1 /*- 2 * Copyright (c) 2004 Tim J. Robbins 3 * Copyright (c) 2003 Peter Wemm 4 * Copyright (c) 2002 Doug Rabson 5 * Copyright (c) 1998-1999 Andrew Gallatin 6 * Copyright (c) 1994-1996 Søren Schmidt 7 * All rights reserved. 8 * Copyright (c) 2013, 2021 Dmitry Chagin <dchagin@FreeBSD.org> 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer 15 * in this position and unchanged. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #define __ELF_WORD_SIZE 64 38 39 #include <sys/param.h> 40 #include <sys/exec.h> 41 #include <sys/imgact.h> 42 #include <sys/imgact_elf.h> 43 #include <sys/kernel.h> 44 #include <sys/ktr.h> 45 #include <sys/lock.h> 46 #include <sys/malloc.h> 47 #include <sys/module.h> 48 #include <sys/mutex.h> 49 #include <sys/proc.h> 50 #include <sys/stddef.h> 51 #include <sys/syscallsubr.h> 52 #include <sys/sysctl.h> 53 #include <sys/sysent.h> 54 55 #include <vm/pmap.h> 56 #include <vm/vm.h> 57 #include <vm/vm_map.h> 58 #include <vm/vm_page.h> 59 60 #include <machine/cpu.h> 61 #include <machine/md_var.h> 62 #include <machine/pcb.h> 63 #include <machine/specialreg.h> 64 #include <machine/trap.h> 65 66 #include <x86/linux/linux_x86.h> 67 #include <amd64/linux/linux.h> 68 #include <amd64/linux/linux_proto.h> 69 #include <compat/linux/linux_elf.h> 70 #include <compat/linux/linux_emul.h> 71 #include <compat/linux/linux_fork.h> 72 #include <compat/linux/linux_ioctl.h> 73 #include <compat/linux/linux_mib.h> 74 #include <compat/linux/linux_misc.h> 75 #include <compat/linux/linux_signal.h> 76 #include <compat/linux/linux_sysproto.h> 77 #include <compat/linux/linux_util.h> 78 #include <compat/linux/linux_vdso.h> 79 80 #include <x86/linux/linux_x86_sigframe.h> 81 82 MODULE_VERSION(linux64, 1); 83 84 #define LINUX_VDSOPAGE_SIZE PAGE_SIZE * 2 85 #define LINUX_VDSOPAGE_LA48 (VM_MAXUSER_ADDRESS_LA48 - \ 86 LINUX_VDSOPAGE_SIZE) 87 #define LINUX_SHAREDPAGE_LA48 (LINUX_VDSOPAGE_LA48 - PAGE_SIZE) 88 /* 89 * PAGE_SIZE - the size 90 * of the native SHAREDPAGE 91 */ 92 #define LINUX_USRSTACK_LA48 LINUX_SHAREDPAGE_LA48 93 #define LINUX_PS_STRINGS_LA48 (LINUX_USRSTACK_LA48 - \ 94 sizeof(struct ps_strings)) 95 96 static int linux_szsigcode; 97 static vm_object_t linux_vdso_obj; 98 static char *linux_vdso_mapping; 99 extern char _binary_linux_vdso_so_o_start; 100 extern char _binary_linux_vdso_so_o_end; 101 static vm_offset_t linux_vdso_base; 102 103 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL]; 104 extern const char *linux_syscallnames[]; 105 106 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler); 107 108 static void linux_vdso_install(const void *param); 109 static void linux_vdso_deinstall(const void *param); 110 static void linux_vdso_reloc(char *mapping, Elf_Addr offset); 111 static void linux_set_syscall_retval(struct thread *td, int error); 112 static int linux_fetch_syscall_args(struct thread *td); 113 static void linux_exec_setregs(struct thread *td, struct image_params *imgp, 114 uintptr_t stack); 115 static void linux_exec_sysvec_init(void *param); 116 static int linux_on_exec_vmspace(struct proc *p, 117 struct image_params *imgp); 118 static void linux_set_fork_retval(struct thread *td); 119 static int linux_vsyscall(struct thread *td); 120 121 LINUX_VDSO_SYM_INTPTR(linux_rt_sigcode); 122 LINUX_VDSO_SYM_CHAR(linux_platform); 