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sys/i386/i386/sys_machdep.c
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1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * from: @(#)sys_machdep.c 5.5 (Berkeley) 1/19/91 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD: releng/6.0/sys/i386/i386/sys_machdep.c 150588 2005-09-26 19:38:12Z jhb $"); 34 35 #include "opt_kstack_pages.h" 36 #include "opt_mac.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/lock.h> 41 #include <sys/mac.h> 42 #include <sys/malloc.h> 43 #include <sys/mutex.h> 44 #include <sys/proc.h> 45 #include <sys/smp.h> 46 #include <sys/sysproto.h> 47 48 #include <vm/vm.h> 49 #include <vm/pmap.h> 50 #include <vm/vm_map.h> 51 #include <vm/vm_extern.h> 52 53 #include <machine/cpu.h> 54 #include <machine/pcb.h> 55 #include <machine/pcb_ext.h> 56 #include <machine/proc.h> 57 #include <machine/sysarch.h> 58 59 #include <vm/vm_kern.h> /* for kernel_map */ 60 61 #define MAX_LD 8192 62 #define LD_PER_PAGE 512 63 #define NEW_MAX_LD(num) ((num + LD_PER_PAGE) & ~(LD_PER_PAGE-1)) 64 #define SIZE_FROM_LARGEST_LD(num) (NEW_MAX_LD(num) << 3) 65 66 67 68 static int i386_set_ldt_data(struct thread *, int start, int num, 69 union descriptor *descs); 70 static int i386_ldt_grow(struct thread *td, int len); 71 #ifdef SMP 72 static void set_user_ldt_rv(struct thread *); 73 #endif 74 75 #ifndef _SYS_SYSPROTO_H_ 76 struct sysarch_args { 77 int op; 78 char *parms; 79 }; 80 #endif 81 82 int 83 sysarch(td, uap) 84 struct thread *td; 85 register struct sysarch_args *uap; 86 { 87 int error; 88 union descriptor *lp; 89 union { 90 struct i386_ldt_args largs; 91 struct i386_ioperm_args iargs; 92 } kargs; 93 uint32_t base; 94 struct segment_descriptor sd, *sdp; 95 96 switch (uap->op) { 97 case I386_GET_IOPERM: 98 case I386_SET_IOPERM: 99 if ((error = copyin(uap->parms, &kargs.iargs, 100 sizeof(struct i386_ioperm_args))) != 0) 101 return (error); 102 break; 103 case I386_GET_LDT: 104 case I386_SET_LDT: 105 if ((error = copyin(uap->parms, &kargs.largs, 106 sizeof(struct i386_ldt_args))) != 0) 107 return (error); 108 if (kargs.largs.num > MAX_LD || kargs.largs.num <= 0) 109 return (EINVAL); 110 break; 111 default: 112 break; 113 } 114 115 mtx_lock(&Giant); 116 switch(uap->op) { 117 case I386_GET_LDT: 118 error = i386_get_ldt(td, &kargs.largs); 119 break; 120 case I386_SET_LDT: 121 if (kargs.largs.descs != NULL) { 122 lp = (union descriptor *)kmem_alloc(kernel_map, 123 kargs.largs.num * sizeof(union descriptor)); 124 if (lp == NULL) { 125 error = ENOMEM; 126 break; 127 } 128 error = copyin(kargs.largs.descs, lp, 129 kargs.largs.num * sizeof(union descriptor)); 130 if (error == 0) 131 error = i386_set_ldt(td, &kargs.largs, lp); 132 kmem_free(kernel_map, (vm_offset_t)lp, 133 kargs.largs.num * sizeof(union descriptor)); 134 } else { 135 error = i386_set_ldt(td, &kargs.largs, NULL); 136 } 137 break; 138 case I386_GET_IOPERM: 139 error = i386_get_ioperm(td, &kargs.iargs); 