Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/amd64/amd64/sys_machdep.c
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1 /*- 2 * Copyright (c) 2003 Peter Wemm. 3 * Copyright (c) 1990 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 4. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * from: @(#)sys_machdep.c 5.5 (Berkeley) 1/19/91 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD: releng/10.4/sys/amd64/amd64/sys_machdep.c 307940 2016-10-25 17:16:08Z glebius $"); 35 36 #include "opt_capsicum.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/capsicum.h> 41 #include <sys/kernel.h> 42 #include <sys/lock.h> 43 #include <sys/malloc.h> 44 #include <sys/mutex.h> 45 #include <sys/priv.h> 46 #include <sys/proc.h> 47 #include <sys/sysproto.h> 48 #include <sys/uio.h> 49 50 #include <vm/vm.h> 51 #include <vm/pmap.h> 52 #include <vm/vm_kern.h> /* for kernel_map */ 53 #include <vm/vm_extern.h> 54 55 #include <machine/frame.h> 56 #include <machine/md_var.h> 57 #include <machine/pcb.h> 58 #include <machine/specialreg.h> 59 #include <machine/sysarch.h> 60 #include <machine/tss.h> 61 #include <machine/vmparam.h> 62 63 #include <security/audit/audit.h> 64 65 #define MAX_LD 8192 66 67 int max_ldt_segment = 1024; 68 SYSCTL_INT(_machdep, OID_AUTO, max_ldt_segment, CTLFLAG_RDTUN, 69 &max_ldt_segment, 0, 70 "Maximum number of allowed LDT segments in the single address space"); 71 72 static void 73 max_ldt_segment_init(void *arg __unused) 74 { 75 76 TUNABLE_INT_FETCH("machdep.max_ldt_segment", &max_ldt_segment); 77 if (max_ldt_segment <= 0) 78 max_ldt_segment = 1; 79 if (max_ldt_segment > MAX_LD) 80 max_ldt_segment = MAX_LD; 81 } 82 SYSINIT(maxldt, SI_SUB_VM_CONF, SI_ORDER_ANY, max_ldt_segment_init, NULL); 83 84 #ifdef notyet 85 #ifdef SMP 86 static void set_user_ldt_rv(struct vmspace *vmsp); 87 #endif 88 #endif 89 static void user_ldt_derefl(struct proc_ldt *pldt); 90 91 #ifndef _SYS_SYSPROTO_H_ 92 struct sysarch_args { 93 int op; 94 char *parms; 95 }; 96 #endif 97 98 int 99 sysarch_ldt(struct thread *td, struct sysarch_args *uap, int uap_space) 100 { 101 struct i386_ldt_args *largs, la; 102 struct user_segment_descriptor *lp; 103 int error = 0; 104 105 /* 106 * XXXKIB check that the BSM generation code knows to encode 107 * the op argument. 108 */ 109 AUDIT_ARG_CMD(uap->op); 110 if (uap_space == UIO_USERSPACE) { 111 error = copyin(uap->parms, &la, sizeof(struct i386_ldt_args)); 112 if (error != 0) 113 return (error); 114 largs = &la; 115 } else 116 largs = (struct i386_ldt_args *)uap->parms; 117 118 switch (uap->op) { 119 case I386_GET_LDT: 120 error = amd64_get_ldt(td, largs); 121 break; 122 case I386_SET_LDT: 123 if (largs->descs != NULL && largs->num > max_ldt_segment) 124 return (EINVAL); 125 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 126 if (largs->descs != NULL) { 127 lp = malloc(largs->num * sizeof(struct 128 user_segment_descriptor), M_TEMP, M_WAITOK); 129 error = copyin(largs->descs, lp, largs->num * 130 sizeof(struct user_segment_descriptor)); 131 if (error == 0) 132 error = amd64_set_ldt(td, largs, lp); 133 free(lp, M_TEMP); 134 } else { 135 error = amd64_set_ldt(td, largs, NULL); 136 } 137 break; 138 } 139 return (error); 140 } 141 142 void 143 update_gdt_gsbase(struct thread *td, uint32_t base) 144 { 145 struct user_segment_descriptor *sd; 146 147 if (td != curthread) 148 return; 149 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 150 critical_enter(); 151 sd = PCPU_GET(gs32p); 152 sd->sd_lobase = base & 0xffffff; 153 sd->sd_hibase = (base >> 24) & 0xff; 154 critical_exit(); 155 } 156 157 void 158 update_gdt_fsbase(struct thread *td, uint32_t base) 159 { 160 struct user_segment_descriptor *sd; 161 162 if (td != curthread) 163 return; 164 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 165 critical_enter(); 166 sd = PCPU_GET(fs32p); 167 sd->sd_lobase = base & 0xffffff; 168 sd->sd_hibase = (base >> 24) & 0xff; 169 critical_exit(); 170 } 171 172 int 173 sysarch(td, uap) 174 struct thread *td; 175 register struct sysarch_args *uap; 176 { 177 int error = 0; 178 struct pcb *pcb = curthread->td_pcb; 179 uint32_t i386base; 180 uint64_t a64base; 181 struct i386_ioperm_args iargs; 182 struct i386_get_xfpustate i386xfpu; 183 struct amd64_get_xfpustate a64xfpu; 184 185 #ifdef CAPABILITY_MODE 186 /* 187 * When adding new operations, add a new case statement here to 188 * explicitly indicate whether or not the operation is safe to 189 * perform in capability mode. 190 */ 191 if (IN_CAPABILITY_MODE(td)) { 192 switch (uap->op) { 193 case I386_GET_LDT: 194 case I386_SET_LDT: 195 case I386_GET_IOPERM: 196 case I386_GET_FSBASE: 197 case I386_SET_FSBASE: 198 case I386_GET_GSBASE: 199 case I386_SET_GSBASE: 200 case I386_GET_XFPUSTATE: 201 case AMD64_GET_FSBASE: 202 case AMD64_SET_FSBASE: 203 case AMD64_GET_GSBASE: 204 case AMD64_SET_GSBASE: 205 case AMD64_GET_XFPUSTATE: 206 break; 207 208 case I386_SET_IOPERM: 209 default: 210 #ifdef KTRACE 211 if (KTRPOINT(td, KTR_CAPFAIL)) 212 ktrcapfail(CAPFAIL_SYSCALL, NULL, NULL); 213 #endif 214 return (ECAPMODE); 215 } 216 } 217 #endif 218 219 if (uap->op == I386_GET_LDT || uap->op == I386_SET_LDT) 220 return (sysarch_ldt(td, uap, UIO_USERSPACE)); 221 /* 222 * XXXKIB check that the BSM generation code knows to encode 223 * the op argument. 224 */ 225 AUDIT_ARG_CMD(uap->op); 226 switch (uap->op) { 227 case I386_GET_IOPERM: 228 case I386_SET_IOPERM: 229 if ((error = copyin(uap->parms, &iargs, 230 sizeof(struct i386_ioperm_args))) != 0) 231 return (error); 232 break; 233 case I386_GET_XFPUSTATE: 234 if ((error = copyin(uap->parms, &i386xfpu, 235 sizeof(struct i386_get_xfpustate))) != 0) 236 return (error); 237 a64xfpu.addr = (void *)(uintptr_t)i386xfpu.addr; 238 a64xfpu.len = i386xfpu.len; 239 break; 240 case AMD64_GET_XFPUSTATE: 241 if ((error = copyin(uap->parms, &a64xfpu, 242 sizeof(struct amd64_get_xfpustate))) != 0) 243 return (error); 244 break; 245 default: 246 break; 247 } 248 249 switch (uap->op) { 250 case I386_GET_IOPERM: 251 error = amd64_get_ioperm(td, &iargs); 252 if (error == 0) 253 error = copyout(&iargs, uap->parms, 254 sizeof(struct i386_ioperm_args)); 255 break; 256 case I386_SET_IOPERM: 257 error = amd64_set_ioperm(td, &iargs); 258 break; 259 case I386_GET_FSBASE: 260 i386base = pcb->pcb_fsbase; 261 error = copyout(&i386base, uap->parms, sizeof(i386base)); 262 break; 263 case I386_SET_FSBASE: 264 error = copyin(uap->parms, &i386base, sizeof(i386base)); 265 if (!error) { 266 pcb->pcb_fsbase = i386base; 267 td->td_frame->tf_fs = _ufssel; 268 update_gdt_fsbase(td, i386base); 269 } 270 break; 271 case I386_GET_GSBASE: 272 i386base = pcb->pcb_gsbase; 273 error = copyout(&i386base, uap->parms, sizeof(i386base)); 274 break; 275 case I386_SET_GSBASE: 276 error = copyin(uap->parms, &i386base, sizeof(i386base)); 277 if (!error) { 278 pcb->pcb_gsbase = i386base; 279 td->td_frame->tf_gs = _ugssel; 280 update_gdt_gsbase(td, i386base); 281 } 282 break; 283 case AMD64_GET_FSBASE: 284 error = copyout(&pcb->pcb_fsbase, uap->parms, sizeof(pcb->pcb_fsbase)); 285 break; 286 287 case AMD64_SET_FSBASE: 288 error = copyin(uap->parms, &a64base, sizeof(a64base)); 289 if (!error) { 290 if (a64base < VM_MAXUSER_ADDRESS) { 291 pcb->pcb_fsbase = a64base; 292 set_pcb_flags(pcb, PCB_FULL_IRET); 293 td->td_frame->tf_fs = _ufssel; 294 } else 295 error = EINVAL; 296 } 297 break; 298 299 case AMD64_GET_GSBASE: 300 error = copyout(&pcb->pcb_gsbase, uap->parms, sizeof(pcb->pcb_gsbase)); 301 break; 302 303 case AMD64_SET_GSBASE: 304 error = copyin(uap->parms, &a64base, sizeof(a64base)); 305 if (!error) { 306 if (a64base < VM_MAXUSER_ADDRESS) { 307 pcb->pcb_gsbase = a64base; 308 set_pcb_flags(pcb, PCB_FULL_IRET); 309 td->td_frame->tf_gs = _ugssel; 310 } else 311 error = EINVAL; 312 } 313 break; 314 315 case I386_GET_XFPUSTATE: 316 case AMD64_GET_XFPUSTATE: 317 if (a64xfpu.len > cpu_max_ext_state_size - 318 sizeof(struct savefpu)) 319 return (EINVAL); 320 fpugetregs(td); 321 error = copyout((char *)(get_pcb_user_save_td(td) + 1), 322 a64xfpu.addr, a64xfpu.len); 323 break; 324 325 default: 326 error = EINVAL; 327 break; 328 } 329 return (error); 330 } 331 332 int 333 amd64_set_ioperm(td, uap) 334 struct thread *td; 335 struct i386_ioperm_args *uap; 336 { 337 char *iomap; 338 struct amd64tss *tssp; 339 struct system_segment_descriptor *tss_sd; 340 u_long *addr; 341 struct pcb *pcb; 342 u_int i; 343 int error; 344 345 if ((error = priv_check(td, PRIV_IO)) != 0) 346 return (error); 347 if ((error = securelevel_gt(td->td_ucred, 0)) != 0) 348 return (error); 349 if (uap->start > uap->start + uap->length || 350 uap->start + uap->length > IOPAGES * PAGE_SIZE * NBBY) 351 return (EINVAL); 352 353 /* 354 * XXX 355 * While this is restricted to root, we should probably figure out 356 * whether any other driver is using this i/o address, as so not to 357 * cause confusion. This probably requires a global 'usage registry'. 358 */ 359 pcb = td->td_pcb; 360 if (pcb->pcb_tssp == NULL) { 361 tssp = (struct amd64tss *)kmem_malloc(kernel_arena, 362 ctob(IOPAGES+1), M_WAITOK); 363 if (tssp == NULL) 364 return (ENOMEM); 365 iomap = (char *)&tssp[1]; 366 addr = (u_long *)iomap; 367 for (i = 0; i < (ctob(IOPAGES) + 1) / sizeof(u_long); i++) 368 *addr++ = ~0; 369 critical_enter(); 370 /* Takes care of tss_rsp0. */ 371 memcpy(tssp, &common_tss[PCPU_GET(cpuid)], 372 sizeof(struct amd64tss)); 373 tssp->tss_iobase = sizeof(*tssp); 374 pcb->pcb_tssp = tssp; 375 tss_sd = PCPU_GET(tss); 376 tss_sd->sd_lobase = (u_long)tssp & 0xffffff; 377 tss_sd->sd_hibase = ((u_long)tssp >> 24) & 0xfffffffffful; 378 tss_sd->sd_type = SDT_SYSTSS; 379 ltr(GSEL(GPROC0_SEL, SEL_KPL)); 380 PCPU_SET(tssp, tssp); 381 critical_exit(); 382 } else 383 iomap = (char *)&pcb->pcb_tssp[1]; 384 for (i = uap->start; i < uap->start + uap->length; i++) { 385 if (uap->enable) 386 iomap[i >> 3] &= ~(1 << (i & 7)); 387 else 388 iomap[i >> 3] |= (1 << (i & 7)); 389 } 390 return (error); 