Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/linux/linux_sysvec.c
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1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1994-1996 Søren Schmidt 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/exec.h> 35 #include <sys/fcntl.h> 36 #include <sys/imgact.h> 37 #include <sys/imgact_aout.h> 38 #include <sys/imgact_elf.h> 39 #include <sys/kernel.h> 40 #include <sys/lock.h> 41 #include <sys/malloc.h> 42 #include <sys/module.h> 43 #include <sys/mutex.h> 44 #include <sys/proc.h> 45 #include <sys/signalvar.h> 46 #include <sys/syscallsubr.h> 47 #include <sys/sysctl.h> 48 #include <sys/sysent.h> 49 #include <sys/sysproto.h> 50 #include <sys/vnode.h> 51 #include <sys/eventhandler.h> 52 53 #include <vm/vm.h> 54 #include <vm/pmap.h> 55 #include <vm/vm_extern.h> 56 #include <vm/vm_map.h> 57 #include <vm/vm_object.h> 58 #include <vm/vm_page.h> 59 #include <vm/vm_param.h> 60 61 #include <machine/cpu.h> 62 #include <machine/cputypes.h> 63 #include <machine/md_var.h> 64 #include <machine/pcb.h> 65 #include <machine/trap.h> 66 67 #include <i386/linux/linux.h> 68 #include <i386/linux/linux_proto.h> 69 #include <compat/linux/linux_emul.h> 70 #include <compat/linux/linux_ioctl.h> 71 #include <compat/linux/linux_mib.h> 72 #include <compat/linux/linux_misc.h> 73 #include <compat/linux/linux_signal.h> 74 #include <compat/linux/linux_util.h> 75 #include <compat/linux/linux_vdso.h> 76 77 MODULE_VERSION(linux, 1); 78 79 #define LINUX_PS_STRINGS (LINUX_USRSTACK - sizeof(struct ps_strings)) 80 81 static int linux_szsigcode; 82 static vm_object_t linux_shared_page_obj; 83 static char *linux_shared_page_mapping; 84 extern char _binary_linux_locore_o_start; 85 extern char _binary_linux_locore_o_end; 86 87 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL]; 88 89 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler); 90 91 static int linux_fixup(register_t **stack_base, 92 struct image_params *iparams); 93 static int linux_fixup_elf(register_t **stack_base, 94 struct image_params *iparams); 95 static void linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask); 96 static void linux_exec_setregs(struct thread *td, 97 struct image_params *imgp, u_long stack); 98 static register_t *linux_copyout_strings(struct image_params *imgp); 99 static bool linux_trans_osrel(const Elf_Note *note, int32_t *osrel); 100 static void linux_vdso_install(void *param); 101 static void linux_vdso_deinstall(void *param); 102 103 static int linux_szplatform; 104 const char *linux_kplatform; 105 106 static eventhandler_tag linux_exit_tag; 107 static eventhandler_tag linux_exec_tag; 108 static eventhandler_tag linux_thread_dtor_tag; 109 110 #define LINUX_T_UNKNOWN 255 111 static int _bsd_to_linux_trapcode[] = { 112 LINUX_T_UNKNOWN, /* 0 */ 113 6, /* 1 T_PRIVINFLT */ 114 LINUX_T_UNKNOWN, /* 2 */ 115 3, /* 3 T_BPTFLT */ 116 LINUX_T_UNKNOWN, /* 4 */ 117 LINUX_T_UNKNOWN, /* 5 */ 118 16, /* 6 T_ARITHTRAP */ 119 254, /* 7 T_ASTFLT */ 120 LINUX_T_UNKNOWN, /* 8 */ 121 13, /* 9 T_PROTFLT */ 122 1, /* 10 T_TRCTRAP */ 123 LINUX_T_UNKNOWN, /* 11 */ 124 14, /* 12 T_PAGEFLT */ 125 LINUX_T_UNKNOWN, /* 13 */ 126 17, /* 14 T_ALIGNFLT */ 127 LINUX_T_UNKNOWN, /* 15 */ 128 LINUX_T_UNKNOWN, /* 16 */ 129 LINUX_T_UNKNOWN, /* 17 */ 130 0, /* 18 T_DIVIDE */ 131 2, /* 19 T_NMI */ 132 4, /* 20 T_OFLOW */ 133 5, /* 21 T_BOUND */ 134 7, /* 22 T_DNA */ 135 8, /* 23 T_DOUBLEFLT */ 136 9, /* 24 T_FPOPFLT */ 137 10, /* 25 T_TSSFLT */ 138 11, /* 26 T_SEGNPFLT */ 139 12, /* 27 T_STKFLT */ 140 18, /* 28 T_MCHK */ 141 19, /* 29 T_XMMFLT */ 142 15 /* 30 T_RESERVED */ 143 }; 144 #define bsd_to_linux_trapcode(code) \ 145 ((code)<nitems(_bsd_to_linux_trapcode)? \ 146 _bsd_to_linux_trapcode[(code)]: \ 147 LINUX_T_UNKNOWN) 148 149 LINUX_VDSO_SYM_INTPTR(linux_sigcode); 150 LINUX_VDSO_SYM_INTPTR(linux_rt_sigcode); 151 LINUX_VDSO_SYM_INTPTR(linux_vsyscall); 152 153 /* 154 * If FreeBSD & Linux have a difference of opinion about what a trap 155 * means, deal with it here. 156 * 157 * MPSAFE 158 */ 159 