1 /*-
2 * Copyright (c) 2003 Peter Wemm
3 * Copyright (c) 1982, 1987, 1990 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * William Jolitz.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
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
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD: src/sys/amd64/ia32/ia32_signal.c,v 1.19 2008/09/02 17:52:11 kib Exp $");
36
37 #include "opt_compat.h"
38
39 #include <sys/param.h>
40 #include <sys/exec.h>
41 #include <sys/fcntl.h>
42 #include <sys/imgact.h>
43 #include <sys/kernel.h>
44 #include <sys/lock.h>
45 #include <sys/malloc.h>
46 #include <sys/mutex.h>
47 #include <sys/mman.h>
48 #include <sys/namei.h>
49 #include <sys/pioctl.h>
50 #include <sys/proc.h>
51 #include <sys/procfs.h>
52 #include <sys/resourcevar.h>
53 #include <sys/systm.h>
54 #include <sys/signalvar.h>
55 #include <sys/stat.h>
56 #include <sys/sx.h>
57 #include <sys/syscall.h>
58 #include <sys/sysctl.h>
59 #include <sys/sysent.h>
60 #include <sys/vnode.h>
61
62 #include <vm/vm.h>
63 #include <vm/vm_kern.h>
64 #include <vm/vm_param.h>
65 #include <vm/pmap.h>
66 #include <vm/vm_map.h>
67 #include <vm/vm_object.h>
68 #include <vm/vm_extern.h>
69
70 #include <compat/freebsd32/freebsd32_signal.h>
71 #include <compat/freebsd32/freebsd32_util.h>
72 #include <compat/freebsd32/freebsd32_proto.h>
73 #include <compat/ia32/ia32_signal.h>
74 #include <machine/psl.h>
75 #include <machine/segments.h>
76 #include <machine/specialreg.h>
77 #include <machine/frame.h>
78 #include <machine/md_var.h>
79 #include <machine/pcb.h>
80 #include <machine/cpufunc.h>
81
82 #ifdef COMPAT_FREEBSD4
83 static void freebsd4_ia32_sendsig(sig_t, ksiginfo_t *, sigset_t *);
84 #endif
85 static void ia32_get_fpcontext(struct thread *td, struct ia32_mcontext *mcp);
86 static int ia32_set_fpcontext(struct thread *td, const struct ia32_mcontext *mcp);
87
88 extern int _ucode32sel, _udatasel;
89
90 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL)
91 #define EFL_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
92
93 static void
94 ia32_get_fpcontext(struct thread *td, struct ia32_mcontext *mcp)
95 {
96
97 mcp->mc_ownedfp = fpugetregs(td, (struct savefpu *)&mcp->mc_fpstate);
98 mcp->mc_fpformat = fpuformat();
99 }
100
101 static int
102 ia32_set_fpcontext(struct thread *td, const struct ia32_mcontext *mcp)
103 {
104
105 if (mcp->mc_fpformat == _MC_FPFMT_NODEV)
106 return (0);
107 else if (mcp->mc_fpformat != _MC_FPFMT_XMM)
108 return (EINVAL);
109 else if (mcp->mc_ownedfp == _MC_FPOWNED_NONE)
110 /* We don't care what state is left in the FPU or PCB. */
111 fpstate_drop(td);
112 else if (mcp->mc_ownedfp == _MC_FPOWNED_FPU ||
113 mcp->mc_ownedfp == _MC_FPOWNED_PCB) {
114 /*
115 * XXX we violate the dubious requirement that fpusetregs()
116 * be called with interrupts disabled.
117 */
118 fpusetregs(td, (struct savefpu *)&mcp->mc_fpstate);
119 } else
120 return (EINVAL);
121 return (0);
122 }
123
124 /*
125 * Get machine context.
