Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
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("$FreeBSD$"); 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_get_ldt(struct thread *, char *); 69 static int i386_set_ldt(struct thread *, char *); 70 static int i386_set_ldt_data(struct thread *, int start, int num, 71 union descriptor *descs); 72 static int i386_ldt_grow(struct thread *td, int len); 73 static int i386_get_ioperm(struct thread *, char *); 74 static int i386_set_ioperm(struct thread *, char *); 75 #ifdef SMP 76 static void set_user_ldt_rv(struct thread *); 77 #endif 78 79 #ifndef _SYS_SYSPROTO_H_ 80 struct sysarch_args { 81 int op; 82 char *parms; 83 }; 84 #endif 85 86 int 87 sysarch(td, uap) 88 struct thread *td; 89 register struct sysarch_args *uap; 90 { 91 int error; 92 uint32_t base; 93 struct segment_descriptor sd, *sdp; 94 95 96 mtx_lock(&Giant); 97 switch(uap->op) { 98 case I386_GET_LDT: 99 error = i386_get_ldt(td, uap->parms); 100 break; 101 102 case I386_SET_LDT: 103 error = i386_set_ldt(td, uap->parms); 104 break; 105 case I386_GET_IOPERM: 106 error = i386_get_ioperm(td, uap->parms); 107 break; 108 case I386_SET_IOPERM: 109 error = i386_set_ioperm(td, uap->parms); 110 break; 111 case I386_VM86: 112 error = vm86_sysarch(td, uap->parms); 113 break; 114 case I386_GET_FSBASE: 115 sdp = (struct segment_descriptor *)&td->td_pcb->pcb_fsd; 116 base = sdp->sd_hibase << 24 | sdp->sd_lobase; 117 error = copyout(&base, uap->parms, sizeof(base)); 118 break; 119 case I386_SET_FSBASE: 120 error = copyin(uap->parms, &base, sizeof(base)); 121 if (!error) { 122 /* 123 * Construct a descriptor and store it in the pcb for 124 * the next context switch. Also store it in the gdt 125 * so that the load of tf_fs into %fs will activate it 126 * at return to userland. 127 */ 128 sd.sd_lobase = base & 0xffffff; 129 sd.sd_hibase = (base >> 24) & 0xff; 130 sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */ 131 sd.sd_hilimit = 0xf; 132 sd.sd_type = SDT_MEMRWA; 133 sd.sd_dpl = SEL_UPL; 134 sd.sd_p = 1; 135 sd.sd_xx = 0; 136 sd.sd_def32 = 1; 137 sd.sd_gran = 1; 138 critical_enter(); 139 *(struct segment_descriptor *)&td->td_pcb->pcb_fsd = sd; 140 PCPU_GET(fsgs_gdt)[0] = sd; 141 critical_exit(); 142 td->td_frame->tf_fs = GSEL(GUFS_SEL, SEL_UPL); 143 } 144 break; 145 case I386_GET_GSBASE: 146 sdp = (struct segment_descriptor *)&td->td_pcb->pcb_gsd; 147 base = sdp->sd_hibase << 24 | sdp->sd_lobase; 148 error = copyout(&base, uap->parms, sizeof(base)); 149 break; 150 case I386_SET_GSBASE: 151 error = copyin(uap->parms, &base, sizeof(base)); 152 if (!error) { 153 /* 154 * Construct a descriptor and store it in the pcb for 155 * the next context switch. Also store it in the gdt 156 * because we have to do a load_gs() right now. 157 */ 158 sd.sd_lobase = base & 0xffffff; 159 sd.sd_hibase = (base >> 24) & 0xff; 160 sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */ 161 sd.sd_hilimit = 0xf; 162 sd.sd_type = SDT_MEMRWA; 163 sd.sd_dpl = SEL_UPL; 164 sd.sd_p = 1; 165 sd.sd_xx = 0; 166 sd.sd_def32 = 1; 167 sd.sd_gran = 1; 168 critical_enter(); 169 *(struct segment_descriptor *)&td->td_pcb->pcb_gsd = sd; 170 PCPU_GET(fsgs_gdt)[1] = sd; 171 critical_exit(); 172 load_gs(GSEL(GUGS_SEL, SEL_UPL)); 173 } 174 break; 175 default: 176 error = EINVAL; 177 break; 