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/8.4/sys/amd64/amd64/sys_machdep.c 237009 2012-06-13 15:25:52Z jhb $");
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/priv.h>
43 #include <sys/proc.h>
44 #include <sys/sysproto.h>
45 #include <sys/uio.h>
46
47 #include <vm/vm.h>
48 #include <vm/pmap.h>
49 #include <vm/vm_kern.h> /* for kernel_map */
50 #include <vm/vm_extern.h>
51
52 #include <machine/frame.h>
53 #include <machine/md_var.h>
54 #include <machine/pcb.h>
55 #include <machine/specialreg.h>
56 #include <machine/sysarch.h>
57 #include <machine/tss.h>
58 #include <machine/vmparam.h>
59
60 #include <security/audit/audit.h>
61
62 #define MAX_LD 8192
63
64 int max_ldt_segment = 1024;
65 SYSCTL_INT(_machdep, OID_AUTO, max_ldt_segment, CTLFLAG_RDTUN,
66 &max_ldt_segment, 0,
67 "Maximum number of allowed LDT segments in the single address space");
68
69 static void
70 max_ldt_segment_init(void *arg __unused)
71 {
72
73 TUNABLE_INT_FETCH("machdep.max_ldt_segment", &max_ldt_segment);
74 if (max_ldt_segment <= 0)
75 max_ldt_segment = 1;
76 if (max_ldt_segment > MAX_LD)
77 max_ldt_segment = MAX_LD;
78 }
79 SYSINIT(maxldt, SI_SUB_VM_CONF, SI_ORDER_ANY, max_ldt_segment_init, NULL);
80
81 #ifdef notyet
82 #ifdef SMP
83 static void set_user_ldt_rv(struct vmspace *vmsp);
84 #endif
85 #endif
86 static void user_ldt_derefl(struct proc_ldt *pldt);
87
88 #ifndef _SYS_SYSPROTO_H_
89 struct sysarch_args {
90 int op;
91 char *parms;
92 };
93 #endif
94
95 int
96 sysarch_ldt(struct thread *td, struct sysarch_args *uap, int uap_space)
97 {
98 struct i386_ldt_args *largs, la;
99 struct user_segment_descriptor *lp;
100 int error = 0;
101
102 /*
103 * XXXKIB check that the BSM generation code knows to encode
104 * the op argument.
105 */
106 AUDIT_ARG_CMD(uap->op);
107 if (uap_space == UIO_USERSPACE) {
108 error = copyin(uap->parms, &la, sizeof(struct i386_ldt_args));
109 if (error != 0)
110 return (error);
111 largs = &la;
112 } else
113 largs = (struct i386_ldt_args *)uap->parms;
114 if (largs->num > max_ldt_segment || largs->num <= 0)
115 return (EINVAL);
116
117 switch (uap->op) {
118 case I386_GET_LDT:
119 error = amd64_get_ldt(td, largs);
120 break;
121 case I386_SET_LDT:
122 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
123 if (largs->descs != NULL) {
124 lp = malloc(largs->num * sizeof(struct
125 user_segment_descriptor), M_TEMP, M_WAITOK);
126 error = copyin(largs->descs, lp, largs->num *
127 sizeof(struct user_segment_descriptor));
128 if (error == 0)
129 error = amd64_set_ldt(td, largs, lp);
130 free(lp, M_TEMP);
131 } else {
132 error = amd64_set_ldt(td, largs, NULL);
133 }
134 break;
135 }
136 return (error);
137 }
138
139 void
140 update_gdt_gsbase(struct thread *td, uint32_t base)
141 {
142 struct user_segment_descriptor *sd;
143
144 if (td != curthread)
145 return;
146 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
147 critical_enter();
148 sd = PCPU_GET(gs32p);
149 sd->sd_lobase = base & 0xffffff;
150 sd->sd_hibase = (base >> 24) & 0xff;
151 critical_exit();
152 }
153
154 void
155 update_gdt_fsbase(struct thread *td, uint32_t base)
156 {
157 struct user_segment_descriptor *sd;
158
159 if (td != curthread)
160 return;
161 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
162 critical_enter();
163 sd = PCPU_GET(fs32p);
164 sd->sd_lobase = base & 0xffffff;
165 sd->sd_hibase = (base >> 24) & 0xff;
166 critical_exit();
167 }
168
169 int
170 sysarch(td, uap)
171 struct thread *td;
172 register struct sysarch_args *uap;
173 {
174 int error = 0;
175 struct pcb *pcb = curthread->td_pcb;
176 uint32_t i386base;
177 uint64_t a64base;
178 struct i386_ioperm_args iargs;
179 struct i386_get_xfpustate i386xfpu;
180 struct amd64_get_xfpustate a64xfpu;
181
182 if (uap->op == I386_GET_LDT || uap->op == I386_SET_LDT)
183 return (sysarch_ldt(td, uap, UIO_USERSPACE));
184 /*
185 * XXXKIB check that the BSM generation code knows to encode
186 * the op argument.