126 */
127 static int
128 ia32_get_mcontext(struct thread *td, struct ia32_mcontext *mcp, int flags)
129 {
130 struct trapframe *tp;
131
132 tp = td->td_frame;
133
134 PROC_LOCK(curthread->td_proc);
135 mcp->mc_onstack = sigonstack(tp->tf_rsp);
136 PROC_UNLOCK(curthread->td_proc);
137 mcp->mc_gs = td->td_pcb->pcb_gs;
138 mcp->mc_fs = td->td_pcb->pcb_fs;
139 mcp->mc_es = td->td_pcb->pcb_es;
140 mcp->mc_ds = td->td_pcb->pcb_ds;
141 mcp->mc_edi = tp->tf_rdi;
142 mcp->mc_esi = tp->tf_rsi;
143 mcp->mc_ebp = tp->tf_rbp;
144 mcp->mc_isp = tp->tf_rsp;
145 if (flags & GET_MC_CLEAR_RET) {
146 mcp->mc_eax = 0;
147 mcp->mc_edx = 0;
148 } else {
149 mcp->mc_eax = tp->tf_rax;
150 mcp->mc_edx = tp->tf_rdx;
151 }
152 mcp->mc_ebx = tp->tf_rbx;
153 mcp->mc_ecx = tp->tf_rcx;
154 mcp->mc_eip = tp->tf_rip;
155 mcp->mc_cs = tp->tf_cs;
156 mcp->mc_eflags = tp->tf_rflags;
157 mcp->mc_esp = tp->tf_rsp;
158 mcp->mc_ss = tp->tf_ss;
159 mcp->mc_len = sizeof(*mcp);
160 ia32_get_fpcontext(td, mcp);
161 return (0);
162 }
163
164 /*
165 * Set machine context.
166 *
167 * However, we don't set any but the user modifiable flags, and we won't
168 * touch the cs selector.
169 */
170 static int
171 ia32_set_mcontext(struct thread *td, const struct ia32_mcontext *mcp)
172 {
173 struct trapframe *tp;
174 long rflags;
175 int ret;
176
177 tp = td->td_frame;
178 if (mcp->mc_len != sizeof(*mcp))
179 return (EINVAL);
180 rflags = (mcp->mc_eflags & PSL_USERCHANGE) |
181 (tp->tf_rflags & ~PSL_USERCHANGE);
182 ret = ia32_set_fpcontext(td, mcp);
183 if (ret != 0)
184 return (ret);
185 #if 0 /* XXX deal with load_fs() and friends */
186 tp->tf_fs = mcp->mc_fs;
187 tp->tf_es = mcp->mc_es;
188 tp->tf_ds = mcp->mc_ds;
189 #endif
190 tp->tf_rdi = mcp->mc_edi;
191 tp->tf_rsi = mcp->mc_esi;
192 tp->tf_rbp = mcp->mc_ebp;
193 tp->tf_rbx = mcp->mc_ebx;
194 tp->tf_rdx = mcp->mc_edx;
195 tp->tf_rcx = mcp->mc_ecx;
196 tp->tf_rax = mcp->mc_eax;
197 /* trapno, err */
198 tp->tf_rip = mcp->mc_eip;
199 tp->tf_rflags = rflags;
200 tp->tf_rsp = mcp->mc_esp;
201 tp->tf_ss = mcp->mc_ss;
202 #if 0 /* XXX deal with load_gs() and friends */
203 td->td_pcb->pcb_gs = mcp->mc_gs;
204 #endif
205 td->td_pcb->pcb_flags |= PCB_FULLCTX;
206 return (0);
207 }
208
209 /*
210 * The first two fields of a ucontext_t are the signal mask and
211 * the machine context. The next field is uc_link; we want to
212 * avoid destroying the link when copying out contexts.
