1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2010 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 #include <sys/param.h>
31 #include <sys/types.h>
32 #include <sys/vmparam.h>
33 #include <sys/systm.h>
34 #include <sys/signal.h>
35 #include <sys/stack.h>
36 #include <sys/frame.h>
37 #include <sys/proc.h>
38 #include <sys/brand.h>
39 #include <sys/ucontext.h>
40 #include <sys/asm_linkage.h>
41 #include <sys/kmem.h>
42 #include <sys/errno.h>
43 #include <sys/archsystm.h>
44 #include <sys/fpu/fpusystm.h>
45 #include <sys/debug.h>
46 #include <sys/model.h>
47 #include <sys/cmn_err.h>
48 #include <sys/sysmacros.h>
49 #include <sys/privregs.h>
50 #include <sys/schedctl.h>
51
52
53 /*
54 * Save user context.
55 */
56 void
savecontext(ucontext_t * ucp,const k_sigset_t * mask)57 savecontext(ucontext_t *ucp, const k_sigset_t *mask)
58 {
59 proc_t *p = ttoproc(curthread);
60 klwp_t *lwp = ttolwp(curthread);
61
62 /*
63 * We assign to every field through uc_mcontext.fpregs.fpu_en,
64 * but we have to bzero() everything after that.
65 */
66 bzero(&ucp->uc_mcontext.fpregs.fpu_en, sizeof (ucontext_t) -
67 offsetof(ucontext_t, uc_mcontext.fpregs.fpu_en));
68 /*
69 * There are unused holes in the ucontext_t structure, zero-fill
70 * them so that we don't expose kernel data to the user.
71 */
72 (&ucp->uc_flags)[1] = 0;
73 (&ucp->uc_stack.ss_flags)[1] = 0;
74
75 /*
76 * Flushing the user windows isn't strictly necessary; we do
77 * it to maintain backward compatibility.
78 */
79 (void) flush_user_windows_to_stack(NULL);
80
81 ucp->uc_flags = UC_ALL;
82 ucp->uc_link = (ucontext_t *)lwp->lwp_oldcontext;
83
84 /*
85 * Try to copyin() the ustack if one is registered. If the stack
86 * has zero size, this indicates that stack bounds checking has
87 * been disabled for this LWP. If stack bounds checking is disabled
88 * or the copyin() fails, we fall back to the legacy behavior.
89 */
90 if (lwp->lwp_ustack == (uintptr_t)NULL ||
91 copyin((void *)lwp->lwp_ustack, &ucp->uc_stack,
92 sizeof (ucp->uc_stack)) != 0 ||
93 ucp->uc_stack.ss_size == 0) {
94
95 if (lwp->lwp_sigaltstack.ss_flags == SS_ONSTACK) {
96 ucp->uc_stack = lwp->lwp_sigaltstack;
97 } else {
98 ucp->uc_stack.ss_sp = p->p_usrstack - p->p_stksize;
99 ucp->uc_stack.ss_size = p->p_stksize;
100 ucp->uc_stack.ss_flags = 0;
101 }
102 }
103
104 getgregs(lwp, ucp->uc_mcontext.gregs);
105 getasrs(lwp, ucp->uc_mcontext.asrs);
106
107 getfpregs(lwp, &ucp->uc_mcontext.fpregs);
108 getfpasrs(lwp, ucp->uc_mcontext.asrs);
109 if (ucp->uc_mcontext.fpregs.fpu_en == 0)
110 ucp->uc_flags &= ~UC_FPU;
111 ucp->uc_mcontext.gwins = (gwindows_t *)NULL;
112
113 /*
114 * Save signal mask.
