vm_machdep.c revision 222813
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 222813 2011-06-07 08:46:13Z attilio $"); 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/sched.h> 63#include <sys/sf_buf.h> 64#include <sys/smp.h> 65#include <sys/sysctl.h> 66#include <sys/sysent.h> 67#include <sys/unistd.h> 68#include <sys/vnode.h> 69#include <sys/vmmeter.h> 70 71#include <machine/cpu.h> 72#include <machine/md_var.h> 73#include <machine/pcb.h> 74#include <machine/smp.h> 75#include <machine/specialreg.h> 76#include <machine/tss.h> 77 78#include <vm/vm.h> 79#include <vm/vm_extern.h> 80#include <vm/vm_kern.h> 81#include <vm/vm_page.h> 82#include <vm/vm_map.h> 83#include <vm/vm_param.h> 84 85#include <x86/isa/isa.h> 86 87static void cpu_reset_real(void); 88#ifdef SMP 89static void cpu_reset_proxy(void); 90static u_int cpu_reset_proxyid; 91static volatile u_int cpu_reset_proxy_active; 92#endif 93 94/* 95 * Finish a fork operation, with process p2 nearly set up. 96 * Copy and update the pcb, set up the stack so that the child 97 * ready to run and return to user mode. 98 */ 99void 100cpu_fork(td1, p2, td2, flags) 101 register struct thread *td1; 102 register struct proc *p2; 103 struct thread *td2; 104 int flags; 105{ 106 register struct proc *p1; 107 struct pcb *pcb2; 108 struct mdproc *mdp1, *mdp2; 109 struct proc_ldt *pldt; 110 pmap_t pmap2; 111 112 p1 = td1->td_proc; 113 if ((flags & RFPROC) == 0) { 114 if ((flags & RFMEM) == 0) { 115 /* unshare user LDT */ 116 mdp1 = &p1->p_md; 117 mtx_lock(&dt_lock); 118 if ((pldt = mdp1->md_ldt) != NULL && 119 pldt->ldt_refcnt > 1 && 120 user_ldt_alloc(p1, 1) == NULL) 121 panic("could not copy LDT"); 122 mtx_unlock(&dt_lock); 123 } 124 return; 125 } 126 127 /* Ensure that td1's pcb is up to date. */ 128 fpuexit(td1); 129 130 /* Point the pcb to the top of the stack */ 131 pcb2 = (struct pcb *)(td2->td_kstack + 132 td2->td_kstack_pages * PAGE_SIZE) - 1; 133 td2->td_pcb = pcb2; 134 135 /* Copy td1's pcb */ 136 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 137 138 /* Properly initialize pcb_save */ 139 pcb2->pcb_save = &pcb2->pcb_user_save; 140 141 /* Point mdproc and then copy over td1's contents */ 142 mdp2 = &p2->p_md; 143 bcopy(&p1->p_md, mdp2, sizeof(*mdp2)); 144 145 /* 146 * Create a new fresh stack for the new process. 147 * Copy the trap frame for the return to user mode as if from a 148 * syscall. This copies most of the user mode register values. 149 */ 150 td2->td_frame = (struct trapframe *)td2->td_pcb - 1; 151 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); 152 153 td2->td_frame->tf_rax = 0; /* Child returns zero */ 154 td2->td_frame->tf_rflags &= ~PSL_C; /* success */ 155 td2->td_frame->tf_rdx = 1; 156 157 /* 158 * If the parent process has the trap bit set (i.e. a debugger had 159 * single stepped the process to the system call), we need to clear 160 * the trap flag from the new frame unless the debugger had set PF_FORK 161 * on the parent. Otherwise, the child will receive a (likely 162 * unexpected) SIGTRAP when it executes the first instruction after 163 * returning to userland. 164 */ 165 if ((p1->p_pfsflags & PF_FORK) == 0) 166 td2->td_frame->tf_rflags &= ~PSL_T; 167 168 /* 169 * Set registers for trampoline to user mode. Leave space for the 170 * return address on stack. These are the kernel mode register values. 