vm.h>
86 #include <vm/vm_extern.h>
87 #include <vm/vm_kern.h>
88 #include <vm/vm_page.h>
89 #include <vm/vm_map.h>
90 #include <vm/vm_param.h>
91
92 #ifdef PC98
93 #include <pc98/cbus/cbus.h>
94 #else
95 #include <i386/isa/isa.h>
96 #endif
97
98 #ifdef XBOX
99 #include <machine/xbox.h>
100 #endif
101
102 #ifndef NSFBUFS
103 #define NSFBUFS (512 + maxusers * 16)
104 #endif
105
106 static void cpu_reset_real(void);
107 #ifdef SMP
108 static void cpu_reset_proxy(void);
109 static u_int cpu_reset_proxyid;
110 static volatile u_int cpu_reset_proxy_active;
111 #endif
112 static void sf_buf_init(void *arg);
113 SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL)
114
115 LIST_HEAD(sf_head, sf_buf);
116
117 /*
118 * A hash table of active sendfile(2) buffers
119 */
120 static struct sf_head *sf_buf_active;
121 static u_long sf_buf_hashmask;
122
123 #define SF_BUF_HASH(m) (((m) - vm_page_array) & sf_buf_hashmask)
124
125 static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
126 static u_int sf_buf_alloc_want;
127
128 /*
129 * A lock used to synchronize access to the hash table and free list
130 */
131 static struct mtx sf_buf_lock;
132
133 extern int _ucodesel, _udatasel;
134
135 /*
136 * Finish a fork operation, with process p2 nearly set up.
137 * Copy and update the pcb, set up the stack so that the child
138 * ready to run and return to user mode.
139 */
140 void
141 cpu_fork(td1, p2, td2, flags)
142 register struct thread *td1;
143 register struct proc *p2;
144 struct thread *td2;
145 int flags;
146 {
147 register struct proc *p1;
148 struct pcb *pcb2;
149 struct mdproc *mdp2;
150 #ifdef DEV_NPX
151 register_t savecrit;
152 #endif
153
154 p1 = td1->td_proc;
155 if ((flags & RFPROC) == 0) {
156 if ((flags & RFMEM) == 0) {
157 /* unshare user LDT */
158 struct mdproc *mdp1 = &p1->p_md;
159 struct proc_ldt *pldt;
160
161 pldt = mdp1->md_ldt;
162 if (pldt && pldt->ldt_refcnt > 1) {
163 pldt = user_ldt_alloc(mdp1, pldt->ldt_len);
164 if (pldt == NULL)
165 panic("could not copy LDT");
166 mdp1->md_ldt = pldt;
167 set_user_ldt(mdp1);
168 user_ldt_free(td1);
169 }
170 }
171 return;
172 }
173
174 /* Ensure that p1's pcb is up to date. */
175 #ifdef DEV_NPX
176 if (td1 == curthread)
177 td1->td_pcb->pcb_gs = rgs();
178 savecrit = intr_disable();
179 if (PCPU_GET(fpcurthread) == td1)
180 npxsave(&td1->td_pcb->pcb_save);
181 intr_restore(savecrit);
182 #endif
183
184 /* Point the pcb to the top of the stack */
185 pcb2 = (struct pcb *)(td2->td_kstack +
186 td2->td_kstack_pages * PAGE_SIZE) - 1;
187 td2->td_pcb = pcb2;
188
189 /* Copy p1's pcb */
190 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
191
192 /* Point mdproc and then copy over td1's contents */
193 mdp2 = &p2->p_md;
194 bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
195
196 /*
197 * Create a new fresh stack for the new process.
198 * Copy the trap frame for the return to user mode as if from a
199 * syscall. This copies most of the user mode register values.
200 * The -16 is so we can expand the trapframe if we go to vm86.
201 */
202 td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb - 16) - 1;
203 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
204
205 td2->td_frame->tf_eax = 0; /* Child returns zero */
206 td2->td_frame->tf_eflags &= ~PSL_C; /* success */
207 td2->td_frame->tf_edx = 1;
208
209 /*
210 * If the parent process has the trap bit set (i.e. a debugger had
211 * single stepped the process to the system call), we need to clear
212 * the trap flag from the new frame unless the debugger had set PF_FORK
213 * on the parent. Otherwise, the child will receive a (likely
214 * unexpected) SIGTRAP when it executes the first instruction after
215 * returning to userland.