213 */
214 #define UC_COPY_SIZE offsetof(struct ia32_ucontext, uc_link)
215
216 int
217 freebsd32_getcontext(struct thread *td, struct freebsd32_getcontext_args *uap)
218 {
219 struct ia32_ucontext uc;
220 int ret;
221
222 if (uap->ucp == NULL)
223 ret = EINVAL;
224 else {
225 ia32_get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
226 PROC_LOCK(td->td_proc);
227 uc.uc_sigmask = td->td_sigmask;
228 PROC_UNLOCK(td->td_proc);
229 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE);
230 }
231 return (ret);
232 }
233
234 int
235 freebsd32_setcontext(struct thread *td, struct freebsd32_setcontext_args *uap)
236 {
237 struct ia32_ucontext uc;
238 int ret;
239
240 if (uap->ucp == NULL)
241 ret = EINVAL;
242 else {
243 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
244 if (ret == 0) {
245 ret = ia32_set_mcontext(td, &uc.uc_mcontext);
246 if (ret == 0) {
247 SIG_CANTMASK(uc.uc_sigmask);
248 PROC_LOCK(td->td_proc);
249 td->td_sigmask = uc.uc_sigmask;
250 PROC_UNLOCK(td->td_proc);
251 }
252 }
253 }
254 return (ret == 0 ? EJUSTRETURN : ret);
255 }
256
257 int
258 freebsd32_swapcontext(struct thread *td, struct freebsd32_swapcontext_args *uap)
259 {
260 struct ia32_ucontext uc;
261 int ret;
262
263 if (uap->oucp == NULL || uap->ucp == NULL)
264 ret = EINVAL;
265 else {
266 ia32_get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
267 PROC_LOCK(td->td_proc);
268 uc.uc_sigmask = td->td_sigmask;
269 PROC_UNLOCK(td->td_proc);
270 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE);
271 if (ret == 0) {
272 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
273 if (ret == 0) {
274 ret = ia32_set_mcontext(td, &uc.uc_mcontext);
275 if (ret == 0) {
276 SIG_CANTMASK(uc.uc_sigmask);
277 PROC_LOCK(td->td_proc);
278 td->td_sigmask = uc.uc_sigmask;
279 PROC_UNLOCK(td->td_proc);
280 }
281 }
282 }
283 }
284 return (ret == 0 ? EJUSTRETURN : ret);
285 }
286
287 /*
288 * Send an interrupt to process.
289 *
290 * Stack is set up to allow sigcode stored
291 * at top to call routine, followed by kcall
292 * to sigreturn routine below. After sigreturn
293 * resets the signal mask, the stack, and the
294 * frame pointer, it returns to the user
295 * specified pc, psl.
296 */
297 #ifdef COMPAT_FREEBSD4
298 static void
299 freebsd4_ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
300 {
301 struct ia32_sigframe4 sf, *sfp;
302 struct siginfo32 siginfo;
303 struct proc *p;
304 struct thread *td;
305 struct sigacts *psp;
306 struct trapframe *regs;
307 int oonstack;
308 int sig;
309
310 td = curthread;
311 p = td->td_proc;
312 siginfo_to_siginfo32(&ksi->ksi_info, &siginfo);
313
314 PROC_LOCK_ASSERT(p, MA_OWNED);
315 sig = siginfo.si_signo;
316 psp = p->p_sigacts;