123 LINUX_VDSO_SYM_INTPTR(kern_timekeep_base); 124 LINUX_VDSO_SYM_INTPTR(kern_tsc_selector); 125 LINUX_VDSO_SYM_INTPTR(kern_cpu_selector); 126 127 /* 128 * According to the Intel x86 ISA 64-bit syscall 129 * saves %rip to %rcx and rflags to %r11. Registers on syscall entry: 130 * %rax system call number 131 * %rcx return address 132 * %r11 saved rflags 133 * %rdi arg1 134 * %rsi arg2 135 * %rdx arg3 136 * %r10 arg4 137 * %r8 arg5 138 * %r9 arg6 139 * 140 * Then FreeBSD fast_syscall() move registers: 141 * %rcx -> trapframe.tf_rip 142 * %r10 -> trapframe.tf_rcx 143 */ 144 static int 145 linux_fetch_syscall_args(struct thread *td) 146 { 147 struct proc *p; 148 struct trapframe *frame; 149 struct syscall_args *sa; 150 151 p = td->td_proc; 152 frame = td->td_frame; 153 sa = &td->td_sa; 154 155 sa->args[0] = frame->tf_rdi; 156 sa->args[1] = frame->tf_rsi; 157 sa->args[2] = frame->tf_rdx; 158 sa->args[3] = frame->tf_rcx; 159 sa->args[4] = frame->tf_r8; 160 sa->args[5] = frame->tf_r9; 161 sa->code = frame->tf_rax; 162 sa->original_code = sa->code; 163 164 if (sa->code >= p->p_sysent->sv_size) 165 /* nosys */ 166 sa->callp = &p->p_sysent->sv_table[p->p_sysent->sv_size - 1]; 167 else 168 sa->callp = &p->p_sysent->sv_table[sa->code]; 169 170 /* Restore r10 earlier to avoid doing this multiply times. */ 171 frame->tf_r10 = frame->tf_rcx; 172 /* Restore %rcx for machine context. */ 173 frame->tf_rcx = frame->tf_rip; 174 175 td->td_retval[0] = 0; 176 return (0); 177 } 178 179 static void 180 linux_set_syscall_retval(struct thread *td, int error) 181 { 182 struct trapframe *frame; 183 184 frame = td->td_frame; 185 186 switch (error) { 187 case 0: 188 frame->tf_rax = td->td_retval[0]; 189 break; 190 191 case ERESTART: 192 /* 193 * Reconstruct pc, we know that 'syscall' is 2 bytes, 194 * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. 195 * We saved this in tf_err. 196 * 197 */ 198 frame->tf_rip -= frame->tf_err; 199 break; 200 201 case EJUSTRETURN: 202 break; 203 204 default: 205 frame->tf_rax = bsd_to_linux_errno(error); 206 break; 207 } 208 209 /* 210 * Differently from FreeBSD native ABI, on Linux only %rcx 211 * and %r11 values are not preserved across the syscall. 212 * Require full context restore to get all registers except 213 * those two restored at return to usermode. 214 */ 215 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 216 } 217 218 static void 219 linux_set_fork_retval(struct thread *td) 220 { 221 struct trapframe *frame = td->td_frame; 222 223 frame->tf_rax = 0; 224 } 225 226 void 227 linux64_arch_copyout_auxargs(struct image_params *imgp, Elf_Auxinfo **pos) 228 { 229 230 AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base); 231 AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, cpu_feature); 232 AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, 0); 233 AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform)); 234 } 235 236 /* 237 * Reset registers to default values on exec. 238 */ 239 static void 240 linux_exec_setregs(struct thread *td, struct image_params *imgp, 241 uintptr_t stack) 242 { 243 struct trapframe *regs; 244 struct pcb *pcb; 245 register_t saved_rflags; 246 247 regs = td->td_frame; 248 pcb = td->td_pcb; 249 250 if (td->td_proc->p_md.md_ldt != NULL) 251 user_ldt_free(td); 