216 */
217 if ((p1->p_pfsflags & PF_FORK) == 0)
218 td2->td_frame->tf_eflags &= ~PSL_T;
219
220 /*
221 * Set registers for trampoline to user mode. Leave space for the
222 * return address on stack. These are the kernel mode register values.
223 */
224 #ifdef PAE
225 pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdpt);
226 #else
227 pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir);
228 #endif
229 pcb2->pcb_edi = 0;
230 pcb2->pcb_esi = (int)fork_return; /* fork_trampoline argument */
231 pcb2->pcb_ebp = 0;
232 pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *);
233 pcb2->pcb_ebx = (int)td2; /* fork_trampoline argument */
234 pcb2->pcb_eip = (int)fork_trampoline;
235 pcb2->pcb_psl = PSL_KERNEL; /* ints disabled */
236 pcb2->pcb_gs = rgs();
237 /*-
238 * pcb2->pcb_dr*: cloned above.
239 * pcb2->pcb_savefpu: cloned above.
240 * pcb2->pcb_flags: cloned above.
241 * pcb2->pcb_onfault: cloned above (always NULL here?).
242 * pcb2->pcb_gs: cloned above.
243 * pcb2->pcb_ext: cleared below.
244 */
245
246 /*
247 * XXX don't copy the i/o pages. this should probably be fixed.
248 */
249 pcb2->pcb_ext = 0;
250
251 /* Copy the LDT, if necessary. */
252 mtx_lock_spin(&sched_lock);
253 if (mdp2->md_ldt != NULL) {
254 if (flags & RFMEM) {
255 mdp2->md_ldt->ldt_refcnt++;
256 } else {
257 mdp2->md_ldt = user_ldt_alloc(mdp2,
258 mdp2->md_ldt->ldt_len);
259 if (mdp2->md_ldt == NULL)
260 panic("could not copy LDT");
261 }
262 }
263 mtx_unlock_spin(&sched_lock);
264
265 /* Setup to release sched_lock in fork_exit(). */
266 td2->td_md.md_spinlock_count = 1;
267 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
268
269 /*
270 * Now, cpu_switch() can schedule the new process.
271 * pcb_esp is loaded pointing to the cpu_switch() stack frame
272 * containing the return address when exiting cpu_switch.
273 * This will normally be to fork_trampoline(), which will have
274 * %ebx loaded with the new proc's pointer. fork_trampoline()
275 * will set up a stack to call fork_return(p, frame); to complete
276 * the return to user-mode.
277 */
278 }
279
280 /*
281 * Intercept the return address from a freshly forked process that has NOT
282 * been scheduled yet.
283 *
284 * This is needed to make kernel threads stay in kernel mode.
285 */
286 void
287 cpu_set_fork_handler(td, func, arg)
288 struct thread *td;
289 void (*func)(void *);
290 void *arg;
291 {
292 /*
293 * Note that the trap frame follows the args, so the function
294 * is really called like this: func(arg, frame);
295 */
296 td->td_pcb->pcb_esi = (int) func; /* function */
297 td->td_pcb->pcb_ebx = (int) arg; /* first arg */
298 }
299
300 void
301 cpu_exit(struct thread *td)
302 {
303
304 /*
305 * If this process has a custom LDT, release it. Reset pc->pcb_gs
306 * and %gs before we free it in case they refer to an LDT entry.
