vm_machdep.c revision 296908
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: head/sys/amd64/amd64/vm_machdep.c 296908 2016-03-15 15:42:53Z kib $"); 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 <isa/isareg.h> 84 85static void cpu_reset_real(void); 86#ifdef SMP 87static void cpu_reset_proxy(void); 88static u_int cpu_reset_proxyid; 89static 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_Static_assert(OFFSETOF_MONITORBUF == offsetof(struct pcpu, pc_monitorbuf), 97 "OFFSETOF_MONINORBUF does not correspond with offset of pc_monitorbuf."); 98 99struct savefpu * 100get_pcb_user_save_td(struct thread *td) 101{ 102 vm_offset_t p; 103 104 p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE - 105 roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN); 106 KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area")); 107 return ((struct savefpu *)p); 108} 109 110struct savefpu * 111get_pcb_user_save_pcb(struct pcb *pcb) 112{ 113 vm_offset_t p; 114 115 p = (vm_offset_t)(pcb + 1); 116 return ((struct savefpu *)p); 117} 118 119struct pcb * 120get_pcb_td(struct thread *td) 121{ 122 vm_offset_t p; 123 124 p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE - 125 roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) - 126 sizeof(struct pcb); 127 return ((struct pcb *)p); 128} 129 130void * 131alloc_fpusave(int flags) 132{ 133 void *res; 134 struct savefpu_ymm *sf; 135 136 res = malloc(cpu_max_ext_state_size, M_DEVBUF, flags); 137 if (use_xsave) { 138 sf = (struct savefpu_ymm *)res; 139 bzero(&sf->sv_xstate.sx_hd, sizeof(sf->sv_xstate.sx_hd)); 140 sf->sv_xstate.sx_hd.xstate_bv = xsave_mask; 141 } 142 return (res); 143} 144 145/* 146 * Finish a fork operation, with process p2 nearly set up. 147 * Copy and update the pcb, set up the stack so that the child 148 * ready to run and return to user mode. 149 */ 150void 151cpu_fork(td1, p2, td2, flags) 152 register struct thread *td1; 153 register struct proc *p2; 154 struct thread *td2; 155 int flags; 156{ 157 register struct proc *p1; 158 struct pcb *pcb2; 159 struct mdproc *mdp1, *mdp2; 160 struct proc_ldt *pldt; 161 162 p1 = td1->td_proc; 163 if ((flags & RFPROC) == 0) { 164 if ((flags & RFMEM) == 0) { 165 /* unshare user LDT */ 166 mdp1 = &p1->p_md; 167 mtx_lock(&dt_lock); 168 if ((pldt = mdp1->md_ldt) != NULL && 169 pldt->ldt_refcnt > 1 && 170 user_ldt_alloc(p1, 1) == NULL) 171 panic("could not copy LDT"); 172 mtx_unlock(&dt_lock); 173 } 174 return; 175 } 176 177 /* Ensure that td1's pcb is up to date. */ 178 fpuexit(td1); 179 180 /* Point the pcb to the top of the stack */ 181 pcb2 = get_pcb_td(td2); 182 td2->td_pcb = pcb2; 183 184 /* Copy td1's pcb */ 185 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 186 187 /* Properly initialize pcb_save */ 188 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); 189 bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2), 190 cpu_max_ext_state_size); 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 */ 201 td2->td_frame = (struct trapframe *)td2->td_pcb - 1; 202 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); 203 204 td2->td_frame->tf_rax = 0; /* Child returns zero */ 205 td2->td_frame->tf_rflags &= ~PSL_C; /* success */ 206 td2->td_frame->tf_rdx = 1; 207 208 /* 209 * If the parent process has the trap bit set (i.e. a debugger had 210 * single stepped the process to the system call), we need to clear 211 * the trap flag from the new frame unless the debugger had set PF_FORK 212 * on the parent. Otherwise, the child will receive a (likely 213 * unexpected) SIGTRAP when it executes the first instruction after 214 * returning to userland. 