178 } 179 mtx_unlock(&Giant); 180 return (error); 181 } 182 183 int 184 i386_extend_pcb(struct thread *td) 185 { 186 int i, offset; 187 u_long *addr; 188 struct pcb_ext *ext; 189 struct soft_segment_descriptor ssd = { 190 0, /* segment base address (overwritten) */ 191 ctob(IOPAGES + 1) - 1, /* length */ 192 SDT_SYS386TSS, /* segment type */ 193 0, /* priority level */ 194 1, /* descriptor present */ 195 0, 0, 196 0, /* default 32 size */ 197 0 /* granularity */ 198 }; 199 200 if (td->td_proc->p_flag & P_SA) 201 return (EINVAL); /* XXXKSE */ 202 /* XXXKSE All the code below only works in 1:1 needs changing */ 203 ext = (struct pcb_ext *)kmem_alloc(kernel_map, ctob(IOPAGES+1)); 204 if (ext == 0) 205 return (ENOMEM); 206 bzero(ext, sizeof(struct pcb_ext)); 207 /* -16 is so we can convert a trapframe into vm86trapframe inplace */ 208 ext->ext_tss.tss_esp0 = td->td_kstack + ctob(KSTACK_PAGES) - 209 sizeof(struct pcb) - 16; 210 ext->ext_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL); 211 /* 212 * The last byte of the i/o map must be followed by an 0xff byte. 213 * We arbitrarily allocate 16 bytes here, to keep the starting 214 * address on a doubleword boundary. 215 */ 216 offset = PAGE_SIZE - 16; 217 ext->ext_tss.tss_ioopt = 218 (offset - ((unsigned)&ext->ext_tss - (unsigned)ext)) << 16; 219 ext->ext_iomap = (caddr_t)ext + offset; 220 ext->ext_vm86.vm86_intmap = (caddr_t)ext + offset - 32; 221 222 addr = (u_long *)ext->ext_vm86.vm86_intmap; 223 for (i = 0; i < (ctob(IOPAGES) + 32 + 16) / sizeof(u_long); i++) 224 *addr++ = ~0; 225 226 ssd.ssd_base = (unsigned)&ext->ext_tss; 227 ssd.ssd_limit -= ((unsigned)&ext->ext_tss - (unsigned)ext); 228 ssdtosd(&ssd, &ext->ext_tssd); 229 230 KASSERT(td == curthread, ("giving TSS to !curthread")); 231 KASSERT(td->td_pcb->pcb_ext == 0, ("already have a TSS!")); 232 233 /* Switch to the new TSS. */ 234 mtx_lock_spin(&sched_lock); 235 td->td_pcb->pcb_ext = ext; 236 private_tss |= PCPU_GET(cpumask); 237 *PCPU_GET(tss_gdt) = ext->ext_tssd; 238 ltr(GSEL(GPROC0_SEL, SEL_KPL)); 239 mtx_unlock_spin(&sched_lock); 240 241 return 0; 242 } 243 244 static int 245 i386_set_ioperm(td, args) 246 struct thread *td; 247 char *args; 248 { 249 int i, error; 250 struct i386_ioperm_args ua; 251 char *iomap; 252 253 if ((error = copyin(args, &ua, sizeof(struct i386_ioperm_args))) != 0) 254 return (error); 255 256 #ifdef MAC 257 if ((error = mac_check_sysarch_ioperm(td->td_ucred)) != 0) 258 return (error); 259 #endif 260 if ((error = suser(td)) != 0) 261 return (error); 262 if ((error = securelevel_gt(td->td_ucred, 0)) != 0) 263 return (error); 264 /* 265 * XXX 266 * While this is restricted to root, we should probably figure out 267 * whether any other driver is using this i/o address, as so not to 268 * cause confusion. This probably requires a global 'usage registry'. 