subr_copy.c revision 1.9
1 /* $NetBSD: subr_copy.c,v 1.9 2019/04/06 03:06:28 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008, 2019 5 * The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 10 * NASA Ames Research Center. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Copyright (c) 1992, 1993 44 * The Regents of the University of California. All rights reserved. 45 * 46 * This software was developed by the Computer Systems Engineering group 47 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 48 * contributed to Berkeley. 49 * 50 * All advertising materials mentioning features or use of this software 51 * must display the following acknowledgement: 52 * This product includes software developed by the University of 53 * California, Lawrence Berkeley Laboratory. 54 * 55 * Redistribution and use in source and binary forms, with or without 56 * modification, are permitted provided that the following conditions 57 * are met: 58 * 1. Redistributions of source code must retain the above copyright 59 * notice, this list of conditions and the following disclaimer. 60 * 2. Redistributions in binary form must reproduce the above copyright 61 * notice, this list of conditions and the following disclaimer in the 62 * documentation and/or other materials provided with the distribution. 63 * 3. Neither the name of the University nor the names of its contributors 64 * may be used to endorse or promote products derived from this software 65 * without specific prior written permission. 66 * 67 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 68 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 69 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 70 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 71 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 72 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 73 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 74 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 75 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 76 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 77 * SUCH DAMAGE. 78 * 79 * @(#)kern_subr.c 8.4 (Berkeley) 2/14/95 80 */ 81 82 #include <sys/cdefs.h> 83 __KERNEL_RCSID(0, "$NetBSD: subr_copy.c,v 1.9 2019/04/06 03:06:28 thorpej Exp $"); 84 85 #define __UFETCHSTORE_PRIVATE 86 #define __UCAS_PRIVATE 87 88 #include <sys/param.h> 89 #include <sys/fcntl.h> 90 #include <sys/proc.h> 91 #include <sys/systm.h> 92 93 #include <uvm/uvm_extern.h> 94 95 void 96 uio_setup_sysspace(struct uio *uio) 97 { 98 99 uio->uio_vmspace = vmspace_kernel(); 100 } 101 102 int 103 uiomove(void *buf, size_t n, struct uio *uio) 104 { 105 struct vmspace *vm = uio->uio_vmspace; 106 struct iovec *iov; 107 size_t cnt; 108 int error = 0; 109 char *cp = buf; 110 111 ASSERT_SLEEPABLE(); 112 113 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE); 114 while (n > 0 && uio->uio_resid) { 115 iov = uio->uio_iov; 116 cnt = iov->iov_len; 117 if (cnt == 0) { 118 KASSERT(uio->uio_iovcnt > 0); 119 uio->uio_iov++; 120 uio->uio_iovcnt--; 121 continue; 122 } 123 if (cnt > n) 124 cnt = n; 125 if (!VMSPACE_IS_KERNEL_P(vm)) { 126 if (curcpu()->ci_schedstate.spc_flags & 127 SPCF_SHOULDYIELD) 128 preempt(); 129 } 130 131 if (uio->uio_rw == UIO_READ) { 132 error = copyout_vmspace(vm, cp, iov->iov_base, 133 cnt); 134 } else { 135 error = copyin_vmspace(vm, iov->iov_base, cp, 136 cnt); 137 } 138 if (error) { 139 break; 140 } 141 iov->iov_base = (char *)iov->iov_base + cnt; 142 iov->iov_len -= cnt; 143 uio->uio_resid -= cnt; 144 uio->uio_offset += cnt; 145 cp += cnt; 146 KDASSERT(cnt <= n); 147 n -= cnt; 148 } 149 150 return (error); 151 } 152 153 /* 154 * Wrapper for uiomove() that validates the arguments against a known-good 155 * kernel buffer. 156 */ 157 int 158 uiomove_frombuf(void *buf, size_t buflen, struct uio *uio) 159 { 160 size_t offset; 161 162 if (uio->uio_offset < 0 || /* uio->uio_resid < 0 || */ 163 (offset = uio->uio_offset) != uio->uio_offset) 164 return (EINVAL); 165 if (offset >= buflen) 166 return (0); 167 return (uiomove((char *)buf + offset, buflen - offset, uio)); 168 } 169 170 /* 171 * Give next character to user as result of read. 172 */ 173 int 174 ureadc(int c, struct uio *uio) 175 { 176 struct iovec *iov; 177 178 if (uio->uio_resid <= 0) 179 panic("ureadc: non-positive resid"); 180 again: 181 if (uio->uio_iovcnt <= 0) 182 panic("ureadc: non-positive iovcnt"); 183 iov = uio->uio_iov; 184 if (iov->iov_len <= 0) { 185 uio->uio_iovcnt--; 186 uio->uio_iov++; 187 goto again; 188 } 189 if (!VMSPACE_IS_KERNEL_P(uio->uio_vmspace)) { 190 int error; 191 if ((error = ustore_char(iov->iov_base, c)) != 0) 192 return (error); 193 } else { 194 *(char *)iov->iov_base = c; 195 } 196 iov->iov_base = (char *)iov->iov_base + 1; 197 iov->iov_len--; 198 uio->uio_resid--; 199 uio->uio_offset++; 200 return (0); 201 } 202 203 /* 204 * Like copyin(), but operates on an arbitrary vmspace. 