static int 160 linux_translate_traps(int signal, int trap_code) 161 { 162 if (signal != SIGBUS) 163 return (signal); 164 switch (trap_code) { 165 case T_PROTFLT: 166 case T_TSSFLT: 167 case T_DOUBLEFLT: 168 case T_PAGEFLT: 169 return (SIGSEGV); 170 default: 171 return (signal); 172 } 173 } 174 175 static int 176 linux_fixup(register_t **stack_base, struct image_params *imgp) 177 { 178 register_t *argv, *envp; 179 180 argv = *stack_base; 181 envp = *stack_base + (imgp->args->argc + 1); 182 (*stack_base)--; 183 suword(*stack_base, (intptr_t)(void *)envp); 184 (*stack_base)--; 185 suword(*stack_base, (intptr_t)(void *)argv); 186 (*stack_base)--; 187 suword(*stack_base, imgp->args->argc); 188 return (0); 189 } 190 191 static int 192 linux_fixup_elf(register_t **stack_base, struct image_params *imgp) 193 { 194 struct proc *p; 195 Elf32_Auxargs *args; 196 Elf32_Auxinfo *argarray, *pos; 197 Elf32_Addr *auxbase, *uplatform; 198 struct ps_strings *arginfo; 199 int error, issetugid; 200 201 KASSERT(curthread->td_proc == imgp->proc, 202 ("unsafe linux_fixup_elf(), should be curproc")); 203 204 p = imgp->proc; 205 issetugid = imgp->proc->p_flag & P_SUGID ? 1 : 0; 206 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 207 uplatform = (Elf32_Addr *)((caddr_t)arginfo - linux_szplatform); 208 args = (Elf32_Auxargs *)imgp->auxargs; 209 auxbase = *stack_base + imgp->args->argc + 1 + imgp->args->envc + 1; 210 argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP, 211 M_WAITOK | M_ZERO); 212 213 AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR, 214 imgp->proc->p_sysent->sv_shared_page_base); 215 AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO, linux_vsyscall); 216 AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, cpu_feature); 217 218 /* 219 * Do not export AT_CLKTCK when emulating Linux kernel prior to 2.4.0, 220 * as it has appeared in the 2.4.0-rc7 first time. 221 * Being exported, AT_CLKTCK is returned by sysconf(_SC_CLK_TCK), 222 * glibc falls back to the hard-coded CLK_TCK value when aux entry 223 * is not present. 224 * Also see linux_times() implementation. 225 */ 226 if (linux_kernver(curthread) >= LINUX_KERNVER_2004000) 227 AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz); 228 AUXARGS_ENTRY(pos, AT_PHDR, args->phdr); 229 AUXARGS_ENTRY(pos, AT_PHENT, args->phent); 230 AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum); 231 AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz); 232 AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); 233 AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); 234 AUXARGS_ENTRY(pos, AT_BASE, args->base); 235 AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid); 236 AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid); 237 AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid); 238 AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid); 239 AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid); 240 AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(uplatform)); 241 AUXARGS_ENTRY(pos, LINUX_AT_RANDOM, imgp->canary); 242 if (imgp->execpathp != 0) 243 AUXARGS_ENTRY(pos, LINUX_AT_EXECFN, imgp->execpathp); 244 if (args->execfd != -1) 245 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd); 246 AUXARGS_ENTRY(pos, AT_NULL, 0); 247 248 free(imgp->auxargs, M_TEMP); 249 imgp->auxargs = NULL; 250 KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs")); 251 252 error = copyout(argarray, auxbase, sizeof(*argarray) * LINUX_AT_COUNT); 253 free(argarray, M_TEMP); 254 if (error != 0) 255 return (error); 256 257 (*stack_base)--; 258 if (suword(*stack_base, (register_t)imgp->args->argc) == -1) 259 return (EFAULT); 260 return (0); 261 } 262 263 /* 264 * Copied from kern/kern_exec.c 265 */ 266 static register_t * 267 linux_copyout_strings(struct image_params *imgp) 268 { 269 int argc, envc; 270 char **vectp; 271 char *stringp, *destp; 272 register_t *stack_base; 273 struct ps_strings *arginfo; 274 char canary[LINUX_AT_RANDOM_LEN]; 275 size_t execpath_len; 276 struct proc *p; 277 278 /* Calculate string base and vector table pointers. */ 279 p = imgp->proc; 280 if (imgp->execpath != NULL && imgp->auxargs != NULL) 281 execpath_len = strlen(imgp->execpath) + 1; 282 else 283 execpath_len = 0; 284 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 285 destp = (caddr_t)arginfo - SPARE_USRSPACE - linux_szplatform - 286 roundup(sizeof(canary), sizeof(char *)) - 287 roundup(execpath_len, sizeof(char *)) - 288 roundup(ARG_MAX - imgp->args->stringspace, sizeof(char *)); 289 290 /* Install LINUX_PLATFORM. */ 291 copyout(linux_kplatform, ((caddr_t)arginfo - linux_szplatform), 292 linux_szplatform); 293 294 if (execpath_len != 0) { 295 imgp->execpathp = (uintptr_t)arginfo - 296 linux_szplatform - execpath_len; 297 copyout(imgp->execpath, (void *)imgp->execpathp, execpath_len); 298 } 299 300 /* Prepare the canary for SSP. */ 301 arc4rand(canary, sizeof(canary), 0); 302 imgp->canary = (uintptr_t)arginfo - linux_szplatform - 303 roundup(execpath_len, sizeof(char *)) - 304 roundup(sizeof(canary), sizeof(char *)); 305 copyout(canary, (void *)imgp->canary, sizeof(canary)); 306 307 vectp = (char **)destp; 308 if (imgp->auxargs) { 309 /* 310 * Allocate room on the stack for the ELF auxargs 311 * array. It has LINUX_AT_COUNT entries. 312 */ 313 vectp -= howmany(LINUX_AT_COUNT * sizeof(Elf32_Auxinfo), 314 sizeof(*vectp)); 315 } 316 317 /* 318 * Allocate room for the argv[] and env vectors including the 319 * terminating NULL pointers. 320 */ 321 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1; 322 323 /* vectp also becomes our initial stack base. */ 324 stack_base = (register_t *)vectp; 325 326 stringp = imgp->args->begin_argv; 327 argc = imgp->args->argc; 328 envc = imgp->args->envc; 329 330 /* Copy out strings - arguments and environment. */ 331 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 332 333 /* Fill in "ps_strings" struct for ps, w, etc. */ 334 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 335 suword(&arginfo->ps_nargvstr, argc); 336 337 /* Fill in argument portion of vector table. */ 338 for (; argc > 0; --argc) { 339 suword(vectp++, (long)(intptr_t)destp); 340 while (*stringp++ != 0) 341 destp++; 342 destp++; 343 } 344 345 /* A null vector table pointer separates the argp's from the envp's. */ 346 suword(vectp++, 0); 347 348 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 349 suword(&arginfo->ps_nenvstr, envc); 350 351 /* Fill in environment portion of vector table. */ 352 for (; envc > 0; --envc) { 353 suword(vectp++, (long)(intptr_t)destp); 354 while (*stringp++ != 0) 355 destp++; 356 destp++; 357 } 358 359 /* The end of the vector table is a null pointer. */ 360 suword(vectp, 0); 361 362 return (stack_base); 363 } 364 365 static void 366 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 367 { 368 struct thread *td = curthread; 369 struct proc *p = td->td_proc; 370 struct sigacts *psp; 371 struct trapframe *regs; 372 struct l_rt_sigframe *fp, frame; 373 int sig, code; 374 int oonstack; 375 376 sig = ksi->ksi_signo; 377 code = ksi->ksi_code; 378 PROC_LOCK_ASSERT(p, MA_OWNED); 379 psp = p->p_sigacts; 380 mtx_assert(&psp->ps_mtx, MA_OWNED); 381 regs = td->td_frame; 382 oonstack = sigonstack(regs->tf_esp); 383 384 /* Allocate space for the signal handler context. */ 385 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 386 SIGISMEMBER(psp->ps_sigonstack, sig)) { 387 fp = (struct l_rt_sigframe *)((uintptr_t)td->td_sigstk.ss_sp + 388 td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe)); 389 } else 390 fp = (struct l_rt_sigframe *)regs->tf_esp - 1; 391 mtx_unlock(&psp->ps_mtx); 392 393 /* Build the argument list for the signal handler. */ 394 sig = bsd_to_linux_signal(sig); 395 396 bzero(&frame, sizeof(frame)); 397 398 frame.sf_handler = catcher; 399 frame.sf_sig = sig; 400 frame.sf_siginfo = &fp->sf_si; 401 frame.sf_ucontext = &fp->sf_sc; 402 403 /* Fill in POSIX parts. */ 404 ksiginfo_to_lsiginfo(ksi, &frame.sf_si, sig); 405 406 /* Build the signal context to be used by sigreturn. */ 407 frame.sf_sc.uc_flags = 0; /* XXX ??? */ 408 frame.sf_sc.uc_link = NULL; /* XXX ??? */ 409 410 frame.sf_sc.uc_stack.ss_sp = td->td_sigstk.ss_sp; 411 frame.