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("$FreeBSD$"); 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_util.h> 71 #include <compat/freebsd32/freebsd32_proto.h> 72 #include <compat/ia32/ia32_signal.h> 73 #include <machine/psl.h> 74 #include <machine/segments.h> 75 #include <machine/specialreg.h> 76 #include <machine/frame.h> 77 #include <machine/md_var.h> 78 #include <machine/pcb.h> 79 #include <machine/cpufunc.h> 80 81 #ifdef COMPAT_FREEBSD4 82 static void freebsd4_ia32_sendsig(sig_t, ksiginfo_t *, sigset_t *); 83 #endif 84 static void ia32_get_fpcontext(struct thread *td, struct ia32_mcontext *mcp); 85 static int ia32_set_fpcontext(struct thread *td, const struct ia32_mcontext *mcp); 86 87 extern int _ucode32sel, _udatasel; 88 89 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 90 #define EFL_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 91 92 static void 93 ia32_get_fpcontext(struct thread *td, struct ia32_mcontext *mcp) 94 { 95 96 mcp->mc_ownedfp = fpugetregs(td, (struct savefpu *)&mcp->mc_fpstate); 97 mcp->mc_fpformat = fpuformat(); 98 } 99 100 static int 101 ia32_set_fpcontext(struct thread *td, const struct ia32_mcontext *mcp) 102 { 103 104 if (mcp->mc_fpformat == _MC_FPFMT_NODEV) 105 return (0); 106 else if (mcp->mc_fpformat != _MC_FPFMT_XMM) 107 return (EINVAL); 108 else if (mcp->mc_ownedfp == _MC_FPOWNED_NONE) 109 /* We don't care what state is left in the FPU or PCB. */ 110 fpstate_drop(td); 111 else if (mcp->mc_ownedfp == _MC_FPOWNED_FPU || 112 mcp->mc_ownedfp == _MC_FPOWNED_PCB) { 113 /* 114 * XXX we violate the dubious requirement that fpusetregs() 115 * be called with interrupts disabled. 116 */ 117 fpusetregs(td, (struct savefpu *)&mcp->mc_fpstate); 118 } else 119 return (EINVAL); 120 return (0); 121 } 122 123 /* 124 * Get machine context. 125 */ 126 static int 127 ia32_get_mcontext(struct thread *td, struct ia32_mcontext *mcp, int flags) 128 { 129 struct trapframe *tp; 130 131 tp = td->td_frame; 132 133 PROC_LOCK(curthread->td_proc); 134 mcp->mc_onstack = sigonstack(tp->tf_rsp); 135 PROC_UNLOCK(curthread->td_proc); 136 mcp->mc_gs = td->td_pcb->pcb_gs; 137 mcp->mc_fs = td->td_pcb->pcb_fs; 138 mcp->mc_es = td->td_pcb->pcb_es; 139 mcp->mc_ds = td->td_pcb->pcb_ds; 140 mcp->mc_edi = tp->tf_rdi; 141 mcp->mc_esi = tp->tf_rsi; 142 mcp->mc_ebp = tp->tf_rbp; 143 mcp->mc_isp = tp->tf_rsp; 144 if (flags & GET_MC_CLEAR_RET) { 145 mcp->mc_eax = 0; 146 mcp->mc_edx = 0; 147 } else { 148 mcp->mc_eax = tp->tf_rax; 149 mcp->mc_edx = tp->tf_rdx; 150 } 151 mcp->mc_ebx = tp->tf_rbx; 152 mcp->mc_ecx = tp->tf_rcx; 153 mcp->mc_eip = tp->tf_rip; 154 mcp->mc_cs = tp->tf_cs; 155 mcp->mc_eflags = tp->tf_rflags; 156 mcp->mc_esp = tp->tf_rsp; 157 mcp->mc_ss = tp->tf_ss; 158 mcp->mc_len = sizeof(*mcp); 159 ia32_get_fpcontext(td, mcp); 160 return (0); 161 } 162 163 /* 164 * Set machine context. 165 * 166 * However, we don't set any but the user modifiable flags, and we won't 167 * touch the cs selector. 