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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)sys_machdep.c 5.5 (Berkeley) 1/19/91 34 * $FreeBSD: releng/5.0/sys/i386/i386/sys_machdep.c 104474 2002-10-04 20:19:36Z jhb $ 35 * 36 */ 37 38 #include "opt_kstack_pages.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/lock.h> 43 #include <sys/malloc.h> 44 #include <sys/mutex.h> 45 #include <sys/proc.h> 46 #include <sys/smp.h> 47 #include <sys/sysproto.h> 48 #include <sys/user.h> 49 50 #include <vm/vm.h> 51 #include <vm/pmap.h> 52 #include <vm/vm_map.h> 53 #include <vm/vm_extern.h> 54 55 #include <machine/cpu.h> 56 #include <machine/pcb_ext.h> /* pcb.h included by sys/user.h */ 57 #include <machine/proc.h> 58 #include <machine/sysarch.h> 59 60 #include <vm/vm_kern.h> /* for kernel_map */ 61 62 #define MAX_LD 8192 63 #define LD_PER_PAGE 512 64 #define NEW_MAX_LD(num) ((num + LD_PER_PAGE) & ~(LD_PER_PAGE-1)) 65 #define SIZE_FROM_LARGEST_LD(num) (NEW_MAX_LD(num) << 3) 66 67 68 69 static int i386_get_ldt(struct thread *, char *); 70 static int i386_set_ldt(struct thread *, char *); 71 static int i386_get_ioperm(struct thread *, char *); 72 static int i386_set_ioperm(struct thread *, char *); 73 #ifdef SMP 74 static void set_user_ldt_rv(struct thread *); 75 #endif 76 77 #ifndef _SYS_SYSPROTO_H_ 78 struct sysarch_args { 79 int op; 80 char *parms; 81 }; 82 #endif 83 84 int 85 sysarch(td, uap) 86 struct thread *td; 87 register struct sysarch_args *uap; 88 { 89 int error = 0; 90 91 switch(uap->op) { 92 case I386_GET_LDT: 93 error = i386_get_ldt(td, uap->parms); 94 break; 95 96 case I386_SET_LDT: 97 error = i386_set_ldt(td, uap->parms); 98 break; 99 case I386_GET_IOPERM: 100 error = i386_get_ioperm(td, uap->parms); 101 break; 102 case I386_SET_IOPERM: 103 error = i386_set_ioperm(td, uap->parms); 104 break; 105 case I386_VM86: 106 error = vm86_sysarch(td, uap->parms); 107 break; 108 default: 109 error = EOPNOTSUPP; 110 break; 111 } 112 return (error); 113 } 114 115 int 116 i386_extend_pcb(struct thread *td) 117 { 118 int i, offset; 119 u_long *addr; 120 struct pcb_ext *ext; 121 struct soft_segment_descriptor ssd = { 122 0, /* segment base address (overwritten) */ 123 ctob(IOPAGES + 1) - 1, /* length */ 124 SDT_SYS386TSS, /* segment type */ 125 0, /* priority level */ 126 1, /* descriptor present */ 127 0, 0, 128 0, /* default 32 size */ 129 0 /* granularity */ 130 }; 131 132 if (td->td_proc->p_flag & P_KSES) 133 return (EINVAL); /* XXXKSE */ 134 /* XXXKSE All the code below only works in 1:1 needs changing */ 135 ext = (struct pcb_ext *)kmem_alloc(kernel_map, ctob(IOPAGES+1)); 136 if (ext == 0) 137 return (ENOMEM); 138 bzero(ext, sizeof(struct pcb_ext)); 139 /* -16 is so we can convert a trapframe into vm86trapframe inplace */ 140 ext->ext_tss.tss_esp0 = td->td_kstack + ctob(KSTACK_PAGES) - 141 sizeof(struct pcb) - 16; 142 ext->ext_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL); 143 /* 144 * The last byte of the i/o map must be followed by an 0xff byte. 145 * We arbitrarily allocate 16 bytes here, to keep the starting 146 * address on a doubleword boundary. 