vm_machdep.c revision 332758
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: stable/11/sys/amd64/amd64/vm_machdep.c 332758 2018-04-19 06:18:21Z avg $"); 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(struct thread *td1, struct proc *p2, struct thread *td2, int flags) 152{ 153 struct proc *p1; 154 struct pcb *pcb2; 155 struct mdproc *mdp1, *mdp2; 156 struct proc_ldt *pldt; 157 158 p1 = td1->td_proc; 159 if ((flags & RFPROC) == 0) { 160 if ((flags & RFMEM) == 0) { 161 /* unshare user LDT */ 162 mdp1 = &p1->p_md; 163 mtx_lock(&dt_lock); 164 if ((pldt = mdp1->md_ldt) != NULL && 165 pldt->ldt_refcnt > 1 && 166 user_ldt_alloc(p1, 1) == NULL) 167 panic("could not copy LDT"); 168 mtx_unlock(&dt_lock); 169 } 170 return; 171 } 172 173 /* Ensure that td1's pcb is up to date. */ 174 fpuexit(td1); 175 update_pcb_bases(td1->td_pcb); 176 177 /* Point the pcb to the top of the stack */ 178 pcb2 = get_pcb_td(td2); 179 td2->td_pcb = pcb2; 180 181 /* Copy td1's pcb */ 182 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 183 184 /* Properly initialize pcb_save */ 185 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); 186 bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2), 187 cpu_max_ext_state_size); 188 189 /* Point mdproc and then copy over td1's contents */ 190 mdp2 = &p2->p_md; 191 bcopy(&p1->p_md, mdp2, sizeof(*mdp2)); 192 193 /* 194 * Create a new fresh stack for the new process. 195 * Copy the trap frame for the return to user mode as if from a 196 * syscall. This copies most of the user mode register values. 197 */ 198 td2->td_frame = (struct trapframe *)td2->td_pcb - 1; 199 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); 200 201 td2->td_frame->tf_rax = 0; /* Child returns zero */ 202 td2->td_frame->tf_rflags &= ~PSL_C; /* success */ 203 td2->td_frame->tf_rdx = 1; 204 205 /* 206 * If the parent process has the trap bit set (i.e. a debugger had 207 * single stepped the process to the system call), we need to clear 208 * the trap flag from the new frame unless the debugger had set PF_FORK 209 * on the parent. Otherwise, the child will receive a (likely 210 * unexpected) SIGTRAP when it executes the first instruction after 211 * returning to userland. 212 */ 213 if ((p1->p_pfsflags & PF_FORK) == 0) 214 td2->td_frame->tf_rflags &= ~PSL_T; 215 216 /* 217 * Set registers for trampoline to user mode. Leave space for the 218 * return address on stack. These are the kernel mode register values. 219 */ 220 pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */ 221 pcb2->pcb_rbp = 0; 222 pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *); 223 pcb2->pcb_rbx = (register_t)td2; /* fork_trampoline argument */ 224 pcb2->pcb_rip = (register_t)fork_trampoline; 225 /*- 226 * pcb2->pcb_dr*: cloned above. 227 * pcb2->pcb_savefpu: cloned above. 228 * pcb2->pcb_flags: cloned above. 229 * pcb2->pcb_onfault: cloned above (always NULL here?). 230 * pcb2->pcb_[fg]sbase: cloned above 231 */ 232 233 /* Setup to release spin count in fork_exit(). */ 234 td2->td_md.md_spinlock_count = 1; 235 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 236 td2->td_md.md_invl_gen.gen = 0; 237 238 /* As an i386, do not copy io permission bitmap. */ 239 pcb2->pcb_tssp = NULL; 240 241 /* New segment registers. */ 242 set_pcb_flags_raw(pcb2, PCB_FULL_IRET); 243 244 /* Copy the LDT, if necessary. */ 245 mdp1 = &td1->td_proc->p_md; 246 mdp2 = &p2->p_md; 247 mtx_lock(&dt_lock); 248 if (mdp1->md_ldt != NULL) { 249 if (flags & RFMEM) { 250 mdp1->md_ldt->ldt_refcnt++; 251 mdp2->md_ldt = mdp1->md_ldt; 252 bcopy(&mdp1->md_ldt_sd, &mdp2->md_ldt_sd, sizeof(struct 253 system_segment_descriptor)); 254 } else { 255 mdp2->md_ldt = NULL; 256 mdp2->md_ldt = user_ldt_alloc(p2, 0); 257 if (mdp2->md_ldt == NULL) 258 panic("could not copy LDT"); 259 amd64_set_ldt_data(td2, 0, max_ldt_segment, 260 (struct user_segment_descriptor *) 261 mdp1->md_ldt->ldt_base); 262 } 263 } else 264 mdp2->md_ldt = NULL; 265 mtx_unlock(&dt_lock); 266 267 /* 268 * Now, cpu_switch() can schedule the new process. 