vm_machdep.c revision 223758
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 223758 2011-07-04 12:04:52Z 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/sf_buf.h> 63#include <sys/smp.h> 64#include <sys/sysctl.h> 65#include <sys/sysent.h> 66#include <sys/unistd.h> 67#include <sys/vnode.h> 68#include <sys/vmmeter.h> 69 70#include <machine/cpu.h> 71#include <machine/md_var.h> 72#include <machine/pcb.h> 73#include <machine/smp.h> 74#include <machine/specialreg.h> 75#include <machine/tss.h> 76 77#include <vm/vm.h> 78#include <vm/vm_extern.h> 79#include <vm/vm_kern.h> 80#include <vm/vm_page.h> 81#include <vm/vm_map.h> 82#include <vm/vm_param.h> 83 84#include <x86/isa/isa.h> 85 86static void cpu_reset_real(void); 87#ifdef SMP 88static void cpu_reset_proxy(void); 89static u_int cpu_reset_proxyid; 90static volatile u_int cpu_reset_proxy_active; 91#endif 92 93/* 94 * Finish a fork operation, with process p2 nearly set up. 95 * Copy and update the pcb, set up the stack so that the child 96 * ready to run and return to user mode. 97 */ 98void 99cpu_fork(td1, p2, td2, flags) 100 register struct thread *td1; 101 register struct proc *p2; 102 struct thread *td2; 103 int flags; 104{ 105 register struct proc *p1; 106 struct pcb *pcb2; 107 struct mdproc *mdp1, *mdp2; 108 struct proc_ldt *pldt; 109 pmap_t pmap2; 110 111 p1 = td1->td_proc; 112 if ((flags & RFPROC) == 0) { 113 if ((flags & RFMEM) == 0) { 114 /* unshare user LDT */ 115 mdp1 = &p1->p_md; 116 mtx_lock(&dt_lock); 117 if ((pldt = mdp1->md_ldt) != NULL && 118 pldt->ldt_refcnt > 1 && 119 user_ldt_alloc(p1, 1) == NULL) 120 panic("could not copy LDT"); 121 mtx_unlock(&dt_lock); 122 } 123 return; 124 } 125 126 /* Ensure that td1's pcb is up to date. */ 127 fpuexit(td1); 128 129 /* Point the pcb to the top of the stack */ 130 pcb2 = (struct pcb *)(td2->td_kstack + 131 td2->td_kstack_pages * PAGE_SIZE) - 1; 132 td2->td_pcb = pcb2; 133 134 /* Copy td1's pcb */ 135 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 136 137 /* Properly initialize pcb_save */ 138 pcb2->pcb_save = &pcb2->pcb_user_save; 139 140 /* Point mdproc and then copy over td1's contents */ 141 mdp2 = &p2->p_md; 142 bcopy(&p1->p_md, mdp2, sizeof(*mdp2)); 143 144 /* 145 * Create a new fresh stack for the new process. 146 * Copy the trap frame for the return to user mode as if from a 147 * syscall. This copies most of the user mode register values. 148 */ 149 td2->td_frame = (struct trapframe *)td2->td_pcb - 1; 150 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); 151 152 td2->td_frame->tf_rax = 0; /* Child returns zero */ 153 td2->td_frame->tf_rflags &= ~PSL_C; /* success */ 154 td2->td_frame->tf_rdx = 1; 155 156 /* 157 * If the parent process has the trap bit set (i.e. a debugger had 158 * single stepped the process to the system call), we need to clear 159 * the trap flag from the new frame unless the debugger had set PF_FORK 160 * on the parent. Otherwise, the child will receive a (likely 161 * unexpected) SIGTRAP when it executes the first instruction after 162 * returning to userland. 163 */ 164 if ((p1->p_pfsflags & PF_FORK) == 0) 165 td2->td_frame->tf_rflags &= ~PSL_T; 166 167 /* 168 * Set registers for trampoline to user mode. Leave space for the 169 * return address on stack. These are the kernel mode register values. 