168 */ 169 static int 170 ia32_set_mcontext(struct thread *td, const struct ia32_mcontext *mcp) 171 { 172 struct trapframe *tp; 173 long rflags; 174 int ret; 175 176 tp = td->td_frame; 177 if (mcp->mc_len != sizeof(*mcp)) 178 return (EINVAL); 179 rflags = (mcp->mc_eflags & PSL_USERCHANGE) | 180 (tp->tf_rflags & ~PSL_USERCHANGE); 181 ret = ia32_set_fpcontext(td, mcp); 182 if (ret != 0) 183 return (ret); 184 #if 0 /* XXX deal with load_fs() and friends */ 185 tp->tf_fs = mcp->mc_fs; 186 tp->tf_es = mcp->mc_es; 187 tp->tf_ds = mcp->mc_ds; 188 #endif 189 tp->tf_rdi = mcp->mc_edi; 190 tp->tf_rsi = mcp->mc_esi; 191 tp->tf_rbp = mcp->mc_ebp; 192 tp->tf_rbx = mcp->mc_ebx; 193 tp->tf_rdx = mcp->mc_edx; 194 tp->tf_rcx = mcp->mc_ecx; 195 tp->tf_rax = mcp->mc_eax; 196 /* trapno, err */ 197 tp->tf_rip = mcp->mc_eip; 198 tp->tf_rflags = rflags; 199 tp->tf_rsp = mcp->mc_esp; 200 tp->tf_ss = mcp->mc_ss; 201 #if 0 /* XXX deal with load_gs() and friends */ 202 td->td_pcb->pcb_gs = mcp->mc_gs; 203 #endif 204 td->td_pcb->pcb_flags |= PCB_FULLCTX; 205 return (0); 206 } 207 208 /* 209 * The first two fields of a ucontext_t are the signal mask and 210 * the machine context. The next field is uc_link; we want to 211 * avoid destroying the link when copying out contexts. 212 */ 213 #define UC_COPY_SIZE offsetof(struct ia32_ucontext, uc_link) 214 215 int 216 freebsd32_getcontext(struct thread *td, struct freebsd32_getcontext_args *uap) 217 { 218 struct ia32_ucontext uc; 219 int ret; 220 221 if (uap->ucp == NULL) 222 ret = EINVAL; 223 else { 224 ia32_get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 225 PROC_LOCK(td->td_proc); 226 uc.uc_sigmask = td->td_sigmask; 227 PROC_UNLOCK(td->td_proc); 228 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE); 229 } 230 return (ret); 231 } 232 233 int 234 freebsd32_setcontext(struct thread *td, struct freebsd32_setcontext_args *uap) 235 { 236 struct ia32_ucontext uc; 237 int ret; 238 239 if (uap->ucp == NULL) 240 ret = EINVAL; 241 else { 242 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 243 if (ret == 0) { 244 ret = ia32_set_mcontext(td, &uc.uc_mcontext); 245 if (ret == 0) { 246 SIG_CANTMASK(uc.uc_sigmask); 247 PROC_LOCK(td->td_proc); 248 td->td_sigmask = uc.uc_sigmask; 249 PROC_UNLOCK(td->td_proc); 250 } 251 } 252 } 253 return (ret == 0 ? EJUSTRETURN : ret); 254 } 255 256 int 257 freebsd32_swapcontext(struct thread *td, struct freebsd32_swapcontext_args *uap) 258 { 259 struct ia32_ucontext uc; 260 int ret; 261 262 if (uap->oucp == NULL || uap->ucp == NULL) 263 ret = EINVAL; 264 else { 265 ia32_get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 266 PROC_LOCK(td->td_proc); 267 uc.uc_sigmask = td->td_sigmask; 268 PROC_UNLOCK(td->td_proc); 269 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE); 270 if (ret == 0) { 271 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 272 if (ret == 0) { 273 ret = ia32_set_mcontext(td, &uc.uc_mcontext); 274 if (ret == 0) { 275 SIG_CANTMASK(uc.uc_sigmask); 276 PROC_LOCK(td->td_proc); 277 td->td_sigmask = uc.uc_sigmask; 278 PROC_UNLOCK(td->td_proc); 279 } 280 } 281 } 282 } 283 return (ret == 0 ? EJUSTRETURN : ret); 284 } 285 286 /* 287 * Send an interrupt to process. 