215 */ 216 if ((p1->p_pfsflags & PF_FORK) == 0) 217 td2->td_frame->tf_rflags &= ~PSL_T; 218 219 /* 220 * Set registers for trampoline to user mode. Leave space for the 221 * return address on stack. These are the kernel mode register values. 222 */ 223 pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */ 224 pcb2->pcb_rbp = 0; 225 pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *); 226 pcb2->pcb_rbx = (register_t)td2; /* fork_trampoline argument */ 227 pcb2->pcb_rip = (register_t)fork_trampoline; 228 /*- 229 * pcb2->pcb_dr*: cloned above. 230 * pcb2->pcb_savefpu: cloned above. 231 * pcb2->pcb_flags: cloned above. 232 * pcb2->pcb_onfault: cloned above (always NULL here?). 233 * pcb2->pcb_[fg]sbase: cloned above 234 */ 235 236 /* Setup to release spin count in fork_exit(). */ 237 td2->td_md.md_spinlock_count = 1; 238 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 239 240 /* As an i386, do not copy io permission bitmap. */ 241 pcb2->pcb_tssp = NULL; 242 243 /* New segment registers. */ 244 set_pcb_flags(pcb2, PCB_FULL_IRET); 245 246 /* Copy the LDT, if necessary. */ 247 mdp1 = &td1->td_proc->p_md; 248 mdp2 = &p2->p_md; 249 mtx_lock(&dt_lock); 250 if (mdp1->md_ldt != NULL) { 251 if (flags & RFMEM) { 252 mdp1->md_ldt->ldt_refcnt++; 253 mdp2->md_ldt = mdp1->md_ldt; 254 bcopy(&mdp1->md_ldt_sd, &mdp2->md_ldt_sd, sizeof(struct 255 system_segment_descriptor)); 256 } else { 257 mdp2->md_ldt = NULL; 258 mdp2->md_ldt = user_ldt_alloc(p2, 0); 259 if (mdp2->md_ldt == NULL) 260 panic("could not copy LDT"); 261 amd64_set_ldt_data(td2, 0, max_ldt_segment, 262 (struct user_segment_descriptor *) 263 mdp1->md_ldt->ldt_base); 264 } 265 } else 266 mdp2->md_ldt = NULL; 267 mtx_unlock(&dt_lock); 268 269 /* 270 * Now, cpu_switch() can schedule the new process. 271 * pcb_rsp 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 */ 286void 287cpu_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_r12 = (long) func; /* function */ 297 td->td_pcb->pcb_rbx = (long) arg; /* first arg */ 298} 299 300void 301cpu_exit(struct thread *td) 302{ 303 304 /* 305 * If this process has a custom LDT, release it. 306 */ 307 mtx_lock(&dt_lock); 308 if (td->td_proc->p_md.md_ldt != 0) 309 user_ldt_free(td); 310 else 311 mtx_unlock(&dt_lock); 312} 313 314void 315cpu_thread_exit(struct thread *td) 316{ 317 struct pcb *pcb; 318 319 critical_enter(); 320 if (td == PCPU_GET(fpcurthread)) 321 fpudrop(); 322 critical_exit(); 323 324 pcb = td->td_pcb; 325 326 /* Disable any hardware breakpoints. */ 327 if (pcb->pcb_flags & PCB_DBREGS) { 328 reset_dbregs(); 329 clear_pcb_flags(pcb, PCB_DBREGS); 330 } 331} 332 333void 334cpu_thread_clean(struct thread *td) 335{ 336 struct pcb *pcb; 337 338 pcb = td->td_pcb; 339 340 /* 341 * Clean TSS/iomap 342 */ 343 if (pcb->pcb_tssp != NULL) { 344 kmem_free(kernel_arena, (vm_offset_t)pcb->pcb_tssp, 345 ctob(IOPAGES + 1)); 346 pcb->pcb_tssp = NULL; 347 } 348} 349 350void 351cpu_thread_swapin(struct thread *td) 352{ 353} 354 355void 356cpu_thread_swapout(struct thread *td) 357{ 358} 359 360void 361cpu_thread_alloc(struct thread *td) 362{ 363 struct pcb *pcb; 364 struct xstate_hdr *xhdr; 365 366 td->td_pcb = pcb = get_pcb_td(td); 367 td->td_frame = (struct