140 if (error == 0) 141 error = copyout(&kargs.iargs, uap->parms, 142 sizeof(struct i386_ioperm_args)); 143 break; 144 case I386_SET_IOPERM: 145 error = i386_set_ioperm(td, &kargs.iargs); 146 break; 147 case I386_VM86: 148 error = vm86_sysarch(td, uap->parms); 149 break; 150 case I386_GET_FSBASE: 151 sdp = &td->td_pcb->pcb_fsd; 152 base = sdp->sd_hibase << 24 | sdp->sd_lobase; 153 error = copyout(&base, uap->parms, sizeof(base)); 154 break; 155 case I386_SET_FSBASE: 156 error = copyin(uap->parms, &base, sizeof(base)); 157 if (!error) { 158 /* 159 * Construct a descriptor and store it in the pcb for 160 * the next context switch. Also store it in the gdt 161 * so that the load of tf_fs into %fs will activate it 162 * at return to userland. 163 */ 164 sd.sd_lobase = base & 0xffffff; 165 sd.sd_hibase = (base >> 24) & 0xff; 166 sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */ 167 sd.sd_hilimit = 0xf; 168 sd.sd_type = SDT_MEMRWA; 169 sd.sd_dpl = SEL_UPL; 170 sd.sd_p = 1; 171 sd.sd_xx = 0; 172 sd.sd_def32 = 1; 173 sd.sd_gran = 1; 174 critical_enter(); 175 td->td_pcb->pcb_fsd = sd; 176 PCPU_GET(fsgs_gdt)[0] = sd; 177 critical_exit(); 178 td->td_frame->tf_fs = GSEL(GUFS_SEL, SEL_UPL); 179 } 180 break; 181 case I386_GET_GSBASE: 182 sdp = &td->td_pcb->pcb_gsd; 183 base = sdp->sd_hibase << 24 | sdp->sd_lobase; 184 error = copyout(&base, uap->parms, sizeof(base)); 185 break; 186 case I386_SET_GSBASE: 187 error = copyin(uap->parms, &base, sizeof(base)); 188 if (!error) { 189 /* 190 * Construct a descriptor and store it in the pcb for 191 * the next context switch. Also store it in the gdt 192 * because we have to do a load_gs() right now. 193 */ 194 sd.sd_lobase = base & 0xffffff; 195 sd.sd_hibase = (base >> 24) & 0xff; 196 sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */ 197 sd.sd_hilimit = 0xf; 198 sd.sd_type = SDT_MEMRWA; 199 sd.sd_dpl = SEL_UPL; 200 sd.sd_p = 1; 201 sd.sd_xx = 0; 202 sd.sd_def32 = 1; 203 sd.sd_gran = 1; 204 critical_enter(); 205 td->td_pcb->pcb_gsd = sd; 206 PCPU_GET(fsgs_gdt)[1] = sd; 207 critical_exit(); 208 load_gs(GSEL(GUGS_SEL, SEL_UPL)); 209 } 210 break; 211 default: 212 error = EINVAL; 213 break; 214 } 215 mtx_unlock(&Giant); 216 return (error); 217 } 218 219 int 220 i386_extend_pcb(struct thread *td) 221 { 222 int i, offset; 223 u_long *addr; 224 struct pcb_ext *ext; 225 struct soft_segment_descriptor ssd = { 226 0, /* segment base address (overwritten) */ 227 ctob(IOPAGES + 1) - 1, /* length */ 228 SDT_SYS386TSS, /* segment type */ 229 0, /* priority level */ 230 1, /* descriptor present */ 231 0, 0, 232 0, /* default 32 size */ 233 0 /* granularity */ 234 }; 235 236 if (td->td_proc->p_flag & P_SA) 237 return (EINVAL); /* XXXKSE */ 238 /* XXXKSE All the code below only works in 1:1 needs changing */ 239 ext = (struct pcb_ext *)kmem_alloc(kernel_map, ctob(IOPAGES+1)); 240 if (ext == 0) 241 return (ENOMEM); 242 bzero(ext, sizeof(struct pcb_ext)); 243 /* -16 is so we can convert a trapframe into vm86trapframe inplace */ 244 ext->ext_tss.tss_esp0 = td->td_kstack + ctob(KSTACK_PAGES) - 245 sizeof(struct pcb) - 16; 246 ext->ext_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL); 247 /* 248 * The last byte of the i/o map must be followed by an 0xff byte. 249 * We arbitrarily allocate 16 bytes here, to keep the starting 250 * address on a doubleword boundary. 