187 */
188 AUDIT_ARG_CMD(uap->op);
189 switch (uap->op) {
190 case I386_GET_IOPERM:
191 case I386_SET_IOPERM:
192 if ((error = copyin(uap->parms, &iargs,
193 sizeof(struct i386_ioperm_args))) != 0)
194 return (error);
195 break;
196 case I386_GET_XFPUSTATE:
197 if ((error = copyin(uap->parms, &i386xfpu,
198 sizeof(struct i386_get_xfpustate))) != 0)
199 return (error);
200 a64xfpu.addr = (void *)(uintptr_t)i386xfpu.addr;
201 a64xfpu.len = i386xfpu.len;
202 break;
203 case AMD64_GET_XFPUSTATE:
204 if ((error = copyin(uap->parms, &a64xfpu,
205 sizeof(struct amd64_get_xfpustate))) != 0)
206 return (error);
207 break;
208 default:
209 break;
210 }
211
212 switch (uap->op) {
213 case I386_GET_IOPERM:
214 error = amd64_get_ioperm(td, &iargs);
215 if (error == 0)
216 error = copyout(&iargs, uap->parms,
217 sizeof(struct i386_ioperm_args));
218 break;
219 case I386_SET_IOPERM:
220 error = amd64_set_ioperm(td, &iargs);
221 break;
222 case I386_GET_FSBASE:
223 i386base = pcb->pcb_fsbase;
224 error = copyout(&i386base, uap->parms, sizeof(i386base));
225 break;
226 case I386_SET_FSBASE:
227 error = copyin(uap->parms, &i386base, sizeof(i386base));
228 if (!error) {
229 pcb->pcb_fsbase = i386base;
230 td->td_frame->tf_fs = _ufssel;
231 update_gdt_fsbase(td, i386base);
232 }
233 break;
234 case I386_GET_GSBASE:
235 i386base = pcb->pcb_gsbase;
236 error = copyout(&i386base, uap->parms, sizeof(i386base));
237 break;
238 case I386_SET_GSBASE:
239 error = copyin(uap->parms, &i386base, sizeof(i386base));
240 if (!error) {
241 pcb->pcb_gsbase = i386base;
242 td->td_frame->tf_gs = _ugssel;
243 update_gdt_gsbase(td, i386base);
244 }
245 break;
246 case AMD64_GET_FSBASE:
247 error = copyout(&pcb->pcb_fsbase, uap->parms, sizeof(pcb->pcb_fsbase));
248 break;
249
250 case AMD64_SET_FSBASE:
251 error = copyin(uap->parms, &a64base, sizeof(a64base));
252 if (!error) {
253 if (a64base < VM_MAXUSER_ADDRESS) {
254 pcb->pcb_fsbase = a64base;
255 set_pcb_flags(pcb, PCB_FULL_IRET);
256 td->td_frame->tf_fs = _ufssel;
257 } else
258 error = EINVAL;
259 }
260 break;
261
262 case AMD64_GET_GSBASE:
263 error = copyout(&pcb->pcb_gsbase, uap->parms, sizeof(pcb->pcb_gsbase));
264 break;
265
266 case AMD64_SET_GSBASE:
267 error = copyin(uap->parms, &a64base, sizeof(a64base));
268 if (!error) {
269 if (a64base < VM_MAXUSER_ADDRESS) {
270 pcb->pcb_gsbase = a64base;
271 set_pcb_flags(pcb, PCB_FULL_IRET);
272 td->td_frame->tf_gs = _ugssel;
273 } else
274 error = EINVAL;
275 }
276 break;
277
278 case I386_GET_XFPUSTATE:
279 case AMD64_GET_XFPUSTATE:
280 if (a64xfpu.len > cpu_max_ext_state_size -
281 sizeof(struct savefpu))
282 return (EINVAL);
283 fpugetregs(td);