171 */ 172 pmap2 = vmspace_pmap(p2->p_vmspace); 173 pcb2->pcb_cr3 = DMAP_TO_PHYS((vm_offset_t)pmap2->pm_pml4); 174 pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */ 175 pcb2->pcb_rbp = 0; 176 pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *); 177 pcb2->pcb_rbx = (register_t)td2; /* fork_trampoline argument */ 178 pcb2->pcb_rip = (register_t)fork_trampoline; 179 /*- 180 * pcb2->pcb_dr*: cloned above. 181 * pcb2->pcb_savefpu: cloned above. 182 * pcb2->pcb_flags: cloned above. 183 * pcb2->pcb_onfault: cloned above (always NULL here?). 184 * pcb2->pcb_[fg]sbase: cloned above 185 */ 186 187 /* Setup to release spin count in fork_exit(). */ 188 td2->td_md.md_spinlock_count = 1; 189 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 190 191 /* As an i386, do not copy io permission bitmap. */ 192 pcb2->pcb_tssp = NULL; 193 194 /* New segment registers. */ 195 set_pcb_flags(pcb2, PCB_FULL_IRET); 196 197 /* Copy the LDT, if necessary. */ 198 mdp1 = &td1->td_proc->p_md; 199 mdp2 = &p2->p_md; 200 mtx_lock(&dt_lock); 201 if (mdp1->md_ldt != NULL) { 202 if (flags & RFMEM) { 203 mdp1->md_ldt->ldt_refcnt++; 204 mdp2->md_ldt = mdp1->md_ldt; 205 bcopy(&mdp1->md_ldt_sd, &mdp2->md_ldt_sd, sizeof(struct 206 system_segment_descriptor)); 207 } else { 208 mdp2->md_ldt = NULL; 209 mdp2->md_ldt = user_ldt_alloc(p2, 0); 210 if (mdp2->md_ldt == NULL) 211 panic("could not copy LDT"); 212 amd64_set_ldt_data(td2, 0, max_ldt_segment, 213 (struct user_segment_descriptor *) 214 mdp1->md_ldt->ldt_base); 215 } 216 } else 217 mdp2->md_ldt = NULL; 218 mtx_unlock(&dt_lock); 219 220 /* 221 * Now, cpu_switch() can schedule the new process. 222 * pcb_rsp is loaded pointing to the cpu_switch() stack frame 223 * containing the return address when exiting cpu_switch. 224 * This will normally be to fork_trampoline(), which will have 225 * %ebx loaded with the new proc's pointer. fork_trampoline() 226 * will set up a stack to call fork_return(p, frame); to complete 227 * the return to user-mode. 228 */ 229} 230 231/* 232 * Intercept the return address from a freshly forked process that has NOT 233 * been scheduled yet. 234 * 235 * This is needed to make kernel threads stay in kernel mode. 236 */ 237void 238cpu_set_fork_handler(td, func, arg) 239 struct thread *td; 240 void (*func)(void *); 241 void *arg; 242{ 243 /* 244 * Note that the trap frame follows the args, so the function 245 * is really called like this: func(arg, frame); 246 */ 247 td->td_pcb->pcb_r12 = (long) func; /* function */ 248 td->td_pcb->pcb_rbx = (long) arg; /* first arg */ 249} 250 251void 252cpu_exit(struct thread *td) 253{ 254 255 /* 256 * If this process has a custom LDT, release it. 257 */ 258 mtx_lock(&dt_lock); 259 if (td->td_proc->p_md.md_ldt != 0) 260 user_ldt_free(td); 261 else 262 mtx_unlock(&dt_lock); 263} 264 265void 266cpu_thread_exit(struct thread *td) 267{ 268 struct pcb *pcb; 269 270 critical_enter(); 271 if (td == PCPU_GET(fpcurthread)) 272 fpudrop(); 273 critical_exit(); 274 275 pcb = td->td_pcb; 276 277 /* Disable any hardware breakpoints. */ 278 if (pcb->pcb_flags & PCB_DBREGS) { 279 reset_dbregs(); 280 clear_pcb_flags(pcb, PCB_DBREGS); 281 } 282} 283 284void 285cpu_thread_clean(struct thread *td) 286{ 287 struct pcb *pcb; 288 289 pcb = td->td_pcb; 290 291 /* 292 * Clean TSS/iomap 293 */ 294 if (pcb->pcb_tssp != NULL) { 295 kmem_free(kernel_map, (vm_offset_t)pcb->pcb_tssp, 296 ctob(IOPAGES + 1)); 297 pcb->pcb_tssp = NULL; 298 } 299} 300 301void 302cpu_thread_swapin(struct thread *td) 303{ 304} 305 306void 307cpu_thread_swapout(struct thread *td) 308{ 309} 310 311void 312cpu_thread_alloc(struct