307 */
308 if (td->td_proc->p_md.md_ldt) {
309 td->td_pcb->pcb_gs = _udatasel;
310 load_gs(_udatasel);
311 user_ldt_free(td);
312 }
313 }
314
315 void
316 cpu_thread_exit(struct thread *td)
317 {
318
319 #ifdef DEV_NPX
320 if (td == PCPU_GET(fpcurthread))
321 npxdrop();
322 #endif
323
324 /* Disable any hardware breakpoints. */
325 if (td->td_pcb->pcb_flags & PCB_DBREGS) {
326 reset_dbregs();
327 td->td_pcb->pcb_flags &= ~PCB_DBREGS;
328 }
329 }
330
331 void
332 cpu_thread_clean(struct thread *td)
333 {
334 struct pcb *pcb;
335
336 pcb = td->td_pcb;
337 if (pcb->pcb_ext != NULL) {
338 /* XXXKSE XXXSMP not SMP SAFE.. what locks do we have? */
339 /* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */
340 /*
341 * XXX do we need to move the TSS off the allocated pages
342 * before freeing them? (not done here)
343 */
344 kmem_free(kernel_map, (vm_offset_t)pcb->pcb_ext,
345 ctob(IOPAGES + 1));
346 pcb->pcb_ext = NULL;
347 }
348 }
349
350 void
351 cpu_thread_swapin(struct thread *td)
352 {
353 }
354
355 void
356 cpu_thread_swapout(struct thread *td)
357 {
358 }
359
360 void
361 cpu_thread_setup(struct thread *td)
362 {
363
364 td->td_pcb = (struct pcb *)(td->td_kstack +
365 td->td_kstack_pages * PAGE_SIZE) - 1;
366 td->td_frame = (struct trapframe *)((caddr_t)td->td_pcb - 16) - 1;
367 td->td_pcb->pcb_ext = NULL;
368 }
369
370 /*
371 * Initialize machine state (pcb and trap frame) for a new thread about to
372 * upcall. Put enough state in the new thread's PCB to get it to go back
373 * userret(), where we can intercept it again to set the return (upcall)
374 * Address and stack, along with those from upcals that are from other sources
375 * such as those generated in thread_userret() itself.
376 */
377 void
378 cpu_set_upcall(struct thread *td, struct thread *td0)
379 {
380 struct pcb *pcb2;
381
382 /* Point the pcb to the top of the stack. */
383 pcb2 = td->td_pcb;
384
385 /*
386 * Copy the upcall pcb. This loads kernel regs.
387 * Those not loaded individually below get their default
388 * values here.
389 *
390 * XXXKSE It might be a good idea to simply skip this as
391 * the values of the other registers may be unimportant.
392 * This would remove any requirement for knowing the KSE
393 * at this time (see the matching comment below for
394 * more analysis) (need a good safe default).
395 */
396 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
397 pcb2->pcb_flags &= ~(PCB_NPXTRAP|PCB_NPXINITDONE);
398
399 /*
400 * Create a new fresh stack for the new thread.
401 * The -16 is so we can expand the trapframe if we go to vm86.
402 * Don't forget to set this stack value into whatever supplies
403 * the address for the fault handlers.
404 * The contexts are filled in at the time we actually DO the
405 * upcall as only then do we know which KSE we got.
406 */
407 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
408
409 /*
410 * Set registers for trampoline to user mode. Leave space for the
411 * return address on stack. These are the kernel mode register values.
412 */
413 #ifdef PAE
414 pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pdpt);
415 #else
416 pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pdir);
417 #endif
418 pcb2->pcb_edi = 0;
419 pcb2->pcb_esi = (int)fork_return; /* trampoline arg */
420 pcb2->pcb_ebp = 0;
421 pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */
422 pcb2->pcb_ebx = (int)td; /* trampoline arg */
423 pcb2->pcb_eip = (int)fork_trampoline;
424 pcb2->pcb_psl &= ~(PSL_I); /* interrupts must be disabled */
425 pcb2->pcb_gs = rgs();
426 /*
427 * If we didn't copy the pcb, we'd need to do the following registers:
428 * pcb2->pcb_dr*: cloned above.
429 * pcb2->pcb_savefpu: cloned above.
430 * pcb2->pcb_flags: cloned above.
431 * pcb2->pcb_onfault: cloned above (always NULL here?).
432 * pcb2->pcb_gs: cloned above. XXXKSE ???
433 * pcb2->pcb_ext: cleared below.