170 */ 171 pmap2 = vmspace_pmap(p2->p_vmspace); 172 pcb2->pcb_cr3 = DMAP_TO_PHYS((vm_offset_t)pmap2->pm_pml4); 173 pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */ 174 pcb2->pcb_rbp = 0; 175 pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *); 176 pcb2->pcb_rbx = (register_t)td2; /* fork_trampoline argument */ 177 pcb2->pcb_rip = (register_t)fork_trampoline; 178 /*- 179 * pcb2->pcb_dr*: cloned above. 180 * pcb2->pcb_savefpu: cloned above. 181 * pcb2->pcb_flags: cloned above. 182 * pcb2->pcb_onfault: cloned above (always NULL here?). 183 * pcb2->pcb_[fg]sbase: cloned above 184 */ 185 186 /* Setup to release spin count in fork_exit(). */ 187 td2->td_md.md_spinlock_count = 1; 188 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 189 190 /* As an i386, do not copy io permission bitmap. */ 191 pcb2->pcb_tssp = NULL; 192 193 /* New segment registers. */ 194 set_pcb_flags(pcb2, PCB_FULL_IRET); 195 196 /* Copy the LDT, if necessary. */ 197 mdp1 = &td1->td_proc->p_md; 198 mdp2 = &p2->p_md; 199 mtx_lock(&dt_lock); 200 if (mdp1->md_ldt != NULL) { 201 if (flags & RFMEM) { 202 mdp1->md_ldt->ldt_refcnt++; 203 mdp2->md_ldt = mdp1->md_ldt; 204 bcopy(&mdp1->md_ldt_sd, &mdp2->md_ldt_sd, sizeof(struct 205 system_segment_descriptor)); 206 } else { 207 mdp2->md_ldt = NULL; 208 mdp2->md_ldt = user_ldt_alloc(p2, 0); 209 if (mdp2->md_ldt == NULL) 210 panic("could not copy LDT"); 211 amd64_set_ldt_data(td2, 0, max_ldt_segment, 212 (struct user_segment_descriptor *) 213 mdp1->md_ldt->ldt_base); 214 } 215 } else 216 mdp2->md_ldt = NULL; 217 mtx_unlock(&dt_lock); 218 219 /* 220 * Now, cpu_switch() can schedule the new process. 221 * pcb_rsp is loaded pointing to the cpu_switch() stack frame 222 * containing the return address when exiting cpu_switch. 223 * This will normally be to fork_trampoline(), which will have 224 * %ebx loaded with the new proc's pointer. fork_trampoline() 225 * will set up a stack to call fork_return(p, frame); to complete 226 * the return to user-mode. 227 */ 228} 229 230/* 231 * Intercept the return address from a freshly forked process that has NOT 232 * been scheduled yet. 233 * 234 * This is needed to make kernel threads stay in kernel mode. 235 */ 236void 237cpu_set_fork_handler(td, func, arg) 238 struct thread *td; 239 void (*func)(void *); 240 void *arg; 241{ 242 /* 243 * Note that the trap frame follows the args, so the function 244 * is really called like this: func(arg, frame); 245 */ 246 td->td_pcb->pcb_r12 = (long) func; /* function */ 247 td->td_pcb->pcb_rbx = (long) arg; /* first arg */ 248} 249 250void 251cpu_exit(struct thread *td) 252{ 253 254 /* 255 * If this process has a custom LDT, release it. 256 */ 257 mtx_lock(&dt_lock); 258 if (td->td_proc->p_md.md_ldt != 0) 259 user_ldt_free(td); 260 else 261 mtx_unlock(&dt_lock); 262} 263 264void 265cpu_thread_exit(struct thread *td) 266{ 267 struct pcb *pcb; 268 269 critical_enter(); 270 if (td == PCPU_GET(fpcurthread)) 271 fpudrop(); 272 critical_exit(); 273 274 pcb = td->td_pcb; 275 276 /* Disable any hardware breakpoints. */ 277 if (pcb->pcb_flags & PCB_DBREGS) { 278 reset_dbregs(); 279 clear_pcb_flags(pcb, PCB_DBREGS); 280 } 281} 282 283void 284cpu_thread_clean(struct thread *td) 285{ 286 struct pcb *pcb; 287 288 pcb = td->td_pcb; 289 290 /* 291 * Clean TSS/iomap 292 */ 293 if (pcb->pcb_tssp != NULL) { 294 kmem_free(kernel_map, (vm_offset_t)pcb->pcb_tssp, 295 ctob(IOPAGES + 1)); 296 pcb->pcb_tssp = NULL; 297 } 298} 299 300void 301cpu_thread_swapin(struct thread *td) 302{ 303} 304 305void 306cpu_thread_swapout(struct thread *td) 307{ 308} 309 310void 311cpu_thread_alloc(struct thread *td) 312{ 313 314 td->td_pcb = (struct pcb *)(td->td_kstack + 315 td->td_kstack_pages * PAGE_SIZE) - 1; 316 td->td_frame = (struct trapframe *)td->td_pcb - 1; 317 td->td_pcb->pcb_save = &td->td_pcb->pcb_user_save; 318} 319 320void 321cpu_thread_free(struct thread *td) 322{ 323 324 cpu_thread_clean(td); 325} 326 327void 328cpu_set_syscall_retval(struct thread *td, int error) 329{ 330 331 switch (error) { 332 case 0: 333 td->td_frame->tf_rax = td->td_retval[0]; 334 td->td_frame->tf_rdx = td->td_retval[1]; 335 td->td_frame->tf_rflags &= ~PSL_C; 336 break; 337 338 case ERESTART: 339 /* 340 * Reconstruct pc, we know that 'syscall' is 2 bytes, 341 * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. 342 * We saved this in tf_err. 343 * %r10 (which was holding the value of %rcx) is restored 344 * for the next iteration. 345 * %r10 restore is only required for freebsd/amd64 processes, 346 * but shall be innocent for any ia32 ABI. 347 */ 348 td->td_frame->tf_rip -= td->td_frame->tf_err; 349 td->td_frame->tf_r10 = td->td_frame->tf_rcx; 350 break; 351 352 case EJUSTRETURN: 353 break; 354 355 default: 356 if (td->td_proc->p_sysent->sv_errsize) { 357 if (error >= td->td_proc->p_sysent->sv_errsize) 358 error = -1; /* XXX */ 359 else 360 error = td->td_proc->p_sysent->sv_errtbl[error]; 361 } 362 td->td_frame->tf_rax = error; 363 td->td_frame->tf_rflags |= PSL_C; 364 break; 365 } 366} 367 368/* 369 * Initialize machine state (pcb and trap frame) for a new thread about to 370 * upcall. Put enough state in the new thread's PCB to get it to go back 371 * userret(), where we can intercept it again to set the return (upcall) 372 * Address and stack, along with those from upcals that are from other sources 373 * such as those generated in thread_userret() itself. 374 */ 375void 376cpu_set_upcall(struct thread *td, struct thread *td0) 377{ 378 struct pcb *pcb2; 379 380 /* Point the pcb to the top of the stack. */ 381 pcb2 = td->td_pcb; 382 383 /* 384 * Copy the upcall pcb. This loads kernel regs. 385 * Those not loaded individually below get their default 386 * values here. 387 */ 388 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); 389 clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE); 390 pcb2->pcb_save = &pcb2->pcb_user_save; 391 set_pcb_flags(pcb2, PCB_FULL_IRET); 392 393 /* 394 * Create a new fresh stack for the new thread. 395 */ 396 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 397 398 /* If the current thread has the trap bit set (i.e. a debugger had 399 * single stepped the process to the system call), we need to clear 400 * the trap flag from the new frame. Otherwise, the new thread will 401 * receive a (likely unexpected) SIGTRAP when it executes the first 402 * instruction after returning to userland. 403 */ 404 td->td_frame->tf_rflags &= ~PSL_T; 405 406 /* 407 * Set registers for trampoline to user mode. Leave space for the 408 * return address on stack. These are the kernel mode register values. 409 */ 410 pcb2->pcb_r12 = (register_t)fork_return; /* trampoline arg */ 411 pcb2->pcb_rbp = 0; 412 pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *); /* trampoline arg */ 413 pcb2->pcb_rbx = (register_t)td; /* trampoline arg */ 414 pcb2->pcb_rip = (register_t)fork_trampoline; 415 /* 416 * If we didn't copy the pcb, we'd need to do the following registers: 417 * pcb2->pcb_cr3: cloned above. 418 * pcb2->pcb_dr*: cloned above. 419 * pcb2->pcb_savefpu: cloned above. 