Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/i386/i386/vm_machdep.c
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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/5.3/sys/i386/i386/vm_machdep.c 132422 2004-07-20 01:38:59Z davidxu $"); 45 46 #include "opt_isa.h" 47 #include "opt_npx.h" 48 #ifdef PC98 49 #include "opt_pc98.h" 50 #endif 51 #include "opt_reset.h" 52 #include "opt_cpu.h" 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/bio.h> 57 #include <sys/buf.h> 58 #include <sys/kse.h> 59 #include <sys/kernel.h> 60 #include <sys/ktr.h> 61 #include <sys/lock.h> 62 #include <sys/malloc.h> 63 #include <sys/mbuf.h> 64 #include <sys/mutex.h> 65 #include <sys/proc.h> 66 #include <sys/sf_buf.h> 67 #include <sys/smp.h> 68 #include <sys/sysctl.h> 69 #include <sys/unistd.h> 70 #include <sys/user.h> 71 #include <sys/vnode.h> 72 #include <sys/vmmeter.h> 73 74 #include <machine/cpu.h> 75 #include <machine/cputypes.h> 76 #include <machine/md_var.h> 77 #include <machine/pcb.h> 78 #include <machine/pcb_ext.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/pc98/pc98.h> 94 #else 95 #include <i386/isa/isa.h> 96 #endif 97 98 #ifndef NSFBUFS 99 #define NSFBUFS (512 + maxusers * 16) 100 #endif 101 102 static void cpu_reset_real(void); 103 #ifdef SMP 104 static void cpu_reset_proxy(void); 105 static u_int cpu_reset_proxyid; 106 static volatile u_int cpu_reset_proxy_active; 107 #endif 108 static void sf_buf_init(void *arg); 109 SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL) 110 111 LIST_HEAD(sf_head, sf_buf); 112 113 /* 114 * A hash table of active sendfile(2) buffers 115 */ 116 static struct sf_head *sf_buf_active; 117 static u_long sf_buf_hashmask; 118 119 #define SF_BUF_HASH(m) (((m) - vm_page_array) & sf_buf_hashmask) 120 121 static TAILQ_HEAD(, sf_buf) sf_buf_freelist; 122 static u_int sf_buf_alloc_want; 123 124 /* 125 * A lock used to synchronize access to the hash table and free list 126 */ 127 static struct mtx sf_buf_lock; 128 129 extern int _ucodesel, _udatasel; 130 131 /* 132 * Finish a fork operation, with process p2 nearly set up. 133 * Copy and update the pcb, set up the stack so that the child 134 * ready to run and return to user mode. 135 */ 136 void 137 cpu_fork(td1, p2, td2, flags) 138 register struct thread *td1; 139 register struct proc *p2; 140 struct thread *td2; 141 int flags; 142 { 143 register struct proc *p1; 144 struct pcb *pcb2; 145 struct mdproc *mdp2; 146 #ifdef DEV_NPX 147 register_t savecrit; 148 #endif 149 150 p1 = td1->td_proc; 151 if ((flags & RFPROC) == 0) { 152 if ((flags & RFMEM) == 0) { 153 /* unshare user LDT */ 154 struct mdproc *mdp1 = &p1->p_md; 155 struct proc_ldt *pldt = mdp1->md_ldt; 156 if (pldt && pldt->ldt_refcnt > 1) { 157 pldt = user_ldt_alloc(mdp1, pldt->ldt_len); 158 if (pldt == NULL) 159 panic("could not copy LDT"); 160 mdp1->md_ldt = pldt; 161 set_user_ldt(mdp1); 162 user_ldt_free(td1); 163 } 164 } 165 return; 166 } 167 168 /* Ensure that p1's pcb is up to date. */ 169 #ifdef DEV_NPX 170 if (td1 == curthread) 171 td1->td_pcb->pcb_gs = rgs(); 172 savecrit = intr_disable(); 173 if (PCPU_GET(fpcurthread) == td1) 174 npxsave(&td1->td_pcb->pcb_save); 175 intr_restore(savecrit); 176 #endif 177 178 /* Point the pcb to the top of the stack */ 179 pcb2 = (struct pcb *)(td2->td_kstack + 180 td2->td_kstack_pages * PAGE_SIZE) - 1; 181 td2->td_pcb = pcb2; 182 183 /* Copy p1's pcb */ 184 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 185 186 /* Point mdproc and then copy over td1's contents */ 187 mdp2 = &p2->p_md; 188 bcopy(&p1->p_md, mdp2, sizeof(*mdp2)); 189 190 /* 191 * Create a new fresh stack for the new process. 