284 error = copyout((char *)(get_pcb_user_save_td(td) + 1),
285 a64xfpu.addr, a64xfpu.len);
286 return (error);
287
288 default:
289 error = EINVAL;
290 break;
291 }
292 return (error);
293 }
294
295 int
296 amd64_set_ioperm(td, uap)
297 struct thread *td;
298 struct i386_ioperm_args *uap;
299 {
300 int i, error;
301 char *iomap;
302 struct amd64tss *tssp;
303 struct system_segment_descriptor *tss_sd;
304 u_long *addr;
305 struct pcb *pcb;
306
307 if ((error = priv_check(td, PRIV_IO)) != 0)
308 return (error);
309 if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
310 return (error);
311 if (uap->start + uap->length > IOPAGES * PAGE_SIZE * NBBY)
312 return (EINVAL);
313
314 /*
315 * XXX
316 * While this is restricted to root, we should probably figure out
317 * whether any other driver is using this i/o address, as so not to
318 * cause confusion. This probably requires a global 'usage registry'.
319 */
320 pcb = td->td_pcb;
321 if (pcb->pcb_tssp == NULL) {
322 tssp = (struct amd64tss *)kmem_alloc(kernel_map,
323 ctob(IOPAGES+1));
324 if (tssp == NULL)
325 return (ENOMEM);
326 iomap = (char *)&tssp[1];
327 addr = (u_long *)iomap;
328 for (i = 0; i < (ctob(IOPAGES) + 1) / sizeof(u_long); i++)
329 *addr++ = ~0;
330 critical_enter();
331 /* Takes care of tss_rsp0. */
332 memcpy(tssp, &common_tss[PCPU_GET(cpuid)],
333 sizeof(struct amd64tss));
334 tssp->tss_iobase = sizeof(*tssp);
335 pcb->pcb_tssp = tssp;
336 tss_sd = PCPU_GET(tss);
337 tss_sd->sd_lobase = (u_long)tssp & 0xffffff;
338 tss_sd->sd_hibase = ((u_long)tssp >> 24) & 0xfffffffffful;
339 tss_sd->sd_type = SDT_SYSTSS;
340 ltr(GSEL(GPROC0_SEL, SEL_KPL));
341 PCPU_SET(tssp, tssp);
342 critical_exit();
343 } else
344 iomap = (char *)&pcb->pcb_tssp[1];
345 for (i = uap->start; i < uap->start + uap->length; i++) {
346 if (uap->enable)
347 iomap[i >> 3] &= ~(1 << (i & 7));
348 else
349 iomap[i >> 3] |= (1 << (i & 7));
350 }
351 return (error);
352 }
353
354 int
355 amd64_get_ioperm(td, uap)
356 struct thread *td;
357 struct i386_ioperm_args *uap;
358 {
359 int i, state;
360 char *iomap;
361
362 if (uap->start >= IOPAGES * PAGE_SIZE * NBBY)
363 return (EINVAL);
364 if (td->td_pcb->pcb_tssp == NULL) {
365 uap->length = 0;
366 goto done;
367 }
368
369 iomap = (char *)&td->td_pcb->pcb_tssp[1];
370
371 i = uap->start;
372 state = (iomap[i >> 3] >> (i & 7)) & 1;
373 uap->enable = !state;
374 uap->length = 1;
375
376 for (i = uap->start + 1; i < IOPAGES * PAGE_SIZE * NBBY; i++) {
377 if (state != ((iomap[i >> 3] >> (i & 7)) & 1))
378 break;
379 uap->length++;
380 }
381
382 done:
383 return (0);
384 }
385
386 /*
387 * Update the GDT entry pointing to the LDT to point to the LDT of the
388 * current process.