115 */
116 sigktou(mask, &ucp->uc_sigmask);
117 }
118
119
120 void
restorecontext(ucontext_t * ucp)121 restorecontext(ucontext_t *ucp)
122 {
123 kthread_t *t = curthread;
124 klwp_t *lwp = ttolwp(t);
125 mcontext_t *mcp = &ucp->uc_mcontext;
126 model_t model = lwp_getdatamodel(lwp);
127
128 (void) flush_user_windows_to_stack(NULL);
129 if (lwp->lwp_pcb.pcb_xregstat != XREGNONE)
130 xregrestore(lwp, 0);
131
132 lwp->lwp_oldcontext = (uintptr_t)ucp->uc_link;
133
134 if (ucp->uc_flags & UC_STACK) {
135 if (ucp->uc_stack.ss_flags == SS_ONSTACK)
136 lwp->lwp_sigaltstack = ucp->uc_stack;
137 else
138 lwp->lwp_sigaltstack.ss_flags &= ~SS_ONSTACK;
139 }
140
141 if (ucp->uc_flags & UC_CPU) {
142 if (mcp->gwins != 0)
143 setgwins(lwp, mcp->gwins);
144 setgregs(lwp, mcp->gregs);
145 if (model == DATAMODEL_LP64)
146 setasrs(lwp, mcp->asrs);
147 else
148 xregs_setgregs(lwp, xregs_getptr(lwp, ucp));
149 }
150
151 if (ucp->uc_flags & UC_FPU) {
152 fpregset_t *fp = &ucp->uc_mcontext.fpregs;
153
154 setfpregs(lwp, fp);
155 if (model == DATAMODEL_LP64)
156 setfpasrs(lwp, mcp->asrs);
157 else
158 xregs_setfpregs(lwp, xregs_getptr(lwp, ucp));
159 run_fpq(lwp, fp);
160 }
161
162 if (ucp->uc_flags & UC_SIGMASK) {
163 /*
164 * We don't need to acquire p->p_lock here;
165 * we are manipulating thread-private data.
166 */
167 schedctl_finish_sigblock(t);
168 sigutok(&ucp->uc_sigmask, &t->t_hold);
169 if (sigcheck(ttoproc(t), t))
170 t->t_sig_check = 1;
171 }
172 }
173
174
175 int
getsetcontext(int flag,void * arg)176 getsetcontext(int flag, void *arg)
177 {
178 ucontext_t uc;
179 struct _fq fpu_q[MAXFPQ]; /* to hold floating queue */
180 fpregset_t *fpp;
181 gwindows_t *gwin = NULL; /* to hold windows */
182 caddr_t xregs = NULL;
183 int xregs_size = 0;
184 extern int nwindows;
185 ucontext_t *ucp;
186 klwp_t *lwp = ttolwp(curthread);
187 stack_t dummy_stk;
188
189 /*
190 * In future releases, when the ucontext structure grows,
191 * getcontext should be modified to only return the fields
192 * specified in the uc_flags. That way, the structure can grow
193 * and still be binary compatible will all .o's which will only
194 * have old fields defined in uc_flags
195 */
196
197 switch (flag) {
198 default:
199 return (set_errno(EINVAL));
200
201 case GETCONTEXT:
202 schedctl_finish_sigblock(curthread);
203 savecontext(&uc, &curthread->t_hold);
204 if (uc.uc_flags & UC_SIGMASK)
205 SIGSET_NATIVE_TO_BRAND(&uc.uc_sigmask);
206 /*
207 * When using floating point it should not be possible to
208 * get here with a fpu_qcnt other than zero since we go
209 * to great pains to handle all outstanding FP exceptions
210 * before any system call code gets executed. However we
211 * clear fpu_q and fpu_qcnt here before copyout anyway -
212 * this will prevent us from interpreting the garbage we
213 * get back (when FP is not enabled) as valid queue data on
214 * a later setcontext(2).
215 */
216 uc.uc_mcontext.fpregs.fpu_qcnt = 0;
217 uc.uc_mcontext.fpregs.fpu_q = (struct _fq *)NULL;
218
219 if (copyout(&uc, arg, sizeof (ucontext_t)))
220 return (set_errno(EFAULT));
221 return (0);
222
223 case SETCONTEXT:
224 ucp = arg;
225 if (ucp == NULL)
226 exit(CLD_EXITED, 0);
227 /*
228 * Don't copyin filler or floating state unless we need it.