317 mtx_assert(&psp->ps_mtx, MA_OWNED);
318 regs = td->td_frame;
319 oonstack = sigonstack(regs->tf_rsp);
320
321 /* Save user context. */
322 bzero(&sf, sizeof(sf));
323 sf.sf_uc.uc_sigmask = *mask;
324 sf.sf_uc.uc_stack.ss_sp = (uintptr_t)td->td_sigstk.ss_sp;
325 sf.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size;
326 sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
327 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
328 sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
329 sf.sf_uc.uc_mcontext.mc_gs = rgs();
330 sf.sf_uc.uc_mcontext.mc_fs = rfs();
331 __asm __volatile("movl %%es,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_es));
332 __asm __volatile("movl %%ds,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_ds));
333 sf.sf_uc.uc_mcontext.mc_edi = regs->tf_rdi;
334 sf.sf_uc.uc_mcontext.mc_esi = regs->tf_rsi;
335 sf.sf_uc.uc_mcontext.mc_ebp = regs->tf_rbp;
336 sf.sf_uc.uc_mcontext.mc_isp = regs->tf_rsp; /* XXX */
337 sf.sf_uc.uc_mcontext.mc_ebx = regs->tf_rbx;
338 sf.sf_uc.uc_mcontext.mc_edx = regs->tf_rdx;
339 sf.sf_uc.uc_mcontext.mc_ecx = regs->tf_rcx;
340 sf.sf_uc.uc_mcontext.mc_eax = regs->tf_rax;
341 sf.sf_uc.uc_mcontext.mc_trapno = regs->tf_trapno;
342 sf.sf_uc.uc_mcontext.mc_err = regs->tf_err;
343 sf.sf_uc.uc_mcontext.mc_eip = regs->tf_rip;
344 sf.sf_uc.uc_mcontext.mc_cs = regs->tf_cs;
345 sf.sf_uc.uc_mcontext.mc_eflags = regs->tf_rflags;
346 sf.sf_uc.uc_mcontext.mc_esp = regs->tf_rsp;
347 sf.sf_uc.uc_mcontext.mc_ss = regs->tf_ss;
348
349 /* Allocate space for the signal handler context. */
350 if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
351 SIGISMEMBER(psp->ps_sigonstack, sig)) {
352 sfp = (struct ia32_sigframe4 *)(td->td_sigstk.ss_sp +
353 td->td_sigstk.ss_size - sizeof(sf));
354 } else
355 sfp = (struct ia32_sigframe4 *)regs->tf_rsp - 1;
356 PROC_UNLOCK(p);
357
358 /* Translate the signal if appropriate. */
359 if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize)
360 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
361
362 /* Build the argument list for the signal handler. */
363 sf.sf_signum = sig;
364 sf.sf_ucontext = (register_t)&sfp->sf_uc;
365 if (SIGISMEMBER(psp->ps_siginfo, sig)) {
366 /* Signal handler installed with SA_SIGINFO. */
367 sf.sf_siginfo = (u_int32_t)(uintptr_t)&sfp->sf_si;
368 sf.sf_ah = (u_int32_t)(uintptr_t)catcher;
369
370 /* Fill in POSIX parts */
371 sf.sf_si = siginfo;
372 sf.sf_si.si_signo = sig;
373 } else {
374 /* Old FreeBSD-style arguments. */
375 sf.sf_siginfo = siginfo.si_code;
376 sf.sf_addr = (u_int32_t)siginfo.si_addr;
377 sf.sf_ah = (u_int32_t)(uintptr_t)catcher;
378 }
379 mtx_unlock(&psp->ps_mtx);
380
381 /*
382 * Copy the sigframe out to the user's stack.