389 */
390 void
391 set_user_ldt(struct mdproc *mdp)
392 {
393
394 critical_enter();
395 *PCPU_GET(ldt) = mdp->md_ldt_sd;
396 lldt(GSEL(GUSERLDT_SEL, SEL_KPL));
397 critical_exit();
398 }
399
400 #ifdef notyet
401 #ifdef SMP
402 static void
403 set_user_ldt_rv(struct vmspace *vmsp)
404 {
405 struct thread *td;
406
407 td = curthread;
408 if (vmsp != td->td_proc->p_vmspace)
409 return;
410
411 set_user_ldt(&td->td_proc->p_md);
412 }
413 #endif
414 #endif
415
416 struct proc_ldt *
417 user_ldt_alloc(struct proc *p, int force)
418 {
419 struct proc_ldt *pldt, *new_ldt;
420 struct mdproc *mdp;
421 struct soft_segment_descriptor sldt;
422
423 mtx_assert(&dt_lock, MA_OWNED);
424 mdp = &p->p_md;
425 if (!force && mdp->md_ldt != NULL)
426 return (mdp->md_ldt);
427 mtx_unlock(&dt_lock);
428 new_ldt = malloc(sizeof(struct proc_ldt), M_SUBPROC, M_WAITOK);
429 new_ldt->ldt_base = (caddr_t)kmem_alloc(kernel_map,
430 max_ldt_segment * sizeof(struct user_segment_descriptor));
431 if (new_ldt->ldt_base == NULL) {
432 FREE(new_ldt, M_SUBPROC);
433 mtx_lock(&dt_lock);
434 return (NULL);
435 }
436 new_ldt->ldt_refcnt = 1;
437 sldt.ssd_base = (uint64_t)new_ldt->ldt_base;
438 sldt.ssd_limit = max_ldt_segment *
439 sizeof(struct user_segment_descriptor) - 1;
440 sldt.ssd_type = SDT_SYSLDT;
441 sldt.ssd_dpl = SEL_KPL;
442 sldt.ssd_p = 1;
443 sldt.ssd_long = 0;
444 sldt.ssd_def32 = 0;
445 sldt.ssd_gran = 0;
446 mtx_lock(&dt_lock);
447 pldt = mdp->md_ldt;
448 if (pldt != NULL && !force) {
449 kmem_free(kernel_map, (vm_offset_t)new_ldt->ldt_base,
450 max_ldt_segment * sizeof(struct user_segment_descriptor));
451 free(new_ldt, M_SUBPROC);
452 return (pldt);
453 }
454
455 if (pldt != NULL) {
456 bcopy(pldt->ldt_base, new_ldt->ldt_base, max_ldt_segment *
457 sizeof(struct user_segment_descriptor));
458 user_ldt_derefl(pldt);
459 }
460 ssdtosyssd(&sldt, &p->p_md.md_ldt_sd);
461 atomic_store_rel_ptr((volatile uintptr_t *)&mdp->md_ldt,
462 (uintptr_t)new_ldt);
463 if (p == curproc)
464 set_user_ldt(mdp);
465
466 return (mdp->md_ldt);
467 }
468
469 void
470 user_ldt_free(struct thread *td)
471 {
472 struct proc *p = td->td_proc;
473 struct mdproc *mdp = &p->p_md;
474 struct proc_ldt *pldt;
475
476 mtx_assert(&dt_lock, MA_OWNED);
477 if ((pldt = mdp->md_ldt) == NULL) {
478 mtx_unlock(&dt_lock);
479 return;
480 }
481
482 mdp->md_ldt = NULL;
483 bzero(&mdp->md_ldt_sd, sizeof(mdp->md_ldt_sd));
484 if (td == curthread)
485 lldt(GSEL(GNULL_SEL, SEL_KPL));
486 user_ldt_deref(pldt);
487 }
488
489 static void
490 user_ldt_derefl(struct proc_ldt *pldt)
491 {
492
493 if (--pldt->ldt_refcnt == 0) {
494 kmem_free(kernel_map, (vm_offset_t)pldt->ldt_base,
495 max_ldt_segment * sizeof(struct user_segment_descriptor));
496 free(pldt, M_SUBPROC);
497 }
498 }
499
500 void
501 user_ldt_deref(struct proc_ldt *pldt)
502 {
503
504 mtx_assert(&dt_lock, MA_OWNED);
505 user_ldt_derefl(pldt);
506 mtx_unlock(&dt_lock);
507 }
508
509 /*
510 * Note for the authors of compat layers (linux, etc): copyout() in
511 * the function below is not a problem since it presents data in
512 * arch-specific format (i.e. i386-specific in this case), not in
513 * the OS-specific one.