269 */ 270 271 if (td->td_pcb->pcb_ext == 0) 272 if ((error = i386_extend_pcb(td)) != 0) 273 return (error); 274 iomap = (char *)td->td_pcb->pcb_ext->ext_iomap; 275 276 if (ua.start + ua.length > IOPAGES * PAGE_SIZE * NBBY) 277 return (EINVAL); 278 279 for (i = ua.start; i < ua.start + ua.length; i++) { 280 if (ua.enable) 281 iomap[i >> 3] &= ~(1 << (i & 7)); 282 else 283 iomap[i >> 3] |= (1 << (i & 7)); 284 } 285 return (error); 286 } 287 288 static int 289 i386_get_ioperm(td, args) 290 struct thread *td; 291 char *args; 292 { 293 int i, state, error; 294 struct i386_ioperm_args ua; 295 char *iomap; 296 297 if ((error = copyin(args, &ua, sizeof(struct i386_ioperm_args))) != 0) 298 return (error); 299 if (ua.start >= IOPAGES * PAGE_SIZE * NBBY) 300 return (EINVAL); 301 302 if (td->td_pcb->pcb_ext == 0) { 303 ua.length = 0; 304 goto done; 305 } 306 307 iomap = (char *)td->td_pcb->pcb_ext->ext_iomap; 308 309 i = ua.start; 310 state = (iomap[i >> 3] >> (i & 7)) & 1; 311 ua.enable = !state; 312 ua.length = 1; 313 314 for (i = ua.start + 1; i < IOPAGES * PAGE_SIZE * NBBY; i++) { 315 if (state != ((iomap[i >> 3] >> (i & 7)) & 1)) 316 break; 317 ua.length++; 318 } 319 320 done: 321 error = copyout(&ua, args, sizeof(struct i386_ioperm_args)); 322 return (error); 323 } 324 325 /* 326 * Update the GDT entry pointing to the LDT to point to the LDT of the 327 * current process. 328 * 329 * This must be called with sched_lock held. Unfortunately, we can't use a 330 * mtx_assert() here because cpu_switch() calls this function after changing 331 * curproc but before sched_lock's owner is updated in mi_switch(). 332 */ 333 void 334 set_user_ldt(struct mdproc *mdp) 335 { 336 struct proc_ldt *pldt; 337 338 pldt = mdp->md_ldt; 339 #ifdef SMP 340 gdt[PCPU_GET(cpuid) * NGDT + GUSERLDT_SEL].sd = pldt->ldt_sd; 341 #else 342 gdt[GUSERLDT_SEL].sd = pldt->ldt_sd; 343 #endif 344 lldt(GSEL(GUSERLDT_SEL, SEL_KPL)); 345 PCPU_SET(currentldt, GSEL(GUSERLDT_SEL, SEL_KPL)); 346 } 347 348 #ifdef SMP 349 static void 350 set_user_ldt_rv(struct thread *td) 351 { 352 353 if (td->td_proc != curthread->td_proc) 354 return; 355 356 set_user_ldt(&td->td_proc->p_md); 357 } 358 #endif 359 360 /* 361 * Must be called with either sched_lock free or held but not recursed. 362 * If it does not return NULL, it will return with it owned. 363 */ 364 struct proc_ldt * 365 user_ldt_alloc(struct mdproc *mdp, int len) 366 { 367 struct proc_ldt *pldt, *new_ldt; 368 369 if (mtx_owned(&sched_lock)) 370 mtx_unlock_spin(&sched_lock); 371 mtx_assert(&sched_lock, MA_NOTOWNED); 372 MALLOC(new_ldt, struct proc_ldt *, sizeof(struct proc_ldt), 373 M_SUBPROC, M_WAITOK); 374 375 new_ldt->ldt_len = len = NEW_MAX_LD(len); 376 new_ldt->ldt_base = (caddr_t)kmem_alloc(kernel_map, 377 len * sizeof(union descriptor)); 378 if (new_ldt->ldt_base == NULL) { 379 FREE(new_ldt, M_SUBPROC); 380 return NULL; 381 } 382 new_ldt->ldt_refcnt = 1; 383 new_ldt->ldt_active = 0; 384 385 mtx_lock_spin(&sched_lock); 386 gdt_segs[GUSERLDT_SEL].ssd_base = (unsigned)new_ldt->ldt_base; 387 gdt_segs[GUSERLDT_SEL].ssd_limit = len * sizeof(union descriptor) - 1; 388 ssdtosd(&gdt_segs[GUSERLDT_SEL], &new_ldt->ldt_sd); 389 390 if ((pldt = mdp->md_ldt)) { 391 if (len > pldt->ldt_len) 392 len = pldt->ldt_len; 393 bcopy(pldt->ldt_base, new_ldt->ldt_base, 394 len * sizeof(union descriptor)); 395 } else { 396 bcopy(ldt, new_ldt->ldt_base, sizeof(ldt)); 397 } 398 return new_ldt; 399 } 400 401 /* 402 * Must be called either with sched_lock free or held but not recursed. 403 * If md_ldt is not NULL, it will return with sched_lock released. 