trapframe *)pcb - 1; 368 pcb->pcb_save = get_pcb_user_save_pcb(pcb); 369 if (use_xsave) { 370 xhdr = (struct xstate_hdr *)(pcb->pcb_save + 1); 371 bzero(xhdr, sizeof(*xhdr)); 372 xhdr->xstate_bv = xsave_mask; 373 } 374} 375 376void 377cpu_thread_free(struct thread *td) 378{ 379 380 cpu_thread_clean(td); 381} 382 383void 384cpu_set_syscall_retval(struct thread *td, int error) 385{ 386 387 switch (error) { 388 case 0: 389 td->td_frame->tf_rax = td->td_retval[0]; 390 td->td_frame->tf_rdx = td->td_retval[1]; 391 td->td_frame->tf_rflags &= ~PSL_C; 392 break; 393 394 case ERESTART: 395 /* 396 * Reconstruct pc, we know that 'syscall' is 2 bytes, 397 * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. 398 * We saved this in tf_err. 399 * %r10 (which was holding the value of %rcx) is restored 400 * for the next iteration. 401 * %r10 restore is only required for freebsd/amd64 processes, 402 * but shall be innocent for any ia32 ABI. 403 * 404 * Require full context restore to get the arguments 405 * in the registers reloaded at return to usermode. 406 */ 407 td->td_frame->tf_rip -= td->td_frame->tf_err; 408 td->td_frame->tf_r10 = td->td_frame->tf_rcx; 409 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 410 break; 411 412 case EJUSTRETURN: 413 break; 414 415 default: 416 if (td->td_proc->p_sysent->sv_errsize) { 417 if (error >= td->td_proc->p_sysent->sv_errsize) 418 error = -1; /* XXX */ 419 else 420 error = td->td_proc->p_sysent->sv_errtbl[error]; 421 } 422 td->td_frame->tf_rax = error; 423 td->td_frame->tf_rflags |= PSL_C; 424 break; 425 } 426} 427 428/* 429 * Initialize machine state (pcb and trap frame) for a new thread about to 430 * upcall. Put enough state in the new thread's PCB to get it to go back 431 * userret(), where we can intercept it again to set the return (upcall) 432 * Address and stack, along with those from upcals that are from other sources 433 * such as those generated in thread_userret() itself. 434 */ 435void 436cpu_set_upcall(struct thread *td, struct thread *td0) 437{ 438 struct pcb *pcb2; 439 440 /* Point the pcb to the top of the stack. */ 441 pcb2 = td->td_pcb; 442 443 /* 444 * Copy the upcall pcb. This loads kernel regs. 445 * Those not loaded individually below get their default 446 * values here. 447 */ 448 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); 449 clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE | 450 PCB_KERNFPU); 451 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); 452 bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save, 453 cpu_max_ext_state_size); 454 set_pcb_flags(pcb2, PCB_FULL_IRET); 455 456 /* 457 * Create a new fresh stack for the new thread. 458 */ 459 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 460 461 /* If the current thread has the trap bit set (i.e. a debugger had 462 * single stepped the process to the system call), we need to clear 463 * the trap flag from the new frame. Otherwise, the new thread will 464 * receive a (likely unexpected) SIGTRAP when it executes the first 465 * instruction after returning to userland. 466 */ 467 td->td_frame->tf_rflags &= ~PSL_T; 468 469 /* 470 * Set registers for trampoline to user mode. Leave space for the 471 * return address on stack. These are the kernel mode register values. 