514 */
515 int
516 amd64_get_ldt(td, uap)
517 struct thread *td;
518 struct i386_ldt_args *uap;
519 {
520 int error = 0;
521 struct proc_ldt *pldt;
522 int num;
523 struct user_segment_descriptor *lp;
524
525 #ifdef DEBUG
526 printf("amd64_get_ldt: start=%d num=%d descs=%p\n",
527 uap->start, uap->num, (void *)uap->descs);
528 #endif
529
530 if ((pldt = td->td_proc->p_md.md_ldt) != NULL) {
531 lp = &((struct user_segment_descriptor *)(pldt->ldt_base))
532 [uap->start];
533 num = min(uap->num, max_ldt_segment);
534 } else
535 return (EINVAL);
536
537 if ((uap->start > (unsigned int)max_ldt_segment) ||
538 ((unsigned int)num > (unsigned int)max_ldt_segment) ||
539 ((unsigned int)(uap->start + num) > (unsigned int)max_ldt_segment))
540 return(EINVAL);
541
542 error = copyout(lp, uap->descs, num *
543 sizeof(struct user_segment_descriptor));
544 if (!error)
545 td->td_retval[0] = num;
546
547 return(error);
548 }
549
550 int
551 amd64_set_ldt(td, uap, descs)
552 struct thread *td;
553 struct i386_ldt_args *uap;
554 struct user_segment_descriptor *descs;
555 {
556 int error = 0, i;
557 int largest_ld;
558 struct mdproc *mdp = &td->td_proc->p_md;
559 struct proc_ldt *pldt;
560 struct user_segment_descriptor *dp;
561 struct proc *p;
562
563 #ifdef DEBUG
564 printf("amd64_set_ldt: start=%d num=%d descs=%p\n",
565 uap->start, uap->num, (void *)uap->descs);
566 #endif
567
568 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
569 p = td->td_proc;
570 if (descs == NULL) {
571 /* Free descriptors */
572 if (uap->start == 0 && uap->num == 0)
573 uap->num = max_ldt_segment;
574 if (uap->num <= 0)
575 return (EINVAL);
576 if ((pldt = mdp->md_ldt) == NULL ||
577 uap->start >= max_ldt_segment)
578 return (0);
579 largest_ld = uap->start + uap->num;
580 if (largest_ld > max_ldt_segment)
581 largest_ld = max_ldt_segment;
582 i = largest_ld - uap->start;
583 mtx_lock(&dt_lock);
584 bzero(&((struct user_segment_descriptor *)(pldt->ldt_base))
585 [uap->start], sizeof(struct user_segment_descriptor) * i);
586 mtx_unlock(&dt_lock);
587 return (0);
588 }
589
590 if (!(uap->start == LDT_AUTO_ALLOC && uap->num == 1)) {
591 /* verify range of descriptors to modify */
592 largest_ld = uap->start + uap->num;
593 if (uap->start >= max_ldt_segment ||
594 uap->num < 0 || largest_ld > max_ldt_segment)
595 return (EINVAL);
596 }
597
598 /* Check descriptors for access violations */
599 for (i = 0; i < uap->num; i++) {
600 dp = &descs[i];
601
602 switch (dp->sd_type) {
603 case SDT_SYSNULL: /* system null */
604 dp->sd_p = 0;
605 break;
606 case SDT_SYS286TSS:
607 case SDT_SYSLDT:
608 case SDT_SYS286BSY:
609 case SDT_SYS286CGT:
610 case SDT_SYSTASKGT:
611 case SDT_SYS286IGT:
612 case SDT_SYS286TGT:
613 case SDT_SYSNULL2:
614 case SDT_SYSTSS:
615 case SDT_SYSNULL3:
616 case SDT_SYSBSY:
617 case SDT_SYSCGT:
618 case SDT_SYSNULL4:
619 case SDT_SYSIGT:
620 case SDT_SYSTGT:
621 /* I can't think of any reason to allow a user proc
622 * to create a segment of these types. They are
623 * for OS use only.