251 */ 252 offset = PAGE_SIZE - 16; 253 ext->ext_tss.tss_ioopt = 254 (offset - ((unsigned)&ext->ext_tss - (unsigned)ext)) << 16; 255 ext->ext_iomap = (caddr_t)ext + offset; 256 ext->ext_vm86.vm86_intmap = (caddr_t)ext + offset - 32; 257 258 addr = (u_long *)ext->ext_vm86.vm86_intmap; 259 for (i = 0; i < (ctob(IOPAGES) + 32 + 16) / sizeof(u_long); i++) 260 *addr++ = ~0; 261 262 ssd.ssd_base = (unsigned)&ext->ext_tss; 263 ssd.ssd_limit -= ((unsigned)&ext->ext_tss - (unsigned)ext); 264 ssdtosd(&ssd, &ext->ext_tssd); 265 266 KASSERT(td == curthread, ("giving TSS to !curthread")); 267 KASSERT(td->td_pcb->pcb_ext == 0, ("already have a TSS!")); 268 269 /* Switch to the new TSS. */ 270 mtx_lock_spin(&sched_lock); 271 td->td_pcb->pcb_ext = ext; 272 private_tss |= PCPU_GET(cpumask); 273 *PCPU_GET(tss_gdt) = ext->ext_tssd; 274 ltr(GSEL(GPROC0_SEL, SEL_KPL)); 275 mtx_unlock_spin(&sched_lock); 276 277 return 0; 278 } 279 280 int 281 i386_set_ioperm(td, uap) 282 struct thread *td; 283 struct i386_ioperm_args *uap; 284 { 285 int i, error; 286 char *iomap; 287 288 #ifdef MAC 289 if ((error = mac_check_sysarch_ioperm(td->td_ucred)) != 0) 290 return (error); 291 #endif 292 if ((error = suser(td)) != 0) 293 return (error); 294 if ((error = securelevel_gt(td->td_ucred, 0)) != 0) 295 return (error); 296 /* 297 * XXX 298 * While this is restricted to root, we should probably figure out 299 * whether any other driver is using this i/o address, as so not to 300 * cause confusion. This probably requires a global 'usage registry'. 301 */ 302 303 if (td->td_pcb->pcb_ext == 0) 304 if ((error = i386_extend_pcb(td)) != 0) 305 return (error); 306 iomap = (char *)td->td_pcb->pcb_ext->ext_iomap; 307 308 if (uap->start + uap->length > IOPAGES * PAGE_SIZE * NBBY) 309 return (EINVAL); 310 311 for (i = uap->start; i < uap->start + uap->length; i++) { 312 if (uap->enable) 313 iomap[i >> 3] &= ~(1 << (i & 7)); 314 else 315 iomap[i >> 3] |= (1 << (i & 7)); 316 } 317 return (error); 318 } 319 320 int 321 i386_get_ioperm(td, uap) 322 struct thread *td; 323 struct i386_ioperm_args *uap; 324 { 325 int i, state; 326 char *iomap; 327 328 if (uap->start >= IOPAGES * PAGE_SIZE * NBBY) 329 return (EINVAL); 330 331 if (td->td_pcb->pcb_ext == 0) { 332 uap->length = 0; 333 goto done; 334 } 335 336 iomap = (char *)td->td_pcb->pcb_ext->ext_iomap; 337 338 i = uap->start; 339 state = (iomap[i >> 3] >> (i & 7)) & 1; 340 uap->enable = !state; 341 uap->length = 1; 342 343 for (i = uap->start + 1; i < IOPAGES * PAGE_SIZE * NBBY; i++) { 344 if (state != ((iomap[i >> 3] >> (i & 7)) & 1)) 345 break; 346 uap->length++; 347 } 348 349 done: 350 return (0); 351 } 352 353 /* 354 * Update the GDT entry pointing to the LDT to point to the LDT of the 355 * current process. 