472 */ 473 pcb2->pcb_r12 = (register_t)fork_return; /* trampoline arg */ 474 pcb2->pcb_rbp = 0; 475 pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *); /* trampoline arg */ 476 pcb2->pcb_rbx = (register_t)td; /* trampoline arg */ 477 pcb2->pcb_rip = (register_t)fork_trampoline; 478 /* 479 * If we didn't copy the pcb, we'd need to do the following registers: 480 * pcb2->pcb_dr*: cloned above. 481 * pcb2->pcb_savefpu: cloned above. 482 * pcb2->pcb_onfault: cloned above (always NULL here?). 483 * pcb2->pcb_[fg]sbase: cloned above 484 */ 485 486 /* Setup to release spin count in fork_exit(). */ 487 td->td_md.md_spinlock_count = 1; 488 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 489} 490 491/* 492 * Set that machine state for performing an upcall that has to 493 * be done in thread_userret() so that those upcalls generated 494 * in thread_userret() itself can be done as well. 495 */ 496void 497cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg, 498 stack_t *stack) 499{ 500 501 /* 502 * Do any extra cleaning that needs to be done. 503 * The thread may have optional components 504 * that are not present in a fresh thread. 505 * This may be a recycled thread so make it look 506 * as though it's newly allocated. 507 */ 508 cpu_thread_clean(td); 509 510#ifdef COMPAT_FREEBSD32 511 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 512 /* 513 * Set the trap frame to point at the beginning of the uts 514 * function. 515 */ 516 td->td_frame->tf_rbp = 0; 517 td->td_frame->tf_rsp = 518 (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4; 519 td->td_frame->tf_rip = (uintptr_t)entry; 520 521 /* 522 * Pass the address of the mailbox for this kse to the uts 523 * function as a parameter on the stack. 524 */ 525 suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)), 526 (uint32_t)(uintptr_t)arg); 527 528 return; 529 } 530#endif 531 532 /* 533 * Set the trap frame to point at the beginning of the uts 534 * function. 535 */ 536 td->td_frame->tf_rbp = 0; 537 td->td_frame->tf_rsp = 538 ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f; 539 td->td_frame->tf_rsp -= 8; 540 td->td_frame->tf_rip = (register_t)entry; 541 td->td_frame->tf_ds = _udatasel; 542 td->td_frame->tf_es = _udatasel; 543 td->td_frame->tf_fs = _ufssel; 544 td->td_frame->tf_gs = _ugssel; 545 td->td_frame->tf_flags = TF_HASSEGS; 546 547 /* 548 * Pass the address of the mailbox for this kse to the uts 549 * function as a parameter on the stack. 550 */ 551 td->td_frame->tf_rdi = (register_t)arg; 552} 553 554int 555cpu_set_user_tls(struct thread *td, void *tls_base) 556{ 557 struct pcb *pcb; 558 559 if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS) 560 return (EINVAL); 561 562 pcb = td->td_pcb; 563 set_pcb_flags(pcb, PCB_FULL_IRET); 564#ifdef COMPAT_FREEBSD32 565 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 566 pcb->pcb_gsbase = (register_t)tls_base; 567 return (0); 568 } 569#endif 570 pcb->pcb_fsbase = (register_t)tls_base; 571 return (0); 572} 573 574#ifdef SMP 575static void 576cpu_reset_proxy() 577{ 578 cpuset_t tcrp; 579 580 cpu_reset_proxy_active = 1; 581 while (cpu_reset_proxy_active == 1) 582 ia32_pause(); /* Wait for other cpu to see that we've started */ 583 584 CPU_SETOF(cpu_reset_proxyid, &tcrp); 585 stop_cpus(tcrp); 586 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid); 587 DELAY(1000000); 588 cpu_reset_real(); 589} 590#endif 591 592void 593cpu_reset() 594{ 595#ifdef SMP 596 cpuset_t map; 597 u_int cnt; 598 599 if (smp_started) { 600 map = all_cpus; 601 CPU_CLR(PCPU_GET(cpuid), &map); 602 