252 253 pcb->pcb_fsbase = 0; 254 pcb->pcb_gsbase = 0; 255 clear_pcb_flags(pcb, PCB_32BIT); 256 pcb->pcb_initial_fpucw = __LINUX_NPXCW__; 257 set_pcb_flags(pcb, PCB_FULL_IRET); 258 259 saved_rflags = regs->tf_rflags & PSL_T; 260 bzero((char *)regs, sizeof(struct trapframe)); 261 regs->tf_rip = imgp->entry_addr; 262 regs->tf_rsp = stack; 263 regs->tf_rflags = PSL_USER | saved_rflags; 264 regs->tf_ss = _udatasel; 265 regs->tf_cs = _ucodesel; 266 regs->tf_ds = _udatasel; 267 regs->tf_es = _udatasel; 268 regs->tf_fs = _ufssel; 269 regs->tf_gs = _ugssel; 270 regs->tf_flags = TF_HASSEGS; 271 272 x86_clear_dbregs(pcb); 273 274 /* 275 * Drop the FP state if we hold it, so that the process gets a 276 * clean FP state if it uses the FPU again. 277 */ 278 fpstate_drop(td); 279 } 280 281 /* 282 * Copied from amd64/amd64/machdep.c 283 */ 284 int 285 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args) 286 { 287 struct proc *p; 288 struct l_rt_sigframe sf; 289 struct l_sigcontext *context; 290 struct trapframe *regs; 291 mcontext_t mc; 292 unsigned long rflags; 293 sigset_t bmask; 294 int error, i; 295 ksiginfo_t ksi; 296 297 regs = td->td_frame; 298 error = copyin((void *)regs->tf_rbx, &sf, sizeof(sf)); 299 if (error != 0) 300 return (error); 301 302 p = td->td_proc; 303 context = &sf.sf_uc.uc_mcontext; 304 rflags = context->sc_rflags; 305 306 /* 307 * Don't allow users to change privileged or reserved flags. 308 */ 309 /* 310 * XXX do allow users to change the privileged flag PSL_RF. 311 * The cpu sets PSL_RF in tf_rflags for faults. Debuggers 312 * should sometimes set it there too. tf_rflags is kept in 313 * the signal context during signal handling and there is no 314 * other place to remember it, so the PSL_RF bit may be 315 * corrupted by the signal handler without us knowing. 316 * Corruption of the PSL_RF bit at worst causes one more or 317 * one less debugger trap, so allowing it is fairly harmless. 318 */ 319 if (!EFL_SECURE(rflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) { 320 uprintf("pid %d comm %s linux mangled rflags %#lx\n", 321 p->p_pid, p->p_comm, rflags); 322 return (EINVAL); 323 } 324 325 /* 326 * Don't allow users to load a valid privileged %cs. Let the 327 * hardware check for invalid selectors, excess privilege in 328 * other selectors, invalid %eip's and invalid %esp's. 329 */ 330 if (!CS_SECURE(context->sc_cs)) { 331 uprintf("pid %d comm %s linux mangled cs %#x\n", 332 p->p_pid, p->p_comm, context->sc_cs); 333 ksiginfo_init_trap(&ksi); 334 ksi.ksi_signo = SIGBUS; 335 ksi.ksi_code = BUS_OBJERR; 336 ksi.ksi_trapno = T_PROTFLT; 337 ksi.ksi_addr = (void *)regs->tf_rip; 338 trapsignal(td, &ksi); 339 return (EINVAL); 340 } 341 342 linux_to_bsd_sigset(&sf.sf_uc.uc_sigmask, &bmask); 343 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0); 344 345 regs->tf_rdi = context->sc_rdi; 346 regs->tf_rsi = context->sc_rsi; 347 regs->tf_rdx = context->sc_rdx; 348 regs->tf_rbp = context->sc_rbp; 349 regs->tf_rbx = context->sc_rbx; 350 regs->tf_rcx = context->sc_rcx; 351 regs->tf_rax = context->sc_rax; 352 regs->tf_rip = context->sc_rip; 353 regs->tf_rsp = context->sc_rsp; 354 regs->tf_r8 = context->sc_r8; 355 regs->tf_r9 = context->sc_r9; 356 regs->tf_r10 = context->sc_r10; 357 regs->tf_r11 = context->sc_r11; 358 