Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/i386/i386/exec_machdep.c
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1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 2018 The FreeBSD Foundation 5 * Copyright (c) 1992 Terrence R. Lambert. 6 * Copyright (c) 1982, 1987, 1990 The Regents of the University of California. 7 * All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * William Jolitz. 11 * 12 * Portions of this software were developed by A. Joseph Koshy under 13 * sponsorship from the FreeBSD Foundation and Google, Inc. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. All advertising materials mentioning features or use of this software 24 * must display the following acknowledgement: 25 * This product includes software developed by the University of 26 * California, Berkeley and its contributors. 27 * 4. Neither the name of the University nor the names of its contributors 28 * may be used to endorse or promote products derived from this software 29 * without specific prior written permission. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 32 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 33 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 34 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 35 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 39 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 40 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 41 * SUCH DAMAGE. 42 * 43 * from: @(#)machdep.c 7.4 (Berkeley) 6/3/91 44 */ 45 46 #include <sys/cdefs.h> 47 __FBSDID("$FreeBSD$"); 48 49 #include "opt_cpu.h" 50 #include "opt_ddb.h" 51 #include "opt_kstack_pages.h" 52 53 #include <sys/param.h> 54 #include <sys/proc.h> 55 #include <sys/systm.h> 56 #include <sys/exec.h> 57 #include <sys/imgact.h> 58 #include <sys/kdb.h> 59 #include <sys/kernel.h> 60 #include <sys/ktr.h> 61 #include <sys/linker.h> 62 #include <sys/lock.h> 63 #include <sys/malloc.h> 64 #include <sys/mutex.h> 65 #include <sys/pcpu.h> 66 #include <sys/ptrace.h> 67 #include <sys/reg.h> 68 #include <sys/rwlock.h> 69 #include <sys/signalvar.h> 70 #include <sys/syscallsubr.h> 71 #include <sys/sysctl.h> 72 #include <sys/sysent.h> 73 #include <sys/sysproto.h> 74 #include <sys/ucontext.h> 75 #include <sys/vmmeter.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_param.h> 79 #include <vm/vm_extern.h> 80 #include <vm/vm_kern.h> 81 #include <vm/vm_page.h> 82 #include <vm/vm_map.h> 83 #include <vm/vm_object.h> 84 85 #ifdef DDB 86 #ifndef KDB 87 #error KDB must be enabled in order for DDB to work! 88 #endif 89 #include <ddb/ddb.h> 90 #include <ddb/db_sym.h> 91 #endif 92 93 #include <machine/cpu.h> 94 #include <machine/cputypes.h> 95 #include <machine/md_var.h> 96 #include <machine/pcb.h> 97 #include <machine/pcb_ext.h> 98 #include <machine/proc.h> 99 #include <machine/sigframe.h> 100 #include <machine/specialreg.h> 101 #include <machine/sysarch.h> 102 #include <machine/trap.h> 103 104 static void fpstate_drop(struct thread *td); 105 static void get_fpcontext(struct thread *td, mcontext_t *mcp, 106 char *xfpusave, size_t xfpusave_len); 107 static int set_fpcontext(struct thread *td, mcontext_t *mcp, 108 char *xfpustate, size_t xfpustate_len); 109 #ifdef COMPAT_43 110 static void osendsig(sig_t catcher, ksiginfo_t *, sigset_t *mask); 111 #endif 112 #ifdef COMPAT_FREEBSD4 113 static void freebsd4_sendsig(sig_t catcher, ksiginfo_t *, sigset_t *mask); 114 #endif 115 116 extern struct sysentvec elf32_freebsd_sysvec; 117 118 _Static_assert(sizeof(mcontext_t) == 640, "mcontext_t size incorrect"); 119 _Static_assert(sizeof(ucontext_t) == 704, "ucontext_t size incorrect"); 120 _Static_assert(sizeof(siginfo_t) == 64, "siginfo_t size incorrect"); 121 122 /* 123 * Send an interrupt to process. 124 * 125 * Stack is set up to allow sigcode stored at top to call routine, 126 * followed by call to sigreturn routine below. After sigreturn 127 * resets the signal mask, the stack, and the frame pointer, it 128 * returns to the user specified pc, psl. 129 */ 130 #ifdef COMPAT_43 131 static void 132 osendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 133 { 134 struct osigframe sf, *fp; 135 struct proc *p; 136 struct thread *td; 137 struct sigacts *psp; 138 struct trapframe *regs; 139 int sig; 140 int oonstack; 141 142 td = curthread; 143 p = td->td_proc; 144 PROC_LOCK_ASSERT(p, MA_OWNED); 145 sig = ksi->ksi_signo; 146 psp = p->p_sigacts; 147 mtx_assert(&psp->ps_mtx, MA_OWNED); 148 regs = td->td_frame; 149 oonstack = sigonstack(regs->tf_esp); 150 151 /* Allocate space for the signal handler context. */ 152 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 153 SIGISMEMBER(psp->ps_sigonstack, sig)) { 154 fp = (struct osigframe *)((uintptr_t)td->td_sigstk.ss_sp + 155 td->td_sigstk.ss_size - sizeof(struct osigframe)); 156 #if defined(COMPAT_43) 157 td->td_sigstk.ss_flags |= SS_ONSTACK; 158 #endif 159 } else 160 fp = (struct osigframe *)regs->tf_esp - 1; 161 162 /* Build the argument list for the signal handler. */ 163 sf.sf_signum = sig; 164 sf.sf_scp = (register_t)&fp->sf_siginfo.si_sc; 165 bzero(&sf.sf_siginfo, sizeof(sf.sf_siginfo)); 166 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 167 /* Signal handler installed with SA_SIGINFO. */ 168 sf.sf_arg2 = (register_t)&fp->sf_siginfo; 169 sf.sf_siginfo.si_signo = sig; 170 sf.sf_siginfo.si_code = ksi->ksi_code; 171 sf.sf_ahu.sf_action = (__osiginfohandler_t *)catcher; 172 sf.sf_addr = 0; 173 } else { 174 /* Old FreeBSD-style arguments. */ 175 sf.sf_arg2 = ksi->ksi_code; 176 sf.sf_addr = (register_t)ksi->ksi_addr; 177 sf.sf_ahu.sf_handler = catcher; 178 } 179 mtx_unlock(&psp->ps_mtx); 180 PROC_UNLOCK(p); 181 182 /* Save most if not all of trap frame. */ 183 sf.sf_siginfo.si_sc.sc_eax = regs->tf_eax; 184 sf.sf_siginfo.si_sc.sc_ebx = regs->tf_ebx; 185 sf.sf_siginfo.si_sc.sc_ecx = regs->tf_ecx; 186 sf.sf_siginfo.si_sc.sc_edx = regs->tf_edx; 187 sf.sf_siginfo.si_sc.sc_esi = regs->tf_esi; 188 sf.sf_siginfo.si_sc.sc_edi = regs->tf_edi; 189 sf.sf_siginfo.si_sc.sc_cs = regs->tf_cs; 190 sf.sf_siginfo.si_sc.sc_ds = regs->tf_ds; 191 sf.sf_siginfo.si_sc.sc_ss = regs->tf_ss; 192 sf.sf_siginfo.si_sc.sc_es = regs->tf_es; 193 sf.sf_siginfo.si_sc.sc_fs = regs->tf_fs; 194 sf.sf_siginfo.si_sc.sc_gs = rgs(); 195 sf.sf_siginfo.si_sc.sc_isp = regs->tf_isp; 196 197 /* Build the signal context to be used by osigreturn(). */ 198 sf.sf_siginfo.si_sc.sc_onstack = (oonstack) ? 1 : 0; 199 SIG2OSIG(*mask, sf.sf_siginfo.si_sc.sc_mask); 200 sf.sf_siginfo.si_sc.sc_sp = regs->tf_esp; 201 sf.sf_siginfo.si_sc.sc_fp = regs->tf_ebp; 202 sf.sf_siginfo.si_sc.sc_pc = regs->tf_eip; 203 sf.sf_siginfo.si_sc.sc_ps = regs->tf_eflags; 204 sf.sf_siginfo.si_sc.sc_trapno = regs->tf_trapno; 205 sf.sf_siginfo.si_sc.sc_err = regs->tf_err; 206 207 /* 208 * If we're a vm86 process, we want to save the segment registers. 209 * We also change eflags to be our emulated eflags, not the actual 210 * eflags. 211 */ 212 if (regs->tf_eflags & PSL_VM) { 213 /* XXX confusing names: `tf' isn't a trapframe; `regs' is. */ 214 struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs; 215 struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86; 216 217 sf.sf_siginfo.si_sc.sc_gs = tf->tf_vm86_gs; 218 sf.sf_siginfo.si_sc.sc_fs = tf->tf_vm86_fs; 219 sf.sf_siginfo.si_sc.sc_es = tf->tf_vm86_es; 220 sf.sf_siginfo.si_sc.sc_ds = tf->tf_vm86_ds; 221 222 if (vm86->vm86_has_vme == 0) 223 sf.sf_siginfo.si_sc.sc_ps = 224 (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) | 225 (vm86->vm86_eflags & (PSL_VIF | PSL_VIP)); 226 227 /* See sendsig() for comments. */ 228 tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP); 229 } 230 231 /* 232 * Copy the sigframe out to the user's stack. 233 */ 234 if (copyout(&sf, fp, sizeof(*fp)) != 0) { 235 PROC_LOCK(p); 236 sigexit(td, SIGILL); 237 } 238 239 regs->tf_esp = (int)fp; 240 if (PROC_HAS_SHP(p)) { 241 regs->tf_eip = PROC_SIGCODE(p) + szsigcode - 242 szosigcode; 243 } else { 244 /* a.out sysentvec does not use shared page */ 245 regs->tf_eip = PROC_PS_STRINGS(p) - szosigcode; 246 } 247 regs->tf_eflags &= ~(PSL_T | PSL_D); 248 regs->tf_cs = _ucodesel; 249 regs->tf_ds = _udatasel; 250 regs->tf_es = _udatasel; 251 regs->tf_fs = _udatasel; 252 load_gs(_udatasel); 253 regs->tf_ss = _udatasel; 254 PROC_LOCK(p); 255 mtx_lock(&psp->ps_mtx); 256 } 257 #endif /* COMPAT_43 */ 258 259 #ifdef COMPAT_FREEBSD4 260 static void 261 freebsd4_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 262 { 263 struct freebsd4_sigframe sf, *sfp; 264 struct proc *p; 265 struct thread *td; 266 struct sigacts *psp; 267 struct trapframe *regs; 268 int sig; 269 int oonstack; 270 271 td = curthread; 272 p = td->td_proc; 273 PROC_LOCK_ASSERT(p, MA_OWNED); 274 sig = ksi->ksi_signo; 275 psp = p->p_sigacts; 276 mtx_assert(&psp->ps_mtx, MA_OWNED); 277 regs = td->td_frame; 278 oonstack = sigonstack(regs->tf_esp); 279 280 /* Save user context. */ 281 bzero(&sf, sizeof(sf)); 282 sf.sf_uc.uc_sigmask = *mask; 283 sf.sf_uc.uc_stack = td->td_sigstk; 284 sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 285 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 286 sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0; 287 sf.sf_uc.uc_mcontext.mc_gs = rgs(); 288 bcopy(regs, &sf.sf_uc.uc_mcontext.mc_fs, sizeof(*regs)); 289 bzero(sf.sf_uc.uc_mcontext.mc_fpregs, 290 sizeof(sf.sf_uc.uc_mcontext.mc_fpregs)); 291 bzero(sf.sf_uc.uc_mcontext.__spare__, 292 sizeof(sf.sf_uc.uc_mcontext.__spare__)); 293 bzero(sf.sf_uc.__spare__, sizeof(sf.sf_uc.__spare__)); 294 295 /* Allocate space for the signal handler context. */ 296 if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack && 297 SIGISMEMBER(psp->ps_sigonstack, sig)) { 298 sfp = (struct freebsd4_sigframe *)((uintptr_t)td->td_sigstk.ss_sp + 299 td->td_sigstk.ss_size - sizeof(struct freebsd4_sigframe)); 300 #if defined(COMPAT_43) 301 td->td_sigstk.ss_flags |= SS_ONSTACK; 302 #endif 303 } else 304 sfp = (struct freebsd4_sigframe *)regs->tf_esp - 1; 305 306 /* Build the argument list for the signal handler. */ 307 sf.sf_signum = sig; 308 sf.sf_ucontext = (register_t)&sfp->sf_uc; 309 bzero(&sf.sf_si, sizeof(sf.sf_si)); 310 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 311 /* Signal handler installed with SA_SIGINFO. */ 312 sf.sf_siginfo = (register_t)&sfp->sf_si; 313 sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher; 314 315 /* Fill in POSIX parts */ 316 sf.sf_si.si_signo = sig; 317 sf.sf_si.si_code = ksi->ksi_code; 318 sf.sf_si.si_addr = ksi->ksi_addr; 319 } else { 320 /* Old FreeBSD-style arguments. */ 321 sf.sf_siginfo = ksi->ksi_code; 322 sf.sf_addr = (register_t)ksi->ksi_addr; 323 sf.sf_ahu.sf_handler = catcher; 324 } 325 mtx_unlock(&psp->ps_mtx); 326 PROC_UNLOCK(p); 327 328 /* 329 * If we're a vm86 process, we want to save the segment registers. 