288 * 289 * Stack is set up to allow sigcode stored 290 * at top to call routine, followed by kcall 291 * to sigreturn routine below. After sigreturn 292 * resets the signal mask, the stack, and the 293 * frame pointer, it returns to the user 294 * specified pc, psl. 295 */ 296 #ifdef COMPAT_FREEBSD4 297 static void 298 freebsd4_ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 299 { 300 struct ia32_sigframe4 sf, *sfp; 301 struct ia32_siginfo siginfo; 302 struct proc *p; 303 struct thread *td; 304 struct sigacts *psp; 305 struct trapframe *regs; 306 int oonstack; 307 int sig; 308 309 td = curthread; 310 p = td->td_proc; 311 siginfo_to_ia32siginfo(&ksi->ksi_info, &siginfo); 312 313 PROC_LOCK_ASSERT(p, MA_OWNED); 314 sig = siginfo.si_signo; 315 psp = p->p_sigacts; 316 mtx_assert(&psp->ps_mtx, MA_OWNED); 317 regs = td->td_frame; 318 oonstack = sigonstack(regs->tf_rsp); 319 320 /* Save user context. */ 321 bzero(&sf, sizeof(sf)); 322 sf.sf_uc.uc_sigmask = *mask; 323 sf.sf_uc.uc_stack.ss_sp = (uintptr_t)td->td_sigstk.ss_sp; 324 sf.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size; 325 sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 326 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 327 sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0; 328 sf.sf_uc.uc_mcontext.mc_gs = rgs(); 329 sf.sf_uc.uc_mcontext.mc_fs = rfs(); 330 __asm __volatile("movl %%es,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_es)); 331 __asm __volatile("movl %%ds,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_ds)); 332 sf.sf_uc.uc_mcontext.mc_edi = regs->tf_rdi; 333 sf.sf_uc.uc_mcontext.mc_esi = regs->tf_rsi; 334 sf.sf_uc.uc_mcontext.mc_ebp = regs->tf_rbp; 335 sf.sf_uc.uc_mcontext.mc_isp = regs->tf_rsp; /* XXX */ 336 sf.sf_uc.uc_mcontext.mc_ebx = regs->tf_rbx; 337 sf.sf_uc.uc_mcontext.mc_edx = regs->tf_rdx; 338 sf.sf_uc.uc_mcontext.mc_ecx = regs->tf_rcx; 339 sf.sf_uc.uc_mcontext.mc_eax = regs->tf_rax; 340 sf.sf_uc.uc_mcontext.mc_trapno = regs->tf_trapno; 341 sf.sf_uc.uc_mcontext.mc_err = regs->tf_err; 342 sf.sf_uc.uc_mcontext.mc_eip = regs->tf_rip; 343 sf.sf_uc.uc_mcontext.mc_cs = regs->tf_cs; 344 sf.sf_uc.uc_mcontext.mc_eflags = regs->tf_rflags; 345 sf.sf_uc.uc_mcontext.mc_esp = regs->tf_rsp; 346 sf.sf_uc.uc_mcontext.mc_ss = regs->tf_ss; 347 348 /* Allocate space for the signal handler context. */ 349 if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack && 350 SIGISMEMBER(psp->ps_sigonstack, sig)) { 351 sfp = (struct ia32_sigframe4 *)(td->td_sigstk.ss_sp + 352 td->td_sigstk.ss_size - sizeof(sf)); 353 } else 354 sfp = (struct ia32_sigframe4 *)regs->tf_rsp - 1; 355 PROC_UNLOCK(p); 356 357 /* Translate the signal if appropriate. */ 358 if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize) 359 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)]; 360 361 /* Build the argument list for the signal handler. */ 362 sf.sf_signum = sig; 363 sf.sf_ucontext = (register_t)&sfp->sf_uc; 364 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 365 /* Signal handler installed with SA_SIGINFO. */ 366 sf.sf_siginfo = (u_int32_t)(uintptr_t)&sfp->sf_si; 367 sf.sf_ah = (u_int32_t)(uintptr_t)catcher; 368 369 /* Fill in POSIX parts */ 370 sf.sf_si = siginfo; 371 sf.sf_si.si_signo = sig; 372 } else { 373 /* Old FreeBSD-style arguments. */ 374 sf.sf_siginfo = siginfo.si_code; 375 sf.sf_addr = (u_int32_t)siginfo.si_addr; 376 sf.sf_ah = (u_int32_t)(uintptr_t)catcher; 377 } 378 mtx_unlock(&psp->ps_mtx); 379 380 /* 381 * Copy the sigframe out to the user's stack. 