404 */ 405 void 406 user_ldt_free(struct thread *td) 407 { 408 struct mdproc *mdp = &td->td_proc->p_md; 409 struct proc_ldt *pldt = mdp->md_ldt; 410 411 if (pldt == NULL) 412 return; 413 414 if (!mtx_owned(&sched_lock)) 415 mtx_lock_spin(&sched_lock); 416 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 417 if (td == PCPU_GET(curthread)) { 418 lldt(_default_ldt); 419 PCPU_SET(currentldt, _default_ldt); 420 } 421 422 mdp->md_ldt = NULL; 423 if (--pldt->ldt_refcnt == 0) { 424 mtx_unlock_spin(&sched_lock); 425 kmem_free(kernel_map, (vm_offset_t)pldt->ldt_base, 426 pldt->ldt_len * sizeof(union descriptor)); 427 FREE(pldt, M_SUBPROC); 428 } else 429 mtx_unlock_spin(&sched_lock); 430 } 431 432 static int 433 i386_get_ldt(td, args) 434 struct thread *td; 435 char *args; 436 { 437 int error = 0; 438 struct proc_ldt *pldt = td->td_proc->p_md.md_ldt; 439 int nldt, num; 440 union descriptor *lp; 441 struct i386_ldt_args ua, *uap = &ua; 442 443 if ((error = copyin(args, uap, sizeof(struct i386_ldt_args))) < 0) 444 return(error); 445 446 #ifdef DEBUG 447 printf("i386_get_ldt: start=%d num=%d descs=%p\n", 448 uap->start, uap->num, (void *)uap->descs); 449 #endif 450 451 if (pldt) { 452 nldt = pldt->ldt_len; 453 num = min(uap->num, nldt); 454 lp = &((union descriptor *)(pldt->ldt_base))[uap->start]; 455 } else { 456 nldt = sizeof(ldt)/sizeof(ldt[0]); 457 num = min(uap->num, nldt); 458 lp = &ldt[uap->start]; 459 } 460 461 if ((uap->start > (unsigned int)nldt) || 462 ((unsigned int)num > (unsigned int)nldt) || 463 ((unsigned int)(uap->start + num) > (unsigned int)nldt)) 464 return(EINVAL); 465 466 error = copyout(lp, uap->descs, num * sizeof(union descriptor)); 467 if (!error) 468 td->td_retval[0] = num; 469 470 return(error); 471 } 472 473 static int ldt_warnings; 474 #define NUM_LDT_WARNINGS 10 475 476 static int 477 i386_set_ldt(td, args) 478 struct thread *td; 479 char *args; 480 { 481 int error = 0, i; 482 int largest_ld; 483 struct mdproc *mdp = &td->td_proc->p_md; 484 struct proc_ldt *pldt = 0; 485 struct i386_ldt_args ua, *uap = &ua; 486 union descriptor *descs, *dp; 487 int descs_size; 488 489 if ((error = copyin(args, uap, sizeof(struct i386_ldt_args))) < 0) 490 return(error); 491 492 #ifdef DEBUG 493 printf("i386_set_ldt: start=%d num=%d descs=%p\n", 494 uap->start, uap->num, (void *)uap->descs); 495 #endif 496 497 if (uap->descs == NULL) { 498 /* Free descriptors */ 499 if (uap->start == 0 && uap->num == 0) { 500 /* 501 * Treat this as a special case, so userland needn't 502 * know magic number NLDT. 503 */ 504 uap->start = NLDT; 505 uap->num = MAX_LD - NLDT; 506 } 507 if (uap->start <= LUDATA_SEL || uap->num <= 0) 508 return (EINVAL); 509 mtx_lock_spin(&sched_lock); 510 pldt = mdp->md_ldt; 511 if (pldt == NULL || uap->start >= pldt->ldt_len) { 512 mtx_unlock_spin(&sched_lock); 513 return (0); 514 } 515 largest_ld = uap->start + uap->num; 516 if (largest_ld > pldt->ldt_len) 517 largest_ld = pldt->ldt_len; 518 i = largest_ld - uap->start; 519 bzero(&((union descriptor *)(pldt->ldt_base))[uap->start], 520 sizeof(union descriptor) * i); 521 mtx_unlock_spin(&sched_lock); 522 return (0); 523 } 524 525 if (!(uap->start == LDT_AUTO_ALLOC && uap->num == 1)) { 526 /* complain a for a while if using old methods */ 527 if (ldt_warnings++ < NUM_LDT_WARNINGS) { 528 printf("Warning: pid %d used static ldt allocation.