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size; 412 frame.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 413 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE; 414 PROC_UNLOCK(p); 415 416 bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask); 417 418 frame.sf_sc.uc_mcontext.sc_mask = frame.sf_sc.uc_sigmask.__mask; 419 frame.sf_sc.uc_mcontext.sc_gs = rgs(); 420 frame.sf_sc.uc_mcontext.sc_fs = regs->tf_fs; 421 frame.sf_sc.uc_mcontext.sc_es = regs->tf_es; 422 frame.sf_sc.uc_mcontext.sc_ds = regs->tf_ds; 423 frame.sf_sc.uc_mcontext.sc_edi = regs->tf_edi; 424 frame.sf_sc.uc_mcontext.sc_esi = regs->tf_esi; 425 frame.sf_sc.uc_mcontext.sc_ebp = regs->tf_ebp; 426 frame.sf_sc.uc_mcontext.sc_ebx = regs->tf_ebx; 427 frame.sf_sc.uc_mcontext.sc_esp = regs->tf_esp; 428 frame.sf_sc.uc_mcontext.sc_edx = regs->tf_edx; 429 frame.sf_sc.uc_mcontext.sc_ecx = regs->tf_ecx; 430 frame.sf_sc.uc_mcontext.sc_eax = regs->tf_eax; 431 frame.sf_sc.uc_mcontext.sc_eip = regs->tf_eip; 432 frame.sf_sc.uc_mcontext.sc_cs = regs->tf_cs; 433 frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_eflags; 434 frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_esp; 435 frame.sf_sc.uc_mcontext.sc_ss = regs->tf_ss; 436 frame.sf_sc.uc_mcontext.sc_err = regs->tf_err; 437 frame.sf_sc.uc_mcontext.sc_cr2 = (register_t)ksi->ksi_addr; 438 frame.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code); 439 440 if (copyout(&frame, fp, sizeof(frame)) != 0) { 441 /* 442 * Process has trashed its stack; give it an illegal 443 * instruction to halt it in its tracks. 444 */ 445 PROC_LOCK(p); 446 sigexit(td, SIGILL); 447 } 448 449 /* Build context to run handler in. */ 450 regs->tf_esp = (int)fp; 451 regs->tf_eip = linux_rt_sigcode; 452 regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D); 453 regs->tf_cs = _ucodesel; 454 regs->tf_ds = _udatasel; 455 regs->tf_es = _udatasel; 456 regs->tf_fs = _udatasel; 457 regs->tf_ss = _udatasel; 458 PROC_LOCK(p); 459 mtx_lock(&psp->ps_mtx); 460 } 461 462 463 /* 464 * Send an interrupt to process. 465 * 466 * Stack is set up to allow sigcode stored 467 * in u. to call routine, followed by kcall 468 * to sigreturn routine below. After sigreturn 469 * resets the signal mask, the stack, and the 470 * frame pointer, it returns to the user 471 * specified pc, psl. 472 */ 473 static void 474 linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 475 { 476 struct thread *td = curthread; 477 struct proc *p = td->td_proc; 478 struct sigacts *psp; 479 struct trapframe *regs; 480 struct l_sigframe *fp, frame; 481 l_sigset_t lmask; 482 int sig, code; 483 int oonstack; 484 485 PROC_LOCK_ASSERT(p, MA_OWNED); 486 psp = p->p_sigacts; 487 sig = ksi->ksi_signo; 488 code = ksi->ksi_code; 489 mtx_assert(&psp->ps_mtx, MA_OWNED); 490 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 491 /* Signal handler installed with SA_SIGINFO. */ 492 linux_rt_sendsig(catcher, ksi, mask); 493 return; 494 } 495 regs = td->td_frame; 496 oonstack = sigonstack(regs->tf_esp); 497 498 /* Allocate space for the signal handler context. */ 499 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 500 SIGISMEMBER(psp->ps_sigonstack, sig)) { 501 fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp + 502 td->td_sigstk.ss_size - sizeof(struct l_sigframe)); 503 } else 504 fp = (struct l_sigframe *)regs->tf_esp - 1; 505 mtx_unlock(&psp->ps_mtx); 506 PROC_UNLOCK(p); 507 508 /* Build the argument list for the signal handler. */ 509 sig = bsd_to_linux_signal(sig); 510 511 bzero(&frame, sizeof(frame)); 512 513 frame.sf_handler = catcher; 514 frame.sf_sig = sig; 515 516 bsd_to_linux_sigset(mask, &lmask); 517 518 /* Build the signal context to be used by sigreturn. */ 519 frame.sf_sc.sc_mask = lmask.