229 * The ucontext_t struct and fields are specified in the ABI.
230 */
231 if (copyin(ucp, &uc, sizeof (ucontext_t) -
232 sizeof (uc.uc_filler) -
233 sizeof (uc.uc_mcontext.fpregs) -
234 sizeof (uc.uc_mcontext.xrs) -
235 sizeof (uc.uc_mcontext.asrs) -
236 sizeof (uc.uc_mcontext.filler))) {
237 return (set_errno(EFAULT));
238 }
239 if (uc.uc_flags & UC_SIGMASK)
240 SIGSET_BRAND_TO_NATIVE(&uc.uc_sigmask);
241 if (copyin(&ucp->uc_mcontext.xrs, &uc.uc_mcontext.xrs,
242 sizeof (uc.uc_mcontext.xrs))) {
243 return (set_errno(EFAULT));
244 }
245 fpp = &uc.uc_mcontext.fpregs;
246 if (uc.uc_flags & UC_FPU) {
247 /*
248 * Need to copyin floating point state
249 */
250 if (copyin(&ucp->uc_mcontext.fpregs,
251 &uc.uc_mcontext.fpregs,
252 sizeof (uc.uc_mcontext.fpregs)))
253 return (set_errno(EFAULT));
254 /* if floating queue not empty */
255 if ((fpp->fpu_q) && (fpp->fpu_qcnt)) {
256 if (fpp->fpu_qcnt > MAXFPQ ||
257 fpp->fpu_q_entrysize <= 0 ||
258 fpp->fpu_q_entrysize > sizeof (struct _fq))
259 return (set_errno(EINVAL));
260 if (copyin(fpp->fpu_q, fpu_q,
261 fpp->fpu_qcnt * fpp->fpu_q_entrysize))
262 return (set_errno(EFAULT));
263 fpp->fpu_q = fpu_q;
264 } else {
265 fpp->fpu_qcnt = 0; /* avoid confusion later */
266 }
267 } else {
268 fpp->fpu_qcnt = 0;
269 }
270 if (uc.uc_mcontext.gwins) { /* if windows in context */
271 size_t gwin_size;
272
273 /*
274 * We do the same computation here to determine
275 * how many bytes of gwindows_t to copy in that
276 * is also done in sendsig() to decide how many
277 * bytes to copy out. We just *know* that wbcnt
278 * is the first element of the structure.
279 */
280 gwin = kmem_zalloc(sizeof (gwindows_t), KM_SLEEP);
281 if (copyin(uc.uc_mcontext.gwins,
282 &gwin->wbcnt, sizeof (gwin->wbcnt))) {
283 kmem_free(gwin, sizeof (gwindows_t));
284 return (set_errno(EFAULT));
285 }
286 if (gwin->wbcnt < 0 || gwin->wbcnt > nwindows) {
287 kmem_free(gwin, sizeof (gwindows_t));
288 return (set_errno(EINVAL));
289 }
290 gwin_size = gwin->wbcnt * sizeof (struct rwindow) +
291 SPARC_MAXREGWINDOW * sizeof (int *) + sizeof (long);
292 if (gwin_size > sizeof (gwindows_t) ||
293 copyin(uc.uc_mcontext.gwins, gwin, gwin_size)) {
294 kmem_free(gwin, sizeof (gwindows_t));
295 return (set_errno(EFAULT));
296 }
297 uc.uc_mcontext.gwins = gwin;
298 }
299
300 /*
301 * get extra register state or asrs if any exists
302 * there is no extra register state for _LP64 user programs
303 */
304 xregs_clrptr(lwp, &uc);
305 if (copyin(&ucp->uc_mcontext.asrs, &uc.uc_mcontext.asrs,
306 sizeof (asrset_t))) {
307 /* Free up gwin structure if used */
308 if (gwin)
309 kmem_free(gwin, sizeof (gwindows_t));
310 return (set_errno(EFAULT));
311 }
312
313 restorecontext(&uc);
314
315 if ((uc.uc_flags & UC_STACK) && (lwp->lwp_ustack != 0)) {
316 (void) copyout(&uc.uc_stack, (stack_t *)lwp->lwp_ustack,
317 sizeof (stack_t));
318 }
319
320 /*
321 * free extra register state area
322 */
323 if (xregs_size)
324 kmem_free(xregs, xregs_size);
325
326 if (gwin)
327 kmem_free(gwin, sizeof (gwindows_t));
328
329 return (0);
330
331 case GETUSTACK:
332 if (copyout(&lwp->lwp_ustack, arg, sizeof (caddr_t)))
333 return (set_errno(EFAULT));
334
335 return (0);
336
337 case SETUSTACK:
338 if (copyin(arg, &dummy_stk, sizeof (dummy_stk)))
339 return (set_errno(EFAULT));
340
341 lwp->lwp_ustack = (uintptr_t)arg;
342
343 return (0);
344 }
345 }
346
347
348 #ifdef _SYSCALL32_IMPL
349
350 /*
351 * Save user context for 32-bit processes.