624 */
625 return (EACCES);
626 /*NOTREACHED*/
627
628 /* memory segment types */
629 case SDT_MEMEC: /* memory execute only conforming */
630 case SDT_MEMEAC: /* memory execute only accessed conforming */
631 case SDT_MEMERC: /* memory execute read conforming */
632 case SDT_MEMERAC: /* memory execute read accessed conforming */
633 /* Must be "present" if executable and conforming. */
634 if (dp->sd_p == 0)
635 return (EACCES);
636 break;
637 case SDT_MEMRO: /* memory read only */
638 case SDT_MEMROA: /* memory read only accessed */
639 case SDT_MEMRW: /* memory read write */
640 case SDT_MEMRWA: /* memory read write accessed */
641 case SDT_MEMROD: /* memory read only expand dwn limit */
642 case SDT_MEMRODA: /* memory read only expand dwn lim accessed */
643 case SDT_MEMRWD: /* memory read write expand dwn limit */
644 case SDT_MEMRWDA: /* memory read write expand dwn lim acessed */
645 case SDT_MEME: /* memory execute only */
646 case SDT_MEMEA: /* memory execute only accessed */
647 case SDT_MEMER: /* memory execute read */
648 case SDT_MEMERA: /* memory execute read accessed */
649 break;
650 default:
651 return(EINVAL);
652 /*NOTREACHED*/
653 }
654
655 /* Only user (ring-3) descriptors may be present. */
656 if ((dp->sd_p != 0) && (dp->sd_dpl != SEL_UPL))
657 return (EACCES);
658 }
659
660 if (uap->start == LDT_AUTO_ALLOC && uap->num == 1) {
661 /* Allocate a free slot */
662 mtx_lock(&dt_lock);
663 pldt = user_ldt_alloc(p, 0);
664 if (pldt == NULL) {
665 mtx_unlock(&dt_lock);
666 return (ENOMEM);
667 }
668
669 /*
670 * start scanning a bit up to leave room for NVidia and
671 * Wine, which still user the "Blat" method of allocation.
672 */
673 i = 16;
674 dp = &((struct user_segment_descriptor *)(pldt->ldt_base))[i];
675 for (; i < max_ldt_segment; ++i, ++dp) {
676 if (dp->sd_type == SDT_SYSNULL)
677 break;
678 }
679 if (i >= max_ldt_segment) {
680 mtx_unlock(&dt_lock);
681 return (ENOSPC);
682 }
683 uap->start = i;
684 error = amd64_set_ldt_data(td, i, 1, descs);
685 mtx_unlock(&dt_lock);
686 } else {
687 largest_ld = uap->start + uap->num;
688 if (largest_ld > max_ldt_segment)
689 return (EINVAL);
690 mtx_lock(&dt_lock);
691 if (user_ldt_alloc(p, 0) != NULL) {
692 error = amd64_set_ldt_data(td, uap->start, uap->num,
693 descs);
694 }
695 mtx_unlock(&dt_lock);
696 }
697 if (error == 0)
698 td->td_retval[0] = uap->start;
699 return (error);
700 }
701
702 int
703 amd64_set_ldt_data(struct thread *td, int start, int num,
704 struct user_segment_descriptor *descs)
705 {
706 struct mdproc *mdp = &td->td_proc->p_md;
707 struct proc_ldt *pldt = mdp->md_ldt;
708
709 mtx_assert(&dt_lock, MA_OWNED);
710
711 /* Fill in range */
712 bcopy(descs,
713 &((struct user_segment_descriptor *)(pldt->ldt_base))[start],
714 num * sizeof(struct user_segment_descriptor));
715 return (0);
716 }
Cache object: 7b2508220bd517d4619bc927e4ae86b8
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