269 * pcb_rsp is loaded pointing to the cpu_switch() stack frame 270 * containing the return address when exiting cpu_switch. 271 * This will normally be to fork_trampoline(), which will have 272 * %ebx loaded with the new proc's pointer. fork_trampoline() 273 * will set up a stack to call fork_return(p, frame); to complete 274 * the return to user-mode. 275 */ 276} 277 278/* 279 * Intercept the return address from a freshly forked process that has NOT 280 * been scheduled yet. 281 * 282 * This is needed to make kernel threads stay in kernel mode. 283 */ 284void 285cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg) 286{ 287 /* 288 * Note that the trap frame follows the args, so the function 289 * is really called like this: func(arg, frame); 290 */ 291 td->td_pcb->pcb_r12 = (long) func; /* function */ 292 td->td_pcb->pcb_rbx = (long) arg; /* first arg */ 293} 294 295void 296cpu_exit(struct thread *td) 297{ 298 299 /* 300 * If this process has a custom LDT, release it. 301 */ 302 mtx_lock(&dt_lock); 303 if (td->td_proc->p_md.md_ldt != 0) 304 user_ldt_free(td); 305 else 306 mtx_unlock(&dt_lock); 307} 308 309void 310cpu_thread_exit(struct thread *td) 311{ 312 struct pcb *pcb; 313 314 critical_enter(); 315 if (td == PCPU_GET(fpcurthread)) 316 fpudrop(); 317 critical_exit(); 318 319 pcb = td->td_pcb; 320 321 /* Disable any hardware breakpoints. */ 322 if (pcb->pcb_flags & PCB_DBREGS) { 323 reset_dbregs(); 324 clear_pcb_flags(pcb, PCB_DBREGS); 325 } 326} 327 328void 329cpu_thread_clean(struct thread *td) 330{ 331 struct pcb *pcb; 332 333 pcb = td->td_pcb; 334 335 /* 336 * Clean TSS/iomap 337 */ 338 if (pcb->pcb_tssp != NULL) { 339 pmap_pti_remove_kva((vm_offset_t)pcb->pcb_tssp, 340 (vm_offset_t)pcb->pcb_tssp + ctob(IOPAGES + 1)); 341 kmem_free(kernel_arena, (vm_offset_t)pcb->pcb_tssp, 342 ctob(IOPAGES + 1)); 343 pcb->pcb_tssp = NULL; 344 } 345} 346 347void 348cpu_thread_swapin(struct thread *td) 349{ 350} 351 352void 353cpu_thread_swapout(struct thread *td) 354{ 355} 356 357void 358cpu_thread_alloc(struct thread *td) 359{ 360 struct pcb *pcb; 361 struct xstate_hdr *xhdr; 362 363 td->td_pcb = pcb = get_pcb_td(td); 364 td->td_frame = (struct trapframe *)pcb - 1; 365 pcb->pcb_save = get_pcb_user_save_pcb(pcb); 366 if (use_xsave) { 367 xhdr = (struct xstate_hdr *)(pcb->pcb_save + 1); 368 bzero(xhdr, sizeof(*xhdr)); 369 xhdr->xstate_bv = xsave_mask; 370 } 371} 372 373void 374cpu_thread_free(struct thread *td) 375{ 376 377 cpu_thread_clean(td); 378} 379 380void 381cpu_set_syscall_retval(struct thread *td, int error) 382{ 383 384 switch (error) { 385 case 0: 386 td->td_frame->tf_rax = td->td_retval[0]; 387 td->td_frame->tf_rdx = td->td_retval[1]; 388 td->td_frame->tf_rflags &= ~PSL_C; 389 break; 390 391 case ERESTART: 392 /* 393 * Reconstruct pc, we know that 'syscall' is 2 bytes, 394 * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. 395 * We saved this in tf_err. 396 * %r10 (which was holding the value of %rcx) is restored 397 * for the next iteration. 398 * %r10 restore is only required for freebsd/amd64 processes, 399 * but shall be innocent for any ia32 ABI. 400 * 401 * Require full context restore to get the arguments 402 * in the registers reloaded at return to usermode. 403 */ 404 td->td_frame->tf_rip -= td->td_frame->tf_err; 405 td->td_frame->tf_r10 = td->td_frame->tf_rcx; 406 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 407 break; 408 409 case EJUSTRETURN: 410 break; 411 412 default: 413 td->td_frame->tf_rax = SV_ABI_ERRNO(td->td_proc, error); 414 td->td_frame->tf_rflags |= PSL_C; 415 break; 416 } 417} 418 419/* 420 * Initialize machine state, mostly pcb and trap frame for a new 421 * thread, about to return to userspace. Put enough state in the new 422 * thread's PCB to get it to go back to the fork_return(), which 423 * finalizes the thread state and handles peculiarities of the first 424 * return to userspace for the new thread. 