thread *td) 313{ 314 315 td->td_pcb = (struct pcb *)(td->td_kstack + 316 td->td_kstack_pages * PAGE_SIZE) - 1; 317 td->td_frame = (struct trapframe *)td->td_pcb - 1; 318 td->td_pcb->pcb_save = &td->td_pcb->pcb_user_save; 319} 320 321void 322cpu_thread_free(struct thread *td) 323{ 324 325 cpu_thread_clean(td); 326} 327 328void 329cpu_set_syscall_retval(struct thread *td, int error) 330{ 331 332 switch (error) { 333 case 0: 334 td->td_frame->tf_rax = td->td_retval[0]; 335 td->td_frame->tf_rdx = td->td_retval[1]; 336 td->td_frame->tf_rflags &= ~PSL_C; 337 break; 338 339 case ERESTART: 340 /* 341 * Reconstruct pc, we know that 'syscall' is 2 bytes, 342 * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. 343 * We saved this in tf_err. 344 * %r10 (which was holding the value of %rcx) is restored 345 * for the next iteration. 346 * %r10 restore is only required for freebsd/amd64 processes, 347 * but shall be innocent for any ia32 ABI. 348 */ 349 td->td_frame->tf_rip -= td->td_frame->tf_err; 350 td->td_frame->tf_r10 = td->td_frame->tf_rcx; 351 break; 352 353 case EJUSTRETURN: 354 break; 355 356 default: 357 if (td->td_proc->p_sysent->sv_errsize) { 358 if (error >= td->td_proc->p_sysent->sv_errsize) 359 error = -1; /* XXX */ 360 else 361 error = td->td_proc->p_sysent->sv_errtbl[error]; 362 } 363 td->td_frame->tf_rax = error; 364 td->td_frame->tf_rflags |= PSL_C; 365 break; 366 } 367} 368 369/* 370 * Initialize machine state (pcb and trap frame) for a new thread about to 371 * upcall. Put enough state in the new thread's PCB to get it to go back 372 * userret(), where we can intercept it again to set the return (upcall) 373 * Address and stack, along with those from upcals that are from other sources 374 * such as those generated in thread_userret() itself. 375 */ 376void 377cpu_set_upcall(struct thread *td, struct thread *td0) 378{ 379 struct pcb *pcb2; 380 381 /* Point the pcb to the top of the stack. */ 382 pcb2 = td->td_pcb; 383 384 /* 385 * Copy the upcall pcb. This loads kernel regs. 386 * Those not loaded individually below get their default 387 * values here. 388 */ 389 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); 390 clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE); 391 pcb2->pcb_save = &pcb2->pcb_user_save; 392 set_pcb_flags(pcb2, PCB_FULL_IRET); 393 394 /* 395 * Create a new fresh stack for the new thread. 396 */ 397 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 398 399 /* If the current thread has the trap bit set (i.e. a debugger had 400 * single stepped the process to the system call), we need to clear 401 * the trap flag from the new frame. Otherwise, the new thread will 402 * receive a (likely unexpected) SIGTRAP when it executes the first 403 * instruction after returning to userland. 404 */ 405 td->td_frame->tf_rflags &= ~PSL_T; 406 407 /* 408 * Set registers for trampoline to user mode. Leave space for the 409 * return address on stack. These are the kernel mode register values. 410 */ 411 pcb2->pcb_r12 = (register_t)fork_return; /* trampoline arg */ 412 pcb2->pcb_rbp = 0; 413 pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *); /* trampoline arg */ 414 pcb2->pcb_rbx = (register_t)td; /* trampoline arg */ 415 pcb2->pcb_rip = (register_t)fork_trampoline; 416 /* 417 * If we didn't copy the pcb, we'd need to do the following registers: 418 * pcb2->pcb_cr3: cloned above. 419 * pcb2->pcb_dr*: cloned above. 420 * pcb2->pcb_savefpu: cloned above. 421 * pcb2->pcb_onfault: cloned above (always NULL here?). 