382 */ 383 if (copyout(&sf, sfp, sizeof(*sfp)) != 0) { 384 #ifdef DEBUG 385 printf("process %ld has trashed its stack\n", (long)p->p_pid); 386 #endif 387 PROC_LOCK(p); 388 sigexit(td, SIGILL); 389 } 390 391 regs->tf_rsp = (uintptr_t)sfp; 392 regs->tf_rip = FREEBSD32_PS_STRINGS - sz_freebsd4_ia32_sigcode; 393 regs->tf_rflags &= ~PSL_T; 394 regs->tf_cs = _ucode32sel; 395 regs->tf_ss = _udatasel; 396 load_ds(_udatasel); 397 td->td_pcb->pcb_ds = _udatasel; 398 load_es(_udatasel); 399 td->td_pcb->pcb_es = _udatasel; 400 /* leave user %fs and %gs untouched */ 401 PROC_LOCK(p); 402 mtx_lock(&psp->ps_mtx); 403 } 404 #endif /* COMPAT_FREEBSD4 */ 405 406 void 407 ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 408 { 409 struct ia32_sigframe sf, *sfp; 410 struct ia32_siginfo siginfo; 411 struct proc *p; 412 struct thread *td; 413 struct sigacts *psp; 414 char *sp; 415 struct trapframe *regs; 416 int oonstack; 417 int sig; 418 419 siginfo_to_ia32siginfo(&ksi->ksi_info, &siginfo); 420 td = curthread; 421 p = td->td_proc; 422 PROC_LOCK_ASSERT(p, MA_OWNED); 423 sig = siginfo.si_signo; 424 psp = p->p_sigacts; 425 #ifdef COMPAT_FREEBSD4 426 if (SIGISMEMBER(psp->ps_freebsd4, sig)) { 427 freebsd4_ia32_sendsig(catcher, ksi, mask); 428 return; 429 } 430 #endif 431 mtx_assert(&psp->ps_mtx, MA_OWNED); 432 regs = td->td_frame; 433 oonstack = sigonstack(regs->tf_rsp); 434 435 /* Save user context. */ 436 bzero(&sf, sizeof(sf)); 437 sf.sf_uc.uc_sigmask = *mask; 438 sf.sf_uc.uc_stack.ss_sp = (uintptr_t)td->td_sigstk.ss_sp; 439 sf.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size; 440 sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 441 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 442 sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0; 443 sf.sf_uc.uc_mcontext.mc_gs = rgs(); 444 sf.sf_uc.uc_mcontext.mc_fs = rfs(); 445 __asm __volatile("movl %%es,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_es)); 446 __asm __volatile("movl %%ds,%0" : "=rm" (sf.sf_uc.uc_mcontext.mc_ds)); 447 sf.sf_uc.uc_mcontext.mc_edi = regs->tf_rdi; 448 sf.sf_uc.uc_mcontext.mc_esi = regs->tf_rsi; 449 sf.sf_uc.uc_mcontext.mc_ebp = regs->tf_rbp; 450 sf.sf_uc.uc_mcontext.mc_isp = regs->tf_rsp; /* XXX */ 451 sf.sf_uc.uc_mcontext.mc_ebx = regs->tf_rbx; 452 sf.sf_uc.uc_mcontext.mc_edx = regs->tf_rdx; 453 sf.sf_uc.uc_mcontext.mc_ecx = regs->tf_rcx; 454 sf.sf_uc.uc_mcontext.mc_eax = regs->tf_rax; 455 sf.sf_uc.uc_mcontext.mc_trapno = regs->tf_trapno; 456 sf.sf_uc.uc_mcontext.mc_err = regs->tf_err; 457 sf.sf_uc.uc_mcontext.mc_eip = regs->tf_rip; 458 sf.sf_uc.uc_mcontext.mc_cs = regs->tf_cs; 459 sf.sf_uc.uc_mcontext.mc_eflags = regs->tf_rflags; 460 sf.sf_uc.uc_mcontext.mc_esp = regs->tf_rsp; 461 sf.sf_uc.uc_mcontext.mc_ss = regs->tf_ss; 462 sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */ 463 ia32_get_fpcontext(td, &sf.sf_uc.uc_mcontext); 