420 * pcb2->pcb_onfault: cloned above (always NULL here?). 421 * pcb2->pcb_[fg]sbase: cloned above 422 */ 423 424 /* Setup to release spin count in fork_exit(). */ 425 td->td_md.md_spinlock_count = 1; 426 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I; 427} 428 429/* 430 * Set that machine state for performing an upcall that has to 431 * be done in thread_userret() so that those upcalls generated 432 * in thread_userret() itself can be done as well. 433 */ 434void 435cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg, 436 stack_t *stack) 437{ 438 439 /* 440 * Do any extra cleaning that needs to be done. 441 * The thread may have optional components 442 * that are not present in a fresh thread. 443 * This may be a recycled thread so make it look 444 * as though it's newly allocated. 445 */ 446 cpu_thread_clean(td); 447 448#ifdef COMPAT_FREEBSD32 449 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 450 /* 451 * Set the trap frame to point at the beginning of the uts 452 * function. 453 */ 454 td->td_frame->tf_rbp = 0; 455 td->td_frame->tf_rsp = 456 (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4; 457 td->td_frame->tf_rip = (uintptr_t)entry; 458 459 /* 460 * Pass the address of the mailbox for this kse to the uts 461 * function as a parameter on the stack. 462 */ 463 suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)), 464 (uint32_t)(uintptr_t)arg); 465 466 return; 467 } 468#endif 469 470 /* 471 * Set the trap frame to point at the beginning of the uts 472 * function. 473 */ 474 td->td_frame->tf_rbp = 0; 475 td->td_frame->tf_rsp = 476 ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f; 477 td->td_frame->tf_rsp -= 8; 478 td->td_frame->tf_rip = (register_t)entry; 479 td->td_frame->tf_ds = _udatasel; 480 td->td_frame->tf_es = _udatasel; 481 td->td_frame->tf_fs = _ufssel; 482 td->td_frame->tf_gs = _ugssel; 483 td->td_frame->tf_flags = TF_HASSEGS; 484 485 /* 486 * Pass the address of the mailbox for this kse to the uts 487 * function as a parameter on the stack. 488 */ 489 td->td_frame->tf_rdi = (register_t)arg; 490} 491 492int 493cpu_set_user_tls(struct thread *td, void *tls_base) 494{ 495 struct pcb *pcb; 496 497 if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS) 498 return (EINVAL); 499 500 pcb = td->td_pcb; 501#ifdef COMPAT_FREEBSD32 502 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { 503 pcb->pcb_gsbase = (register_t)tls_base; 504 return (0); 505 } 506#endif 507 pcb->pcb_fsbase = (register_t)tls_base; 508 set_pcb_flags(pcb, PCB_FULL_IRET); 509 return (0); 510} 511 512#ifdef SMP 513static void 514cpu_reset_proxy() 515{ 516 cpuset_t tcrp; 517 518 cpu_reset_proxy_active = 1; 519 while (cpu_reset_proxy_active == 1) 520 ; /* Wait for other cpu to see that we've started */ 521 CPU_SETOF(cpu_reset_proxyid, &tcrp); 522 stop_cpus(tcrp); 523 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid); 524 DELAY(1000000); 525 cpu_reset_real(); 526} 527#endif 528 529void 530cpu_reset() 531{ 532#ifdef SMP 533 cpuset_t map; 534 u_int cnt; 535 536 if (smp_active) { 537 map = all_cpus; 538 CPU_CLR(PCPU_GET(cpuid), &map); 539 CPU_NAND(&map, &stopped_cpus); 540 if (!CPU_EMPTY(&map)) { 541 printf("cpu_reset: Stopping other CPUs\n"); 542 stop_cpus(map); 543 } 544 545 if (PCPU_GET(cpuid) != 0) { 546 cpu_reset_proxyid = PCPU_GET(cpuid); 547 cpustop_restartfunc = cpu_reset_proxy; 548 cpu_reset_proxy_active = 0; 549 printf("cpu_reset: Restarting BSP\n"); 550 551 /* Restart CPU #0. */ 552 CPU_SETOF(0, &started_cpus); 