\n", 529 td->td_proc->p_pid); 530 printf("See the i386_set_ldt man page for more info\n"); 531 } 532 /* verify range of descriptors to modify */ 533 largest_ld = uap->start + uap->num; 534 if (uap->start >= MAX_LD || 535 uap->num < 0 || largest_ld > MAX_LD) { 536 return (EINVAL); 537 } 538 } 539 540 descs_size = uap->num * sizeof(union descriptor); 541 descs = (union descriptor *)kmem_alloc(kernel_map, descs_size); 542 if (descs == NULL) 543 return (ENOMEM); 544 error = copyin(uap->descs, descs, descs_size); 545 if (error) { 546 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 547 return (error); 548 } 549 550 /* Check descriptors for access violations */ 551 for (i = 0; i < uap->num; i++) { 552 dp = &descs[i]; 553 554 switch (dp->sd.sd_type) { 555 case SDT_SYSNULL: /* system null */ 556 dp->sd.sd_p = 0; 557 break; 558 case SDT_SYS286TSS: /* system 286 TSS available */ 559 case SDT_SYSLDT: /* system local descriptor table */ 560 case SDT_SYS286BSY: /* system 286 TSS busy */ 561 case SDT_SYSTASKGT: /* system task gate */ 562 case SDT_SYS286IGT: /* system 286 interrupt gate */ 563 case SDT_SYS286TGT: /* system 286 trap gate */ 564 case SDT_SYSNULL2: /* undefined by Intel */ 565 case SDT_SYS386TSS: /* system 386 TSS available */ 566 case SDT_SYSNULL3: /* undefined by Intel */ 567 case SDT_SYS386BSY: /* system 386 TSS busy */ 568 case SDT_SYSNULL4: /* undefined by Intel */ 569 case SDT_SYS386IGT: /* system 386 interrupt gate */ 570 case SDT_SYS386TGT: /* system 386 trap gate */ 571 case SDT_SYS286CGT: /* system 286 call gate */ 572 case SDT_SYS386CGT: /* system 386 call gate */ 573 /* I can't think of any reason to allow a user proc 574 * to create a segment of these types. They are 575 * for OS use only. 576 */ 577 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 578 return (EACCES); 579 /*NOTREACHED*/ 580 581 /* memory segment types */ 582 case SDT_MEMEC: /* memory execute only conforming */ 583 case SDT_MEMEAC: /* memory execute only accessed conforming */ 584 case SDT_MEMERC: /* memory execute read conforming */ 585 case SDT_MEMERAC: /* memory execute read accessed conforming */ 586 /* Must be "present" if executable and conforming. */ 587 if (dp->sd.sd_p == 0) { 588 kmem_free(kernel_map, (vm_offset_t)descs, 589 descs_size); 590 return (EACCES); 591 } 592 break; 593 case SDT_MEMRO: /* memory read only */ 594 case SDT_MEMROA: /* memory read only accessed */ 595 case SDT_MEMRW: /* memory read write */ 596 case SDT_MEMRWA: /* memory read write accessed */ 597 case SDT_MEMROD: /* memory read only expand dwn limit */ 598 case SDT_MEMRODA: /* memory read only expand dwn lim accessed */ 599 case SDT_MEMRWD: /* memory read write expand dwn limit */ 600 case SDT_MEMRWDA: /* memory read write expand dwn lim acessed */ 601 case SDT_MEME: /* memory execute only */ 602 case SDT_MEMEA: /* memory execute only accessed */ 603 case SDT_MEMER: /* memory execute read */ 604 case SDT_MEMERA: /* memory execute read accessed */ 605 break; 606 default: 607 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 608 return(EINVAL); 609 /*NOTREACHED*/ 610 } 611 612 /* Only user (ring-3) descriptors may be present. */ 613 if ((dp->sd.sd_p != 0) && (dp->sd.sd_dpl != SEL_UPL)) { 614 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 615 return (EACCES); 616 } 617 } 618 619 if (uap->start == LDT_AUTO_ALLOC && uap->num == 1) { 620 /* Allocate a free slot */ 621 pldt = mdp->md_ldt; 622 if (pldt == NULL) { 623 error = i386_ldt_grow(td, NLDT+1); 624 if (error) { 625 kmem_free(kernel_map, (vm_offset_t)descs, 626 descs_size); 627 return (error); 628 } 629 pldt = mdp->md_ldt; 630 } 631 again: 632 mtx_lock_spin(&sched_lock); 633 /* 634 * start scanning a bit up to leave room for NVidia and 635 * Wine, which still user the "Blat" method of allocation. 