CPU_NAND(&map, &stopped_cpus); 603 if (!CPU_EMPTY(&map)) { 604 printf("cpu_reset: Stopping other CPUs\n"); 605 stop_cpus(map); 606 } 607 608 if (PCPU_GET(cpuid) != 0) { 609 cpu_reset_proxyid = PCPU_GET(cpuid); 610 cpustop_restartfunc = cpu_reset_proxy; 611 cpu_reset_proxy_active = 0; 612 printf("cpu_reset: Restarting BSP\n"); 613 614 /* Restart CPU #0. */ 615 CPU_SETOF(0, &started_cpus); 616 wmb(); 617 618 cnt = 0; 619 while (cpu_reset_proxy_active == 0 && cnt < 10000000) { 620 ia32_pause(); 621 cnt++; /* Wait for BSP to announce restart */ 622 } 623 if (cpu_reset_proxy_active == 0) 624 printf("cpu_reset: Failed to restart BSP\n"); 625 enable_intr(); 626 cpu_reset_proxy_active = 2; 627 628 while (1) 629 ia32_pause(); 630 /* NOTREACHED */ 631 } 632 633 DELAY(1000000); 634 } 635#endif 636 cpu_reset_real(); 637 /* NOTREACHED */ 638} 639 640static void 641cpu_reset_real() 642{ 643 struct region_descriptor null_idt; 644 int b; 645 646 disable_intr(); 647 648 /* 649 * Attempt to do a CPU reset via the keyboard controller, 650 * do not turn off GateA20, as any machine that fails 651 * to do the reset here would then end up in no man's land. 652 */ 653 outb(IO_KBD + 4, 0xFE); 654 DELAY(500000); /* wait 0.5 sec to see if that did it */ 655 656 /* 657 * Attempt to force a reset via the Reset Control register at 658 * I/O port 0xcf9. Bit 2 forces a system reset when it 659 * transitions from 0 to 1. Bit 1 selects the type of reset 660 * to attempt: 0 selects a "soft" reset, and 1 selects a 661 * "hard" reset. We try a "hard" reset. The first write sets 662 * bit 1 to select a "hard" reset and clears bit 2. The 663 * second write forces a 0 -> 1 transition in bit 2 to trigger 664 * a reset. 665 */ 666 outb(0xcf9, 0x2); 667 outb(0xcf9, 0x6); 668 DELAY(500000); /* wait 0.5 sec to see if that did it */ 669 670 /* 671 * Attempt to force a reset via the Fast A20 and Init register 672 * at I/O port 0x92. Bit 1 serves as an alternate A20 gate. 673 * Bit 0 asserts INIT# when set to 1. We are careful to only 674 * preserve bit 1 while setting bit 0. We also must clear bit 675 * 0 before setting it if it isn't already clear. 676 */ 677 b = inb(0x92); 678 if (b != 0xff) { 679 if ((b & 0x1) != 0) 680 outb(0x92, b & 0xfe); 681 outb(0x92, b | 0x1); 682 DELAY(500000); /* wait 0.5 sec to see if that did it */ 683 } 684 685 printf("No known reset method worked, attempting CPU shutdown\n"); 686 DELAY(1000000); /* wait 1 sec for printf to complete */ 687 688 /* Wipe the IDT. */ 689 null_idt.rd_limit = 0; 690 null_idt.rd_base = 0; 691 lidt(&null_idt); 692 693 /* "good night, sweet prince .... <THUNK!>" */ 694 breakpoint(); 695 696 /* NOTREACHED */ 697 while(1); 698} 699 700/* 701 * Software interrupt handler for queued VM system processing. 702 */ 703void 704swi_vm(void *dummy) 705{ 706 if (busdma_swi_pending != 0) 707 busdma_swi(); 708} 709 710/* 711 * Tell whether this address is in some physical memory region. 712 * Currently used by the kernel coredump code in order to avoid 713 * dumping the ``ISA memory hole'' which could cause indefinite hangs, 714 * or other unpredictable behaviour. 715 */ 716 717int 718is_physical_memory(vm_paddr_t addr) 719{ 720 721#ifdef DEV_ISA 722 /* The ISA ``memory hole''. */ 723 if (addr >= 0xa0000 && addr < 0x100000) 724 return 0; 725#endif 726 727 /* 728 * stuff other tests for known memory-mapped devices (PCI?) 729 * here 730 */ 731 732 return 1; 733} 734