391 } 392 393 int 394 amd64_get_ioperm(td, uap) 395 struct thread *td; 396 struct i386_ioperm_args *uap; 397 { 398 int i, state; 399 char *iomap; 400 401 if (uap->start >= IOPAGES * PAGE_SIZE * NBBY) 402 return (EINVAL); 403 if (td->td_pcb->pcb_tssp == NULL) { 404 uap->length = 0; 405 goto done; 406 } 407 408 iomap = (char *)&td->td_pcb->pcb_tssp[1]; 409 410 i = uap->start; 411 state = (iomap[i >> 3] >> (i & 7)) & 1; 412 uap->enable = !state; 413 uap->length = 1; 414 415 for (i = uap->start + 1; i < IOPAGES * PAGE_SIZE * NBBY; i++) { 416 if (state != ((iomap[i >> 3] >> (i & 7)) & 1)) 417 break; 418 uap->length++; 419 } 420 421 done: 422 return (0); 423 } 424 425 /* 426 * Update the GDT entry pointing to the LDT to point to the LDT of the 427 * current process. 428 */ 429 void 430 set_user_ldt(struct mdproc *mdp) 431 { 432 433 critical_enter(); 434 *PCPU_GET(ldt) = mdp->md_ldt_sd; 435 lldt(GSEL(GUSERLDT_SEL, SEL_KPL)); 436 critical_exit(); 437 } 438 439 #ifdef notyet 440 #ifdef SMP 441 static void 442 set_user_ldt_rv(struct vmspace *vmsp) 443 { 444 struct thread *td; 445 446 td = curthread; 447 if (vmsp != td->td_proc->p_vmspace) 448 return; 449 450 set_user_ldt(&td->td_proc->p_md); 451 } 452 #endif 453 #endif 454 455 struct proc_ldt * 456 user_ldt_alloc(struct proc *p, int force) 457 { 458 struct proc_ldt *pldt, *new_ldt; 459 struct mdproc *mdp; 460 struct soft_segment_descriptor sldt; 461 462 mtx_assert(&dt_lock, MA_OWNED); 463 mdp = &p->p_md; 464 if (!force && mdp->md_ldt != NULL) 465 return (mdp->md_ldt); 466 mtx_unlock(&dt_lock); 467 new_ldt = malloc(sizeof(struct proc_ldt), M_SUBPROC, M_WAITOK); 468 new_ldt->ldt_base = (caddr_t)kmem_malloc(kernel_arena, 469 max_ldt_segment * sizeof(struct user_segment_descriptor), 470 M_WAITOK | M_ZERO); 471 if (new_ldt->ldt_base == NULL) { 472 FREE(new_ldt, M_SUBPROC); 473 mtx_lock(&dt_lock); 474 return (NULL); 475 } 476 new_ldt->ldt_refcnt = 1; 477 sldt.ssd_base = (uint64_t)new_ldt->ldt_base; 478 sldt.ssd_limit = max_ldt_segment * 479 sizeof(struct user_segment_descriptor) - 1; 480 sldt.ssd_type = SDT_SYSLDT; 481 sldt.ssd_dpl = SEL_KPL; 482 sldt.ssd_p = 1; 483 sldt.ssd_long = 0; 484 sldt.ssd_def32 = 0; 485 sldt.ssd_gran = 0; 486 mtx_lock(&dt_lock); 487 pldt = mdp->md_ldt; 488 if (pldt != NULL && !force) { 489 kmem_free(kernel_arena, (vm_offset_t)new_ldt->ldt_base, 490 max_ldt_segment * sizeof(struct user_segment_descriptor)); 491 free(new_ldt, M_SUBPROC); 492 return (pldt); 493 } 494 495 if (pldt != NULL) { 496 bcopy(pldt->ldt_base, new_ldt->ldt_base, max_ldt_segment * 497 sizeof(struct user_segment_descriptor)); 498 user_ldt_derefl(pldt); 499 } 500 ssdtosyssd(&sldt, &p->p_md.md_ldt_sd); 501 atomic_store_rel_ptr((volatile uintptr_t *)&mdp->md_ldt, 502 (uintptr_t)new_ldt); 503 if (p == curproc) 504 set_user_ldt(mdp); 505 506 return (mdp->md_ldt); 507 } 508 509 void 510 user_ldt_free(struct thread *td) 511 { 512 struct proc *p = td->td_proc; 513 struct mdproc *mdp = &p->p_md; 514 struct proc_ldt *pldt; 515 516 mtx_assert(&dt_lock, MA_OWNED); 517 if ((pldt = mdp->md_ldt) == NULL) { 518 mtx_unlock(&dt_lock); 519 return; 520 } 521 522 mdp->md_ldt = NULL; 523 bzero(&mdp->md_ldt_sd, sizeof(mdp->md_ldt_sd)); 524 if (td == curthread) 525 lldt(GSEL(GNULL_SEL, SEL_KPL)); 526 user_ldt_deref(pldt); 527 } 528 529 static void 530 