383 */
384 if (copyout(&sf, sfp, sizeof(*sfp)) != 0) {
385 #ifdef DEBUG
386 printf("process %ld has trashed its stack\n", (long)p->p_pid);
387 #endif
388 PROC_LOCK(p);
389 sigexit(td, SIGILL);
390 }
391
392 regs->tf_rsp = (uintptr_t)sfp;
393 regs->tf_rip = FREEBSD32_PS_STRINGS - sz_freebsd4_ia32_sigcode;
394 regs->tf_rflags &= ~(PSL_T | PSL_D);
395 regs->tf_cs = _ucode32sel;
396 regs->tf_ss = _udatasel;
397 load_ds(_udatasel);
398 td->td_pcb->pcb_ds = _udatasel;
399 load_es(_udatasel);
400 td->td_pcb->pcb_es = _udatasel;
401 /* leave user %fs and %gs untouched */
402 PROC_LOCK(p);
403 mtx_lock(&psp->ps_mtx);
404 }
405 #endif /* COMPAT_FREEBSD4 */
406
407 void
408 ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
409 {
410 struct ia32_sigframe sf, *sfp;
411 struct siginfo32 siginfo;
412 struct proc *p;
413 struct thread *td;
414 struct sigacts *psp;
415 char *sp;
416 struct trapframe *regs;
417 int oonstack;
418 int sig;
419
420 siginfo_to_siginfo32(&ksi->ksi_info, &siginfo);
421 td = curthread;
422 p = td->td_proc;
423 PROC_LOCK_ASSERT(p, MA_OWNED);
424 sig = siginfo.si_signo;
425 psp = p->p_sigacts;
426 #ifdef COMPAT_FREEBSD4
427 if (SIGISMEMBER(psp->ps_freebsd4, sig)) {
428 freebsd4_ia32_sendsig(catcher, ksi, mask);
429 return;
430 }
431 #endif
432 mtx_assert(&psp->ps_mtx, MA_OWNED);
433 regs = td->td_frame;
434 oonstack = sigonstack(regs->tf_rsp);
435
436 /* Save user context. */
437 bzero(&sf, sizeof(sf));
438 sf.sf_uc.uc_sigmask = *mask;
439 sf.sf_uc.uc_stack.ss_sp = (uintptr_t)td->td_sigstk.ss_sp;
440 sf.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size;
441 sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
442 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
443 sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
444 sf.sf_uc.uc_mcontext.mc_gs = rgs();
445 sf.sf_uc.uc_mcontext.mc_fs = rfs();
446 __asm __volatile("movl %%es,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_es));
447 __asm __volatile("movl %%ds,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_ds));
448 sf.sf_uc.uc_mcontext.mc_edi = regs->tf_rdi;
449 sf.sf_uc.uc_mcontext.mc_esi = regs->tf_rsi;
450 sf.sf_uc.uc_mcontext.mc_ebp = regs->tf_rbp;
451 sf.sf_uc.uc_mcontext.mc_isp = regs->tf_rsp; /* XXX */
452 sf.sf_uc.uc_mcontext.mc_ebx = regs->tf_rbx;
453 sf.sf_uc.uc_mcontext.mc_edx = regs->tf_rdx;
454 sf.sf_uc.uc_mcontext.mc_ecx = regs->tf_rcx;
455 sf.sf_uc.uc_mcontext.mc_eax = regs->tf_rax;
456 sf.sf_uc.uc_mcontext.mc_trapno = regs->tf_trapno;
457 sf.sf_uc.uc_mcontext.mc_err = regs->tf_err;
458 sf.sf_uc.uc_mcontext.mc_eip = regs->tf_rip;
459 sf.sf_uc.uc_mcontext.mc_cs = regs->tf_cs;
460 sf.sf_uc.uc_mcontext.mc_eflags = regs->tf_rflags;
461 sf.sf_uc.uc_mcontext.mc_esp = regs->tf_rsp;
462 sf.sf_uc.uc_mcontext.mc_ss = regs->tf_ss;
463 sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */
464 ia32_get_fpcontext(td, &sf.sf_uc.uc_mcontext);
465 fpstate_drop(td);
466
467 /* Allocate space for the signal handler context. */
468 if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
469 SIGISMEMBER(psp->ps_sigonstack, sig)) {
470 sp = td->td_sigstk.ss_sp +
471 td->td_sigstk.ss_size - sizeof(sf);
472 } else
473 sp = (char *)regs->tf_rsp - sizeof(sf);
474 /* Align to 16 bytes. */
475 sfp = (struct ia32_sigframe *)((uintptr_t)sp & ~0xF);
476 PROC_UNLOCK(p);
477
478 /* Translate the signal if appropriate. */
479 if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize)
480 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
481
482 /* Build the argument list for the signal handler. */
483 sf.sf_signum = sig;
484 sf.sf_ucontext = (register_t)&sfp->sf_uc;
485 if (SIGISMEMBER(psp->ps_siginfo, sig)) {
486 /* Signal handler installed with SA_SIGINFO. */
487 sf.sf_siginfo = (u_int32_t)(uintptr_t)&sfp->sf_si;
488 sf.sf_ah = (u_int32_t)(uintptr_t)catcher;
489
490 /* Fill in POSIX parts */
491 sf.sf_si = siginfo;
492 sf.sf_si.si_signo = sig;
493 } else {
494 /* Old FreeBSD-style arguments. */
495 sf.sf_siginfo = siginfo.si_code;
496 sf.sf_addr = (u_int32_t)siginfo.si_addr;
497 sf.sf_ah = (u_int32_t)(uintptr_t)catcher;
498 }
499 mtx_unlock(&psp->ps_mtx);
500
501 /*
502 * Copy the sigframe out to the user's stack.