425 */ 426void 427cpu_copy_thread(struct thread *td, struct thread *td0) 428{ 429 struct pcb *pcb2; 430 431 /* Point the pcb to the top of the stack. */ 432 pcb2 = td->td_pcb; 433 434 /* 435 * Copy the upcall pcb. This loads kernel regs. 436 * Those not loaded individually below get their default 437 * values here. 438 */ 439 update_pcb_bases(td0->td_pcb); 440 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); 441 clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE | 442 PCB_KERNFPU); 443 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); 444 bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save, 445 cpu_max_ext_state_size); 446 set_pcb_flags_raw(pcb2, PCB_FULL_IRET); 447 448 /* 449 * Create a new fresh stack for the new thread. 450 */ 451 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 452 453 /* If the current thread has the trap bit set (i.e. a debugger had 454 * single stepped the process to the system call), we need to clear 455 * the trap flag from the new frame. Otherwise, the new thread will 456 * receive a (likely unexpected) SIGTRAP when it executes the first 457 * instruction after returning to userland. 458 */ 459 td->td_frame->tf_rflags &= ~PSL_T; 460 461 /* 462 * Set registers for trampoline to user mode. Leave space for the 463 * return address on stack. These are the kernel mode register values. 464 */ 465 pcb2->pcb_r12 = (register_t)fork_return; /* trampoline arg */ 466 pcb2->pcb_rbp = 0; 467 pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *); /* trampoline arg */ 468 pcb2->pcb_rbx = (register_t)td; /* trampoline arg */ 469 pcb2->pcb_rip = (register_t)fork_trampoline; 470 /* 471 * If we didn't copy the pcb, we'd need to do the following registers: 472 * pcb2->pcb_dr*: cloned above. 473 * pcb2->pcb_savefpu: cloned above. 474 * pcb2->pcb_onfault: cloned above (always NULL here?). 475 * pcb2->pcb_[fg]sbase: cloned above 476 */ 477 478 /* Setup to release spin count in fork_exit(). */ 479 td->td_md.md_spinlock_count = 1; 480 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 481} 482 483/* 484 * Set that machine state for performing an upcall that starts 485 * the entry function with the given argument. 486 */ 487void 488cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg, 489 stack_t *stack) 490{ 491 492 /* 493 * Do any extra cleaning that needs to be done. 494 * The thread may have optional components 495 * that are not present in a fresh thread. 496 * This may be a recycled thread so make it look 497 * as though it's newly allocated. 498 */ 499 cpu_thread_clean(td); 500 501#ifdef COMPAT_FREEBSD32 502 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 503 /* 504 * Set the trap frame to point at the beginning of the entry 505 * function. 506 */ 507 td->td_frame->tf_rbp = 0; 508 td->td_frame->tf_rsp = 509 (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4; 510 td->td_frame->tf_rip = (uintptr_t)entry; 511 512 /* Return address sentinel value to stop stack unwinding. */ 513 suword32((void *)td->td_frame->tf_rsp, 0); 514 515 /* Pass the argument to the entry point. */ 516 suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)), 517 (uint32_t)(uintptr_t)arg); 518 519 return; 520 } 521#endif 522 523 /* 524 * Set the trap frame to point at the beginning of the uts 525 * function. 526 */ 527 td->td_frame->tf_rbp = 0; 528 td->td_frame->tf_rsp = 529 ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f; 530 td->td_frame->tf_rsp -= 8; 531 td->td_frame->tf_rip = (register_t)entry; 532 td->td_frame->tf_ds = _udatasel; 533 td->td_frame->tf_es = _udatasel; 534 td->td_frame->tf_fs = _ufssel; 535 td->td_frame->tf_gs = _ugssel; 536 td->td_frame->tf_flags = TF_HASSEGS; 537 538 /* Return address sentinel value to stop stack unwinding. */ 539 suword((void *)td->td_frame->tf_rsp, 0); 540 541 /* Pass the argument to the entry point. */ 542 td->td_frame->tf_rdi = (register_t)arg; 543} 544 545int 546cpu_set_user_tls(struct thread *td, void *tls_base) 547{ 548 struct pcb *pcb; 549 550 if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS) 551 return (EINVAL); 552 553 pcb = td->td_pcb; 554 set_pcb_flags(pcb, PCB_FULL_IRET); 555#ifdef COMPAT_FREEBSD32 556 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 