330 * We also change eflags to be our emulated eflags, not the actual 331 * eflags. 332 */ 333 if (regs->tf_eflags & PSL_VM) { 334 struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs; 335 struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86; 336 337 sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs; 338 sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs; 339 sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es; 340 sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds; 341 342 if (vm86->vm86_has_vme == 0) 343 sf.sf_uc.uc_mcontext.mc_eflags = 344 (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) | 345 (vm86->vm86_eflags & (PSL_VIF | PSL_VIP)); 346 347 /* 348 * Clear PSL_NT to inhibit T_TSSFLT faults on return from 349 * syscalls made by the signal handler. This just avoids 350 * wasting time for our lazy fixup of such faults. PSL_NT 351 * does nothing in vm86 mode, but vm86 programs can set it 352 * almost legitimately in probes for old cpu types. 353 */ 354 tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP); 355 } 356 357 /* 358 * Copy the sigframe out to the user's stack. 359 */ 360 if (copyout(&sf, sfp, sizeof(*sfp)) != 0) { 361 PROC_LOCK(p); 362 sigexit(td, SIGILL); 363 } 364 365 regs->tf_esp = (int)sfp; 366 regs->tf_eip = PROC_SIGCODE(p) + szsigcode - 367 szfreebsd4_sigcode; 368 regs->tf_eflags &= ~(PSL_T | PSL_D); 369 regs->tf_cs = _ucodesel; 370 regs->tf_ds = _udatasel; 371 regs->tf_es = _udatasel; 372 regs->tf_fs = _udatasel; 373 regs->tf_ss = _udatasel; 374 PROC_LOCK(p); 375 mtx_lock(&psp->ps_mtx); 376 } 377 #endif /* COMPAT_FREEBSD4 */ 378 379 void 380 sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 381 { 382 struct sigframe sf, *sfp; 383 struct proc *p; 384 struct thread *td; 385 struct sigacts *psp; 386 char *sp; 387 struct trapframe *regs; 388 struct segment_descriptor *sdp; 389 char *xfpusave; 390 size_t xfpusave_len; 391 int sig; 392 int oonstack; 393 394 td = curthread; 395 p = td->td_proc; 396 PROC_LOCK_ASSERT(p, MA_OWNED); 397 sig = ksi->ksi_signo; 398 psp = p->p_sigacts; 399 mtx_assert(&psp->ps_mtx, MA_OWNED); 400 #ifdef COMPAT_FREEBSD4 401 if (SIGISMEMBER(psp->ps_freebsd4, sig)) { 402 freebsd4_sendsig(catcher, ksi, mask); 403 return; 404 } 405 #endif 406 #ifdef COMPAT_43 407 if (SIGISMEMBER(psp->ps_osigset, sig)) { 408 osendsig(catcher, ksi, mask); 409 return; 410 } 411 #endif 412 regs = td->td_frame; 413 oonstack = sigonstack(regs->tf_esp); 414 415 if (cpu_max_ext_state_size > sizeof(union savefpu) && use_xsave) { 416 xfpusave_len = cpu_max_ext_state_size - sizeof(union savefpu); 417 xfpusave = __builtin_alloca(xfpusave_len); 418 } else { 419 xfpusave_len = 0; 420 xfpusave = NULL; 421 } 422 423 /* Save user context. */ 424 bzero(&sf, sizeof(sf)); 425 sf.sf_uc.uc_sigmask = *mask; 426 sf.sf_uc.uc_stack = td->td_sigstk; 427 sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 428 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 429 sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0; 430 sf.sf_uc.uc_mcontext.mc_gs = rgs(); 431 bcopy(regs, &sf.sf_uc.uc_mcontext.mc_fs, sizeof(*regs)); 432 sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */ 433 get_fpcontext(td, &sf.sf_uc.uc_mcontext, xfpusave, xfpusave_len); 434 fpstate_drop(td); 435 /* 436 * Unconditionally fill the fsbase and gsbase into the mcontext. 437 */ 438 sdp = &td->td_pcb->pcb_fsd; 439 sf.sf_uc.uc_mcontext.mc_fsbase = sdp->sd_hibase << 24 | 440 sdp->sd_lobase; 441 sdp = &td->td_pcb->pcb_gsd; 442 sf.sf_uc.uc_mcontext.mc_gsbase = sdp->sd_hibase << 24 | 443 sdp->sd_lobase; 444 bzero(sf.sf_uc.uc_mcontext.mc_spare2, 445 sizeof(sf.sf_uc.uc_mcontext.mc_spare2)); 446 447 /* Allocate space for the signal handler context. */ 448 if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack && 449 SIGISMEMBER(psp->ps_sigonstack, sig)) { 450 sp = (char *)td->td_sigstk.ss_sp + td->td_sigstk.ss_size; 451 #if defined(COMPAT_43) 452 td->td_sigstk.ss_flags |= SS_ONSTACK; 453 #endif 454 } else 455 sp = (char *)regs->tf_esp - 128; 456 if (xfpusave != NULL) { 457 sp -= xfpusave_len; 458 sp = (char *)((unsigned int)sp & ~0x3F); 459 sf.sf_uc.uc_mcontext.mc_xfpustate = (register_t)sp; 460 } 461 sp -= sizeof(struct sigframe); 462 463 /* Align to 16 bytes. */ 464 sfp = (struct sigframe *)((unsigned int)sp & ~0xF); 465 466 /* Build the argument list for the signal handler. */ 467 sf.sf_signum = sig; 468 sf.sf_ucontext = (register_t)&sfp->sf_uc; 469 bzero(&sf.sf_si, sizeof(sf.sf_si)); 470 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 471 /* Signal handler installed with SA_SIGINFO. */ 472 sf.sf_siginfo = (register_t)&sfp->sf_si; 473 sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher; 474 475 /* Fill in POSIX parts */ 476 sf.sf_si = ksi->ksi_info; 477 sf.sf_si.si_signo = sig; /* maybe a translated signal */ 478 } else { 479 /* Old FreeBSD-style arguments. */ 480 sf.sf_siginfo = ksi->ksi_code; 481 sf.sf_addr = (register_t)ksi->ksi_addr; 482 sf.sf_ahu.sf_handler = catcher; 483 } 484 mtx_unlock(&psp->ps_mtx); 485 PROC_UNLOCK(p); 486 487 /* 488 * If we're a vm86 process, we want to save the segment registers. 489 * We also change eflags to be our emulated eflags, not the actual 490 * eflags. 