434 */
435 pcb2->pcb_ext = NULL;
436
437 /* Setup to release sched_lock in fork_exit(). */
438 td->td_md.md_spinlock_count = 1;
439 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
440 }
441
442 /*
443 * Set that machine state for performing an upcall that has to
444 * be done in thread_userret() so that those upcalls generated
445 * in thread_userret() itself can be done as well.
446 */
447 void
448 cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg,
449 stack_t *stack)
450 {
451
452 /*
453 * Do any extra cleaning that needs to be done.
454 * The thread may have optional components
455 * that are not present in a fresh thread.
456 * This may be a recycled thread so make it look
457 * as though it's newly allocated.
458 */
459 cpu_thread_clean(td);
460
461 /*
462 * Set the trap frame to point at the beginning of the uts
463 * function.
464 */
465 td->td_frame->tf_ebp = 0;
466 td->td_frame->tf_esp =
467 (((int)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
468 td->td_frame->tf_eip = (int)entry;
469
470 /*
471 * Pass the address of the mailbox for this kse to the uts
472 * function as a parameter on the stack.
473 */
474 suword((void *)(td->td_frame->tf_esp + sizeof(void *)),
475 (int)arg);
476 }
477
478 int
479 cpu_set_user_tls(struct thread *td, void *tls_base)
480 {
481 struct segment_descriptor sd;
482 uint32_t base;
483
484 /*
485 * Construct a descriptor and store it in the pcb for
486 * the next context switch. Also store it in the gdt
487 * so that the load of tf_fs into %fs will activate it
488 * at return to userland.
489 */
490 base = (uint32_t)tls_base;
491 sd.sd_lobase = base & 0xffffff;
492 sd.sd_hibase = (base >> 24) & 0xff;
493 sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */
494 sd.sd_hilimit = 0xf;
495 sd.sd_type = SDT_MEMRWA;
496 sd.sd_dpl = SEL_UPL;
497 sd.sd_p = 1;
498 sd.sd_xx = 0;
499 sd.sd_def32 = 1;
500 sd.sd_gran = 1;
501 critical_enter();
502 /* set %gs */
503 td->td_pcb->pcb_gsd = sd;
504 if (td == curthread) {
505 PCPU_GET(fsgs_gdt)[1] = sd;
506 load_gs(GSEL(GUGS_SEL, SEL_UPL));
507 }
508 critical_exit();
509 return (0);
510 }
511
512 /*
513 * Convert kernel VA to physical address
514 */
515 vm_paddr_t
516 kvtop(void *addr)
517 {
518 vm_paddr_t pa;
519
520 pa = pmap_kextract((vm_offset_t)addr);
521 if (pa == 0)
522 panic("kvtop: zero page frame");
523 return (pa);
524 }
525
526 #ifdef SMP
527 static void
528 cpu_reset_proxy()
529 {
530
531 cpu_reset_proxy_active = 1;
532 while (cpu_reset_proxy_active == 1)
533 ; /* Wait for other cpu to see that we've started */
534 stop_cpus((1<<cpu_reset_proxyid));
535 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
536 DELAY(1000000);
537 cpu_reset_real();
538 }
539 #endif
540
541 void
542 cpu_reset()
543 {
544 #ifdef XBOX
545 if (arch_i386_is_xbox) {
546 /* Kick the PIC16L, it can reboot the box */
547 pic16l_reboot();
548 for (;;);
549 }
550 #endif
551
552 #ifdef SMP
553 u_int cnt, map;
554
555 if (smp_active) {
556 map = PCPU_GET(other_cpus) & ~stopped_cpus;
557 if (map != 0) {
558 printf("cpu_reset: Stopping other CPUs\n");
559 stop_cpus(map);
560 }
561
562 if (PCPU_GET(cpuid) != 0) {
563 cpu_reset_proxyid = PCPU_GET(cpuid);
564 cpustop_restartfunc = cpu_reset_proxy;
565 cpu_reset_proxy_active = 0;
566 printf("cpu_reset: Restarting BSP\n");
567 started_cpus = (1<<0); /* Restart CPU #0 */
568
569 cnt = 0;
570 while (cpu_reset_proxy_active == 0 && cnt < 10000000)
571 cnt++; /* Wait for BSP to announce restart */
572 if (cpu_reset_proxy_active == 0)
573 printf("cpu_reset: Failed to restart BSP\n");
574 enable_intr();
575 cpu_reset_proxy_active = 2;
576
577 while (1);
578 /* NOTREACHED */
579 }
580
581 DELAY(1000000);
582 }
583 #endif
584 cpu_reset_real();
585 /* NOTREACHED */
586 }
587
588 static void
589 cpu_reset_real()
590 {
591
592 #ifdef CPU_ELAN
593 if (elan_mmcr != NULL)
594 elan_mmcr->RESCFG = 1;
595 #endif
596
597 if (cpu == CPU_GEODE1100) {
598 /* Attempt Geode's own reset */
599 outl(0xcf8, 0x80009044ul);
600 outl(0xcfc, 0xf);
601 }
602
603 #ifdef PC98
604 /*
605 * Attempt to do a CPU reset via CPU reset port.