regs->tf_r12 = context->sc_r12; 359 regs->tf_r13 = context->sc_r13; 360 regs->tf_r14 = context->sc_r14; 361 regs->tf_r15 = context->sc_r15; 362 regs->tf_cs = context->sc_cs; 363 regs->tf_err = context->sc_err; 364 regs->tf_rflags = rflags; 365 366 if (sf.sf_uc.uc_mcontext.sc_fpstate != NULL) { 367 struct savefpu *svfp = (struct savefpu *)mc.mc_fpstate; 368 369 bzero(&mc, sizeof(mc)); 370 mc.mc_ownedfp = _MC_FPOWNED_FPU; 371 mc.mc_fpformat = _MC_FPFMT_XMM; 372 373 svfp->sv_env.en_cw = sf.sf_fs.cwd; 374 svfp->sv_env.en_sw = sf.sf_fs.swd; 375 svfp->sv_env.en_tw = sf.sf_fs.twd; 376 svfp->sv_env.en_opcode = sf.sf_fs.fop; 377 svfp->sv_env.en_rip = sf.sf_fs.rip; 378 svfp->sv_env.en_rdp = sf.sf_fs.rdp; 379 svfp->sv_env.en_mxcsr = sf.sf_fs.mxcsr; 380 svfp->sv_env.en_mxcsr_mask = sf.sf_fs.mxcsr_mask; 381 /* FPU registers */ 382 for (i = 0; i < nitems(svfp->sv_fp); ++i) 383 bcopy(&sf.sf_fs.st[i], svfp->sv_fp[i].fp_acc.fp_bytes, 384 sizeof(svfp->sv_fp[i].fp_acc.fp_bytes)); 385 /* SSE registers */ 386 for (i = 0; i < nitems(svfp->sv_xmm); ++i) 387 bcopy(&sf.sf_fs.xmm[i], svfp->sv_xmm[i].xmm_bytes, 388 sizeof(svfp->sv_xmm[i].xmm_bytes)); 389 error = set_fpcontext(td, &mc, NULL, 0); 390 if (error != 0) { 391 uprintf("pid %d comm %s linux can't restore fpu state %d\n", 392 p->p_pid, p->p_comm, error); 393 return (error); 394 } 395 } 396 397 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 398 return (EJUSTRETURN); 399 } 400 401 /* 402 * copied from amd64/amd64/machdep.c 403 * 404 * Send an interrupt to process. 405 */ 406 static void 407 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 408 { 409 struct l_rt_sigframe sf, *sfp; 410 struct proc *p; 411 struct thread *td; 412 struct sigacts *psp; 413 caddr_t sp; 414 struct trapframe *regs; 415 struct savefpu *svfp; 416 mcontext_t mc; 417 int sig, code; 418 int oonstack, issiginfo, i; 419 420 td = curthread; 421 p = td->td_proc; 422 PROC_LOCK_ASSERT(p, MA_OWNED); 423 sig = linux_translate_traps(ksi->ksi_signo, ksi->ksi_trapno); 424 psp = p->p_sigacts; 425 issiginfo = SIGISMEMBER(psp->ps_siginfo, sig); 426 code = ksi->ksi_code; 427 mtx_assert(&psp->ps_mtx, MA_OWNED); 428 regs = td->td_frame; 429 oonstack = sigonstack(regs->tf_rsp); 430 431 LINUX_CTR4(rt_sendsig, "%p, %d, %p, %u", 432 catcher, sig, mask, code); 433 434 bzero(&sf, sizeof(sf)); 435 sf.sf_uc.uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp); 436 sf.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size; 437 sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 438 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE; 439 440 /* Allocate space for the signal handler context. */ 441 if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack && 442 SIGISMEMBER(psp->ps_sigonstack, sig)) { 443 sp = (caddr_t)td->td_sigstk.ss_sp + td->td_sigstk.ss_size; 444 } else 445 sp = (caddr_t)regs->tf_rsp - 128; 446 447 mtx_unlock(&psp->ps_mtx); 448 PROC_UNLOCK(p); 449 450 /* Make room, keeping the stack aligned. */ 451 sp -= sizeof(struct l_rt_sigframe); 452 sfp = (struct l_rt_sigframe *)((unsigned long)sp & ~0xFul); 453 454 /* Save user context. */ 455 bsd_to_linux_sigset(mask, &sf.sf_uc.uc_sigmask); 456 sf.sf_uc.uc_mcontext.sc_mask = sf.sf_uc.uc_sigmask; 457 sf.sf_uc.uc_mcontext.sc_rdi = regs->tf_rdi; 458 sf.sf_uc.uc_mcontext.sc_rsi = regs->tf_rsi; 459 sf.sf_uc.uc_mcontext.sc_rdx = regs->tf_rdx; 460 sf.sf_uc.uc_mcontext.sc_rbp = regs->tf_rbp; 461 sf.sf_uc.uc_mcontext.sc_rbx = regs->tf_rbx; 462 sf.sf_uc.uc_mcontext.sc_rcx = regs->tf_rcx; 463 sf.sf_uc.uc_mcontext.sc_rax = regs->tf_rax; 464 sf.sf_uc.uc_mcontext.sc_rip = regs->tf_rip; 465 sf.sf_uc.uc_mcontext.sc_rsp = regs->tf_rsp; 466 sf.sf_uc.uc_mcontext.sc_r8 = regs->tf_r8; 467 sf.sf_uc.uc_mcontext.sc_r9 = regs->tf_r9; 468 sf.sf_uc.uc_mcontext.sc_r10 = regs->tf_r10; 469 sf.sf_uc.uc_mcontext.sc_r11 = regs->tf_r11; 470 sf.sf_uc.uc_mcontext.sc_r12 = regs->tf_r12; 471 sf.sf_uc.uc_mcontext.sc_r13 = regs->tf_r13; 472 sf.sf_uc.uc_mcontext.sc_r14 = regs->tf_r14; 473 sf.sf_uc.uc_mcontext.sc_r15 = regs->tf_r15; 474 sf.sf_uc.uc_mcontext.sc_cs = regs->tf_cs; 475 sf.sf_uc.uc_mcontext.sc_rflags = regs->tf_rflags; 476 sf.sf_uc.uc_mcontext.sc_err = regs->tf_err; 477 sf.sf_uc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code); 478 sf.sf_uc.uc_mcontext.sc_cr2 = (register_t)ksi->ksi_addr; 479 480 get_fpcontext(td, &mc, NULL, NULL); 481 KASSERT(mc.mc_fpformat != _MC_FPFMT_NODEV, ("fpu not present")); 482 svfp = (struct savefpu *)mc.mc_fpstate; 483 484 sf.sf_fs.cwd = svfp->sv_env.en_cw; 485 sf.sf_fs.swd = svfp->sv_env.en_sw; 486 sf.sf_fs.twd = svfp->sv_env.en_tw; 487 sf.sf_fs.fop = svfp->sv_env.en_opcode; 488 sf.sf_fs.rip = svfp->sv_env.en_rip; 489 sf.sf_fs.rdp = svfp->sv_env.en_rdp; 490 sf.sf_fs.mxcsr = svfp->sv_env.en_mxcsr; 491 sf.sf_fs.mxcsr_mask = svfp->sv_env.en_mxcsr_mask; 492 /* FPU registers */ 493 for (i = 0; i < nitems(svfp->sv_fp); ++i) 494 bcopy(svfp->sv_fp[i].fp_acc.fp_bytes, &sf.sf_fs.st[i], 495 sizeof(svfp->sv_fp[i].fp_acc.fp_bytes)); 496 /* SSE registers */ 497 for (i = 0; i < nitems(svfp->sv_xmm); ++i) 498 bcopy(svfp->sv_xmm[i].xmm_bytes, &sf.sf_fs.xmm[i], 499 sizeof(svfp->sv_xmm[i].xmm_bytes)); 500 sf.sf_uc.uc_mcontext.sc_fpstate = (struct l_fpstate *)((caddr_t)sfp + 501 offsetof(struct l_rt_sigframe, sf_fs)); 502 503 /* Translate the signal. */ 504 sig = bsd_to_linux_signal(sig); 505 /* Fill in POSIX parts. */ 506 siginfo_to_lsiginfo(&ksi->ksi_info, &sf.sf_si, sig); 507 508 /* Copy the sigframe out to the user's stack. */ 509 if (copyout(&sf, sfp, sizeof(*sfp)) != 0) { 510 uprintf("pid %d comm %s has trashed its stack, killing\n", 511 p->p_pid, p->p_comm); 512 PROC_LOCK(p); 513 sigexit(td, SIGILL); 514 } 515 516 fpstate_drop(td); 517 /* Build the argument list for the signal handler. */ 518 regs->tf_rdi = sig; /* arg 1 in %rdi */ 519 regs->tf_rax = 0; 520 if (issiginfo) { 521 regs->tf_rsi = (register_t)&sfp->sf_si; /* arg 2 in %rsi */ 522 regs->tf_rdx = (register_t)&sfp->sf_uc; /* arg 3 in %rdx */ 523 } else { 524 regs->tf_rsi = 0; 525 regs->tf_rdx = 0; 526 } 527 regs->tf_rcx = (register_t)catcher; 528 regs->tf_rsp = (long)sfp; 529 regs->tf_rip = linux_rt_sigcode; 530 regs->tf_rflags &= ~(PSL_T | PSL_D); 531 regs->tf_cs = _ucodesel; 532 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 533 PROC_LOCK(p); 534 mtx_lock(&psp->ps_mtx); 535 } 536 537 #define LINUX_VSYSCALL_START (-10UL << 20) 538 #define LINUX_VSYSCALL_SZ 1024 539 540 const unsigned long linux_vsyscall_vector[] = { 541 LINUX_SYS_gettimeofday, 542 LINUX_SYS_linux_time, 543 LINUX_SYS_linux_getcpu, 544 }; 545 546 static int 547 linux_vsyscall(struct