__mask; 520 frame.sf_sc.sc_gs = rgs(); 521 frame.sf_sc.sc_fs = regs->tf_fs; 522 frame.sf_sc.sc_es = regs->tf_es; 523 frame.sf_sc.sc_ds = regs->tf_ds; 524 frame.sf_sc.sc_edi = regs->tf_edi; 525 frame.sf_sc.sc_esi = regs->tf_esi; 526 frame.sf_sc.sc_ebp = regs->tf_ebp; 527 frame.sf_sc.sc_ebx = regs->tf_ebx; 528 frame.sf_sc.sc_esp = regs->tf_esp; 529 frame.sf_sc.sc_edx = regs->tf_edx; 530 frame.sf_sc.sc_ecx = regs->tf_ecx; 531 frame.sf_sc.sc_eax = regs->tf_eax; 532 frame.sf_sc.sc_eip = regs->tf_eip; 533 frame.sf_sc.sc_cs = regs->tf_cs; 534 frame.sf_sc.sc_eflags = regs->tf_eflags; 535 frame.sf_sc.sc_esp_at_signal = regs->tf_esp; 536 frame.sf_sc.sc_ss = regs->tf_ss; 537 frame.sf_sc.sc_err = regs->tf_err; 538 frame.sf_sc.sc_cr2 = (register_t)ksi->ksi_addr; 539 frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(ksi->ksi_trapno); 540 541 frame.sf_extramask[0] = lmask.__mask; 542 543 if (copyout(&frame, fp, sizeof(frame)) != 0) { 544 /* 545 * Process has trashed its stack; give it an illegal 546 * instruction to halt it in its tracks. 547 */ 548 PROC_LOCK(p); 549 sigexit(td, SIGILL); 550 } 551 552 /* Build context to run handler in. */ 553 regs->tf_esp = (int)fp; 554 regs->tf_eip = linux_sigcode; 555 regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D); 556 regs->tf_cs = _ucodesel; 557 regs->tf_ds = _udatasel; 558 regs->tf_es = _udatasel; 559 regs->tf_fs = _udatasel; 560 regs->tf_ss = _udatasel; 561 PROC_LOCK(p); 562 mtx_lock(&psp->ps_mtx); 563 } 564 565 /* 566 * System call to cleanup state after a signal 567 * has been taken. Reset signal mask and 568 * stack state from context left by sendsig (above). 569 * Return to previous pc and psl as specified by 570 * context left by sendsig. Check carefully to 571 * make sure that the user has not modified the 572 * psl to gain improper privileges or to cause 573 * a machine fault. 574 */ 575 int 576 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args) 577 { 578 struct l_sigframe frame; 579 struct trapframe *regs; 580 l_sigset_t lmask; 581 sigset_t bmask; 582 int eflags; 583 ksiginfo_t ksi; 584 585 regs = td->td_frame; 586 587 /* 588 * The trampoline code hands us the sigframe. 589 * It is unsafe to keep track of it ourselves, in the event that a 590 * program jumps out of a signal handler. 591 */ 592 if (copyin(args->sfp, &frame, sizeof(frame)) != 0) 593 return (EFAULT); 594 595 /* Check for security violations. */ 596 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 597 eflags = frame.sf_sc.sc_eflags; 598 if (!EFLAGS_SECURE(eflags, regs->tf_eflags)) 599 return (EINVAL); 600 601 /* 602 * Don't allow users to load a valid privileged %cs. Let the 603 * hardware check for invalid selectors, excess privilege in 604 * other selectors, invalid %eip's and invalid %esp's. 605 */ 606 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 607 if (!CS_SECURE(frame.sf_sc.sc_cs)) { 608 ksiginfo_init_trap(&ksi); 609 ksi.ksi_signo = SIGBUS; 610 ksi.ksi_code = BUS_OBJERR; 611 ksi.ksi_trapno = T_PROTFLT; 612 ksi.ksi_addr = (void *)regs->tf_eip; 613 trapsignal(td, &ksi); 614 return (EINVAL); 615 } 616 617 lmask.__mask = frame.sf_sc.sc_mask; 618 linux_to_bsd_sigset(&lmask, &bmask); 619 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0); 620 621 /* Restore signal context. */ 622 /* %gs was restored by the trampoline. */ 623 regs->tf_fs = frame.sf_sc.sc_fs; 624 regs->tf_es = frame.sf_sc.sc_es; 625 regs->tf_ds = frame.sf_sc.sc_ds; 626 regs->tf_edi = frame.sf_sc.sc_edi; 627 regs->tf_esi = frame.sf_sc.sc_esi; 628 regs->tf_ebp = frame.sf_sc.sc_ebp; 629 regs->tf_ebx = frame.sf_sc.sc_ebx; 630 regs->tf_edx = frame.sf_sc.sc_edx; 631 regs->tf_ecx = frame.sf_sc.sc_ecx; 632 regs->tf_eax = frame.sf_sc.sc_eax; 633 regs->tf_eip = frame.sf_sc.sc_eip; 634 regs->tf_cs = frame.sf_sc.sc_cs; 635 regs->tf_eflags = eflags; 636 regs->tf_esp = frame.sf_sc.sc_esp_at_signal; 637 regs->tf_ss = frame.sf_sc.sc_ss; 638 639 return (EJUSTRETURN); 640 } 641 642 /* 643 * System call to cleanup state after a signal 644 * has been taken. Reset signal mask and 645 * stack state from context left by rt_sendsig (above). 646 * Return to previous pc and psl as specified by 647 * context left by sendsig. Check carefully to 648 * make sure that the user has not modified the 649 * psl to gain improper privileges or to cause 650 * a machine fault. 