491 */ 492 if (regs->tf_eflags & PSL_VM) { 493 struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs; 494 struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86; 495 496 sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs; 497 sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs; 498 sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es; 499 sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds; 500 501 if (vm86->vm86_has_vme == 0) 502 sf.sf_uc.uc_mcontext.mc_eflags = 503 (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) | 504 (vm86->vm86_eflags & (PSL_VIF | PSL_VIP)); 505 506 /* 507 * Clear PSL_NT to inhibit T_TSSFLT faults on return from 508 * syscalls made by the signal handler. This just avoids 509 * wasting time for our lazy fixup of such faults. PSL_NT 510 * does nothing in vm86 mode, but vm86 programs can set it 511 * almost legitimately in probes for old cpu types. 512 */ 513 tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP); 514 } 515 516 /* 517 * Copy the sigframe out to the user's stack. 518 */ 519 if (copyout(&sf, sfp, sizeof(*sfp)) != 0 || 520 (xfpusave != NULL && copyout(xfpusave, 521 (void *)sf.sf_uc.uc_mcontext.mc_xfpustate, xfpusave_len) 522 != 0)) { 523 PROC_LOCK(p); 524 sigexit(td, SIGILL); 525 } 526 527 regs->tf_esp = (int)sfp; 528 regs->tf_eip = PROC_SIGCODE(p); 529 if (regs->tf_eip == 0) 530 regs->tf_eip = PROC_PS_STRINGS(p) - szsigcode; 531 regs->tf_eflags &= ~(PSL_T | PSL_D); 532 regs->tf_cs = _ucodesel; 533 regs->tf_ds = _udatasel; 534 regs->tf_es = _udatasel; 535 regs->tf_fs = _udatasel; 536 regs->tf_ss = _udatasel; 537 PROC_LOCK(p); 538 mtx_lock(&psp->ps_mtx); 539 } 540 541 /* 542 * System call to cleanup state after a signal has been taken. Reset 543 * signal mask and stack state from context left by sendsig (above). 544 * Return to previous pc and psl as specified by context left by 545 * sendsig. Check carefully to make sure that the user has not 546 * modified the state to gain improper privileges. 547 */ 548 #ifdef COMPAT_43 549 int 550 osigreturn(struct thread *td, struct osigreturn_args *uap) 551 { 552 struct osigcontext sc; 553 struct trapframe *regs; 554 struct osigcontext *scp; 555 int eflags, error; 556 ksiginfo_t ksi; 557 558 regs = td->td_frame; 559 error = copyin(uap->sigcntxp, &sc, sizeof(sc)); 560 if (error != 0) 561 return (error); 562 scp = ≻ 563 eflags = scp->sc_ps; 564 if (eflags & PSL_VM) { 565 struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs; 566 struct vm86_kernel *vm86; 567 568 /* 569 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't 570 * set up the vm86 area, and we can't enter vm86 mode. 571 */ 572 if (td->td_pcb->pcb_ext == 0) 573 return (EINVAL); 574 vm86 = &td->td_pcb->pcb_ext->ext_vm86; 575 if (vm86->vm86_inited == 0) 576 return (EINVAL); 577 578 /* Go back to user mode if both flags are set. */ 579 if ((eflags & PSL_VIP) && (eflags & PSL_VIF)) { 580 ksiginfo_init_trap(&ksi); 581 ksi.ksi_signo = SIGBUS; 582 ksi.ksi_code = BUS_OBJERR; 583 ksi.ksi_addr = (void *)regs->tf_eip; 584 trapsignal(td, &ksi); 585 } 586 587 if (vm86->vm86_has_vme) { 588 eflags = (tf->tf_eflags & ~VME_USERCHANGE) | 589 (eflags & VME_USERCHANGE) | PSL_VM; 590 } else { 591 vm86->vm86_eflags = eflags; /* save VIF, VIP */ 592 eflags = (tf->tf_eflags & ~VM_USERCHANGE) | 593 (eflags & VM_USERCHANGE) | PSL_VM; 594 } 595 tf->tf_vm86_ds = scp->sc_ds; 596 tf->tf_vm86_es = scp->sc_es; 597 tf->tf_vm86_fs = scp->sc_fs; 598 tf->tf_vm86_gs = scp->sc_gs; 599 tf->tf_ds = _udatasel; 600 tf->tf_es = _udatasel; 601 tf->tf_fs = _udatasel; 602 } else { 603 /* 604 * Don't allow users to change privileged or reserved flags. 605 */ 606 if (!EFL_SECURE(eflags, regs->tf_eflags)) { 607 return (EINVAL); 608 } 609 610 /* 611 * Don't allow users to load a valid privileged %cs. Let the 612 * hardware check for invalid selectors, excess privilege in 613 * other selectors, invalid %eip's and invalid %esp's. 614 */ 615 if (!CS_SECURE(scp->sc_cs)) { 616 ksiginfo_init_trap(&ksi); 617 ksi.ksi_signo = SIGBUS; 618 ksi.ksi_code = BUS_OBJERR; 619 ksi.ksi_trapno = T_PROTFLT; 620 ksi.ksi_addr = (void *)regs->tf_eip; 621 trapsignal(td, &ksi); 622 return (EINVAL); 623 } 624 regs->tf_ds = scp->sc_ds; 625 regs->tf_es = scp->sc_es; 626 regs->tf_fs = scp->sc_fs; 627 } 628 629 /* Restore remaining registers. */ 630 regs->tf_eax = scp->sc_eax; 631 regs->tf_ebx = scp->sc_ebx; 632 regs->tf_ecx = scp->sc_ecx; 633 regs->tf_edx = scp->sc_edx; 634 regs->tf_esi = scp->sc_esi; 635 regs->tf_edi = scp->sc_edi; 636 regs->tf_cs = scp->sc_cs; 637 regs->tf_ss = scp->sc_ss; 638 regs->tf_isp = scp->sc_isp; 639 regs->tf_ebp = scp->sc_fp; 640 regs->tf_esp = scp->sc_sp; 641 regs->tf_eip = scp->sc_pc; 642 regs->tf_eflags = eflags; 643 regs->tf_trapno = T_RESERVED; 644 645 #if defined(COMPAT_43) 646 if (scp->sc_onstack & 1) 647 td->td_sigstk.ss_flags |= SS_ONSTACK; 648 else 649 td->td_sigstk.ss_flags &= ~SS_ONSTACK; 650 #endif 651 kern_sigprocmask(td, SIG_SETMASK, (sigset_t *)&scp->sc_mask, NULL, 652 SIGPROCMASK_OLD); 653 return (EJUSTRETURN); 654 } 655 #endif /* COMPAT_43 */ 656 657 #ifdef COMPAT_FREEBSD4 658 int 659 freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap) 660 { 661 struct freebsd4_ucontext uc; 662 struct trapframe *regs; 663 struct freebsd4_ucontext *ucp; 664 int cs, eflags, error; 665 ksiginfo_t ksi; 666 667 error = copyin(uap->sigcntxp, &uc, sizeof(uc)); 668 if (error != 0) 669 return (error); 670 ucp = &uc; 671 regs = td->td_frame; 672 eflags = ucp->uc_mcontext.mc_eflags; 673 if (eflags & PSL_VM) { 674 struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs; 675 struct vm86_kernel *vm86; 676 677 /* 678 