356 * 357 * This must be called with sched_lock held. Unfortunately, we can't use a 358 * mtx_assert() here because cpu_switch() calls this function after changing 359 * curproc but before sched_lock's owner is updated in mi_switch(). 360 */ 361 void 362 set_user_ldt(struct mdproc *mdp) 363 { 364 struct proc_ldt *pldt; 365 366 pldt = mdp->md_ldt; 367 #ifdef SMP 368 gdt[PCPU_GET(cpuid) * NGDT + GUSERLDT_SEL].sd = pldt->ldt_sd; 369 #else 370 gdt[GUSERLDT_SEL].sd = pldt->ldt_sd; 371 #endif 372 lldt(GSEL(GUSERLDT_SEL, SEL_KPL)); 373 PCPU_SET(currentldt, GSEL(GUSERLDT_SEL, SEL_KPL)); 374 } 375 376 #ifdef SMP 377 static void 378 set_user_ldt_rv(struct thread *td) 379 { 380 381 if (td->td_proc != curthread->td_proc) 382 return; 383 384 set_user_ldt(&td->td_proc->p_md); 385 } 386 #endif 387 388 /* 389 * Must be called with either sched_lock free or held but not recursed. 390 * If it does not return NULL, it will return with it owned. 391 */ 392 struct proc_ldt * 393 user_ldt_alloc(struct mdproc *mdp, int len) 394 { 395 struct proc_ldt *pldt, *new_ldt; 396 397 if (mtx_owned(&sched_lock)) 398 mtx_unlock_spin(&sched_lock); 399 mtx_assert(&sched_lock, MA_NOTOWNED); 400 MALLOC(new_ldt, struct proc_ldt *, sizeof(struct proc_ldt), 401 M_SUBPROC, M_WAITOK); 402 403 new_ldt->ldt_len = len = NEW_MAX_LD(len); 404 new_ldt->ldt_base = (caddr_t)kmem_alloc(kernel_map, 405 len * sizeof(union descriptor)); 406 if (new_ldt->ldt_base == NULL) { 407 FREE(new_ldt, M_SUBPROC); 408 return NULL; 409 } 410 new_ldt->ldt_refcnt = 1; 411 new_ldt->ldt_active = 0; 412 413 mtx_lock_spin(&sched_lock); 414 gdt_segs[GUSERLDT_SEL].ssd_base = (unsigned)new_ldt->ldt_base; 415 gdt_segs[GUSERLDT_SEL].ssd_limit = len * sizeof(union descriptor) - 1; 416 ssdtosd(&gdt_segs[GUSERLDT_SEL], &new_ldt->ldt_sd); 417 418 if ((pldt = mdp->md_ldt)) { 419 if (len > pldt->ldt_len) 420 len = pldt->ldt_len; 421 bcopy(pldt->ldt_base, new_ldt->ldt_base, 422 len * sizeof(union descriptor)); 423 } else { 424 bcopy(ldt, new_ldt->ldt_base, sizeof(ldt)); 425 } 426 return new_ldt; 427 } 428 429 /* 430 * Must be called either with sched_lock free or held but not recursed. 431 * If md_ldt is not NULL, it will return with sched_lock released. 432 */ 433 void 434 user_ldt_free(struct thread *td) 435 { 436 struct mdproc *mdp = &td->td_proc->p_md; 437 struct proc_ldt *pldt = mdp->md_ldt; 438 439 if (pldt == NULL) 440 return; 441 442 if (!mtx_owned(&sched_lock)) 443 mtx_lock_spin(&sched_lock); 444 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 445 if (td == PCPU_GET(curthread)) { 446 lldt(_default_ldt); 447 PCPU_SET(currentldt, _default_ldt); 448 } 449 450 mdp->md_ldt = NULL; 451 if (--pldt->ldt_refcnt == 0) { 452 mtx_unlock_spin(&sched_lock); 453 