thread *td) 548 { 549 struct trapframe *frame; 550 uint64_t retqaddr; 551 int code, traced; 552 int error; 553 554 frame = td->td_frame; 555 556 /* Check %rip for vsyscall area. */ 557 if (__predict_true(frame->tf_rip < LINUX_VSYSCALL_START)) 558 return (EINVAL); 559 if ((frame->tf_rip & (LINUX_VSYSCALL_SZ - 1)) != 0) 560 return (EINVAL); 561 code = (frame->tf_rip - LINUX_VSYSCALL_START) / LINUX_VSYSCALL_SZ; 562 if (code >= nitems(linux_vsyscall_vector)) 563 return (EINVAL); 564 565 /* 566 * vsyscall called as callq *(%rax), so we must 567 * use return address from %rsp and also fixup %rsp. 568 */ 569 error = copyin((void *)frame->tf_rsp, &retqaddr, sizeof(retqaddr)); 570 if (error) 571 return (error); 572 573 frame->tf_rip = retqaddr; 574 frame->tf_rax = linux_vsyscall_vector[code]; 575 frame->tf_rsp += 8; 576 577 traced = (frame->tf_flags & PSL_T); 578 579 amd64_syscall(td, traced); 580 581 return (0); 582 } 583 584 struct sysentvec elf_linux_sysvec = { 585 .sv_size = LINUX_SYS_MAXSYSCALL, 586 .sv_table = linux_sysent, 587 .sv_fixup = __elfN(freebsd_fixup), 588 .sv_sendsig = linux_rt_sendsig, 589 .sv_sigcode = &_binary_linux_vdso_so_o_start, 590 .sv_szsigcode = &linux_szsigcode, 591 .sv_name = "Linux ELF64", 592 .sv_coredump = elf64_coredump, 593 .sv_elf_core_osabi = ELFOSABI_NONE, 594 .sv_elf_core_abi_vendor = LINUX_ABI_VENDOR, 595 .sv_elf_core_prepare_notes = linux64_prepare_notes, 596 .sv_imgact_try = linux_exec_imgact_try, 597 .sv_minsigstksz = LINUX_MINSIGSTKSZ, 598 .sv_minuser = VM_MIN_ADDRESS, 599 .sv_maxuser = VM_MAXUSER_ADDRESS_LA48, 600 .sv_usrstack = LINUX_USRSTACK_LA48, 601 .sv_psstrings = LINUX_PS_STRINGS_LA48, 602 .sv_psstringssz = sizeof(struct ps_strings), 603 .sv_stackprot = VM_PROT_ALL, 604 .sv_copyout_auxargs = __linuxN(copyout_auxargs), 605 .sv_copyout_strings = __linuxN(copyout_strings), 606 .sv_setregs = linux_exec_setregs, 607 .sv_fixlimit = NULL, 608 .sv_maxssiz = NULL, 609 .sv_flags = SV_ABI_LINUX | SV_LP64 | SV_SHP | SV_SIG_DISCIGN | 610 SV_SIG_WAITNDQ | SV_TIMEKEEP, 611 .sv_set_syscall_retval = linux_set_syscall_retval, 612 .sv_fetch_syscall_args = linux_fetch_syscall_args, 613 .sv_syscallnames = linux_syscallnames, 614 .sv_shared_page_base = LINUX_SHAREDPAGE_LA48, 615 .sv_shared_page_len = PAGE_SIZE, 616 .sv_schedtail = linux_schedtail, 617 .sv_thread_detach = linux_thread_detach, 618 .sv_trap = linux_vsyscall, 619 .sv_hwcap = NULL, 620 .sv_hwcap2 = NULL, 621 .sv_onexec = linux_on_exec_vmspace, 622 .sv_onexit = linux_on_exit, 623 .sv_ontdexit = linux_thread_dtor, 624 .sv_setid_allowed = &linux_setid_allowed_query, 625 .sv_set_fork_retval = linux_set_fork_retval, 626 }; 627 628 static int 629 linux_on_exec_vmspace(struct proc *p, struct image_params *imgp) 630 { 631 int error; 632 633 error = linux_map_vdso(p, linux_vdso_obj, linux_vdso_base, 634 LINUX_VDSOPAGE_SIZE, imgp); 635 if (error == 0) 636 linux_on_exec(p, imgp); 637 return (error); 638 } 639 640 /* 641 * linux_vdso_install() and linux_exec_sysvec_init() must be called 642 * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY). 