503 */
504 if (copyout(&sf, sfp, sizeof(*sfp)) != 0) {
505 #ifdef DEBUG
506 printf("process %ld has trashed its stack\n", (long)p->p_pid);
507 #endif
508 PROC_LOCK(p);
509 sigexit(td, SIGILL);
510 }
511
512 regs->tf_rsp = (uintptr_t)sfp;
513 regs->tf_rip = FREEBSD32_PS_STRINGS - *(p->p_sysent->sv_szsigcode);
514 regs->tf_rflags &= ~(PSL_T | PSL_D);
515 regs->tf_cs = _ucode32sel;
516 regs->tf_ss = _udatasel;
517 load_ds(_udatasel);
518 td->td_pcb->pcb_ds = _udatasel;
519 load_es(_udatasel);
520 td->td_pcb->pcb_es = _udatasel;
521 /* leave user %fs and %gs untouched */
522 PROC_LOCK(p);
523 mtx_lock(&psp->ps_mtx);
524 }
525
526 /*
527 * System call to cleanup state after a signal
528 * has been taken. Reset signal mask and
529 * stack state from context left by sendsig (above).
530 * Return to previous pc and psl as specified by
531 * context left by sendsig. Check carefully to
532 * make sure that the user has not modified the
533 * state to gain improper privileges.
534 */
535 #ifdef COMPAT_FREEBSD4
536 /*
537 * MPSAFE
538 */
539 int
540 freebsd4_freebsd32_sigreturn(td, uap)
541 struct thread *td;
542 struct freebsd4_freebsd32_sigreturn_args /* {
543 const struct freebsd4_freebsd32_ucontext *sigcntxp;
544 } */ *uap;
545 {
546 struct ia32_ucontext4 uc;
547 struct proc *p = td->td_proc;
548 struct trapframe *regs;
549 const struct ia32_ucontext4 *ucp;
550 int cs, eflags, error;
551 ksiginfo_t ksi;
552
553 error = copyin(uap->sigcntxp, &uc, sizeof(uc));
554 if (error != 0)
555 return (error);
556 ucp = &uc;
557 regs = td->td_frame;
558 eflags = ucp->uc_mcontext.mc_eflags;
559 /*
560 * Don't allow users to change privileged or reserved flags.
561 */
562 /*
563 * XXX do allow users to change the privileged flag PSL_RF.
564 * The cpu sets PSL_RF in tf_eflags for faults. Debuggers
565 * should sometimes set it there too. tf_eflags is kept in
566 * the signal context during signal handling and there is no
567 * other place to remember it, so the PSL_RF bit may be
568 * corrupted by the signal handler without us knowing.
569 * Corruption of the PSL_RF bit at worst causes one more or
570 * one less debugger trap, so allowing it is fairly harmless.
571 */
572 if (!EFL_SECURE(eflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
573 printf("freebsd4_freebsd32_sigreturn: eflags = 0x%x\n", eflags);
574 return (EINVAL);
575 }
576
577 /*
578 * Don't allow users to load a valid privileged %cs. Let the
579 * hardware check for invalid selectors, excess privilege in
580 * other selectors, invalid %eip's and invalid %esp's.