user_ldt_derefl(struct proc_ldt *pldt) 531 { 532 533 if (--pldt->ldt_refcnt == 0) { 534 kmem_free(kernel_arena, (vm_offset_t)pldt->ldt_base, 535 max_ldt_segment * sizeof(struct user_segment_descriptor)); 536 free(pldt, M_SUBPROC); 537 } 538 } 539 540 void 541 user_ldt_deref(struct proc_ldt *pldt) 542 { 543 544 mtx_assert(&dt_lock, MA_OWNED); 545 user_ldt_derefl(pldt); 546 mtx_unlock(&dt_lock); 547 } 548 549 /* 550 * Note for the authors of compat layers (linux, etc): copyout() in 551 * the function below is not a problem since it presents data in 552 * arch-specific format (i.e. i386-specific in this case), not in 553 * the OS-specific one. 554 */ 555 int 556 amd64_get_ldt(td, uap) 557 struct thread *td; 558 struct i386_ldt_args *uap; 559 { 560 int error = 0; 561 struct proc_ldt *pldt; 562 int num; 563 struct user_segment_descriptor *lp; 564 565 #ifdef DEBUG 566 printf("amd64_get_ldt: start=%d num=%d descs=%p\n", 567 uap->start, uap->num, (void *)uap->descs); 568 #endif 569 570 if ((pldt = td->td_proc->p_md.md_ldt) != NULL) { 571 lp = &((struct user_segment_descriptor *)(pldt->ldt_base)) 572 [uap->start]; 573 num = min(uap->num, max_ldt_segment); 574 } else 575 return (EINVAL); 576 577 if ((uap->start > (unsigned int)max_ldt_segment) || 578 ((unsigned int)num > (unsigned int)max_ldt_segment) || 579 ((unsigned int)(uap->start + num) > (unsigned int)max_ldt_segment)) 580 return(EINVAL); 581 582 error = copyout(lp, uap->descs, num * 583 sizeof(struct user_segment_descriptor)); 584 if (!error) 585 td->td_retval[0] = num; 586 587 return(error); 588 } 589 590 int 591 amd64_set_ldt(td, uap, descs) 592 struct thread *td; 593 struct i386_ldt_args *uap; 594 struct user_segment_descriptor *descs; 595 { 596 int error = 0; 597 unsigned int largest_ld, i; 598 struct mdproc *mdp = &td->td_proc->p_md; 599 struct proc_ldt *pldt; 600 struct user_segment_descriptor *dp; 601 struct proc *p; 602 603 #ifdef DEBUG 604 printf("amd64_set_ldt: start=%d num=%d descs=%p\n", 605 uap->start, uap->num, (void *)uap->descs); 606 #endif 607 608 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 609 p = td->td_proc; 610 if (descs == NULL) { 611 /* Free descriptors */ 612 if (uap->start == 0 && uap->num == 0) 613 uap->num = max_ldt_segment; 614 if (uap->num == 0) 615 return (EINVAL); 616 if ((pldt = mdp->md_ldt) == NULL || 617 uap->start >= max_ldt_segment) 618 return (0); 619 largest_ld = uap->start + uap->num; 620 if (largest_ld > max_ldt_segment) 621 largest_ld = max_ldt_segment; 622 if (largest_ld < uap->start) 623 return (EINVAL); 624 i = largest_ld - uap->start; 625 mtx_lock(&dt_lock); 626 bzero(&((struct user_segment_descriptor *)(pldt->ldt_base)) 627 [uap->start], sizeof(struct user_segment_descriptor) * i); 628 mtx_unlock(&dt_lock); 629 return (0); 630 } 631 632 if (!(uap->start == LDT_AUTO_ALLOC && uap->num == 1)) { 633 /* verify range of descriptors to modify */ 634 largest_ld = uap->start + uap->num; 635 if (uap->start >= max_ldt_segment || 636 largest_ld > max_ldt_segment || 637 largest_ld < uap->start) 638 return (EINVAL); 639 } 640 641 /* Check descriptors for access violations */ 642 for (i = 0; i < uap->num; i++) { 643 dp = &descs[i]; 644 645 switch (dp->sd_type) { 646 case SDT_SYSNULL: /* system null */ 647 dp->sd_p = 0; 648 break; 649 case SDT_SYS286TSS: 650 case