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't 679 * set up the vm86 area, and we can't enter vm86 mode. 680 */ 681 if (td->td_pcb->pcb_ext == 0) 682 return (EINVAL); 683 vm86 = &td->td_pcb->pcb_ext->ext_vm86; 684 if (vm86->vm86_inited == 0) 685 return (EINVAL); 686 687 /* Go back to user mode if both flags are set. */ 688 if ((eflags & PSL_VIP) && (eflags & PSL_VIF)) { 689 ksiginfo_init_trap(&ksi); 690 ksi.ksi_signo = SIGBUS; 691 ksi.ksi_code = BUS_OBJERR; 692 ksi.ksi_addr = (void *)regs->tf_eip; 693 trapsignal(td, &ksi); 694 } 695 if (vm86->vm86_has_vme) { 696 eflags = (tf->tf_eflags & ~VME_USERCHANGE) | 697 (eflags & VME_USERCHANGE) | PSL_VM; 698 } else { 699 vm86->vm86_eflags = eflags; /* save VIF, VIP */ 700 eflags = (tf->tf_eflags & ~VM_USERCHANGE) | 701 (eflags & VM_USERCHANGE) | PSL_VM; 702 } 703 bcopy(&ucp->uc_mcontext.mc_fs, tf, sizeof(struct trapframe)); 704 tf->tf_eflags = eflags; 705 tf->tf_vm86_ds = tf->tf_ds; 706 tf->tf_vm86_es = tf->tf_es; 707 tf->tf_vm86_fs = tf->tf_fs; 708 tf->tf_vm86_gs = ucp->uc_mcontext.mc_gs; 709 tf->tf_ds = _udatasel; 710 tf->tf_es = _udatasel; 711 tf->tf_fs = _udatasel; 712 } else { 713 /* 714 * Don't allow users to change privileged or reserved flags. 715 */ 716 if (!EFL_SECURE(eflags, regs->tf_eflags)) { 717 uprintf( 718 "pid %d (%s): freebsd4_sigreturn eflags = 0x%x\n", 719 td->td_proc->p_pid, td->td_name, eflags); 720 return (EINVAL); 721 } 722 723 /* 724 * Don't allow users to load a valid privileged %cs. Let the 725 * hardware check for invalid selectors, excess privilege in 726 * other selectors, invalid %eip's and invalid %esp's. 727 */ 728 cs = ucp->uc_mcontext.mc_cs; 729 if (!CS_SECURE(cs)) { 730 uprintf("pid %d (%s): freebsd4_sigreturn cs = 0x%x\n", 731 td->td_proc->p_pid, td->td_name, cs); 732 ksiginfo_init_trap(&ksi); 733 ksi.ksi_signo = SIGBUS; 734 ksi.ksi_code = BUS_OBJERR; 735 ksi.ksi_trapno = T_PROTFLT; 736 ksi.ksi_addr = (void *)regs->tf_eip; 737 trapsignal(td, &ksi); 738 return (EINVAL); 739 } 740 741 bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs)); 742 } 743 regs->tf_trapno = T_RESERVED; 744 745 #if defined(COMPAT_43) 746 if (ucp->uc_mcontext.mc_onstack & 1) 747 td->td_sigstk.ss_flags |= SS_ONSTACK; 748 else 749 td->td_sigstk.ss_flags &= ~SS_ONSTACK; 750 #endif 751 kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0); 752 return (EJUSTRETURN); 753 } 754 #endif /* COMPAT_FREEBSD4 */ 755 756 int 757 sys_sigreturn(struct thread *td, struct sigreturn_args *uap) 758 { 759 ucontext_t uc; 760 struct proc *p; 761 struct trapframe *regs; 762 ucontext_t *ucp; 763 char *xfpustate; 764 size_t xfpustate_len; 765 int cs, eflags, error, ret; 766 ksiginfo_t ksi; 767 768 p = td->td_proc; 769 770 error = copyin(uap->sigcntxp, &uc, sizeof(uc)); 771 if (error != 0) 772 return (error); 773 ucp = &uc; 774 if ((ucp->uc_mcontext.mc_flags & ~_MC_FLAG_MASK) != 0) { 775 uprintf("pid %d (%s): sigreturn mc_flags %x\n", p->p_pid, 776 td->td_name, ucp->uc_mcontext.mc_flags); 777 return (EINVAL); 778 } 779 regs = td->td_frame; 780 eflags = ucp->uc_mcontext.mc_eflags; 781 if (eflags & PSL_VM) { 782 struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs; 783 struct vm86_kernel *vm86; 784 785 /* 786 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't 787 * set up the vm86 area, and we can't enter vm86 mode. 788 */ 789 if (td->td_pcb->pcb_ext == 0) 790 return (EINVAL); 791 vm86 = &td->td_pcb->pcb_ext->ext_vm86; 792 if (vm86->vm86_inited == 0) 793 return (EINVAL); 794 795 /* Go back to user mode if both flags are set. */ 796 if ((eflags & PSL_VIP) && (eflags & PSL_VIF)) { 797 ksiginfo_init_trap(&ksi); 798 ksi.ksi_signo = SIGBUS; 799 ksi.ksi_code = BUS_OBJERR; 800 ksi.ksi_addr = (void *)regs->tf_eip; 801 trapsignal(td, &ksi); 802 } 803 804 if (vm86->vm86_has_vme) { 805 eflags = (tf->tf_eflags & ~VME_USERCHANGE) | 806 (eflags & VME_USERCHANGE) | PSL_VM; 807 } else { 808 vm86->vm86_eflags = eflags; /* save VIF, VIP */ 809 eflags = (tf->tf_eflags & ~VM_USERCHANGE) | 810 (eflags & VM_USERCHANGE) | PSL_VM; 811 } 812 bcopy(&ucp->uc_mcontext.mc_fs, tf, sizeof(struct trapframe)); 813 tf->tf_eflags = eflags; 814 tf->tf_vm86_ds = tf->tf_ds; 815 tf->tf_vm86_es = tf->tf_es; 816 tf->tf_vm86_fs = tf->tf_fs; 817 tf->tf_vm86_gs = ucp->uc_mcontext.mc_gs; 818 tf->tf_ds = _udatasel; 819 tf->tf_es = _udatasel; 820 tf->tf_fs = _udatasel; 821 } else { 822 /* 823 * Don't allow users to change privileged or reserved flags. 824 */ 825 if (!EFL_SECURE(eflags, regs->tf_eflags)) { 826 uprintf("pid %d (%s): sigreturn eflags = 0x%x\n", 827 td->td_proc->p_pid, td->td_name, eflags); 828 return (EINVAL); 829 } 830 831 /* 832 * Don't allow users to load a valid privileged %cs. Let the 833 * hardware check for invalid selectors, excess privilege in 834 * other selectors, invalid %eip's and invalid %esp's. 835 */ 836 cs = ucp->uc_mcontext.mc_cs; 837 if (!CS_SECURE(cs)) { 838 uprintf("pid %d (%s): sigreturn cs = 0x%x\n", 839 td->td_proc->p_pid, td->td_name, cs); 840 ksiginfo_init_trap(&ksi); 841 ksi.ksi_signo = SIGBUS; 842 ksi.ksi_code = BUS_OBJERR; 843 ksi.ksi_trapno = T_PROTFLT; 844 ksi.ksi_addr = (void *)regs->tf_eip; 845 trapsignal(td, &ksi); 846 return (EINVAL); 847 } 848 849 if ((uc.uc_mcontext.mc_flags & _MC_HASFPXSTATE) != 0) { 850 xfpustate_len = uc.uc_mcontext.mc_xfpustate_len; 851 if (xfpustate_len > cpu_max_ext_state_size - 852 sizeof(union savefpu)) { 853 uprintf( 854 "pid %d (%s): sigreturn