147 */ 148 offset = PAGE_SIZE - 16; 149 ext->ext_tss.tss_ioopt = 150 (offset - ((unsigned)&ext->ext_tss - (unsigned)ext)) << 16; 151 ext->ext_iomap = (caddr_t)ext + offset; 152 ext->ext_vm86.vm86_intmap = (caddr_t)ext + offset - 32; 153 154 addr = (u_long *)ext->ext_vm86.vm86_intmap; 155 for (i = 0; i < (ctob(IOPAGES) + 32 + 16) / sizeof(u_long); i++) 156 *addr++ = ~0; 157 158 ssd.ssd_base = (unsigned)&ext->ext_tss; 159 ssd.ssd_limit -= ((unsigned)&ext->ext_tss - (unsigned)ext); 160 ssdtosd(&ssd, &ext->ext_tssd); 161 162 KASSERT(td->td_proc == curthread->td_proc, ("giving TSS to !curproc")); 163 KASSERT(td->td_pcb->pcb_ext == 0, ("already have a TSS!")); 164 mtx_lock_spin(&sched_lock); 165 td->td_pcb->pcb_ext = ext; 166 167 /* switch to the new TSS after syscall completes */ 168 td->td_kse->ke_flags |= KEF_NEEDRESCHED; 169 mtx_unlock_spin(&sched_lock); 170 171 return 0; 172 } 173 174 static int 175 i386_set_ioperm(td, args) 176 struct thread *td; 177 char *args; 178 { 179 int i, error; 180 struct i386_ioperm_args ua; 181 char *iomap; 182 183 if ((error = copyin(args, &ua, sizeof(struct i386_ioperm_args))) != 0) 184 return (error); 185 186 if ((error = suser(td)) != 0) 187 return (error); 188 if ((error = securelevel_gt(td->td_ucred, 0)) != 0) 189 return (error); 190 /* 191 * XXX 192 * While this is restricted to root, we should probably figure out 193 * whether any other driver is using this i/o address, as so not to 194 * cause confusion. This probably requires a global 'usage registry'. 195 */ 196 197 if (td->td_pcb->pcb_ext == 0) 198 if ((error = i386_extend_pcb(td)) != 0) 199 return (error); 200 iomap = (char *)td->td_pcb->pcb_ext->ext_iomap; 201 202 if (ua.start + ua.length > IOPAGES * PAGE_SIZE * NBBY) 203 return (EINVAL); 204 205 for (i = ua.start; i < ua.start + ua.length; i++) { 206 if (ua.enable) 207 iomap[i >> 3] &= ~(1 << (i & 7)); 208 else 209 iomap[i >> 3] |= (1 << (i & 7)); 210 } 211 return (error); 212 } 213 214 static int 215 i386_get_ioperm(td, args) 216 struct thread *td; 217 char *args; 218 { 219 int i, state, error; 220 struct i386_ioperm_args ua; 221 char *iomap; 222 223 if ((error = copyin(args, &ua, sizeof(struct i386_ioperm_args))) != 0) 224 return (error); 225 if (ua.start >= IOPAGES * PAGE_SIZE * NBBY) 226 return (EINVAL); 227 228 if (td->td_pcb->pcb_ext == 0) { 229 ua.length = 0; 230 goto done; 231 } 232 233 iomap = (char *)td->td_pcb->pcb_ext->ext_iomap; 234 235 i = ua.start; 236 state = (iomap[i >> 3] >> (i & 7)) & 1; 237 ua.enable = !state; 238 ua.length = 1; 239 240 for (i = ua.start + 1; i < IOPAGES * PAGE_SIZE * NBBY; i++) { 241 if (state != ((iomap[i >> 3] >> (i & 7)) & 1)) 242 break; 243 ua.length++; 244 } 245 246 done: 247 error = copyout(&ua, args, sizeof(struct i386_ioperm_args)); 248 return (error); 249 } 250 251 /* 252 * Update the GDT entry pointing to the LDT to point to the LDT of the 253 * current process. 