192 * Copy the trap frame for the return to user mode as if from a 193 * syscall. This copies most of the user mode register values. 194 * The -16 is so we can expand the trapframe if we go to vm86. 195 */ 196 td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb - 16) - 1; 197 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); 198 199 td2->td_frame->tf_eax = 0; /* Child returns zero */ 200 td2->td_frame->tf_eflags &= ~PSL_C; /* success */ 201 td2->td_frame->tf_edx = 1; 202 203 /* 204 * Set registers for trampoline to user mode. Leave space for the 205 * return address on stack. These are the kernel mode register values. 206 */ 207 #ifdef PAE 208 pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdpt); 209 #else 210 pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir); 211 #endif 212 pcb2->pcb_edi = 0; 213 pcb2->pcb_esi = (int)fork_return; /* fork_trampoline argument */ 214 pcb2->pcb_ebp = 0; 215 pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *); 216 pcb2->pcb_ebx = (int)td2; /* fork_trampoline argument */ 217 pcb2->pcb_eip = (int)fork_trampoline; 218 pcb2->pcb_psl = PSL_KERNEL; /* ints disabled */ 219 pcb2->pcb_gs = rgs(); 220 /*- 221 * pcb2->pcb_dr*: cloned above. 222 * pcb2->pcb_savefpu: cloned above. 223 * pcb2->pcb_flags: cloned above. 224 * pcb2->pcb_onfault: cloned above (always NULL here?). 225 * pcb2->pcb_gs: cloned above. 226 * pcb2->pcb_ext: cleared below. 227 */ 228 229 /* 230 * XXX don't copy the i/o pages. this should probably be fixed. 231 */ 232 pcb2->pcb_ext = 0; 233 234 /* Copy the LDT, if necessary. */ 235 mtx_lock_spin(&sched_lock); 236 if (mdp2->md_ldt != 0) { 237 if (flags & RFMEM) { 238 mdp2->md_ldt->ldt_refcnt++; 239 } else { 240 mdp2->md_ldt = user_ldt_alloc(mdp2, 241 mdp2->md_ldt->ldt_len); 242 if (mdp2->md_ldt == NULL) 243 panic("could not copy LDT"); 244 } 245 } 246 mtx_unlock_spin(&sched_lock); 247 248 /* 249 * Now, cpu_switch() can schedule the new process. 250 * pcb_esp is loaded pointing to the cpu_switch() stack frame 251 * containing the return address when exiting cpu_switch. 252 * This will normally be to fork_trampoline(), which will have 253 * %ebx loaded with the new proc's pointer. fork_trampoline() 254 * will set up a stack to call fork_return(p, frame); to complete 255 * the return to user-mode. 256 */ 257 } 258 259 /* 260 * Intercept the return address from a freshly forked process that has NOT 261 * been scheduled yet. 262 * 263 * This is needed to make kernel threads stay in kernel mode. 264 */ 265 void 266 cpu_set_fork_handler(td, func, arg) 267 struct thread *td; 268 void (*func)(void *); 269 void *arg; 270 { 271 /* 272 * Note that the trap frame follows the args, so the function 273 * is really called like this: func(arg, frame); 274 */ 275 td->td_pcb->pcb_esi = (int) func; /* function */ 276 td->td_pcb->pcb_ebx = (int) arg; /* first arg */ 277 } 278 279 void 280 cpu_exit(struct thread *td) 281 { 282 struct mdproc *mdp; 283 struct pcb *pcb = td->td_pcb; 284 285 286 /* Reset pc->pcb_gs and %gs before possibly invalidating it. */ 287 mdp = &td->td_proc->p_md; 288 if (mdp->md_ldt) { 289 td->td_pcb->pcb_gs = _udatasel; 290 load_gs(_udatasel); 291 user_ldt_free(td); 292 } 293 if (pcb->pcb_flags & PCB_DBREGS) { 294 /* disable all hardware breakpoints */ 295 reset_dbregs(); 296 pcb->pcb_flags &= ~PCB_DBREGS; 297 } 298 } 299 300 void 301 cpu_thread_exit(struct thread *td) 302 { 303 struct pcb *pcb = td->td_pcb; 304 #ifdef DEV_NPX 305 if (td == PCPU_GET(fpcurthread)) 306 npxdrop(); 307 #endif 308 if (pcb->pcb_flags & PCB_DBREGS) { 309 /* disable all hardware breakpoints */ 310 reset_dbregs(); 311 pcb->pcb_flags &= ~PCB_DBREGS; 312 } 313 } 314 315 void 316 