xfpusave_len = 0x%zx\n", 855 p->p_pid, td->td_name, xfpustate_len); 856 return (EINVAL); 857 } 858 xfpustate = __builtin_alloca(xfpustate_len); 859 error = copyin( 860 (const void *)uc.uc_mcontext.mc_xfpustate, 861 xfpustate, xfpustate_len); 862 if (error != 0) { 863 uprintf( 864 "pid %d (%s): sigreturn copying xfpustate failed\n", 865 p->p_pid, td->td_name); 866 return (error); 867 } 868 } else { 869 xfpustate = NULL; 870 xfpustate_len = 0; 871 } 872 ret = set_fpcontext(td, &ucp->uc_mcontext, xfpustate, 873 xfpustate_len); 874 if (ret != 0) 875 return (ret); 876 bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs)); 877 } 878 regs->tf_trapno = T_RESERVED; 879 880 #if defined(COMPAT_43) 881 if (ucp->uc_mcontext.mc_onstack & 1) 882 td->td_sigstk.ss_flags |= SS_ONSTACK; 883 else 884 td->td_sigstk.ss_flags &= ~SS_ONSTACK; 885 #endif 886 887 kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0); 888 return (EJUSTRETURN); 889 } 890 891 /* 892 * Reset the hardware debug registers if they were in use. 893 * They won't have any meaning for the newly exec'd process. 894 */ 895 void 896 x86_clear_dbregs(struct pcb *pcb) 897 { 898 if ((pcb->pcb_flags & PCB_DBREGS) == 0) 899 return; 900 901 pcb->pcb_dr0 = 0; 902 pcb->pcb_dr1 = 0; 903 pcb->pcb_dr2 = 0; 904 pcb->pcb_dr3 = 0; 905 pcb->pcb_dr6 = 0; 906 pcb->pcb_dr7 = 0; 907 908 if (pcb == curpcb) { 909 /* 910 * Clear the debug registers on the running CPU, 911 * otherwise they will end up affecting the next 912 * process we switch to. 913 */ 914 reset_dbregs(); 915 } 916 pcb->pcb_flags &= ~PCB_DBREGS; 917 } 918 919 #ifdef COMPAT_43 920 static void 921 setup_priv_lcall_gate(struct proc *p) 922 { 923 struct i386_ldt_args uap; 924 union descriptor desc; 925 u_int lcall_addr; 926 927 bzero(&uap, sizeof(uap)); 928 uap.start = 0; 929 uap.num = 1; 930 lcall_addr = p->p_sysent->sv_psstrings - sz_lcall_tramp; 931 bzero(&desc, sizeof(desc)); 932 desc.sd.sd_type = SDT_MEMERA; 933 desc.sd.sd_dpl = SEL_UPL; 934 desc.sd.sd_p = 1; 935 desc.sd.sd_def32 = 1; 936 desc.sd.sd_gran = 1; 937 desc.sd.sd_lolimit = 0xffff; 938 desc.sd.sd_hilimit = 0xf; 939 desc.sd.sd_lobase = lcall_addr; 940 desc.sd.sd_hibase = lcall_addr >> 24; 941 i386_set_ldt(curthread, &uap, &desc); 942 } 943 #endif 944 945 /* 946 * Reset registers to default values on exec. 947 */ 948 void 949 exec_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack) 950 { 951 struct trapframe *regs; 952 struct pcb *pcb; 953 register_t saved_eflags; 954 955 regs = td->td_frame; 956 pcb = td->td_pcb; 957 958 /* Reset pc->pcb_gs and %gs before possibly invalidating it. */ 959 pcb->pcb_gs = _udatasel; 960 load_gs(_udatasel); 961 962 mtx_lock_spin(&dt_lock); 963 if (td->td_proc->p_md.md_ldt != NULL) 964 user_ldt_free(td); 965 else 966 mtx_unlock_spin(&dt_lock); 967 968 #ifdef COMPAT_43 969 if (td->td_proc->p_sysent->sv_psstrings != 970 elf32_freebsd_sysvec.sv_psstrings) 971 setup_priv_lcall_gate(td->td_proc); 972 #endif 973 974 /* 975 * Reset the fs and gs bases. The values from the old address 976 * space do not make sense for the new program. In particular, 977 * gsbase might be the TLS base for the old program but the new 978 * program has no TLS now. 979 */ 980 set_fsbase(td, 0); 981 set_gsbase(td, 0); 982 983 /* Make sure edx is 0x0 on entry. Linux binaries depend on it. */ 984 saved_eflags = regs->tf_eflags & PSL_T; 985 bzero((char *)regs, sizeof(struct trapframe)); 986 regs->tf_eip = imgp->entry_addr; 987 regs->tf_esp = stack; 988 regs->tf_eflags = PSL_USER | saved_eflags; 989 regs->tf_ss = _udatasel; 990 regs->tf_ds = _udatasel; 991 regs->tf_es = _udatasel; 992 regs->tf_fs = _udatasel; 993 regs->tf_cs = _ucodesel; 994 995 /* PS_STRINGS value for BSD/OS binaries. It is 0 for non-BSD/OS. */ 996 regs->tf_ebx = (register_t)imgp->ps_strings; 997 998 x86_clear_dbregs(pcb); 999 1000 pcb->pcb_initial_npxcw = __INITIAL_NPXCW__; 1001 1002 /* 1003 * Drop the FP state if we hold it, so that the process gets a 1004 * clean FP state if it uses the FPU again. 1005 */ 1006 fpstate_drop(td); 1007 } 1008 1009 int 1010 fill_regs(struct thread *td, struct reg *regs) 1011 { 1012 struct pcb *pcb; 1013 struct trapframe *tp; 1014 1015 tp = td->td_frame; 1016 pcb = td->td_pcb; 1017 regs->r_gs = pcb->pcb_gs; 1018 return (fill_frame_regs(tp, regs)); 1019 } 1020 1021 int 1022 fill_frame_regs(struct trapframe *tp, struct reg *regs) 1023 { 1024 1025 regs->r_fs = tp->tf_fs; 1026 regs->r_es = tp->tf_es; 1027 regs->r_ds = tp->tf_ds; 1028 regs->r_edi = tp->tf_edi; 1029 regs->r_esi = tp->tf_esi; 1030 regs->r_ebp = tp->tf_ebp; 1031 regs->r_ebx = tp->tf_ebx; 1032 regs->r_edx = tp->tf_edx; 1033 regs->r_ecx = tp->tf_ecx; 1034 regs->r_eax = tp->tf_eax; 1035 regs->r_eip = tp->tf_eip; 1036 regs->r_cs = tp->tf_cs; 1037 regs->r_eflags = tp->tf_eflags; 1038 regs->r_esp = tp->tf_esp; 1039 regs->r_ss = tp->tf_ss; 1040 regs->r_err = 0; 1041 regs->r_trapno = 0; 1042 return (0); 1043 } 1044 1045 int 1046 set_regs(struct thread *td, struct reg *regs) 1047 { 1048 struct pcb *pcb; 1049 struct trapframe *tp; 1050 1051 tp = td->td_frame; 1052 if (!EFL_SECURE(regs->r_eflags, tp->tf_eflags) || 1053 !CS_SECURE(regs->r_cs)) 1054 return (EINVAL); 1055 pcb = td->td_pcb; 1056 tp->tf_fs = regs->r_fs; 1057 tp->tf_es = regs->r_es; 1058 tp->tf_ds = regs->r_ds; 1059 tp->tf_edi = regs->r_edi; 1060 tp->tf_esi = regs->r_esi; 1061 tp->tf_ebp = regs->r_ebp; 1062 tp->tf_ebx = regs->r_ebx; 1063 tp->tf_edx = regs->r_edx; 1064 tp->tf_ecx = regs->r_ecx; 1065 tp->tf_eax = regs->r_eax; 1066 tp->tf_eip = regs->r_eip; 1067 tp->tf_cs = regs->r_cs; 1068 tp->tf_eflags = regs->r_eflags; 1069 tp->tf_esp = regs->r_esp; 1070 tp->tf_ss = regs->r_ss; 1071 pcb->pcb_gs = regs->r_gs; 1072 return (0); 1073 } 1074 1075 int 1076 fill_fpregs(struct thread *td, struct fpreg *fpregs) 1077 { 1078 1079 KASSERT(td == curthread || TD_IS_SUSPENDED(td) || 1080 P_SHOULDSTOP(td->td_proc), 1081 ("not suspended thread %p", td)); 1082 npxgetregs(td); 1083 if (cpu_fxsr) 1084 npx_fill_fpregs_xmm(&get_pcb_user_save_td(td)->sv_xmm, 1085 (struct save87 *)fpregs); 1086 else 1087 bcopy(&get_pcb_user_save_td(td)->sv_87, fpregs, 1088 sizeof(*fpregs)); 1089 return (0); 1090 } 1091 1092 int 1093 set_fpregs(struct thread *td, struct fpreg *fpregs) 1094 { 1095 1096 critical_enter(); 1097 if (cpu_fxsr) 1098 npx_set_fpregs_xmm((struct save87 *)fpregs, 1099 &get_pcb_user_save_td(td)->sv_xmm); 1100 else 1101 bcopy(fpregs, &get_pcb_user_save_td(td)->sv_87, 1102 sizeof(*fpregs)); 1103 npxuserinited(td); 1104 critical_exit(); 1105 return (0); 1106 } 1107 1108 /* 1109 * Get machine context. 1110 */ 1111 int 1112 get_mcontext(struct thread *td, mcontext_t *mcp, int flags) 1113 { 1114 struct trapframe *tp; 1115 struct segment_descriptor *sdp; 1116 1117 tp = td->td_frame; 1118 1119 PROC_LOCK(curthread->td_proc); 1120 mcp->mc_onstack = sigonstack(tp->tf_esp); 1121 PROC_UNLOCK(curthread->td_proc); 1122 mcp->mc_gs = td->td_pcb->pcb_gs; 1123 mcp->mc_fs = tp->tf_fs; 1124 mcp->mc_es = tp->tf_es; 1125 mcp->mc_ds = tp->tf_ds; 1126 mcp->mc_edi = tp->tf_edi; 1127 mcp->mc_esi = tp->tf_esi; 1128 mcp->mc_ebp = tp->tf_ebp; 1129 mcp->mc_isp = tp->tf_isp; 1130 mcp->mc_eflags = tp->tf_eflags; 1131 if (flags & GET_MC_CLEAR_RET) { 1132 mcp->mc_eax = 0; 1133 mcp->mc_edx = 0; 1134 mcp->mc_eflags &= ~PSL_C; 1135 } else { 1136 mcp->mc_eax = tp->tf_eax; 1137 mcp->mc_edx = tp->tf_edx; 1138 } 1139 mcp->mc_ebx = tp->tf_ebx; 1140 mcp->mc_ecx = tp->tf_ecx; 1141 mcp->mc_eip = tp->tf_eip; 1142 mcp->mc_cs = tp->tf_cs; 1143 mcp->mc_esp = tp->tf_esp; 1144 mcp->mc_ss = tp->tf_ss; 1145 mcp->mc_len = sizeof(*mcp); 1146 get_fpcontext(td, mcp, NULL, 0); 1147 sdp = &td->td_pcb->pcb_fsd; 1148 mcp->mc_fsbase = sdp->sd_hibase << 24 | sdp->sd_lobase; 1149 sdp = &td->td_pcb->pcb_gsd; 1150 mcp->mc_gsbase = sdp->sd_hibase << 24 | sdp->sd_lobase; 1151 mcp->mc_flags = 0; 1152 mcp->mc_xfpustate = 0; 1153 mcp->mc_xfpustate_len = 0; 1154 bzero(mcp->mc_spare2, sizeof(mcp->mc_spare2)); 1155 return (0); 1156 } 1157 1158 /* 1159 * Set machine context. 1160 * 1161 * However, we don't set any but the user modifiable flags, and we won't 1162 * touch the cs selector. 1163 */ 1164 int 1165 set_mcontext(struct thread *td, mcontext_t *mcp) 1166 { 1167 struct trapframe *tp; 1168 char *xfpustate; 1169 int eflags, ret; 1170 1171 tp = td->td_frame; 1172 if (mcp->mc_len != sizeof(*mcp) || 1173 (mcp->mc_flags & ~_MC_FLAG_MASK) != 0) 1174 return (EINVAL); 1175 eflags = (mcp->mc_eflags & PSL_USERCHANGE) | 1176 (tp->tf_eflags & ~PSL_USERCHANGE); 1177 if (mcp->mc_flags & _MC_HASFPXSTATE) { 1178 if (mcp->mc_xfpustate_len > cpu_max_ext_state_size - 1179 sizeof(union savefpu)) 1180 return (EINVAL); 1181 xfpustate = __builtin_alloca(mcp->mc_xfpustate_len); 1182 ret = copyin((void *)mcp->mc_xfpustate, xfpustate, 1183 mcp->mc_xfpustate_len); 1184 if (ret != 0) 1185 return (ret); 1186 } else 1187 xfpustate = NULL; 1188 ret = set_fpcontext(td, mcp, xfpustate, mcp->mc_xfpustate_len); 1189 if (ret != 0) 1190 return (ret); 1191 tp->tf_fs = mcp->mc_fs; 1192 tp->tf_es = mcp->mc_es; 1193 tp->tf_ds = mcp->mc_ds; 1194 tp->tf_edi = mcp->mc_edi; 1195 tp->tf_esi = mcp->mc_esi; 1196 tp->tf_ebp = mcp->mc_ebp; 1197 tp->tf_ebx = mcp->mc_ebx; 1198 tp->tf_edx = mcp->mc_edx; 1199 tp->tf_ecx = mcp->mc_ecx; 1200 tp->tf_eax = mcp->mc_eax; 1201 tp->tf_eip = mcp->mc_eip; 1202 tp->tf_eflags = eflags; 1203 tp->tf_esp = mcp->mc_esp; 1204 tp->tf_ss = mcp->mc_ss; 1205 td->td_pcb->pcb_gs = mcp->mc_gs; 1206 return (0); 1207 } 1208 1209 static void 1210 get_fpcontext(struct thread *td, mcontext_t *mcp, char *xfpusave, 1211 size_t xfpusave_len) 1212 { 1213 size_t max_len, len; 1214 1215 mcp->mc_ownedfp = npxgetregs(td); 1216 bcopy(get_pcb_user_save_td(td), &mcp->mc_fpstate[0], 1217 sizeof(mcp->mc_fpstate)); 1218 mcp->mc_fpformat = npxformat(); 1219 if (!use_xsave || xfpusave_len == 0) 1220 return; 1221 max_len = cpu_max_ext_state_size - sizeof(union savefpu); 1222 len = xfpusave_len; 1223 if (len > max_len) { 1224 len = max_len; 1225 bzero(xfpusave + max_len, len - max_len); 1226 } 1227 mcp->mc_flags |= _MC_HASFPXSTATE; 1228 mcp->mc_xfpustate_len = len; 1229 bcopy(get_pcb_user_save_td(td) + 1, xfpusave, len); 1230 } 1231 1232 static int 1233 set_fpcontext(struct thread *td, mcontext_t *mcp, char *xfpustate, 1234 size_t xfpustate_len) 1235 { 1236 int error; 1237 1238 if (mcp->mc_fpformat == _MC_FPFMT_NODEV) 1239 return (0); 1240 else if (mcp->mc_fpformat != _MC_FPFMT_387 && 1241 mcp->mc_fpformat != _MC_FPFMT_XMM) 1242 return (EINVAL); 1243 else if (mcp->mc_ownedfp == _MC_FPOWNED_NONE) { 1244 /* We don't care what state is left in the FPU or PCB. */ 1245 fpstate_drop(td); 1246 error = 0; 1247 } else if (mcp->mc_ownedfp == _MC_FPOWNED_FPU || 1248 mcp->mc_ownedfp == _MC_FPOWNED_PCB) { 1249 error = npxsetregs(td, (union savefpu *)&mcp->mc_fpstate, 1250 xfpustate, xfpustate_len); 1251 } else 1252 return (EINVAL); 1253 return (error); 1254 } 1255 1256 static void 1257 fpstate_drop(struct thread *td) 1258 { 1259 1260 KASSERT(PCB_USER_FPU(td->td_pcb), ("fpstate_drop: kernel-owned fpu")); 1261 critical_enter(); 1262 if (PCPU_GET(fpcurthread) == td) 1263 npxdrop(); 1264 /* 1265 * XXX force a full drop of the npx. The above only drops it if we 1266 * owned it. npxgetregs() has the same bug in the !cpu_fxsr case. 1267 * 1268 * XXX I don't much like npxgetregs()'s semantics of doing a full 1269 * drop. Dropping only to the pcb matches fnsave's behaviour. 