352 */
353 void
savecontext32(ucontext32_t * ucp,const k_sigset_t * mask,struct fq32 * dfq)354 savecontext32(ucontext32_t *ucp, const k_sigset_t *mask, struct fq32 *dfq)
355 {
356 proc_t *p = ttoproc(curthread);
357 klwp_t *lwp = ttolwp(curthread);
358 fpregset_t fpregs;
359
360 /*
361 * We assign to every field through uc_mcontext.fpregs.fpu_en,
362 * but we have to bzero() everything after that.
363 */
364 bzero(&ucp->uc_mcontext.fpregs.fpu_en, sizeof (ucontext32_t) -
365 offsetof(ucontext32_t, uc_mcontext.fpregs.fpu_en));
366 /*
367 * There is an unused hole in the ucontext32_t structure; zero-fill
368 * it so that we don't expose kernel data to the user.
369 */
370 (&ucp->uc_stack.ss_flags)[1] = 0;
371
372 /*
373 * Flushing the user windows isn't strictly necessary; we do
374 * it to maintain backward compatibility.
375 */
376 (void) flush_user_windows_to_stack(NULL);
377
378 ucp->uc_flags = UC_ALL;
379 ucp->uc_link = (caddr32_t)lwp->lwp_oldcontext;
380
381 /*
382 * Try to copyin() the ustack if one is registered. If the stack
383 * has zero size, this indicates that stack bounds checking has
384 * been disabled for this LWP. If stack bounds checking is disabled
385 * or the copyin() fails, we fall back to the legacy behavior.
386 */
387 if (lwp->lwp_ustack == (uintptr_t)NULL ||
388 copyin((void *)lwp->lwp_ustack, &ucp->uc_stack,
389 sizeof (ucp->uc_stack)) != 0 ||
390 ucp->uc_stack.ss_size == 0) {
391
392 if (lwp->lwp_sigaltstack.ss_flags == SS_ONSTACK) {
393 ucp->uc_stack.ss_sp =
394 (caddr32_t)(uintptr_t)lwp->lwp_sigaltstack.ss_sp;
395 ucp->uc_stack.ss_size =
396 (size32_t)lwp->lwp_sigaltstack.ss_size;
397 ucp->uc_stack.ss_flags = SS_ONSTACK;
398 } else {
399 ucp->uc_stack.ss_sp =
400 (caddr32_t)(uintptr_t)p->p_usrstack - p->p_stksize;
401 ucp->uc_stack.ss_size =
402 (size32_t)p->p_stksize;
403 ucp->uc_stack.ss_flags = 0;
404 }
405 }
406
407 getgregs32(lwp, ucp->uc_mcontext.gregs);
408 getfpregs(lwp, &fpregs);
409 fpuregset_nto32(&fpregs, &ucp->uc_mcontext.fpregs, dfq);
410
411 if (ucp->uc_mcontext.fpregs.fpu_en == 0)
412 ucp->uc_flags &= ~UC_FPU;
413 ucp->uc_mcontext.gwins = (caddr32_t)(uintptr_t)NULL;
414
415 /*
416 * Save signal mask (the 32- and 64-bit sigset_t structures are
417 * identical).