cpu_thread_clean(struct thread *td) 317 { 318 struct pcb *pcb; 319 320 pcb = td->td_pcb; 321 if (pcb->pcb_ext != 0) { 322 /* XXXKSE XXXSMP not SMP SAFE.. what locks do we have? */ 323 /* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */ 324 /* 325 * XXX do we need to move the TSS off the allocated pages 326 * before freeing them? (not done here) 327 */ 328 kmem_free(kernel_map, (vm_offset_t)pcb->pcb_ext, 329 ctob(IOPAGES + 1)); 330 pcb->pcb_ext = 0; 331 } 332 } 333 334 void 335 cpu_thread_swapin(struct thread *td) 336 { 337 } 338 339 void 340 cpu_thread_swapout(struct thread *td) 341 { 342 } 343 344 void 345 cpu_thread_setup(struct thread *td) 346 { 347 348 td->td_pcb = (struct pcb *)(td->td_kstack + 349 td->td_kstack_pages * PAGE_SIZE) - 1; 350 td->td_frame = (struct trapframe *)((caddr_t)td->td_pcb - 16) - 1; 351 td->td_pcb->pcb_ext = NULL; 352 } 353 354 /* 355 * Initialize machine state (pcb and trap frame) for a new thread about to 356 * upcall. Pu t enough state in the new thread's PCB to get it to go back 357 * userret(), where we can intercept it again to set the return (upcall) 358 * Address and stack, along with those from upcals that are from other sources 359 * such as those generated in thread_userret() itself. 360 */ 361 void 362 cpu_set_upcall(struct thread *td, struct thread *td0) 363 { 364 struct pcb *pcb2; 365 366 /* Point the pcb to the top of the stack. */ 367 pcb2 = td->td_pcb; 368 369 /* 370 * Copy the upcall pcb. This loads kernel regs. 371 * Those not loaded individually below get their default 372 * values here. 373 * 374 * XXXKSE It might be a good idea to simply skip this as 375 * the values of the other registers may be unimportant. 376 * This would remove any requirement for knowing the KSE 377 * at this time (see the matching comment below for 378 * more analysis) (need a good safe default). 379 */ 380 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); 381 pcb2->pcb_flags &= ~(PCB_NPXTRAP|PCB_NPXINITDONE); 382 383 /* 384 * Create a new fresh stack for the new thread. 385 * The -16 is so we can expand the trapframe if we go to vm86. 386 * Don't forget to set this stack value into whatever supplies 387 * the address for the fault handlers. 388 * The contexts are filled in at the time we actually DO the 389 * upcall as only then do we know which KSE we got. 390 */ 391 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 392 393 /* 394 * Set registers for trampoline to user mode. Leave space for the 395 * return address on stack. These are the kernel mode register values. 396 */ 397 #ifdef PAE 398 pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pdpt); 399 #else 400 pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pdir); 401 #endif 402 pcb2->pcb_edi = 0; 403 pcb2->pcb_esi = (int)fork_return; /* trampoline arg */ 404 pcb2->pcb_ebp = 0; 405 pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */ 406 pcb2->pcb_ebx = (int)td; /* trampoline arg */ 407 pcb2->pcb_eip = (int)fork_trampoline; 408 pcb2->pcb_psl &= ~(PSL_I); /* interrupts must be disabled */ 409 pcb2->pcb_gs = rgs(); 410 /* 411 * If we didn't copy the pcb, we'd need to do the following registers: 412 * pcb2->pcb_dr*: cloned above. 413 * pcb2->pcb_savefpu: cloned above. 414 * pcb2->pcb_flags: cloned above. 415 * pcb2->pcb_onfault: cloned above (always NULL here?). 416 * pcb2->pcb_gs: cloned above. XXXKSE ??? 417 * pcb2->pcb_ext: cleared below. 418 */ 419 pcb2->pcb_ext = NULL; 420 } 421 422 /* 423 * Set that machine state for performing an upcall that has to 424 * be done in thread_userret() so that those upcalls generated 425 * in thread_userret() itself can be done as well. 426 */ 427 void 428 cpu_set_upcall_kse(struct thread *td, struct kse_upcall *ku) 429 { 430 431 /* 432 * Do any extra cleaning that needs to be done. 433 * The thread may have optional components 434 * that are not present in a fresh thread. 