1270 * We only need to drop to !PCB_INITDONE in sendsig(). But 1271 * sendsig() is the only caller of npxgetregs()... perhaps we just 1272 * have too many layers. 1273 */ 1274 curthread->td_pcb->pcb_flags &= ~(PCB_NPXINITDONE | 1275 PCB_NPXUSERINITDONE); 1276 critical_exit(); 1277 } 1278 1279 int 1280 fill_dbregs(struct thread *td, struct dbreg *dbregs) 1281 { 1282 struct pcb *pcb; 1283 1284 if (td == NULL) { 1285 dbregs->dr[0] = rdr0(); 1286 dbregs->dr[1] = rdr1(); 1287 dbregs->dr[2] = rdr2(); 1288 dbregs->dr[3] = rdr3(); 1289 dbregs->dr[6] = rdr6(); 1290 dbregs->dr[7] = rdr7(); 1291 } else { 1292 pcb = td->td_pcb; 1293 dbregs->dr[0] = pcb->pcb_dr0; 1294 dbregs->dr[1] = pcb->pcb_dr1; 1295 dbregs->dr[2] = pcb->pcb_dr2; 1296 dbregs->dr[3] = pcb->pcb_dr3; 1297 dbregs->dr[6] = pcb->pcb_dr6; 1298 dbregs->dr[7] = pcb->pcb_dr7; 1299 } 1300 dbregs->dr[4] = 0; 1301 dbregs->dr[5] = 0; 1302 return (0); 1303 } 1304 1305 int 1306 set_dbregs(struct thread *td, struct dbreg *dbregs) 1307 { 1308 struct pcb *pcb; 1309 int i; 1310 1311 if (td == NULL) { 1312 load_dr0(dbregs->dr[0]); 1313 load_dr1(dbregs->dr[1]); 1314 load_dr2(dbregs->dr[2]); 1315 load_dr3(dbregs->dr[3]); 1316 load_dr6(dbregs->dr[6]); 1317 load_dr7(dbregs->dr[7]); 1318 } else { 1319 /* 1320 * Don't let an illegal value for dr7 get set. Specifically, 1321 * check for undefined settings. Setting these bit patterns 1322 * result in undefined behaviour and can lead to an unexpected 1323 * TRCTRAP. 1324 */ 1325 for (i = 0; i < 4; i++) { 1326 if (DBREG_DR7_ACCESS(dbregs->dr[7], i) == 0x02) 1327 return (EINVAL); 1328 if (DBREG_DR7_LEN(dbregs->dr[7], i) == 0x02) 1329 return (EINVAL); 1330 } 1331 1332 pcb = td->td_pcb; 1333 1334 /* 1335 * Don't let a process set a breakpoint that is not within the 1336 * process's address space. If a process could do this, it 1337 * could halt the system by setting a breakpoint in the kernel 1338 * (if ddb was enabled). Thus, we need to check to make sure 1339 * that no breakpoints are being enabled for addresses outside 1340 * process's address space. 1341 * 1342 * XXX - what about when the watched area of the user's 1343 * address space is written into from within the kernel 1344 * ... wouldn't that still cause a breakpoint to be generated 1345 * from within kernel mode? 1346 */ 1347 1348 if (DBREG_DR7_ENABLED(dbregs->dr[7], 0)) { 1349 /* dr0 is enabled */ 1350 if (dbregs->dr[0] >= VM_MAXUSER_ADDRESS) 1351 return (EINVAL); 1352 } 1353 1354 if (DBREG_DR7_ENABLED(dbregs->dr[7], 1)) { 1355 /* dr1 is enabled */ 1356 if (dbregs->dr[1] >= VM_MAXUSER_ADDRESS) 1357 return (EINVAL); 1358 } 1359 1360 if (DBREG_DR7_ENABLED(dbregs->dr[7], 2)) { 1361 /* dr2 is enabled */ 1362 if (dbregs->dr[2] >= VM_MAXUSER_ADDRESS) 1363 return (EINVAL); 1364 } 1365 1366 if (DBREG_DR7_ENABLED(dbregs->dr[7], 3)) { 1367 /* dr3 is enabled */ 1368 if (dbregs->dr[3] >= VM_MAXUSER_ADDRESS) 1369 return (EINVAL); 1370 } 1371 1372 pcb->pcb_dr0 = dbregs->dr[0]; 1373 pcb->pcb_dr1 = dbregs->dr[1]; 1374 pcb->pcb_dr2 = dbregs->dr[2]; 1375 pcb->pcb_dr3 = dbregs->dr[3]; 1376 pcb->pcb_dr6 = dbregs->dr[6]; 1377 pcb->pcb_dr7 = dbregs->dr[7]; 1378 1379 pcb->pcb_flags |= PCB_DBREGS; 1380 } 1381 1382 return (0); 1383 } 1384 1385 /* 1386 * Return > 0 if a hardware breakpoint has been hit, and the 1387 * breakpoint was in user space. Return 0, otherwise. 1388 */ 1389 int 1390 user_dbreg_trap(register_t dr6) 1391 { 1392 u_int32_t dr7; 1393 u_int32_t bp; /* breakpoint bits extracted from dr6 */ 1394 int nbp; /* number of breakpoints that triggered */ 1395 caddr_t addr[4]; /* breakpoint addresses */ 1396 int i; 1397 1398 bp = dr6 & DBREG_DR6_BMASK; 1399 if (bp == 0) { 1400 /* 1401 * None of the breakpoint bits are set meaning this 1402 * trap was not caused by any of the debug registers 1403 */ 1404 return (0); 1405 } 1406 1407 dr7 = rdr7(); 1408 if ((dr7 & 0x000000ff) == 0) { 1409 /* 1410 * all GE and LE bits in the dr7 register are zero, 1411 * thus the trap couldn't have been caused by the 1412 * hardware debug registers 1413 */ 1414 return (0); 1415 } 1416 1417 nbp = 0; 1418 1419 /* 1420 * at least one of the breakpoints were hit, check to see 1421 * which ones and if any of them are user space addresses 1422 */ 1423 1424 if (bp & 0x01) { 1425 addr[nbp++] = (caddr_t)rdr0(); 1426 } 1427 if (bp & 0x02) { 1428 addr[nbp++] = (caddr_t)rdr1(); 1429 } 1430 if (bp & 0x04) { 1431 addr[nbp++] = (caddr_t)rdr2(); 1432 } 1433 if (bp & 0x08) { 1434 addr[nbp++] = (caddr_t)rdr3(); 1435 } 1436 1437 for (i = 0; i < nbp; i++) { 1438 if (addr[i] < (caddr_t)VM_MAXUSER_ADDRESS) { 1439 /* 1440 * addr[i] is in user space 1441 */ 1442 return (nbp); 1443 } 1444 } 1445 1446 /* 1447 * None of the breakpoints are in user space. 1448 */ 1449 return (0); 1450 }
Cache object: 5215cbbfd818b488bdcee4486e66f41e
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