464 fpstate_drop(td); 465 466 /* Allocate space for the signal handler context. */ 467 if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack && 468 SIGISMEMBER(psp->ps_sigonstack, sig)) { 469 sp = td->td_sigstk.ss_sp + 470 td->td_sigstk.ss_size - sizeof(sf); 471 } else 472 sp = (char *)regs->tf_rsp - sizeof(sf); 473 /* Align to 16 bytes. */ 474 sfp = (struct ia32_sigframe *)((uintptr_t)sp & ~0xF); 475 PROC_UNLOCK(p); 476 477 /* Translate the signal if appropriate. */ 478 if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize) 479 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)]; 480 481 /* Build the argument list for the signal handler. */ 482 sf.sf_signum = sig; 483 sf.sf_ucontext = (register_t)&sfp->sf_uc; 484 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 485 /* Signal handler installed with SA_SIGINFO. */ 486 sf.sf_siginfo = (u_int32_t)(uintptr_t)&sfp->sf_si; 487 sf.sf_ah = (u_int32_t)(uintptr_t)catcher; 488 489 /* Fill in POSIX parts */ 490 sf.sf_si = siginfo; 491 sf.sf_si.si_signo = sig; 492 } else { 493 /* Old FreeBSD-style arguments. */ 494 sf.sf_siginfo = siginfo.si_code; 495 sf.sf_addr = (u_int32_t)siginfo.si_addr; 496 sf.sf_ah = (u_int32_t)(uintptr_t)catcher; 497 } 498 mtx_unlock(&psp->ps_mtx); 499 500 /* 501 * Copy the sigframe out to the user's stack. 502 */ 503 if (copyout(&sf, sfp, sizeof(*sfp)) != 0) { 504 #ifdef DEBUG 505 printf("process %ld has trashed its stack\n", (long)p->p_pid); 506 #endif 507 PROC_LOCK(p); 508 sigexit(td, SIGILL); 509 } 510 511 regs->tf_rsp = (uintptr_t)sfp; 512 regs->tf_rip = FREEBSD32_PS_STRINGS - *(p->p_sysent->sv_szsigcode); 513 regs->tf_rflags &= ~PSL_T; 514 regs->tf_cs = _ucode32sel; 515 regs->tf_ss = _udatasel; 516 load_ds(_udatasel); 517 td->td_pcb->pcb_ds = _udatasel; 518 load_es(_udatasel); 519 td->td_pcb->pcb_es = _udatasel; 520 /* leave user %fs and %gs untouched */ 521 PROC_LOCK(p); 522 mtx_lock(&psp->ps_mtx); 523 } 524 525 /* 526 * System call to cleanup state after a signal 527 * has been taken. Reset signal mask and 528 * stack state from context left by sendsig (above). 529 * Return to previous pc and psl as specified by 530 * context left by sendsig. Check carefully to 531 * make sure that the user has not modified the 532 * state to gain improper privileges. 533 */ 534 #ifdef COMPAT_FREEBSD4 535 /* 536 * MPSAFE 537 */ 538 int 539 freebsd4_freebsd32_sigreturn(td, uap) 540 struct thread *td; 541 struct freebsd4_freebsd32_sigreturn_args /* { 542 const struct freebsd4_freebsd32_ucontext *sigcntxp; 543 } */ *uap; 544 { 545 struct ia32_ucontext4 uc; 546 struct proc *p = td->td_proc; 547 struct trapframe *regs; 548 const struct ia32_ucontext4 *ucp; 549 int cs, eflags, error; 550 ksiginfo_t ksi; 551 552 error = copyin(uap->sigcntxp, &uc, sizeof(uc)); 553 if (error != 0) 554 return (error); 555 ucp = &uc; 556 regs = td->td_frame; 557 eflags = ucp->uc_mcontext.mc_eflags; 558 /* 559 * Don't allow users to change privileged or reserved flags. 