422 * pcb2->pcb_[fg]sbase: cloned above 423 */ 424 425 /* Setup to release spin count in fork_exit(). */ 426 td->td_md.md_spinlock_count = 1; 427 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 428} 429 430/* 431 * Set that machine state for performing an upcall that has to 432 * be done in thread_userret() so that those upcalls generated 433 * in thread_userret() itself can be done as well. 434 */ 435void 436cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg, 437 stack_t *stack) 438{ 439 440 /* 441 * Do any extra cleaning that needs to be done. 442 * The thread may have optional components 443 * that are not present in a fresh thread. 444 * This may be a recycled thread so make it look 445 * as though it's newly allocated. 446 */ 447 cpu_thread_clean(td); 448 449#ifdef COMPAT_FREEBSD32 450 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 451 /* 452 * Set the trap frame to point at the beginning of the uts 453 * function. 454 */ 455 td->td_frame->tf_rbp = 0; 456 td->td_frame->tf_rsp = 457 (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4; 458 td->td_frame->tf_rip = (uintptr_t)entry; 459 460 /* 461 * Pass the address of the mailbox for this kse to the uts 462 * function as a parameter on the stack. 463 */ 464 suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)), 465 (uint32_t)(uintptr_t)arg); 466 467 return; 468 } 469#endif 470 471 /* 472 * Set the trap frame to point at the beginning of the uts 473 * function. 474 */ 475 td->td_frame->tf_rbp = 0; 476 td->td_frame->tf_rsp = 477 ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f; 478 td->td_frame->tf_rsp -= 8; 479 td->td_frame->tf_rip = (register_t)entry; 480 td->td_frame->tf_ds = _udatasel; 481 td->td_frame->tf_es = _udatasel; 482 td->td_frame->tf_fs = _ufssel; 483 td->td_frame->tf_gs = _ugssel; 484 td->td_frame->tf_flags = TF_HASSEGS; 485 486 /* 487 * Pass the address of the mailbox for this kse to the uts 488 * function as a parameter on the stack. 489 */ 490 td->td_frame->tf_rdi = (register_t)arg; 491} 492 493int 494cpu_set_user_tls(struct thread *td, void *tls_base) 495{ 496 struct pcb *pcb; 497 498 if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS) 499 return (EINVAL); 500 501 pcb = td->td_pcb; 502#ifdef COMPAT_FREEBSD32 503 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 504 pcb->pcb_gsbase = (register_t)tls_base; 505 return (0); 506 } 507#endif 508 pcb->pcb_fsbase = (register_t)tls_base; 509 set_pcb_flags(pcb, PCB_FULL_IRET); 510 return (0); 511} 512 513#ifdef SMP 514static void 515cpu_reset_proxy() 516{ 517 cpuset_t tcrp; 518 519 cpu_reset_proxy_active = 1; 520 while (cpu_reset_proxy_active == 1) 521 ; /* Wait for other cpu to see that we've started */ 522 CPU_SETOF(cpu_reset_proxyid, &tcrp); 523 stop_cpus(tcrp); 524 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid); 525 DELAY(1000000); 526 cpu_reset_real(); 527} 528#endif 529 530void 531cpu_reset() 532{ 533#ifdef SMP 534 cpuset_t map; 535 u_int cnt; 536 537 if (smp_active) { 538 sched_pin(); 539 map = PCPU_GET(other_cpus); 540 CPU_NAND(&map, &stopped_cpus); 541 if (!CPU_EMPTY(&map)) { 542 printf("cpu_reset: Stopping other CPUs\n"); 543 stop_cpus(map); 544 } 545 546 if (PCPU_GET(cpuid) != 0) { 547 cpu_reset_proxyid = PCPU_GET(cpuid); 548 sched_unpin(); 549 cpustop_restartfunc = cpu_reset_proxy; 550 cpu_reset_proxy_active = 0; 551 printf("cpu_reset: Restarting BSP\n"); 552 553 /* Restart CPU #0. */ 554 CPU_SETOF(0, &started_cpus); 555 