606 */
607 disable_intr();
608 if ((inb(0x35) & 0xa0) != 0xa0) {
609 outb(0x37, 0x0f); /* SHUT0 = 0. */
610 outb(0x37, 0x0b); /* SHUT1 = 0. */
611 }
612 outb(0xf0, 0x00); /* Reset. */
613 #else
614 #if !defined(BROKEN_KEYBOARD_RESET)
615 /*
616 * Attempt to do a CPU reset via the keyboard controller,
617 * do not turn off GateA20, as any machine that fails
618 * to do the reset here would then end up in no man's land.
619 */
620 outb(IO_KBD + 4, 0xFE);
621 DELAY(500000); /* wait 0.5 sec to see if that did it */
622 printf("Keyboard reset did not work, attempting CPU shutdown\n");
623 DELAY(1000000); /* wait 1 sec for printf to complete */
624 #endif
625 #endif /* PC98 */
626
627 /* Force a shutdown by unmapping entire address space. */
628 bzero((caddr_t)PTD, NBPTD);
629
630 /* "good night, sweet prince .... <THUNK!>" */
631 invltlb();
632 /* NOTREACHED */
633 while(1);
634 }
635
636 /*
637 * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
638 */
639 static void
640 sf_buf_init(void *arg)
641 {
642 struct sf_buf *sf_bufs;
643 vm_offset_t sf_base;
644 int i;
645
646 nsfbufs = NSFBUFS;
647 TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
648
649 sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
650 TAILQ_INIT(&sf_buf_freelist);
651 sf_base = kmem_alloc_nofault(kernel_map, nsfbufs * PAGE_SIZE);
652 sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
653 M_NOWAIT | M_ZERO);
654 for (i = 0; i < nsfbufs; i++) {
655 sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
656 TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
657 }
658 sf_buf_alloc_want = 0;
659 mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
660 }
661
662 /*
663 * Get an sf_buf from the freelist. Will block if none are available.
664 */
665 struct sf_buf *
666 sf_buf_alloc(struct vm_page *m, int flags)
667 {
668 pt_entry_t opte, *ptep;
669 struct sf_head *hash_list;
670 struct sf_buf *sf;
671 #ifdef SMP
672 cpumask_t cpumask, other_cpus;
673 #endif
674 int error;
675
676 KASSERT(curthread->td_pinned > 0 || (flags & SFB_CPUPRIVATE) == 0,
677 ("sf_buf_alloc(SFB_CPUPRIVATE): curthread not pinned"));
678 hash_list = &sf_buf_active[SF_BUF_HASH(m)];
679 mtx_lock(&sf_buf_lock);
680 LIST_FOREACH(sf, hash_list, list_entry) {
681 if (sf->m == m) {
682 sf->ref_count++;
683 if (sf->ref_count == 1) {
684 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
685 nsfbufsused++;
686 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
687 }
688 #ifdef SMP
689 goto shootdown;
690 #else
691 goto done;
692 #endif
693 }
694 }
695 while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
696 if (flags & SFB_NOWAIT)
697 goto done;
698 sf_buf_alloc_want++;
699 mbstat.sf_allocwait++;
700 error = msleep(&sf_buf_freelist, &sf_buf_lock,
701 (flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
702 sf_buf_alloc_want--;
703
704 /*
705 * If we got a signal, don't risk going back to sleep.