560 */ 561 /* 562 * XXX do allow users to change the privileged flag PSL_RF. 563 * The cpu sets PSL_RF in tf_eflags for faults. Debuggers 564 * should sometimes set it there too. tf_eflags is kept in 565 * the signal context during signal handling and there is no 566 * other place to remember it, so the PSL_RF bit may be 567 * corrupted by the signal handler without us knowing. 568 * Corruption of the PSL_RF bit at worst causes one more or 569 * one less debugger trap, so allowing it is fairly harmless. 570 */ 571 if (!EFL_SECURE(eflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) { 572 printf("freebsd4_freebsd32_sigreturn: eflags = 0x%x\n", eflags); 573 return (EINVAL); 574 } 575 576 /* 577 * Don't allow users to load a valid privileged %cs. Let the 578 * hardware check for invalid selectors, excess privilege in 579 * other selectors, invalid %eip's and invalid %esp's. 580 */ 581 cs = ucp->uc_mcontext.mc_cs; 582 if (!CS_SECURE(cs)) { 583 printf("freebsd4_sigreturn: cs = 0x%x\n", cs); 584 ksiginfo_init_trap(&ksi); 585 ksi.ksi_signo = SIGBUS; 586 ksi.ksi_code = BUS_OBJERR; 587 ksi.ksi_trapno = T_PROTFLT; 588 ksi.ksi_addr = (void *)regs->tf_rip; 589 trapsignal(td, &ksi); 590 return (EINVAL); 591 } 592 593 /* Segment selectors restored by sigtramp.S */ 594 regs->tf_rdi = ucp->uc_mcontext.mc_edi; 595 regs->tf_rsi = ucp->uc_mcontext.mc_esi; 596 regs->tf_rbp = ucp->uc_mcontext.mc_ebp; 597 regs->tf_rbx = ucp->uc_mcontext.mc_ebx; 598 regs->tf_rdx = ucp->uc_mcontext.mc_edx; 599 regs->tf_rcx = ucp->uc_mcontext.mc_ecx; 600 regs->tf_rax = ucp->uc_mcontext.mc_eax; 601 regs->tf_trapno = ucp->uc_mcontext.mc_trapno; 602 regs->tf_err = ucp->uc_mcontext.mc_err; 603 regs->tf_rip = ucp->uc_mcontext.mc_eip; 604 regs->tf_cs = cs; 605 regs->tf_rflags = ucp->uc_mcontext.mc_eflags; 606 regs->tf_rsp = ucp->uc_mcontext.mc_esp; 607 regs->tf_ss = ucp->uc_mcontext.mc_ss; 608 609 PROC_LOCK(p); 610 td->td_sigmask = ucp->uc_sigmask; 611 SIG_CANTMASK(td->td_sigmask); 612 signotify(td); 613 PROC_UNLOCK(p); 614 return (EJUSTRETURN); 615 } 616 #endif /* COMPAT_FREEBSD4 */ 617 618 /* 619 * MPSAFE 620 */ 621 int 622 freebsd32_sigreturn(td, uap) 623 struct thread *td; 624 struct freebsd32_sigreturn_args /* { 625 const struct freebsd32_ucontext *sigcntxp; 626 } */ *uap; 627 { 628 struct ia32_ucontext uc; 629 struct proc *p = td->td_proc; 630 struct trapframe *regs; 631 const struct ia32_ucontext *ucp; 632 int cs, eflags, error, ret; 633 ksiginfo_t ksi; 634 635 error = copyin(uap->sigcntxp, &uc, sizeof(uc)); 636 if (error != 0) 637 return (error); 638 ucp = &uc; 639 regs = td->td_frame; 640 eflags = ucp->uc_mcontext.mc_eflags; 641 /* 642 * Don't allow users to change privileged or reserved flags. 643 */ 644 /* 645 * XXX do allow users to change the privileged flag PSL_RF. 646 * The cpu sets PSL_RF in tf_eflags for faults. Debuggers 647 * should sometimes set it there too. tf_eflags is kept in 648 * the signal context during signal handling and there is no 649 * other place to remember it, so the PSL_RF bit may be 650 * corrupted by the signal handler without us knowing. 651 * Corruption of the PSL_RF bit at worst causes one more or 652 * one less debugger trap, so allowing it is fairly harmless. 