254 * 255 * This must be called with sched_lock held. Unfortunately, we can't use a 256 * mtx_assert() here because cpu_switch() calls this function after changing 257 * curproc but before sched_lock's owner is updated in mi_switch(). 258 */ 259 void 260 set_user_ldt(struct mdproc *mdp) 261 { 262 struct proc_ldt *pldt; 263 264 pldt = mdp->md_ldt; 265 #ifdef SMP 266 gdt[PCPU_GET(cpuid) * NGDT + GUSERLDT_SEL].sd = pldt->ldt_sd; 267 #else 268 gdt[GUSERLDT_SEL].sd = pldt->ldt_sd; 269 #endif 270 lldt(GSEL(GUSERLDT_SEL, SEL_KPL)); 271 PCPU_SET(currentldt, GSEL(GUSERLDT_SEL, SEL_KPL)); 272 } 273 274 #ifdef SMP 275 static void 276 set_user_ldt_rv(struct thread *td) 277 { 278 279 if (td != PCPU_GET(curthread)) 280 return; 281 282 mtx_lock_spin(&sched_lock); 283 set_user_ldt(&td->td_proc->p_md); 284 mtx_unlock_spin(&sched_lock); 285 } 286 #endif 287 288 /* 289 * Must be called with either sched_lock free or held but not recursed. 290 * If it does not return NULL, it will return with it owned. 291 */ 292 struct proc_ldt * 293 user_ldt_alloc(struct mdproc *mdp, int len) 294 { 295 struct proc_ldt *pldt, *new_ldt; 296 297 if (mtx_owned(&sched_lock)) 298 mtx_unlock_spin(&sched_lock); 299 mtx_assert(&sched_lock, MA_NOTOWNED); 300 MALLOC(new_ldt, struct proc_ldt *, sizeof(struct proc_ldt), 301 M_SUBPROC, M_WAITOK); 302 303 new_ldt->ldt_len = len = NEW_MAX_LD(len); 304 new_ldt->ldt_base = (caddr_t)kmem_alloc(kernel_map, 305 len * sizeof(union descriptor)); 306 if (new_ldt->ldt_base == NULL) { 307 FREE(new_ldt, M_SUBPROC); 308 return NULL; 309 } 310 new_ldt->ldt_refcnt = 1; 311 new_ldt->ldt_active = 0; 312 313 mtx_lock_spin(&sched_lock); 314 gdt_segs[GUSERLDT_SEL].ssd_base = (unsigned)new_ldt->ldt_base; 315 gdt_segs[GUSERLDT_SEL].ssd_limit = len * sizeof(union descriptor) - 1; 316 ssdtosd(&gdt_segs[GUSERLDT_SEL], &new_ldt->ldt_sd); 317 318 if ((pldt = mdp->md_ldt)) { 319 if (len > pldt->ldt_len) 320 len = pldt->ldt_len; 321 bcopy(pldt->ldt_base, new_ldt->ldt_base, 322 len * sizeof(union descriptor)); 323 } else { 324 bcopy(ldt, new_ldt->ldt_base, sizeof(ldt)); 325 } 326 return new_ldt; 327 } 328 329 /* 330 * Must be called either with sched_lock free or held but not recursed. 331 * If md_ldt is not NULL, it will return with sched_lock released. 332 */ 333 void 334 user_ldt_free(struct thread *td) 335 { 336 struct mdproc *mdp = &td->td_proc->p_md; 337 struct proc_ldt *pldt = mdp->md_ldt; 338 339 if (pldt == NULL) 340 return; 341 342 if (!mtx_owned(&sched_lock)) 343 mtx_lock_spin(&sched_lock); 344 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 345 if (td == PCPU_GET(curthread)) { 346 lldt(_default_ldt); 347 PCPU_SET(currentldt, _default_ldt); 348 } 349 350 mdp->md_ldt = NULL; 351 if (--pldt->ldt_refcnt == 0) { 352 mtx_unlock_spin(&sched_lock); 353 kmem_free(kernel_map, (vm_offset_t)pldt->ldt_base, 354 pldt->ldt_len * sizeof(union descriptor)); 355 FREE(pldt, M_SUBPROC); 356 } else 357 mtx_unlock_spin(&sched_lock); 358 } 359 360 static int 361 i386_get_ldt(td, args) 362 struct thread *td; 363 char *args; 364 { 365 int error = 0; 366 struct proc_ldt *pldt = td->td_proc->p_md.md_ldt; 367 int nldt, num; 