435 * This may be a recycled thread so make it look 436 * as though it's newly allocated. 437 */ 438 cpu_thread_clean(td); 439 440 /* 441 * Set the trap frame to point at the beginning of the uts 442 * function. 443 */ 444 td->td_frame->tf_ebp = 0; 445 td->td_frame->tf_esp = 446 (int)ku->ku_stack.ss_sp + ku->ku_stack.ss_size - 16; 447 td->td_frame->tf_eip = (int)ku->ku_func; 448 449 /* 450 * Pass the address of the mailbox for this kse to the uts 451 * function as a parameter on the stack. 452 */ 453 suword((void *)(td->td_frame->tf_esp + sizeof(void *)), 454 (int)ku->ku_mailbox); 455 } 456 457 /* 458 * Convert kernel VA to physical address 459 */ 460 vm_paddr_t 461 kvtop(void *addr) 462 { 463 vm_paddr_t pa; 464 465 pa = pmap_kextract((vm_offset_t)addr); 466 if (pa == 0) 467 panic("kvtop: zero page frame"); 468 return (pa); 469 } 470 471 /* 472 * Force reset the processor by invalidating the entire address space! 473 */ 474 475 #ifdef SMP 476 static void 477 cpu_reset_proxy() 478 { 479 480 cpu_reset_proxy_active = 1; 481 while (cpu_reset_proxy_active == 1) 482 ; /* Wait for other cpu to see that we've started */ 483 stop_cpus((1<<cpu_reset_proxyid)); 484 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid); 485 DELAY(1000000); 486 cpu_reset_real(); 487 } 488 #endif 489 490 void 491 cpu_reset() 492 { 493 #ifdef SMP 494 if (smp_active == 0) { 495 cpu_reset_real(); 496 /* NOTREACHED */ 497 } else { 498 499 u_int map; 500 int cnt; 501 printf("cpu_reset called on cpu#%d\n", PCPU_GET(cpuid)); 502 503 map = PCPU_GET(other_cpus) & ~ stopped_cpus; 504 505 if (map != 0) { 506 printf("cpu_reset: Stopping other CPUs\n"); 507 stop_cpus(map); /* Stop all other CPUs */ 508 } 509 510 if (PCPU_GET(cpuid) == 0) { 511 DELAY(1000000); 512 cpu_reset_real(); 513 /* NOTREACHED */ 514 } else { 515 /* We are not BSP (CPU #0) */ 516 517 cpu_reset_proxyid = PCPU_GET(cpuid); 518 cpustop_restartfunc = cpu_reset_proxy; 519 cpu_reset_proxy_active = 0; 520 printf("cpu_reset: Restarting BSP\n"); 521 started_cpus = (1<<0); /* Restart CPU #0 */ 522 523 cnt = 0; 524 while (cpu_reset_proxy_active == 0 && cnt < 10000000) 525 cnt++; /* Wait for BSP to announce restart */ 526 if (cpu_reset_proxy_active == 0) 527 printf("cpu_reset: Failed to restart BSP\n"); 528 enable_intr(); 529 cpu_reset_proxy_active = 2; 530 531 while (1); 532 /* NOTREACHED */ 533 } 534 } 535 #else 536 cpu_reset_real(); 537 #endif 538 } 539 540 static void 541 cpu_reset_real() 542 { 543 544 #ifdef CPU_ELAN 545 if (elan_mmcr != NULL) 546 elan_mmcr->RESCFG = 1; 547 #endif 548 549 if (cpu == CPU_GEODE1100) { 550 /* Attempt Geode's own reset */ 551 outl(0xcf8, 0x80009044ul); 552 outl(0xcfc, 0xf); 553 } 554 555 #ifdef PC98 556 /* 557 * Attempt to do a CPU reset via CPU reset port. 558 */ 559 disable_intr(); 560 if ((inb(0x35) & 0xa0) != 0xa0) { 561 outb(0x37, 0x0f); /* SHUT0 = 0. */ 562 outb(0x37, 0x0b); /* SHUT1 = 0. */ 563 } 564 outb(0xf0, 0x00); /* Reset. */ 565 #else 566 /* 567 * Attempt to do a CPU reset via the keyboard controller, 568 * do not turn of the GateA20, as any machine that fails 569 * to do the reset here would then end up in no man's land. 570 */ 571 572 #if !defined(BROKEN_KEYBOARD_RESET) 573 outb(IO_KBD + 4, 0xFE); 574 DELAY(500000); /* wait 0.5 sec to see if that did it */ 575 printf("Keyboard reset did not work, attempting CPU shutdown\n"); 576 DELAY(1000000); /* wait 1 sec for printf to complete */ 577 #endif 578 #endif /* PC98 */ 579 /* force a shutdown by unmapping entire address space ! */ 580 bzero((caddr_t)PTD, NBPTD); 581 582 /* "good night, sweet prince .... <THUNK!