636 */ 637 dp = &((union descriptor *)(pldt->ldt_base))[NLDT]; 638 for (i = NLDT; i < pldt->ldt_len; ++i) { 639 if (dp->sd.sd_type == SDT_SYSNULL) 640 break; 641 dp++; 642 } 643 if (i >= pldt->ldt_len) { 644 mtx_unlock_spin(&sched_lock); 645 error = i386_ldt_grow(td, pldt->ldt_len+1); 646 if (error) { 647 kmem_free(kernel_map, (vm_offset_t)descs, 648 descs_size); 649 return (error); 650 } 651 goto again; 652 } 653 uap->start = i; 654 error = i386_set_ldt_data(td, i, 1, descs); 655 mtx_unlock_spin(&sched_lock); 656 } else { 657 largest_ld = uap->start + uap->num; 658 error = i386_ldt_grow(td, largest_ld); 659 if (error == 0) { 660 mtx_lock_spin(&sched_lock); 661 error = i386_set_ldt_data(td, uap->start, uap->num, 662 descs); 663 mtx_unlock_spin(&sched_lock); 664 } 665 } 666 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 667 if (error == 0) 668 td->td_retval[0] = uap->start; 669 return (error); 670 } 671 672 static int 673 i386_set_ldt_data(struct thread *td, int start, int num, 674 union descriptor *descs) 675 { 676 struct mdproc *mdp = &td->td_proc->p_md; 677 struct proc_ldt *pldt = mdp->md_ldt; 678 679 mtx_assert(&sched_lock, MA_OWNED); 680 681 /* Fill in range */ 682 bcopy(descs, 683 &((union descriptor *)(pldt->ldt_base))[start], 684 num * sizeof(union descriptor)); 685 return (0); 686 } 687 688 static int 689 i386_ldt_grow(struct thread *td, int len) 690 { 691 struct mdproc *mdp = &td->td_proc->p_md; 692 struct proc_ldt *pldt; 693 caddr_t old_ldt_base; 694 int old_ldt_len; 695 696 if (len > MAX_LD) 697 return (ENOMEM); 698 if (len < NLDT+1) 699 len = NLDT+1; 700 pldt = mdp->md_ldt; 701 /* allocate user ldt */ 702 if (!pldt || len > pldt->ldt_len) { 703 struct proc_ldt *new_ldt = user_ldt_alloc(mdp, len); 704 if (new_ldt == NULL) 705 return (ENOMEM); 706 pldt = mdp->md_ldt; 707 /* sched_lock was held by user_ldt_alloc */ 708 if (pldt) { 709 if (new_ldt->ldt_len > pldt->ldt_len) { 710 old_ldt_base = pldt->ldt_base; 711 old_ldt_len = pldt->ldt_len; 712 pldt->ldt_sd = new_ldt->ldt_sd; 713 pldt->ldt_base = new_ldt->ldt_base; 714 pldt->ldt_len = new_ldt->ldt_len; 715 mtx_unlock_spin(&sched_lock); 716 kmem_free(kernel_map, (vm_offset_t)old_ldt_base, 717 old_ldt_len * sizeof(union descriptor)); 718 FREE(new_ldt, M_SUBPROC); 719 mtx_lock_spin(&sched_lock); 720 } else { 721 /* 722 * If other threads already did the work, 723 * do nothing 724 */ 725 mtx_unlock_spin(&sched_lock); 726 kmem_free(kernel_map, 727 (vm_offset_t)new_ldt->ldt_base, 728 new_ldt->ldt_len * sizeof(union descriptor)); 729 FREE(new_ldt, M_SUBPROC); 730 return (0); 731 } 732 } else { 733 mdp->md_ldt = pldt = new_ldt; 734 } 735 #ifdef SMP 736 mtx_unlock_spin(&sched_lock); 737 /* signal other cpus to reload ldt */ 738 smp_rendezvous(NULL, (void (*)(void *))set_user_ldt_rv, 739 NULL, td); 740 #else 741 set_user_ldt(mdp); 742 mtx_unlock_spin(&sched_lock); 743 #endif 744 } 745 return (0); 746 }
Cache object: dc8ebabf00722075ba699221c2be294f
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