418 */
419 sigktou(mask, (sigset_t *)&ucp->uc_sigmask);
420 }
421
422 int
getsetcontext32(int flag,void * arg)423 getsetcontext32(int flag, void *arg)
424 {
425 ucontext32_t uc;
426 ucontext_t ucnat;
427 struct _fq fpu_qnat[MAXFPQ]; /* to hold "native" floating queue */
428 struct fq32 fpu_q[MAXFPQ]; /* to hold 32 bit floating queue */
429 fpregset32_t *fpp;
430 gwindows32_t *gwin = NULL; /* to hold windows */
431 caddr_t xregs;
432 int xregs_size = 0;
433 extern int nwindows;
434 klwp_t *lwp = ttolwp(curthread);
435 ucontext32_t *ucp;
436 uint32_t ustack32;
437 stack32_t dummy_stk32;
438
439 /*
440 * In future releases, when the ucontext structure grows,
441 * getcontext should be modified to only return the fields
442 * specified in the uc_flags. That way, the structure can grow
443 * and still be binary compatible will all .o's which will only
444 * have old fields defined in uc_flags
445 */
446
447 switch (flag) {
448 default:
449 return (set_errno(EINVAL));
450
451 case GETCONTEXT:
452 schedctl_finish_sigblock(curthread);
453 savecontext32(&uc, &curthread->t_hold, NULL);
454 if (uc.uc_flags & UC_SIGMASK)
455 SIGSET_NATIVE_TO_BRAND(&uc.uc_sigmask);
456 /*
457 * When using floating point it should not be possible to
458 * get here with a fpu_qcnt other than zero since we go
459 * to great pains to handle all outstanding FP exceptions
460 * before any system call code gets executed. However we
461 * clear fpu_q and fpu_qcnt here before copyout anyway -
462 * this will prevent us from interpreting the garbage we
463 * get back (when FP is not enabled) as valid queue data on
464 * a later setcontext(2).
465 */
466 uc.uc_mcontext.fpregs.fpu_qcnt = 0;
467 uc.uc_mcontext.fpregs.fpu_q = (caddr32_t)(uintptr_t)NULL;
468
469 if (copyout(&uc, arg, sizeof (ucontext32_t)))
470 return (set_errno(EFAULT));
471 return (0);
472
473 case SETCONTEXT:
474 ucp = arg;
475 if (ucp == NULL)
476 exit(CLD_EXITED, 0);
477 /*
478 * Don't copyin filler or floating state unless we need it.
479 * The ucontext_t struct and fields are specified in the ABI.
480 */
481 if (copyin(ucp, &uc, sizeof (uc) - sizeof (uc.uc_filler) -
482 sizeof (uc.uc_mcontext.fpregs) -
483 sizeof (uc.uc_mcontext.xrs) -
484 sizeof (uc.uc_mcontext.filler))) {
485 return (set_errno(EFAULT));
486 }
487 if (uc.uc_flags & UC_SIGMASK)
488 SIGSET_BRAND_TO_NATIVE(&uc.uc_sigmask);
489 if (copyin(&ucp->uc_mcontext.xrs, &uc.uc_mcontext.xrs,
490 sizeof (uc.uc_mcontext.xrs))) {
491 return (set_errno(EFAULT));
492 }
493 fpp = &uc.uc_mcontext.fpregs;
494 if (uc.uc_flags & UC_FPU) {
495 /*
496 * Need to copyin floating point state
497 */
498 if (copyin(&ucp->uc_mcontext.fpregs,
499 &uc.uc_mcontext.fpregs,
500 sizeof (uc.uc_mcontext.fpregs)))
501 return (set_errno(EFAULT));
502 /* if floating queue not empty */
503 if ((fpp->fpu_q) && (fpp->fpu_qcnt)) {
504 if (fpp->fpu_qcnt > MAXFPQ ||
505 fpp->fpu_q_entrysize <= 0 ||
506 fpp->fpu_q_entrysize > sizeof (struct fq32))
507 return (set_errno(EINVAL));
508 if (copyin((void *)(uintptr_t)fpp->fpu_q, fpu_q,
509 fpp->fpu_qcnt * fpp->fpu_q_entrysize))
510 return (set_errno(EFAULT));
511 } else {
512 fpp->fpu_qcnt = 0; /* avoid confusion later */
513 }
514 } else {
515 fpp->fpu_qcnt = 0;
516 }
517
518 if (uc.uc_mcontext.gwins) { /* if windows in context */
519 size_t gwin_size;
520
521 /*
522 * We do the same computation here to determine
523 * how many bytes of gwindows_t to copy in that
524 * is also done in sendsig() to decide how many
525 * bytes to copy out. We just *know* that wbcnt
526 * is the first element of the structure.