651 */ 652 int 653 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args) 654 { 655 struct l_ucontext uc; 656 struct l_sigcontext *context; 657 sigset_t bmask; 658 l_stack_t *lss; 659 stack_t ss; 660 struct trapframe *regs; 661 int eflags; 662 ksiginfo_t ksi; 663 664 regs = td->td_frame; 665 666 /* 667 * The trampoline code hands us the ucontext. 668 * It is unsafe to keep track of it ourselves, in the event that a 669 * program jumps out of a signal handler. 670 */ 671 if (copyin(args->ucp, &uc, sizeof(uc)) != 0) 672 return (EFAULT); 673 674 context = &uc.uc_mcontext; 675 676 /* Check for security violations. */ 677 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 678 eflags = context->sc_eflags; 679 if (!EFLAGS_SECURE(eflags, regs->tf_eflags)) 680 return (EINVAL); 681 682 /* 683 * Don't allow users to load a valid privileged %cs. Let the 684 * hardware check for invalid selectors, excess privilege in 685 * other selectors, invalid %eip's and invalid %esp's. 686 */ 687 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 688 if (!CS_SECURE(context->sc_cs)) { 689 ksiginfo_init_trap(&ksi); 690 ksi.ksi_signo = SIGBUS; 691 ksi.ksi_code = BUS_OBJERR; 692 ksi.ksi_trapno = T_PROTFLT; 693 ksi.ksi_addr = (void *)regs->tf_eip; 694 trapsignal(td, &ksi); 695 return (EINVAL); 696 } 697 698 linux_to_bsd_sigset(&uc.uc_sigmask, &bmask); 699 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0); 700 701 /* Restore signal context. */ 702 /* %gs was restored by the trampoline. */ 703 regs->tf_fs = context->sc_fs; 704 regs->tf_es = context->sc_es; 705 regs->tf_ds = context->sc_ds; 706 regs->tf_edi = context->sc_edi; 707 regs->tf_esi = context->sc_esi; 708 regs->tf_ebp = context->sc_ebp; 709 regs->tf_ebx = context->sc_ebx; 710 regs->tf_edx = context->sc_edx; 711 regs->tf_ecx = context->sc_ecx; 712 regs->tf_eax = context->sc_eax; 713 regs->tf_eip = context->sc_eip; 714 regs->tf_cs = context->sc_cs; 715 regs->tf_eflags = eflags; 716 regs->tf_esp = context->sc_esp_at_signal; 717 regs->tf_ss = context->sc_ss; 718 719 /* Call sigaltstack & ignore results. */ 720 lss = &uc.uc_stack; 721 ss.ss_sp = lss->ss_sp; 722 ss.ss_size = lss->ss_size; 723 ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags); 724 725 (void)kern_sigaltstack(td, &ss, NULL); 726 727 return (EJUSTRETURN); 728 } 729 730 static int 731 linux_fetch_syscall_args(struct thread *td) 732 { 733 struct proc *p; 734 struct trapframe *frame; 735 struct syscall_args *sa; 736 737 p = td->td_proc; 738 frame = td->td_frame; 739 sa = &td->td_sa; 740 741 sa->code = frame->tf_eax; 742 sa->args[0] = frame->tf_ebx; 743 sa->args[1] = frame->tf_ecx; 744 sa->args[2] = frame->tf_edx; 745 sa->args[3] = frame->tf_esi; 746 sa->args[4] = frame->tf_edi; 747 sa->args[5] = frame->tf_ebp; /* Unconfirmed */ 748 749 if (sa->code >= p->p_sysent->sv_size) 750 /* nosys */ 751 sa->callp = &p->p_sysent->sv_table[p->p_sysent->sv_size - 1]; 752 else 753 sa->callp = &p->p_sysent->sv_table[sa->code]; 754 sa->narg = sa->callp->sy_narg; 755 756 td->td_retval[0] = 0; 757 td->td_retval[1] = frame->tf_edx; 758 759 return (0); 760 } 761 762 /* 763 * exec_setregs may initialize some registers differently than Linux 764 * does, thus potentially confusing Linux binaries. If necessary, we 765 * override the exec_setregs default(s) here. 766 */ 767 static void 768 linux_exec_setregs(struct thread *td, struct image_params *imgp, u_long stack) 769 { 770 struct pcb *pcb = td->td_pcb; 771 772 exec_setregs(td, imgp, stack); 773 774 /* Linux sets %gs to 0, we default to _udatasel. */ 775 pcb->pcb_gs = 0; 776 load_gs(0); 777 778 pcb->pcb_initial_npxcw = __LINUX_NPXCW__; 779 } 780 781 static void 782 linux_get_machine(const char **dst) 783 { 784 785 switch (cpu_class) { 786 case CPUCLASS_686: 787 *dst = "i686"; 788 break; 789 case CPUCLASS_586: 790 *dst = "i586"; 791 break; 792 case CPUCLASS_486: 793 *dst = "i486"; 794 break; 795 default: 796 *dst = "i386"; 797 } 798 } 799 800 struct