368 union descriptor *lp; 369 struct i386_ldt_args ua, *uap = &ua; 370 371 if ((error = copyin(args, uap, sizeof(struct i386_ldt_args))) < 0) 372 return(error); 373 374 #ifdef DEBUG 375 printf("i386_get_ldt: start=%d num=%d descs=%p\n", 376 uap->start, uap->num, (void *)uap->descs); 377 #endif 378 379 /* verify range of LDTs exist */ 380 if ((uap->start < 0) || (uap->num <= 0)) 381 return(EINVAL); 382 383 if (pldt) { 384 nldt = pldt->ldt_len; 385 num = min(uap->num, nldt); 386 lp = &((union descriptor *)(pldt->ldt_base))[uap->start]; 387 } else { 388 nldt = sizeof(ldt)/sizeof(ldt[0]); 389 num = min(uap->num, nldt); 390 lp = &ldt[uap->start]; 391 } 392 if (uap->start + num > nldt) 393 return(EINVAL); 394 395 error = copyout(lp, uap->descs, num * sizeof(union descriptor)); 396 if (!error) 397 td->td_retval[0] = num; 398 399 return(error); 400 } 401 402 static int 403 i386_set_ldt(td, args) 404 struct thread *td; 405 char *args; 406 { 407 int error = 0, i, n; 408 int largest_ld; 409 struct mdproc *mdp = &td->td_proc->p_md; 410 struct proc_ldt *pldt = mdp->md_ldt; 411 struct i386_ldt_args ua, *uap = &ua; 412 union descriptor *descs; 413 caddr_t old_ldt_base; 414 int descs_size, old_ldt_len; 415 register_t savecrit; 416 417 if ((error = copyin(args, uap, sizeof(struct i386_ldt_args))) < 0) 418 return(error); 419 420 #ifdef DEBUG 421 printf("i386_set_ldt: start=%d num=%d descs=%p\n", 422 uap->start, uap->num, (void *)uap->descs); 423 #endif 424 425 /* verify range of descriptors to modify */ 426 if ((uap->start < 0) || (uap->start >= MAX_LD) || (uap->num < 0) || 427 (uap->num > MAX_LD)) 428 { 429 return(EINVAL); 430 } 431 largest_ld = uap->start + uap->num - 1; 432 if (largest_ld >= MAX_LD) 433 return(EINVAL); 434 435 /* allocate user ldt */ 436 if (!pldt || largest_ld >= pldt->ldt_len) { 437 struct proc_ldt *new_ldt = user_ldt_alloc(mdp, largest_ld); 438 if (new_ldt == NULL) 439 return ENOMEM; 440 if (pldt) { 441 old_ldt_base = pldt->ldt_base; 442 old_ldt_len = pldt->ldt_len; 443 pldt->ldt_sd = new_ldt->ldt_sd; 444 pldt->ldt_base = new_ldt->ldt_base; 445 pldt->ldt_len = new_ldt->ldt_len; 446 mtx_unlock_spin(&sched_lock); 447 kmem_free(kernel_map, (vm_offset_t)old_ldt_base, 448 old_ldt_len * sizeof(union descriptor)); 449 FREE(new_ldt, M_SUBPROC); 450 #ifndef SMP 451 mtx_lock_spin(&sched_lock); 452 #endif 453 } else { 454 mdp->md_ldt = pldt = new_ldt; 455 #ifdef SMP 456 mtx_unlock_spin(&sched_lock); 457 #endif 458 } 459 #ifdef SMP 460 /* signal other cpus to reload ldt */ 461 smp_rendezvous(NULL, (void (*)(void *))set_user_ldt_rv, 462 NULL, td); 463 #else 464 set_user_ldt(mdp); 465 mtx_unlock_spin(&sched_lock); 466 #endif 467 } 468 469 descs_size = uap->num * sizeof(union descriptor); 470 descs = (union descriptor *)kmem_alloc(kernel_map, descs_size); 471 if (descs == NULL) 472 return (ENOMEM); 473 error = copyin(&uap->descs[0], descs, descs_size); 474 if (error) { 475 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 476 return (error); 477 } 478 /* Check descriptors for access violations */ 479 