581 */
582 cs = ucp->uc_mcontext.mc_cs;
583 if (!CS_SECURE(cs)) {
584 printf("freebsd4_sigreturn: cs = 0x%x\n", cs);
585 ksiginfo_init_trap(&ksi);
586 ksi.ksi_signo = SIGBUS;
587 ksi.ksi_code = BUS_OBJERR;
588 ksi.ksi_trapno = T_PROTFLT;
589 ksi.ksi_addr = (void *)regs->tf_rip;
590 trapsignal(td, &ksi);
591 return (EINVAL);
592 }
593
594 /* Segment selectors restored by sigtramp.S */
595 regs->tf_rdi = ucp->uc_mcontext.mc_edi;
596 regs->tf_rsi = ucp->uc_mcontext.mc_esi;
597 regs->tf_rbp = ucp->uc_mcontext.mc_ebp;
598 regs->tf_rbx = ucp->uc_mcontext.mc_ebx;
599 regs->tf_rdx = ucp->uc_mcontext.mc_edx;
600 regs->tf_rcx = ucp->uc_mcontext.mc_ecx;
601 regs->tf_rax = ucp->uc_mcontext.mc_eax;
602 regs->tf_trapno = ucp->uc_mcontext.mc_trapno;
603 regs->tf_err = ucp->uc_mcontext.mc_err;
604 regs->tf_rip = ucp->uc_mcontext.mc_eip;
605 regs->tf_cs = cs;
606 regs->tf_rflags = ucp->uc_mcontext.mc_eflags;
607 regs->tf_rsp = ucp->uc_mcontext.mc_esp;
608 regs->tf_ss = ucp->uc_mcontext.mc_ss;
609
610 PROC_LOCK(p);
611 td->td_sigmask = ucp->uc_sigmask;
612 SIG_CANTMASK(td->td_sigmask);
613 signotify(td);
614 PROC_UNLOCK(p);
615 return (EJUSTRETURN);
616 }
617 #endif /* COMPAT_FREEBSD4 */
618
619 /*
620 * MPSAFE
621 */
622 int
623 freebsd32_sigreturn(td, uap)
624 struct thread *td;
625 struct freebsd32_sigreturn_args /* {
626 const struct freebsd32_ucontext *sigcntxp;
627 } */ *uap;
628 {
629 struct ia32_ucontext uc;
630 struct proc *p = td->td_proc;
631 struct trapframe *regs;
632 const struct ia32_ucontext *ucp;
633 int cs, eflags, error, ret;
634 ksiginfo_t ksi;
635
636 error = copyin(uap->sigcntxp, &uc, sizeof(uc));
637 if (error != 0)
638 return (error);
639 ucp = &uc;
640 regs = td->td_frame;
641 eflags = ucp->uc_mcontext.mc_eflags;
642 /*
643 * Don't allow users to change privileged or reserved flags.
644 */
645 /*
646 * XXX do allow users to change the privileged flag PSL_RF.
647 * The cpu sets PSL_RF in tf_eflags for faults. Debuggers
648 * should sometimes set it there too. tf_eflags is kept in
649 * the signal context during signal handling and there is no
650 * other place to remember it, so the PSL_RF bit may be
651 * corrupted by the signal handler without us knowing.
652 * Corruption of the PSL_RF bit at worst causes one more or
653 * one less debugger trap, so allowing it is fairly harmless.
654 */
655 if (!EFL_SECURE(eflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
656 printf("freebsd32_sigreturn: eflags = 0x%x\n", eflags);
657 return (EINVAL);
658 }
659
660 /*
661 * Don't allow users to load a valid privileged %cs. Let the
662 * hardware check for invalid selectors, excess privilege in
663 * other selectors, invalid %eip's and invalid %esp's.