553 wmb(); 554 555 cnt = 0; 556 while (cpu_reset_proxy_active == 0 && cnt < 10000000) 557 cnt++; /* Wait for BSP to announce restart */ 558 if (cpu_reset_proxy_active == 0) 559 printf("cpu_reset: Failed to restart BSP\n"); 560 enable_intr(); 561 cpu_reset_proxy_active = 2; 562 563 while (1); 564 /* NOTREACHED */ 565 } 566 567 DELAY(1000000); 568 } 569#endif 570 cpu_reset_real(); 571 /* NOTREACHED */ 572} 573 574static void 575cpu_reset_real() 576{ 577 struct region_descriptor null_idt; 578 int b; 579 580 disable_intr(); 581 582 /* 583 * Attempt to do a CPU reset via the keyboard controller, 584 * do not turn off GateA20, as any machine that fails 585 * to do the reset here would then end up in no man's land. 586 */ 587 outb(IO_KBD + 4, 0xFE); 588 DELAY(500000); /* wait 0.5 sec to see if that did it */ 589 590 /* 591 * Attempt to force a reset via the Reset Control register at 592 * I/O port 0xcf9. Bit 2 forces a system reset when it 593 * transitions from 0 to 1. Bit 1 selects the type of reset 594 * to attempt: 0 selects a "soft" reset, and 1 selects a 595 * "hard" reset. We try a "hard" reset. The first write sets 596 * bit 1 to select a "hard" reset and clears bit 2. The 597 * second write forces a 0 -> 1 transition in bit 2 to trigger 598 * a reset. 599 */ 600 outb(0xcf9, 0x2); 601 outb(0xcf9, 0x6); 602 DELAY(500000); /* wait 0.5 sec to see if that did it */ 603 604 /* 605 * Attempt to force a reset via the Fast A20 and Init register 606 * at I/O port 0x92. Bit 1 serves as an alternate A20 gate. 607 * Bit 0 asserts INIT# when set to 1. We are careful to only 608 * preserve bit 1 while setting bit 0. We also must clear bit 609 * 0 before setting it if it isn't already clear. 610 */ 611 b = inb(0x92); 612 if (b != 0xff) { 613 if ((b & 0x1) != 0) 614 outb(0x92, b & 0xfe); 615 outb(0x92, b | 0x1); 616 DELAY(500000); /* wait 0.5 sec to see if that did it */ 617 } 618 619 printf("No known reset method worked, attempting CPU shutdown\n"); 620 DELAY(1000000); /* wait 1 sec for printf to complete */ 621 622 /* Wipe the IDT. */ 623 null_idt.rd_limit = 0; 624 null_idt.rd_base = 0; 625 lidt(&null_idt); 626 627 /* "good night, sweet prince .... <THUNK!>" */ 628 breakpoint(); 629 630 /* NOTREACHED */ 631 while(1); 632} 633 634/* 635 * Allocate an sf_buf for the given vm_page. On this machine, however, there 636 * is no sf_buf object. Instead, an opaque pointer to the given vm_page is 637 * returned. 638 */ 639struct sf_buf * 640sf_buf_alloc(struct vm_page *m, int pri) 641{ 642 643 return ((struct sf_buf *)m); 644} 645 646/* 647 * Free the sf_buf. In fact, do nothing because there are no resources 648 * associated with the sf_buf. 649 */ 650void 651sf_buf_free(struct sf_buf *sf) 652{ 653} 654 655/* 656 * Software interrupt handler for queued VM system processing. 657 */ 658void 659swi_vm(void *dummy) 660{ 661 if (busdma_swi_pending != 0) 662 busdma_swi(); 663} 664 665/* 666 * Tell whether this address is in some physical memory region. 667 * Currently used by the kernel coredump code in order to avoid 668 * dumping the ``ISA memory hole'' which could cause indefinite hangs, 669 * or other unpredictable behaviour. 670 */ 671 672int 673is_physical_memory(vm_paddr_t addr) 674{ 675 676#ifdef DEV_ISA 677 /* The ISA ``memory hole''. */ 678 if (addr >= 0xa0000 && addr < 0x100000) 679 return 0; 680#endif 681 682 /* 683 * stuff other tests for known memory-mapped devices (PCI?) 684 * here 685 */ 686 687 return 1; 688} 689