sysentvec linux_sysvec = { 801 .sv_size = LINUX_SYS_MAXSYSCALL, 802 .sv_table = linux_sysent, 803 .sv_mask = 0, 804 .sv_errsize = ELAST + 1, 805 .sv_errtbl = linux_errtbl, 806 .sv_transtrap = linux_translate_traps, 807 .sv_fixup = linux_fixup, 808 .sv_sendsig = linux_sendsig, 809 .sv_sigcode = &_binary_linux_locore_o_start, 810 .sv_szsigcode = &linux_szsigcode, 811 .sv_name = "Linux a.out", 812 .sv_coredump = NULL, 813 .sv_imgact_try = linux_exec_imgact_try, 814 .sv_minsigstksz = LINUX_MINSIGSTKSZ, 815 .sv_minuser = VM_MIN_ADDRESS, 816 .sv_maxuser = VM_MAXUSER_ADDRESS, 817 .sv_usrstack = LINUX_USRSTACK, 818 .sv_psstrings = PS_STRINGS, 819 .sv_stackprot = VM_PROT_ALL, 820 .sv_copyout_strings = exec_copyout_strings, 821 .sv_setregs = linux_exec_setregs, 822 .sv_fixlimit = NULL, 823 .sv_maxssiz = NULL, 824 .sv_flags = SV_ABI_LINUX | SV_AOUT | SV_IA32 | SV_ILP32, 825 .sv_set_syscall_retval = cpu_set_syscall_retval, 826 .sv_fetch_syscall_args = linux_fetch_syscall_args, 827 .sv_syscallnames = NULL, 828 .sv_shared_page_base = LINUX_SHAREDPAGE, 829 .sv_shared_page_len = PAGE_SIZE, 830 .sv_schedtail = linux_schedtail, 831 .sv_thread_detach = linux_thread_detach, 832 .sv_trap = NULL, 833 }; 834 INIT_SYSENTVEC(aout_sysvec, &linux_sysvec); 835 836 struct sysentvec elf_linux_sysvec = { 837 .sv_size = LINUX_SYS_MAXSYSCALL, 838 .sv_table = linux_sysent, 839 .sv_mask = 0, 840 .sv_errsize = ELAST + 1, 841 .sv_errtbl = linux_errtbl, 842 .sv_transtrap = linux_translate_traps, 843 .sv_fixup = linux_fixup_elf, 844 .sv_sendsig = linux_sendsig, 845 .sv_sigcode = &_binary_linux_locore_o_start, 846 .sv_szsigcode = &linux_szsigcode, 847 .sv_name = "Linux ELF", 848 .sv_coredump = elf32_coredump, 849 .sv_imgact_try = linux_exec_imgact_try, 850 .sv_minsigstksz = LINUX_MINSIGSTKSZ, 851 .sv_minuser = VM_MIN_ADDRESS, 852 .sv_maxuser = VM_MAXUSER_ADDRESS, 853 .sv_usrstack = LINUX_USRSTACK, 854 .sv_psstrings = LINUX_PS_STRINGS, 855 .sv_stackprot = VM_PROT_ALL, 856 .sv_copyout_strings = linux_copyout_strings, 857 .sv_setregs = linux_exec_setregs, 858 .sv_fixlimit = NULL, 859 .sv_maxssiz = NULL, 860 .sv_flags = SV_ABI_LINUX | SV_IA32 | SV_ILP32 | SV_SHP, 861 .sv_set_syscall_retval = cpu_set_syscall_retval, 862 .sv_fetch_syscall_args = linux_fetch_syscall_args, 863 .sv_syscallnames = NULL, 864 .sv_shared_page_base = LINUX_SHAREDPAGE, 865 .sv_shared_page_len = PAGE_SIZE, 866 .sv_schedtail = linux_schedtail, 867 .sv_thread_detach = linux_thread_detach, 868 .sv_trap = NULL, 869 }; 870 871 static void 872 linux_vdso_install(void *param) 873 { 874 875 linux_szsigcode = (&_binary_linux_locore_o_end - 876 &_binary_linux_locore_o_start); 877 878 if (linux_szsigcode > elf_linux_sysvec.sv_shared_page_len) 879 panic("Linux invalid vdso size\n"); 880 881 __elfN(linux_vdso_fixup)(&elf_linux_sysvec); 882 883 linux_shared_page_obj = __elfN(linux_shared_page_init) 884 (&linux_shared_page_mapping); 885 886 __elfN(linux_vdso_reloc)(&elf_linux_sysvec); 887 888 bcopy(elf_linux_sysvec.sv_sigcode, linux_shared_page_mapping, 889 linux_szsigcode); 890 elf_linux_sysvec.sv_shared_page_obj = linux_shared_page_obj; 891 } 892 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_ANY, 893 linux_vdso_install, NULL); 894 895 static void 896 linux_vdso_deinstall(void *param) 897 { 898 899 __elfN(linux_shared_page_fini)(linux_shared_page_obj); 900 } 901 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST, 902 linux_vdso_deinstall, NULL); 903 904 static char GNU_ABI_VENDOR[] = "GNU"; 905 static int GNULINUX_ABI_DESC = 0; 906 907 static bool 908 linux_trans_osrel(const Elf_Note *note, int32_t *osrel) 909 { 910 const Elf32_Word *desc; 911 uintptr_t p; 912 913 p = (uintptr_t)(note + 1); 914 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 915 916 desc = (const Elf32_Word *)p; 917 if (desc[0] != GNULINUX_ABI_DESC) 918 return (false); 919 920 /* 921 * For Linux we encode osrel using the Linux convention of 922 * (version << 16) | (major << 8) | (minor) 923 * See macro in linux_mib.h 924 */ 925 *osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]); 