664 */
665 cs = ucp->uc_mcontext.mc_cs;
666 if (!CS_SECURE(cs)) {
667 printf("sigreturn: cs = 0x%x\n", cs);
668 ksiginfo_init_trap(&ksi);
669 ksi.ksi_signo = SIGBUS;
670 ksi.ksi_code = BUS_OBJERR;
671 ksi.ksi_trapno = T_PROTFLT;
672 ksi.ksi_addr = (void *)regs->tf_rip;
673 trapsignal(td, &ksi);
674 return (EINVAL);
675 }
676
677 ret = ia32_set_fpcontext(td, &ucp->uc_mcontext);
678 if (ret != 0)
679 return (ret);
680
681 /* Segment selectors restored by sigtramp.S */
682 regs->tf_rdi = ucp->uc_mcontext.mc_edi;
683 regs->tf_rsi = ucp->uc_mcontext.mc_esi;
684 regs->tf_rbp = ucp->uc_mcontext.mc_ebp;
685 regs->tf_rbx = ucp->uc_mcontext.mc_ebx;
686 regs->tf_rdx = ucp->uc_mcontext.mc_edx;
687 regs->tf_rcx = ucp->uc_mcontext.mc_ecx;
688 regs->tf_rax = ucp->uc_mcontext.mc_eax;
689 regs->tf_trapno = ucp->uc_mcontext.mc_trapno;
690 regs->tf_err = ucp->uc_mcontext.mc_err;
691 regs->tf_rip = ucp->uc_mcontext.mc_eip;
692 regs->tf_cs = cs;
693 regs->tf_rflags = ucp->uc_mcontext.mc_eflags;
694 regs->tf_rsp = ucp->uc_mcontext.mc_esp;
695 regs->tf_ss = ucp->uc_mcontext.mc_ss;
696
697 PROC_LOCK(p);
698 td->td_sigmask = ucp->uc_sigmask;
699 SIG_CANTMASK(td->td_sigmask);
700 signotify(td);
701 PROC_UNLOCK(p);
702 return (EJUSTRETURN);
703 }
704
705 /*
706 * Clear registers on exec
707 */
708 void
709 ia32_setregs(td, entry, stack, ps_strings)
710 struct thread *td;
711 u_long entry;
712 u_long stack;
713 u_long ps_strings;
714 {
715 struct trapframe *regs = td->td_frame;
716 struct pcb *pcb = td->td_pcb;
717
718 critical_enter();
719 wrmsr(MSR_FSBASE, 0);
720 wrmsr(MSR_KGSBASE, 0); /* User value while we're in the kernel */
721 pcb->pcb_fsbase = 0;
722 pcb->pcb_gsbase = 0;
723 critical_exit();
724 load_ds(_udatasel);
725 load_es(_udatasel);
726 load_fs(_udatasel);
727 load_gs(_udatasel);
728 pcb->pcb_ds = _udatasel;
729 pcb->pcb_es = _udatasel;
730 pcb->pcb_fs = _udatasel;
731 pcb->pcb_gs = _udatasel;
732
733 bzero((char *)regs, sizeof(struct trapframe));
734 regs->tf_rip = entry;
735 regs->tf_rsp = stack;
736 regs->tf_rflags = PSL_USER | (regs->tf_rflags & PSL_T);
737 regs->tf_ss = _udatasel;
738 regs->tf_cs = _ucode32sel;
739 regs->tf_rbx = ps_strings;
740 load_cr0(rcr0() | CR0_MP | CR0_TS);
741 fpstate_drop(td);
742
743 /* Return via doreti so that we can change to a different %cs */
744 pcb->pcb_flags |= PCB_FULLCTX | PCB_32BIT;
745 pcb->pcb_flags &= ~PCB_GS32BIT;
746 td->td_retval[1] = 0;
747 }
748 Cache object: c623e5a843362a197b4963a2f3dc8ff3
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