557 pcb->pcb_gsbase = (register_t)tls_base; 558 return (0); 559 } 560#endif 561 pcb->pcb_fsbase = (register_t)tls_base; 562 return (0); 563} 564 565#ifdef SMP 566static void 567cpu_reset_proxy() 568{ 569 570 cpu_reset_proxy_active = 1; 571 while (cpu_reset_proxy_active == 1) 572 ia32_pause(); /* Wait for other cpu to see that we've started */ 573 574 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid); 575 DELAY(1000000); 576 cpu_reset_real(); 577} 578#endif 579 580void 581cpu_reset() 582{ 583#ifdef SMP 584 cpuset_t map; 585 u_int cnt; 586 587 if (smp_started) { 588 map = all_cpus; 589 CPU_CLR(PCPU_GET(cpuid), &map); 590 CPU_NAND(&map, &stopped_cpus); 591 if (!CPU_EMPTY(&map)) { 592 printf("cpu_reset: Stopping other CPUs\n"); 593 stop_cpus(map); 594 } 595 596 if (PCPU_GET(cpuid) != 0) { 597 cpu_reset_proxyid = PCPU_GET(cpuid); 598 cpustop_restartfunc = cpu_reset_proxy; 599 cpu_reset_proxy_active = 0; 600 printf("cpu_reset: Restarting BSP\n"); 601 602 /* Restart CPU #0. */ 603 CPU_SETOF(0, &started_cpus); 604 wmb(); 605 606 cnt = 0; 607 while (cpu_reset_proxy_active == 0 && cnt < 10000000) { 608 ia32_pause(); 609 cnt++; /* Wait for BSP to announce restart */ 610 } 611 if (cpu_reset_proxy_active == 0) { 612 printf("cpu_reset: Failed to restart BSP\n"); 613 } else { 614 cpu_reset_proxy_active = 2; 615 while (1) 616 ia32_pause(); 617 /* NOTREACHED */ 618 } 619 } 620 621 DELAY(1000000); 622 } 623#endif 624 cpu_reset_real(); 625 /* NOTREACHED */ 626} 627 628static void 629cpu_reset_real() 630{ 631 struct region_descriptor null_idt; 632 int b; 633 634 disable_intr(); 635 636 /* 637 * Attempt to do a CPU reset via the keyboard controller, 638 * do not turn off GateA20, as any machine that fails 639 * to do the reset here would then end up in no man's land. 640 */ 641 outb(IO_KBD + 4, 0xFE); 642 DELAY(500000); /* wait 0.5 sec to see if that did it */ 643 644 /* 645 * Attempt to force a reset via the Reset Control register at 646 * I/O port 0xcf9. Bit 2 forces a system reset when it 647 * transitions from 0 to 1. Bit 1 selects the type of reset 648 * to attempt: 0 selects a "soft" reset, and 1 selects a 649 * "hard" reset. We try a "hard" reset. The first write sets 650 * bit 1 to select a "hard" reset and clears bit 2. The 651 * second write forces a 0 -> 1 transition in bit 2 to trigger 652 * a reset. 653 */ 654 outb(0xcf9, 0x2); 655 outb(0xcf9, 0x6); 656 DELAY(500000); /* wait 0.5 sec to see if that did it */ 657 658 /* 659 * Attempt to force a reset via the Fast A20 and Init register 660 * at I/O port 0x92. Bit 1 serves as an alternate A20 gate. 661 * Bit 0 asserts INIT# when set to 1. We are careful to only 662 * preserve bit 1 while setting bit 0. We also must clear bit 663 * 0 before setting it if it isn't already clear. 664 */ 665 b = inb(0x92); 666 if (b != 0xff) { 667 if ((b & 0x1) != 0) 668 outb(0x92, b & 0xfe); 669 outb(0x92, b | 0x1); 670 DELAY(500000); /* wait 0.5 sec to see if that did it */ 671 } 672 673 printf("No known reset method worked, attempting CPU shutdown\n"); 674 DELAY(1000000); /* wait 1 sec for printf to complete */ 675 676 /* Wipe the IDT. */ 677 null_idt.rd_limit = 0; 678 null_idt.rd_base = 0; 679 lidt(&null_idt); 680 681 /* "good night, sweet prince .... <THUNK!>" */ 682 breakpoint(); 683 684 /* NOTREACHED */ 685 while(1); 686} 687 688/* 689 * Software interrupt handler for queued VM system processing. 690 */ 691void 692swi_vm(void *dummy) 693{ 694 if (busdma_swi_pending != 0) 695 busdma_swi(); 696} 697 698/* 699 * Tell whether this address is in some physical memory region. 700 * Currently used by the kernel coredump code in order to avoid 701 * dumping the ``ISA memory hole'' which could cause indefinite hangs, 702 * or other unpredictable behaviour. 703 */ 704 705int 706is_physical_memory(vm_paddr_t addr) 707{ 708 709#ifdef DEV_ISA 710 /* The ISA ``memory hole''. */ 711 if (addr >= 0xa0000 && addr < 0x100000) 712 return 0; 713#endif 714 715 /* 716 * stuff other tests for known memory-mapped devices (PCI?) 717 * here 718 */ 719 720 return 1; 721} 722