653 */ 654 if (!EFL_SECURE(eflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) { 655 printf("freebsd32_sigreturn: eflags = 0x%x\n", eflags); 656 return (EINVAL); 657 } 658 659 /* 660 * Don't allow users to load a valid privileged %cs. Let the 661 * hardware check for invalid selectors, excess privilege in 662 * other selectors, invalid %eip's and invalid %esp's. 663 */ 664 cs = ucp->uc_mcontext.mc_cs; 665 if (!CS_SECURE(cs)) { 666 printf("sigreturn: cs = 0x%x\n", cs); 667 ksiginfo_init_trap(&ksi); 668 ksi.ksi_signo = SIGBUS; 669 ksi.ksi_code = BUS_OBJERR; 670 ksi.ksi_trapno = T_PROTFLT; 671 ksi.ksi_addr = (void *)regs->tf_rip; 672 trapsignal(td, &ksi); 673 return (EINVAL); 674 } 675 676 ret = ia32_set_fpcontext(td, &ucp->uc_mcontext); 677 if (ret != 0) 678 return (ret); 679 680 /* Segment selectors restored by sigtramp.S */ 681 regs->tf_rdi = ucp->uc_mcontext.mc_edi; 682 regs->tf_rsi = ucp->uc_mcontext.mc_esi; 683 regs->tf_rbp = ucp->uc_mcontext.mc_ebp; 684 regs->tf_rbx = ucp->uc_mcontext.mc_ebx; 685 regs->tf_rdx = ucp->uc_mcontext.mc_edx; 686 regs->tf_rcx = ucp->uc_mcontext.mc_ecx; 687 regs->tf_rax = ucp->uc_mcontext.mc_eax; 688 regs->tf_trapno = ucp->uc_mcontext.mc_trapno; 689 regs->tf_err = ucp->uc_mcontext.mc_err; 690 regs->tf_rip = ucp->uc_mcontext.mc_eip; 691 regs->tf_cs = cs; 692 regs->tf_rflags = ucp->uc_mcontext.mc_eflags; 693 regs->tf_rsp = ucp->uc_mcontext.mc_esp; 694 regs->tf_ss = ucp->uc_mcontext.mc_ss; 695 696 PROC_LOCK(p); 697 td->td_sigmask = ucp->uc_sigmask; 698 SIG_CANTMASK(td->td_sigmask); 699 signotify(td); 700 PROC_UNLOCK(p); 701 return (EJUSTRETURN); 702 } 703 704 /* 705 * Clear registers on exec 706 */ 707 void 708 ia32_setregs(td, entry, stack, ps_strings) 709 struct thread *td; 710 u_long entry; 711 u_long stack; 712 u_long ps_strings; 713 { 714 struct trapframe *regs = td->td_frame; 715 struct pcb *pcb = td->td_pcb; 716 717 wrmsr(MSR_FSBASE, 0); 718 wrmsr(MSR_KGSBASE, 0); /* User value while we're in the kernel */ 719 pcb->pcb_fsbase = 0; 720 pcb->pcb_gsbase = 0; 721 load_ds(_udatasel); 722 load_es(_udatasel); 723 load_fs(_udatasel); 724 load_gs(_udatasel); 725 pcb->pcb_ds = _udatasel; 726 pcb->pcb_es = _udatasel; 727 pcb->pcb_fs = _udatasel; 728 pcb->pcb_gs = _udatasel; 729 730 bzero((char *)regs, sizeof(struct trapframe)); 731 regs->tf_rip = entry; 732 regs->tf_rsp = stack; 733 regs->tf_rflags = PSL_USER | (regs->tf_rflags & PSL_T); 734 regs->tf_ss = _udatasel; 735 regs->tf_cs = _ucode32sel; 736 regs->tf_rbx = ps_strings; 737 load_cr0(rcr0() | CR0_MP | CR0_TS); 738 fpstate_drop(td); 739 740 /* Return via doreti so that we can change to a different %cs */ 741 pcb->pcb_flags |= PCB_FULLCTX; 742 td->td_retval[1] = 0; 743 } 744 745 void 746 siginfo_to_ia32siginfo(siginfo_t *src, struct ia32_siginfo *dst) 747 { 748 dst->si_signo = src->si_signo; 749 dst->si_errno = src->si_errno; 750 dst->si_code = src->si_code; 751 dst->si_pid = src->si_pid; 752 dst->si_uid = src->si_uid; 753 dst->si_status = src->si_status; 754 dst->si_addr = dst->si_addr; 755 dst->si_value.sigval_int = src->si_value.sival_int; 756 dst->si_band = src->si_band; 757 dst->si_trapno = src->si_trapno; 758 dst->si_timerid = src->si_timerid; 759 dst->si_overrun = src->si_overrun; 760 } 761