706 */
707 if (error)
708 goto done;
709 }
710 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
711 if (sf->m != NULL)
712 LIST_REMOVE(sf, list_entry);
713 LIST_INSERT_HEAD(hash_list, sf, list_entry);
714 sf->ref_count = 1;
715 sf->m = m;
716 nsfbufsused++;
717 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
718
719 /*
720 * Update the sf_buf's virtual-to-physical mapping, flushing the
721 * virtual address from the TLB. Since the reference count for
722 * the sf_buf's old mapping was zero, that mapping is not
723 * currently in use. Consequently, there is no need to exchange
724 * the old and new PTEs atomically, even under PAE.
725 */
726 ptep = vtopte(sf->kva);
727 opte = *ptep;
728 *ptep = VM_PAGE_TO_PHYS(m) | pgeflag | PG_RW | PG_V;
729
730 /*
731 * Avoid unnecessary TLB invalidations: If the sf_buf's old
732 * virtual-to-physical mapping was not used, then any processor
733 * that has invalidated the sf_buf's virtual address from its TLB
734 * since the last used mapping need not invalidate again.
735 */
736 #ifdef SMP
737 if ((opte & (PG_V | PG_A)) == (PG_V | PG_A))
738 sf->cpumask = 0;
739 shootdown:
740 sched_pin();
741 cpumask = PCPU_GET(cpumask);
742 if ((sf->cpumask & cpumask) == 0) {
743 sf->cpumask |= cpumask;
744 invlpg(sf->kva);
745 }
746 if ((flags & SFB_CPUPRIVATE) == 0) {
747 other_cpus = PCPU_GET(other_cpus) & ~sf->cpumask;
748 if (other_cpus != 0) {
749 sf->cpumask |= other_cpus;
750 mtx_lock_spin(&smp_ipi_mtx);
751 smp_masked_invlpg(other_cpus, sf->kva);
752 mtx_unlock_spin(&smp_ipi_mtx);
753 }
754 }
755 sched_unpin();
756 #else
757 if ((opte & (PG_V | PG_A)) == (PG_V | PG_A))
758 pmap_invalidate_page(kernel_pmap, sf->kva);
759 #endif
760 done:
761 mtx_unlock(&sf_buf_lock);
762 return (sf);
763 }
764
765 /*
766 * Remove a reference from the given sf_buf, adding it to the free
767 * list when its reference count reaches zero. A freed sf_buf still,
768 * however, retains its virtual-to-physical mapping until it is
769 * recycled or reactivated by sf_buf_alloc(9).
770 */
771 void
772 sf_buf_free(struct sf_buf *sf)
773 {
774
775 mtx_lock(&sf_buf_lock);
776 sf->ref_count--;
777 if (sf->ref_count == 0) {
778 TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
779 nsfbufsused--;
780 if (sf_buf_alloc_want > 0)
781 wakeup_one(&sf_buf_freelist);
782 }
783 mtx_unlock(&sf_buf_lock);
784 }
785
786 /*
787 * Software interrupt handler for queued VM system processing.
788 */
789 void
790 swi_vm(void *dummy)
791 {
792 if (busdma_swi_pending != 0)
793 busdma_swi();
794 }
795
796 /*
797 * Tell whether this address is in some physical memory region.
798 * Currently used by the kernel coredump code in order to avoid
799 * dumping the ``ISA memory hole'' which could cause indefinite hangs,
800 * or other unpredictable behaviour.
801 */
802
803 int
804 is_physical_memory(vm_paddr_t addr)
805 {
806
807 #ifdef DEV_ISA
808 /* The ISA ``memory hole''. */
809 if (addr >= 0xa0000 && addr < 0x100000)
810 return 0;
811 #endif
812
813 /*
814 * stuff other tests for known memory-mapped devices (PCI?)
815 * here
816 */
817
818 return 1;
819 }
Cache object: 1a67e38995a2fc96c67832cc9bca8038
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