kmem_free(kernel_map, (vm_offset_t)pldt->ldt_base, 454 pldt->ldt_len * sizeof(union descriptor)); 455 FREE(pldt, M_SUBPROC); 456 } else 457 mtx_unlock_spin(&sched_lock); 458 } 459 460 /* 461 * Note for the authors of compat layers (linux, etc): copyout() in 462 * the function below is not a problem since it presents data in 463 * arch-specific format (i.e. i386-specific in this case), not in 464 * the OS-specific one. 465 */ 466 int 467 i386_get_ldt(td, uap) 468 struct thread *td; 469 struct i386_ldt_args *uap; 470 { 471 int error = 0; 472 struct proc_ldt *pldt = td->td_proc->p_md.md_ldt; 473 int nldt, num; 474 union descriptor *lp; 475 476 #ifdef DEBUG 477 printf("i386_get_ldt: start=%d num=%d descs=%p\n", 478 uap->start, uap->num, (void *)uap->descs); 479 #endif 480 481 if (pldt) { 482 nldt = pldt->ldt_len; 483 num = min(uap->num, nldt); 484 lp = &((union descriptor *)(pldt->ldt_base))[uap->start]; 485 } else { 486 nldt = sizeof(ldt)/sizeof(ldt[0]); 487 num = min(uap->num, nldt); 488 lp = &ldt[uap->start]; 489 } 490 491 if ((uap->start > (unsigned int)nldt) || 492 ((unsigned int)num > (unsigned int)nldt) || 493 ((unsigned int)(uap->start + num) > (unsigned int)nldt)) 494 return(EINVAL); 495 496 error = copyout(lp, uap->descs, num * sizeof(union descriptor)); 497 if (!error) 498 td->td_retval[0] = num; 499 500 return(error); 501 } 502 503 static int ldt_warnings; 504 #define NUM_LDT_WARNINGS 10 505 506 int 507 i386_set_ldt(td, uap, descs) 508 struct thread *td; 509 struct i386_ldt_args *uap; 510 union descriptor *descs; 511 { 512 int error = 0, i; 513 int largest_ld; 514 struct mdproc *mdp = &td->td_proc->p_md; 515 struct proc_ldt *pldt; 516 union descriptor *dp; 517 518 #ifdef DEBUG 519 printf("i386_set_ldt: start=%d num=%d descs=%p\n", 520 uap->start, uap->num, (void *)uap->descs); 521 #endif 522 523 if (descs == NULL) { 524 /* Free descriptors */ 525 if (uap->start == 0 && uap->num == 0) { 526 /* 527 * Treat this as a special case, so userland needn't 528 * know magic number NLDT. 529 */ 530 uap->start = NLDT; 531 uap->num = MAX_LD - NLDT; 532 } 533 if (uap->num <= 0) 534 return (EINVAL); 535 mtx_lock_spin(&sched_lock); 536 pldt = mdp->md_ldt; 537 if (pldt == NULL || uap->start >= pldt->ldt_len) { 538 mtx_unlock_spin(&sched_lock); 539 return (0); 540 } 541 largest_ld = uap->start + uap->num; 542 if (largest_ld > pldt->ldt_len) 543 largest_ld = pldt->ldt_len; 544 i = largest_ld - uap->start; 545 bzero(&((union descriptor *)(pldt->ldt_base))[uap->start], 546 sizeof(union descriptor) * i); 547 mtx_unlock_spin(&sched_lock); 548 return (0); 549 } 550 551 if (!(uap->start == LDT_AUTO_ALLOC && uap->num == 1)) { 552 /* complain a for a while if using old methods */ 553 if (ldt_warnings++ < NUM_LDT_WARNINGS) { 554 printf("Warning: pid %d used static ldt allocation.