926 927 return (true); 928 } 929 930 static Elf_Brandnote linux_brandnote = { 931 .hdr.n_namesz = sizeof(GNU_ABI_VENDOR), 932 .hdr.n_descsz = 16, /* XXX at least 16 */ 933 .hdr.n_type = 1, 934 .vendor = GNU_ABI_VENDOR, 935 .flags = BN_TRANSLATE_OSREL, 936 .trans_osrel = linux_trans_osrel 937 }; 938 939 static Elf32_Brandinfo linux_brand = { 940 .brand = ELFOSABI_LINUX, 941 .machine = EM_386, 942 .compat_3_brand = "Linux", 943 .emul_path = linux_emul_path, 944 .interp_path = "/lib/ld-linux.so.1", 945 .sysvec = &elf_linux_sysvec, 946 .interp_newpath = NULL, 947 .brand_note = &linux_brandnote, 948 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 949 }; 950 951 static Elf32_Brandinfo linux_glibc2brand = { 952 .brand = ELFOSABI_LINUX, 953 .machine = EM_386, 954 .compat_3_brand = "Linux", 955 .emul_path = linux_emul_path, 956 .interp_path = "/lib/ld-linux.so.2", 957 .sysvec = &elf_linux_sysvec, 958 .interp_newpath = NULL, 959 .brand_note = &linux_brandnote, 960 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 961 }; 962 963 static Elf32_Brandinfo linux_muslbrand = { 964 .brand = ELFOSABI_LINUX, 965 .machine = EM_386, 966 .compat_3_brand = "Linux", 967 .emul_path = linux_emul_path, 968 .interp_path = "/lib/ld-musl-i386.so.1", 969 .sysvec = &elf_linux_sysvec, 970 .interp_newpath = NULL, 971 .brand_note = &linux_brandnote, 972 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 973 }; 974 975 Elf32_Brandinfo *linux_brandlist[] = { 976 &linux_brand, 977 &linux_glibc2brand, 978 &linux_muslbrand, 979 NULL 980 }; 981 982 static int 983 linux_elf_modevent(module_t mod, int type, void *data) 984 { 985 Elf32_Brandinfo **brandinfo; 986 int error; 987 struct linux_ioctl_handler **lihp; 988 989 error = 0; 990 991 switch(type) { 992 case MOD_LOAD: 993 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 994 ++brandinfo) 995 if (elf32_insert_brand_entry(*brandinfo) < 0) 996 error = EINVAL; 997 if (error == 0) { 998 SET_FOREACH(lihp, linux_ioctl_handler_set) 999 linux_ioctl_register_handler(*lihp); 1000 LIST_INIT(&futex_list); 1001 mtx_init(&futex_mtx, "ftllk", NULL, MTX_DEF); 1002 linux_exit_tag = EVENTHANDLER_REGISTER(process_exit, linux_proc_exit, 1003 NULL, 1000); 1004 linux_exec_tag = EVENTHANDLER_REGISTER(process_exec, linux_proc_exec, 1005 NULL, 1000); 1006 linux_thread_dtor_tag = EVENTHANDLER_REGISTER(thread_dtor, 1007 linux_thread_dtor, NULL, EVENTHANDLER_PRI_ANY); 1008 linux_get_machine(&linux_kplatform); 1009 linux_szplatform = roundup(strlen(linux_kplatform) + 1, 1010 sizeof(char *)); 1011 linux_dev_shm_create(); 1012 linux_osd_jail_register(); 1013 stclohz = (stathz ? stathz : hz); 1014 if (bootverbose) 1015 printf("Linux ELF exec handler installed\n"); 1016 } else 1017 printf("cannot insert Linux ELF brand handler\n"); 1018 break; 1019 case MOD_UNLOAD: 1020 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 1021 ++brandinfo) 1022 if (elf32_brand_inuse(*brandinfo)) 1023 error = EBUSY; 1024 if (error == 0) { 1025 for (brandinfo = &linux_brandlist[0]; 1026 *brandinfo != NULL; ++brandinfo) 1027 if (elf32_remove_brand_entry(*brandinfo) < 0) 1028 error = EINVAL; 1029 } 1030 if (error == 0) { 1031 SET_FOREACH(lihp, linux_ioctl_handler_set) 1032 linux_ioctl_unregister_handler(*lihp); 1033 mtx_destroy(&futex_mtx); 1034 EVENTHANDLER_DEREGISTER(process_exit, linux_exit_tag); 1035 EVENTHANDLER_DEREGISTER(process_exec, linux_exec_tag); 1036 EVENTHANDLER_DEREGISTER(thread_dtor, linux_thread_dtor_tag); 1037 linux_dev_shm_destroy(); 1038 linux_osd_jail_deregister(); 1039 if (bootverbose) 1040 printf("Linux ELF exec handler removed\n"); 1041 } else 1042 printf("Could not deinstall ELF interpreter entry\n"); 1043 break; 1044 default: 1045 return (EOPNOTSUPP); 1046 } 1047 return (error); 1048 } 1049 1050 static moduledata_t linux_elf_mod = { 1051 "linuxelf", 1052 linux_elf_modevent, 1053 0 1054 }; 1055 1056 DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY); 1057 FEATURE(linux, "Linux 32bit support");
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