SDT_SYSLDT: 651 case SDT_SYS286BSY: 652 case SDT_SYS286CGT: 653 case SDT_SYSTASKGT: 654 case SDT_SYS286IGT: 655 case SDT_SYS286TGT: 656 case SDT_SYSNULL2: 657 case SDT_SYSTSS: 658 case SDT_SYSNULL3: 659 case SDT_SYSBSY: 660 case SDT_SYSCGT: 661 case SDT_SYSNULL4: 662 case SDT_SYSIGT: 663 case SDT_SYSTGT: 664 /* I can't think of any reason to allow a user proc 665 * to create a segment of these types. They are 666 * for OS use only. 667 */ 668 return (EACCES); 669 /*NOTREACHED*/ 670 671 /* memory segment types */ 672 case SDT_MEMEC: /* memory execute only conforming */ 673 case SDT_MEMEAC: /* memory execute only accessed conforming */ 674 case SDT_MEMERC: /* memory execute read conforming */ 675 case SDT_MEMERAC: /* memory execute read accessed conforming */ 676 /* Must be "present" if executable and conforming. */ 677 if (dp->sd_p == 0) 678 return (EACCES); 679 break; 680 case SDT_MEMRO: /* memory read only */ 681 case SDT_MEMROA: /* memory read only accessed */ 682 case SDT_MEMRW: /* memory read write */ 683 case SDT_MEMRWA: /* memory read write accessed */ 684 case SDT_MEMROD: /* memory read only expand dwn limit */ 685 case SDT_MEMRODA: /* memory read only expand dwn lim accessed */ 686 case SDT_MEMRWD: /* memory read write expand dwn limit */ 687 case SDT_MEMRWDA: /* memory read write expand dwn lim acessed */ 688 case SDT_MEME: /* memory execute only */ 689 case SDT_MEMEA: /* memory execute only accessed */ 690 case SDT_MEMER: /* memory execute read */ 691 case SDT_MEMERA: /* memory execute read accessed */ 692 break; 693 default: 694 return(EINVAL); 695 /*NOTREACHED*/ 696 } 697 698 /* Only user (ring-3) descriptors may be present. */ 699 if ((dp->sd_p != 0) && (dp->sd_dpl != SEL_UPL)) 700 return (EACCES); 701 } 702 703 if (uap->start == LDT_AUTO_ALLOC && uap->num == 1) { 704 /* Allocate a free slot */ 705 mtx_lock(&dt_lock); 706 pldt = user_ldt_alloc(p, 0); 707 if (pldt == NULL) { 708 mtx_unlock(&dt_lock); 709 return (ENOMEM); 710 } 711 712 /* 713 * start scanning a bit up to leave room for NVidia and 714 * Wine, which still user the "Blat" method of allocation. 715 */ 716 i = 16; 717 dp = &((struct user_segment_descriptor *)(pldt->ldt_base))[i]; 718 for (; i < max_ldt_segment; ++i, ++dp) { 719 if (dp->sd_type == SDT_SYSNULL) 720 break; 721 } 722 if (i >= max_ldt_segment) { 723 mtx_unlock(&dt_lock); 724 return (ENOSPC); 725 } 726 uap->start = i; 727 error = amd64_set_ldt_data(td, i, 1, descs); 728 mtx_unlock(&dt_lock); 729 } else { 730 largest_ld = uap->start + uap->num; 731 if (largest_ld > max_ldt_segment) 732 return (EINVAL); 733 mtx_lock(&dt_lock); 734 if (user_ldt_alloc(p, 0) != NULL) { 735 error = amd64_set_ldt_data(td, uap->start, uap->num, 736 descs); 737 } 738 mtx_unlock(&dt_lock); 739 } 740 if (error == 0) 741 td->td_retval[0] = uap->start; 742 return (error); 743 } 744 745 int 746 amd64_set_ldt_data(struct thread *td, int start, int num, 747 struct user_segment_descriptor *descs) 748 { 749 struct mdproc *mdp = &td->td_proc->p_md; 750 struct proc_ldt *pldt = mdp->md_ldt; 751 752 mtx_assert(&dt_lock, MA_OWNED); 753 754 /* Fill in range */ 755 bcopy(descs, 756 &((struct user_segment_descriptor *)(pldt->ldt_base))[start], 757 num * sizeof(struct user_segment_descriptor)); 758 return (0); 759 }
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