527 */
528 gwin = kmem_zalloc(sizeof (gwindows32_t), KM_SLEEP);
529 if (copyin((void *)(uintptr_t)uc.uc_mcontext.gwins,
530 &gwin->wbcnt, sizeof (gwin->wbcnt))) {
531 kmem_free(gwin, sizeof (gwindows32_t));
532 return (set_errno(EFAULT));
533 }
534 if (gwin->wbcnt < 0 || gwin->wbcnt > nwindows) {
535 kmem_free(gwin, sizeof (gwindows32_t));
536 return (set_errno(EINVAL));
537 }
538 gwin_size = gwin->wbcnt * sizeof (struct rwindow32) +
539 SPARC_MAXREGWINDOW * sizeof (caddr32_t) +
540 sizeof (int32_t);
541 if (gwin_size > sizeof (gwindows32_t) ||
542 copyin((void *)(uintptr_t)uc.uc_mcontext.gwins,
543 gwin, gwin_size)) {
544 kmem_free(gwin, sizeof (gwindows32_t));
545 return (set_errno(EFAULT));
546 }
547 /* restorecontext() should ignore this */
548 uc.uc_mcontext.gwins = (caddr32_t)0;
549 }
550
551 ucontext_32ton(&uc, &ucnat, fpu_q, fpu_qnat);
552
553 /*
554 * get extra register state if any exists
555 */
556 if (xregs_hasptr32(lwp, &uc) &&
557 ((xregs_size = xregs_getsize(curproc)) > 0)) {
558 xregs = kmem_zalloc(xregs_size, KM_SLEEP);
559 if (copyin((void *)(uintptr_t)xregs_getptr32(lwp, &uc),
560 xregs, xregs_size)) {
561 kmem_free(xregs, xregs_size);
562 if (gwin)
563 kmem_free(gwin, sizeof (gwindows32_t));
564 return (set_errno(EFAULT));
565 }
566 xregs_setptr(lwp, &ucnat, xregs);
567 } else {
568 xregs_clrptr(lwp, &ucnat);
569 }
570
571 restorecontext(&ucnat);
572
573 if ((uc.uc_flags & UC_STACK) && (lwp->lwp_ustack != 0)) {
574 (void) copyout(&uc.uc_stack,
575 (stack32_t *)lwp->lwp_ustack, sizeof (stack32_t));
576 }
577
578 if (gwin)
579 setgwins32(lwp, gwin);
580
581 /*
582 * free extra register state area
583 */
584 if (xregs_size)
585 kmem_free(xregs, xregs_size);
586
587 if (gwin)
588 kmem_free(gwin, sizeof (gwindows32_t));
589
590 return (0);
591
592 case GETUSTACK:
593 ustack32 = (uint32_t)lwp->lwp_ustack;
594 if (copyout(&ustack32, arg, sizeof (caddr32_t)))
595 return (set_errno(EFAULT));
596
597 return (0);
598
599 case SETUSTACK:
600 if (copyin(arg, &dummy_stk32, sizeof (dummy_stk32)))
601 return (set_errno(EFAULT));
602
603 lwp->lwp_ustack = (uintptr_t)arg;
604
605 return (0);
606 }
607 }
608
609 #endif /* _SYSCALL32_IMPL */
610