643 */ 644 static void 645 linux_exec_sysvec_init(void *param) 646 { 647 l_uintptr_t *ktimekeep_base, *ktsc_selector; 648 struct sysentvec *sv; 649 ptrdiff_t tkoff; 650 651 sv = param; 652 amd64_lower_shared_page(sv); 653 /* Fill timekeep_base */ 654 exec_sysvec_init(sv); 655 656 tkoff = kern_timekeep_base - linux_vdso_base; 657 ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff); 658 *ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset; 659 660 tkoff = kern_tsc_selector - linux_vdso_base; 661 ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff); 662 *ktsc_selector = linux_vdso_tsc_selector_idx(); 663 if (bootverbose) 664 printf("Linux x86-64 vDSO tsc_selector: %lu\n", *ktsc_selector); 665 666 tkoff = kern_cpu_selector - linux_vdso_base; 667 ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff); 668 *ktsc_selector = linux_vdso_cpu_selector_idx(); 669 if (bootverbose) 670 printf("Linux x86-64 vDSO cpu_selector: %lu\n", *ktsc_selector); 671 } 672 SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY, 673 linux_exec_sysvec_init, &elf_linux_sysvec); 674 675 static void 676 linux_vdso_install(const void *param) 677 { 678 char *vdso_start = &_binary_linux_vdso_so_o_start; 679 char *vdso_end = &_binary_linux_vdso_so_o_end; 680 681 linux_szsigcode = vdso_end - vdso_start; 682 MPASS(linux_szsigcode <= LINUX_VDSOPAGE_SIZE); 683 684 linux_vdso_base = LINUX_VDSOPAGE_LA48; 685 if (hw_lower_amd64_sharedpage != 0) 686 linux_vdso_base -= PAGE_SIZE; 687 688 __elfN(linux_vdso_fixup)(vdso_start, linux_vdso_base); 689 690 linux_vdso_obj = __elfN(linux_shared_page_init) 691 (&linux_vdso_mapping, LINUX_VDSOPAGE_SIZE); 692 bcopy(vdso_start, linux_vdso_mapping, linux_szsigcode); 693 694 linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base); 695 } 696 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST, 697 linux_vdso_install, NULL); 698 699 static void 700 linux_vdso_deinstall(const void *param) 701 { 702 703 __elfN(linux_shared_page_fini)(linux_vdso_obj, 704 linux_vdso_mapping, LINUX_VDSOPAGE_SIZE); 705 } 706 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST, 707 linux_vdso_deinstall, NULL); 708 709 static void 710 linux_vdso_reloc(char *mapping, Elf_Addr offset) 711 { 712 const Elf_Ehdr *ehdr; 713 const Elf_Shdr *shdr; 714 Elf64_Addr *where, val; 715 Elf_Size rtype, symidx; 716 const Elf_Rela *rela; 717 Elf_Addr addr, addend; 718 int relacnt; 719 int i, j; 720 721 MPASS(offset != 0); 722 723 relacnt = 0; 724 ehdr = (const Elf_Ehdr *)mapping; 725 shdr = (const Elf_Shdr *)(mapping + ehdr->e_shoff); 726 for (i = 0; i < ehdr->e_shnum; i++) 727 { 728 switch (shdr[i].sh_type) { 729 case SHT_REL: 730 printf("Linux x86_64 vDSO: unexpected Rel section\n"); 731 break; 732 case SHT_RELA: 733 rela = (const Elf_Rela *)(mapping + shdr[i].sh_offset); 734 relacnt = shdr[i].sh_size / sizeof(*rela); 735 } 736 } 737 738 for (j = 0; j < relacnt; j++, rela++) { 739 where = (Elf_Addr *)(mapping + rela->r_offset); 740 addend = rela->r_addend; 741 rtype = ELF_R_TYPE(rela->r_info); 742 symidx = ELF_R_SYM(rela->r_info); 743 744 switch (rtype) { 745 case R_X86_64_NONE: /* none */ 746 break; 747 748 case R_X86_64_RELATIVE: /* B + A */ 749 addr = (Elf_Addr)(offset + addend); 750 val = addr; 751 if (*where != val) 752 *where = val; 753 break; 754 case R_X86_64_IRELATIVE: 755 printf("Linux x86_64 vDSO: unexpected ifunc relocation, " 756 "symbol index %ld\n", symidx); 757 break; 758 default: 759 printf("Linux x86_64 vDSO: unexpected relocation type %ld, " 760 "symbol index %ld\n", rtype, symidx); 761 } 762 } 763 } 764 765 static Elf_Brandnote linux64_brandnote = { 766 .hdr.n_namesz = sizeof(GNU_ABI_VENDOR), 767 .hdr.n_descsz = 16, 768 .hdr.n_type = 1, 769 .vendor = GNU_ABI_VENDOR, 770 .flags = BN_TRANSLATE_OSREL, 771 .trans_osrel = linux_trans_osrel 772 }; 773 774 static Elf64_Brandinfo linux_glibc2brand = { 775 .brand = ELFOSABI_LINUX, 776 .machine = EM_X86_64, 777 .compat_3_brand = "Linux", 778 .emul_path = linux_emul_path, 779 .interp_path = "/lib64/ld-linux-x86-64.so.2", 780 .sysvec = &elf_linux_sysvec, 781 .interp_newpath = NULL, 782 .brand_note = &linux64_brandnote, 783 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 784 }; 785 786 static Elf64_Brandinfo linux_glibc2brandshort = { 787 .brand = ELFOSABI_LINUX, 788 .machine = EM_X86_64, 789 .compat_3_brand = "Linux", 790 .emul_path = linux_emul_path, 791 .interp_path = "/lib64/ld-linux.so.2", 792 .sysvec = &elf_linux_sysvec, 793 .interp_newpath = NULL, 794 .brand_note = &linux64_brandnote, 795 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 796 }; 797 798 static Elf64_Brandinfo linux_muslbrand = { 799 .brand = ELFOSABI_LINUX, 800 .machine = EM_X86_64, 801 .compat_3_brand = "Linux", 802 .emul_path = linux_emul_path, 803 .interp_path = "/lib/ld-musl-x86_64.so.1", 804 .sysvec = &elf_linux_sysvec, 805 .interp_newpath = NULL, 806 .brand_note = &linux64_brandnote, 807 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE | 808 LINUX_BI_FUTEX_REQUEUE 809 }; 810 811 Elf64_Brandinfo *linux_brandlist[] = { 812 &linux_glibc2brand, 813 &linux_glibc2brandshort, 814 &linux_muslbrand, 815 NULL 816 }; 817 818 static int 819 linux64_elf_modevent(module_t mod, int type, void *data) 820 { 821 Elf64_Brandinfo **brandinfo; 822 int error; 823 struct linux_ioctl_handler **lihp; 824 825 error = 0; 826 827 switch(type) { 828 case MOD_LOAD: 829 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 830 ++brandinfo) 831 if (elf64_insert_brand_entry(*brandinfo) < 0) 832 error = EINVAL; 833 if (error == 0) { 834 SET_FOREACH(lihp, linux_ioctl_handler_set) 835 linux_ioctl_register_handler(*lihp); 836 stclohz = (stathz ? stathz : hz); 837 if (bootverbose) 838 printf("Linux x86-64 ELF exec handler installed\n"); 839 } else 840 printf("cannot insert Linux x86-64 ELF brand handler\n"); 841 break; 842 case MOD_UNLOAD: 843 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 844 ++brandinfo) 845 if (elf64_brand_inuse(*brandinfo)) 846 error = EBUSY; 847 if (error == 0) { 848 for (brandinfo = &linux_brandlist[0]; 849 *brandinfo != NULL; ++brandinfo) 850 if (elf64_remove_brand_entry(*brandinfo) < 0) 851 error = EINVAL; 852 } 853 if (error == 0) { 854 SET_FOREACH(lihp, linux_ioctl_handler_set) 855 linux_ioctl_unregister_handler(*lihp); 856 if (bootverbose) 857 printf("Linux x86_64 ELF exec handler removed\n"); 858 } else 859 printf("Could not deinstall Linux x86_64 ELF interpreter entry\n"); 860 break; 861 default: 862 return (EOPNOTSUPP); 863 } 864 return (error); 865 } 866 867 static moduledata_t linux64_elf_mod = { 868 "linux64elf", 869 linux64_elf_modevent, 870 0 871 }; 872 873 DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY); 874 MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1); 875 FEATURE(linux64, "Linux 64bit support"); 876