\n", 555 td->td_proc->p_pid); 556 printf("See the i386_set_ldt man page for more info\n"); 557 } 558 /* verify range of descriptors to modify */ 559 largest_ld = uap->start + uap->num; 560 if (uap->start >= MAX_LD || 561 uap->num < 0 || largest_ld > MAX_LD) { 562 return (EINVAL); 563 } 564 } 565 566 /* Check descriptors for access violations */ 567 for (i = 0; i < uap->num; i++) { 568 dp = &descs[i]; 569 570 switch (dp->sd.sd_type) { 571 case SDT_SYSNULL: /* system null */ 572 dp->sd.sd_p = 0; 573 break; 574 case SDT_SYS286TSS: /* system 286 TSS available */ 575 case SDT_SYSLDT: /* system local descriptor table */ 576 case SDT_SYS286BSY: /* system 286 TSS busy */ 577 case SDT_SYSTASKGT: /* system task gate */ 578 case SDT_SYS286IGT: /* system 286 interrupt gate */ 579 case SDT_SYS286TGT: /* system 286 trap gate */ 580 case SDT_SYSNULL2: /* undefined by Intel */ 581 case SDT_SYS386TSS: /* system 386 TSS available */ 582 case SDT_SYSNULL3: /* undefined by Intel */ 583 case SDT_SYS386BSY: /* system 386 TSS busy */ 584 case SDT_SYSNULL4: /* undefined by Intel */ 585 case SDT_SYS386IGT: /* system 386 interrupt gate */ 586 case SDT_SYS386TGT: /* system 386 trap gate */ 587 case SDT_SYS286CGT: /* system 286 call gate */ 588 case SDT_SYS386CGT: /* system 386 call gate */ 589 /* I can't think of any reason to allow a user proc 590 * to create a segment of these types. They are 591 * for OS use only. 592 */ 593 return (EACCES); 594 /*NOTREACHED*/ 595 596 /* memory segment types */ 597 case SDT_MEMEC: /* memory execute only conforming */ 598 case SDT_MEMEAC: /* memory execute only accessed conforming */ 599 case SDT_MEMERC: /* memory execute read conforming */ 600 case SDT_MEMERAC: /* memory execute read accessed conforming */ 601 /* Must be "present" if executable and conforming. */ 602 if (dp->sd.sd_p == 0) 603 return (EACCES); 604 break; 605 case SDT_MEMRO: /* memory read only */ 606 case SDT_MEMROA: /* memory read only accessed */ 607 case SDT_MEMRW: /* memory read write */ 608 case SDT_MEMRWA: /* memory read write accessed */ 609 case SDT_MEMROD: /* memory read only expand dwn limit */ 610 case SDT_MEMRODA: /* memory read only expand dwn lim accessed */ 611 case SDT_MEMRWD: /* memory read write expand dwn limit */ 612 case SDT_MEMRWDA: /* memory read write expand dwn lim acessed */ 613 case SDT_MEME: /* memory execute only */ 614 case SDT_MEMEA: /* memory execute only accessed */ 615 case SDT_MEMER: /* memory execute read */ 616 case SDT_MEMERA: /* memory execute read accessed */ 617 break; 618 default: 619 return(EINVAL); 620 /*NOTREACHED*/ 621 } 622 623 /* Only user (ring-3) descriptors may be present. */ 624 if ((dp->sd.sd_p != 0) && (dp->sd.sd_dpl != SEL_UPL)) 625 return (EACCES); 626 } 627 628 if (uap->start == LDT_AUTO_ALLOC && uap->num == 1) { 629 /* Allocate a free slot */ 630 pldt = mdp->md_ldt; 631 if (pldt == NULL) { 632 error = i386_ldt_grow(td, NLDT + 1); 633 if (error) 634 return (error); 635 pldt = mdp->md_ldt; 636 } 637 again: 638 mtx_lock_spin(&sched_lock); 639 /* 640 * start scanning a bit up to leave room for NVidia and 641 * Wine, which still user the "Blat" method of allocation. 