wmb(); 556 557 cnt = 0; 558 while (cpu_reset_proxy_active == 0 && cnt < 10000000) 559 cnt++; /* Wait for BSP to announce restart */ 560 if (cpu_reset_proxy_active == 0) 561 printf("cpu_reset: Failed to restart BSP\n"); 562 enable_intr(); 563 cpu_reset_proxy_active = 2; 564 565 while (1); 566 /* NOTREACHED */ 567 } else 568 sched_unpin(); 569 570 DELAY(1000000); 571 } 572#endif 573 cpu_reset_real(); 574 /* NOTREACHED */ 575} 576 577static void 578cpu_reset_real() 579{ 580 struct region_descriptor null_idt; 581 int b; 582 583 disable_intr(); 584 585 /* 586 * Attempt to do a CPU reset via the keyboard controller, 587 * do not turn off GateA20, as any machine that fails 588 * to do the reset here would then end up in no man's land. 589 */ 590 outb(IO_KBD + 4, 0xFE); 591 DELAY(500000); /* wait 0.5 sec to see if that did it */ 592 593 /* 594 * Attempt to force a reset via the Reset Control register at 595 * I/O port 0xcf9. Bit 2 forces a system reset when it 596 * transitions from 0 to 1. Bit 1 selects the type of reset 597 * to attempt: 0 selects a "soft" reset, and 1 selects a 598 * "hard" reset. We try a "hard" reset. The first write sets 599 * bit 1 to select a "hard" reset and clears bit 2. The 600 * second write forces a 0 -> 1 transition in bit 2 to trigger 601 * a reset. 602 */ 603 outb(0xcf9, 0x2); 604 outb(0xcf9, 0x6); 605 DELAY(500000); /* wait 0.5 sec to see if that did it */ 606 607 /* 608 * Attempt to force a reset via the Fast A20 and Init register 609 * at I/O port 0x92. Bit 1 serves as an alternate A20 gate. 610 * Bit 0 asserts INIT# when set to 1. We are careful to only 611 * preserve bit 1 while setting bit 0. We also must clear bit 612 * 0 before setting it if it isn't already clear. 613 */ 614 b = inb(0x92); 615 if (b != 0xff) { 616 if ((b & 0x1) != 0) 617 outb(0x92, b & 0xfe); 618 outb(0x92, b | 0x1); 619 DELAY(500000); /* wait 0.5 sec to see if that did it */ 620 } 621 622 printf("No known reset method worked, attempting CPU shutdown\n"); 623 DELAY(1000000); /* wait 1 sec for printf to complete */ 624 625 /* Wipe the IDT. */ 626 null_idt.rd_limit = 0; 627 null_idt.rd_base = 0; 628 lidt(&null_idt); 629 630 /* "good night, sweet prince .... <THUNK!>" */ 631 breakpoint(); 632 633 /* NOTREACHED */ 634 while(1); 635} 636 637/* 638 * Allocate an sf_buf for the given vm_page. On this machine, however, there 639 * is no sf_buf object. Instead, an opaque pointer to the given vm_page is 640 * returned. 641 */ 642struct sf_buf * 643sf_buf_alloc(struct vm_page *m, int pri) 644{ 645 646 return ((struct sf_buf *)m); 647} 648 649/* 650 * Free the sf_buf. In fact, do nothing because there are no resources 651 * associated with the sf_buf. 652 */ 653void 654sf_buf_free(struct sf_buf *sf) 655{ 656} 657 658/* 659 * Software interrupt handler for queued VM system processing. 660 */ 661void 662swi_vm(void *dummy) 663{ 664 if (busdma_swi_pending != 0) 665 busdma_swi(); 666} 667 668/* 669 * Tell whether this address is in some physical memory region. 670 * Currently used by the kernel coredump code in order to avoid 671 * dumping the ``ISA memory hole'' which could cause indefinite hangs, 672 * or other unpredictable behaviour. 673 */ 674 675int 676is_physical_memory(vm_paddr_t addr) 677{ 678 679#ifdef DEV_ISA 680 /* The ISA ``memory hole''. */ 681 if (addr >= 0xa0000 && addr < 0x100000) 682 return 0; 683#endif 684 685 /* 686 * stuff other tests for known memory-mapped devices (PCI?) 687 * here 688 */ 689 690 return 1; 691} 692