>" */ 583 invltlb(); 584 /* NOTREACHED */ 585 while(1); 586 } 587 588 /* 589 * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-)) 590 */ 591 static void 592 sf_buf_init(void *arg) 593 { 594 struct sf_buf *sf_bufs; 595 vm_offset_t sf_base; 596 int i; 597 598 nsfbufs = NSFBUFS; 599 TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs); 600 601 sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask); 602 TAILQ_INIT(&sf_buf_freelist); 603 sf_base = kmem_alloc_nofault(kernel_map, nsfbufs * PAGE_SIZE); 604 sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP, 605 M_NOWAIT | M_ZERO); 606 for (i = 0; i < nsfbufs; i++) { 607 sf_bufs[i].kva = sf_base + i * PAGE_SIZE; 608 TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry); 609 } 610 sf_buf_alloc_want = 0; 611 mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF); 612 } 613 614 /* 615 * Get an sf_buf from the freelist. Will block if none are available. 616 */ 617 struct sf_buf * 618 sf_buf_alloc(struct vm_page *m, int pri) 619 { 620 struct sf_head *hash_list; 621 struct sf_buf *sf; 622 int error; 623 624 hash_list = &sf_buf_active[SF_BUF_HASH(m)]; 625 mtx_lock(&sf_buf_lock); 626 LIST_FOREACH(sf, hash_list, list_entry) { 627 if (sf->m == m) { 628 sf->ref_count++; 629 if (sf->ref_count == 1) { 630 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry); 631 nsfbufsused++; 632 nsfbufspeak = imax(nsfbufspeak, nsfbufsused); 633 } 634 goto done; 635 } 636 } 637 while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) { 638 sf_buf_alloc_want++; 639 mbstat.sf_allocwait++; 640 error = msleep(&sf_buf_freelist, &sf_buf_lock, PVM | pri, 641 "sfbufa", 0); 642 sf_buf_alloc_want--; 643 644 /* 645 * If we got a signal, don't risk going back to sleep. 646 */ 647 if (error) 648 goto done; 649 } 650 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry); 651 if (sf->m != NULL) 652 LIST_REMOVE(sf, list_entry); 653 LIST_INSERT_HEAD(hash_list, sf, list_entry); 654 sf->ref_count = 1; 655 sf->m = m; 656 nsfbufsused++; 657 nsfbufspeak = imax(nsfbufspeak, nsfbufsused); 658 pmap_qenter(sf->kva, &sf->m, 1); 659 done: 660 mtx_unlock(&sf_buf_lock); 661 return (sf); 662 } 663 664 /* 665 * Remove a reference from the given sf_buf, adding it to the free 666 * list when its reference count reaches zero. A freed sf_buf still, 667 * however, retains its virtual-to-physical mapping until it is 668 * recycled or reactivated by sf_buf_alloc(9). 669 */ 670 void 671 sf_buf_free(struct sf_buf *sf) 672 { 673 674 mtx_lock(&sf_buf_lock); 675 sf->ref_count--; 676 if (sf->ref_count == 0) { 677 TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry); 678 nsfbufsused--; 679 if (sf_buf_alloc_want > 0) 680 wakeup_one(&sf_buf_freelist); 681 } 682 mtx_unlock(&sf_buf_lock); 683 } 684 685 /* 686 * Software interrupt handler for queued VM system processing. 687 */ 688 void 689 swi_vm(void *dummy) 690 { 691 if (busdma_swi_pending != 0) 692 busdma_swi(); 693 } 694 695 /* 696 * Tell whether this address is in some physical memory region. 697 * Currently used by the kernel coredump code in order to avoid 698 * dumping the ``ISA memory hole'' which could cause indefinite hangs, 699 * or other unpredictable behaviour. 700 */ 701 702 int 703 is_physical_memory(vm_paddr_t addr) 704 { 705 706 #ifdef DEV_ISA 707 /* The ISA ``memory hole''. */ 708 if (addr >= 0xa0000 && addr < 0x100000) 709 return 0; 710 #endif 711 712 /* 713 * stuff other tests for known memory-mapped devices (PCI?) 714 * here 715 */ 716 717 return 1; 718 }
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