642 */ 643 dp = &((union descriptor *)(pldt->ldt_base))[NLDT]; 644 for (i = NLDT; i < pldt->ldt_len; ++i) { 645 if (dp->sd.sd_type == SDT_SYSNULL) 646 break; 647 dp++; 648 } 649 if (i >= pldt->ldt_len) { 650 mtx_unlock_spin(&sched_lock); 651 error = i386_ldt_grow(td, pldt->ldt_len+1); 652 if (error) 653 return (error); 654 goto again; 655 } 656 uap->start = i; 657 error = i386_set_ldt_data(td, i, 1, descs); 658 mtx_unlock_spin(&sched_lock); 659 } else { 660 largest_ld = uap->start + uap->num; 661 error = i386_ldt_grow(td, largest_ld); 662 if (error == 0) { 663 mtx_lock_spin(&sched_lock); 664 error = i386_set_ldt_data(td, uap->start, uap->num, 665 descs); 666 mtx_unlock_spin(&sched_lock); 667 } 668 } 669 if (error == 0) 670 td->td_retval[0] = uap->start; 671 return (error); 672 } 673 674 static int 675 i386_set_ldt_data(struct thread *td, int start, int num, 676 union descriptor *descs) 677 { 678 struct mdproc *mdp = &td->td_proc->p_md; 679 struct proc_ldt *pldt = mdp->md_ldt; 680 681 mtx_assert(&sched_lock, MA_OWNED); 682 683 /* Fill in range */ 684 bcopy(descs, 685 &((union descriptor *)(pldt->ldt_base))[start], 686 num * sizeof(union descriptor)); 687 return (0); 688 } 689 690 static int 691 i386_ldt_grow(struct thread *td, int len) 692 { 693 struct mdproc *mdp = &td->td_proc->p_md; 694 struct proc_ldt *pldt; 695 caddr_t old_ldt_base; 696 int old_ldt_len; 697 698 if (len > MAX_LD) 699 return (ENOMEM); 700 if (len < NLDT + 1) 701 len = NLDT + 1; 702 703 /* Allocate a user ldt. */ 704 pldt = mdp->md_ldt; 705 if (!pldt || len > pldt->ldt_len) { 706 struct proc_ldt *new_ldt; 707 708 new_ldt = user_ldt_alloc(mdp, len); 709 if (new_ldt == NULL) 710 return (ENOMEM); 711 pldt = mdp->md_ldt; 712 713 /* sched_lock was acquired by user_ldt_alloc. */ 714 if (pldt) { 715 if (new_ldt->ldt_len > pldt->ldt_len) { 716 old_ldt_base = pldt->ldt_base; 717 old_ldt_len = pldt->ldt_len; 718 pldt->ldt_sd = new_ldt->ldt_sd; 719 pldt->ldt_base = new_ldt->ldt_base; 720 pldt->ldt_len = new_ldt->ldt_len; 721 mtx_unlock_spin(&sched_lock); 722 kmem_free(kernel_map, (vm_offset_t)old_ldt_base, 723 old_ldt_len * sizeof(union descriptor)); 724 FREE(new_ldt, M_SUBPROC); 725 mtx_lock_spin(&sched_lock); 726 } else { 727 /* 728 * If other threads already did the work, 729 * do nothing. 730 */ 731 mtx_unlock_spin(&sched_lock); 732 kmem_free(kernel_map, 733 (vm_offset_t)new_ldt->ldt_base, 734 new_ldt->ldt_len * sizeof(union descriptor)); 735 FREE(new_ldt, M_SUBPROC); 736 return (0); 737 } 738 } else { 739 mdp->md_ldt = pldt = new_ldt; 740 } 741 #ifdef SMP 742 mtx_unlock_spin(&sched_lock); 743 /* signal other cpus to reload ldt */ 744 smp_rendezvous(NULL, (void (*)(void *))set_user_ldt_rv, 745 NULL, td); 746 #else 747 set_user_ldt(mdp); 748 mtx_unlock_spin(&sched_lock); 749 #endif 750 } 751 return (0); 752 }
Cache object: 396ab346c9e7da2c6e29640d45e719ea
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