for (i = 0, n = uap->start; i < uap->num; i++, n++) { 480 union descriptor *dp; 481 dp = &descs[i]; 482 483 switch (dp->sd.sd_type) { 484 case SDT_SYSNULL: /* system null */ 485 dp->sd.sd_p = 0; 486 break; 487 case SDT_SYS286TSS: /* system 286 TSS available */ 488 case SDT_SYSLDT: /* system local descriptor table */ 489 case SDT_SYS286BSY: /* system 286 TSS busy */ 490 case SDT_SYSTASKGT: /* system task gate */ 491 case SDT_SYS286IGT: /* system 286 interrupt gate */ 492 case SDT_SYS286TGT: /* system 286 trap gate */ 493 case SDT_SYSNULL2: /* undefined by Intel */ 494 case SDT_SYS386TSS: /* system 386 TSS available */ 495 case SDT_SYSNULL3: /* undefined by Intel */ 496 case SDT_SYS386BSY: /* system 386 TSS busy */ 497 case SDT_SYSNULL4: /* undefined by Intel */ 498 case SDT_SYS386IGT: /* system 386 interrupt gate */ 499 case SDT_SYS386TGT: /* system 386 trap gate */ 500 case SDT_SYS286CGT: /* system 286 call gate */ 501 case SDT_SYS386CGT: /* system 386 call gate */ 502 /* I can't think of any reason to allow a user proc 503 * to create a segment of these types. They are 504 * for OS use only. 505 */ 506 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 507 return EACCES; 508 /*NOTREACHED*/ 509 510 /* memory segment types */ 511 case SDT_MEMEC: /* memory execute only conforming */ 512 case SDT_MEMEAC: /* memory execute only accessed conforming */ 513 case SDT_MEMERC: /* memory execute read conforming */ 514 case SDT_MEMERAC: /* memory execute read accessed conforming */ 515 /* Must be "present" if executable and conforming. */ 516 if (dp->sd.sd_p == 0) { 517 kmem_free(kernel_map, (vm_offset_t)descs, 518 descs_size); 519 return (EACCES); 520 } 521 break; 522 case SDT_MEMRO: /* memory read only */ 523 case SDT_MEMROA: /* memory read only accessed */ 524 case SDT_MEMRW: /* memory read write */ 525 case SDT_MEMRWA: /* memory read write accessed */ 526 case SDT_MEMROD: /* memory read only expand dwn limit */ 527 case SDT_MEMRODA: /* memory read only expand dwn lim accessed */ 528 case SDT_MEMRWD: /* memory read write expand dwn limit */ 529 case SDT_MEMRWDA: /* memory read write expand dwn lim acessed */ 530 case SDT_MEME: /* memory execute only */ 531 case SDT_MEMEA: /* memory execute only accessed */ 532 case SDT_MEMER: /* memory execute read */ 533 case SDT_MEMERA: /* memory execute read accessed */ 534 break; 535 default: 536 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 537 return(EINVAL); 538 /*NOTREACHED*/ 539 } 540 541 /* Only user (ring-3) descriptors may be present. */ 542 if ((dp->sd.sd_p != 0) && (dp->sd.sd_dpl != SEL_UPL)) { 543 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 544 return (EACCES); 545 } 546 } 547 548 /* Fill in range */ 549 savecrit = intr_disable(); 550 bcopy(descs, 551 &((union descriptor *)(pldt->ldt_base))[uap->start], 552 uap->num * sizeof(union descriptor)); 553 td->td_retval[0] = uap->start; 554 intr_restore(savecrit); 555 kmem_free(kernel_map, (vm_offset_t)descs, descs_size); 556 return (0); 557 }
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