205 */ 206 int 207 copyin_vmspace(struct vmspace *vm, const void *uaddr, void *kaddr, size_t len) 208 { 209 struct iovec iov; 210 struct uio uio; 211 int error; 212 213 if (len == 0) 214 return (0); 215 216 if (VMSPACE_IS_KERNEL_P(vm)) { 217 return kcopy(uaddr, kaddr, len); 218 } 219 if (__predict_true(vm == curproc->p_vmspace)) { 220 return copyin(uaddr, kaddr, len); 221 } 222 223 iov.iov_base = kaddr; 224 iov.iov_len = len; 225 uio.uio_iov = &iov; 226 uio.uio_iovcnt = 1; 227 uio.uio_offset = (off_t)(uintptr_t)uaddr; 228 uio.uio_resid = len; 229 uio.uio_rw = UIO_READ; 230 UIO_SETUP_SYSSPACE(&uio); 231 error = uvm_io(&vm->vm_map, &uio, 0); 232 233 return (error); 234 } 235 236 /* 237 * Like copyout(), but operates on an arbitrary vmspace. 238 */ 239 int 240 copyout_vmspace(struct vmspace *vm, const void *kaddr, void *uaddr, size_t len) 241 { 242 struct iovec iov; 243 struct uio uio; 244 int error; 245 246 if (len == 0) 247 return (0); 248 249 if (VMSPACE_IS_KERNEL_P(vm)) { 250 return kcopy(kaddr, uaddr, len); 251 } 252 if (__predict_true(vm == curproc->p_vmspace)) { 253 return copyout(kaddr, uaddr, len); 254 } 255 256 iov.iov_base = __UNCONST(kaddr); /* XXXUNCONST cast away const */ 257 iov.iov_len = len; 258 uio.uio_iov = &iov; 259 uio.uio_iovcnt = 1; 260 uio.uio_offset = (off_t)(uintptr_t)uaddr; 261 uio.uio_resid = len; 262 uio.uio_rw = UIO_WRITE; 263 UIO_SETUP_SYSSPACE(&uio); 264 error = uvm_io(&vm->vm_map, &uio, 0); 265 266 return (error); 267 } 268 269 /* 270 * Like copyin(), but operates on an arbitrary process. 271 */ 272 int 273 copyin_proc(struct proc *p, const void *uaddr, void *kaddr, size_t len) 274 { 275 struct vmspace *vm; 276 int error; 277 278 error = proc_vmspace_getref(p, &vm); 279 if (error) { 280 return error; 281 } 282 error = copyin_vmspace(vm, uaddr, kaddr, len); 283 uvmspace_free(vm); 284 285 return error; 286 } 287 288 /* 289 * Like copyout(), but operates on an arbitrary process. 290 */ 291 int 292 copyout_proc(struct proc *p, const void *kaddr, void *uaddr, size_t len) 293 { 294 struct vmspace *vm; 295 int error; 296 297 error = proc_vmspace_getref(p, &vm); 298 if (error) { 299 return error; 300 } 301 error = copyout_vmspace(vm, kaddr, uaddr, len); 302 uvmspace_free(vm); 303 304 return error; 305 } 306 307 /* 308 * Like copyin(), but operates on an arbitrary pid. 309 */ 310 int 311 copyin_pid(pid_t pid, const void *uaddr, void *kaddr, size_t len) 312 { 313 struct proc *p; 314 struct vmspace *vm; 315 int error; 316 317 mutex_enter(proc_lock); 318 p = proc_find(pid); 319 if (p == NULL) { 320 mutex_exit(proc_lock); 321 return ESRCH; 322 } 323 mutex_enter(p->p_lock); 324 proc_vmspace_getref(p, &vm); 325 mutex_exit(p->p_lock); 326 mutex_exit(proc_lock); 327 328 error = copyin_vmspace(vm, uaddr, kaddr, len); 329 330 uvmspace_free(vm); 331 return error; 332 } 333 334 /* 335 * Like copyin(), except it operates on kernel addresses when the FKIOCTL 336 * flag is passed in `ioctlflags' from the ioctl call. 337 */ 338 int 339 ioctl_copyin(int ioctlflags, const void *src, void *dst, size_t len) 340 { 341 if (ioctlflags & FKIOCTL) 342 return kcopy(src, dst, len); 343 return copyin(src, dst, len); 344 } 345 346 /* 347 * Like copyout(), except it operates on kernel addresses when the FKIOCTL 348 * flag is passed in `ioctlflags' from the ioctl call. 349 */ 350 int 351 ioctl_copyout(int ioctlflags, const void *src, void *dst, size_t len) 352 { 353 if (ioctlflags & FKIOCTL) 354 return kcopy(src, dst, len); 355 return copyout(src, dst, len); 356 } 357 358 /* 359 * User-space CAS / fetch / store 360 */ 361 362 #ifdef __NO_STRICT_ALIGNMENT 363 #define CHECK_ALIGNMENT(x) __nothing 364 #else /* ! __NO_STRICT_ALIGNMENT */ 365 static bool 366 ufetchstore_aligned(uintptr_t uaddr, size_t size) 367 { 368 return (uaddr & (size - 1)) == 0; 369 } 370 371 #define CHECK_ALIGNMENT() \ 372 do { \ 373 if (!ufetchstore_aligned((uintptr_t)uaddr, sizeof(*uaddr))) \ 374 return EFAULT; \ 375 } while (/*CONSTCOND*/0) 376 #endif /* __NO_STRICT_ALIGNMENT */ 377 378 #ifndef __HAVE_UCAS_FULL 379 #if !defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 380 #include <sys/atomic.h> 381 #include <sys/cpu.h> 382 #include <sys/once.h> 383 #include <sys/mutex.h> 384 #include <sys/ipi.h> 385 386 static int ucas_critical_splcookie; 387 static volatile u_int ucas_critical_pausing_cpus; 388 static u_int ucas_critical_ipi; 389 static ONCE_DECL(ucas_critical_init_once) 390 391 static void 392 ucas_critical_cpu_gate(void *arg __unused) 393 { 394 int count = SPINLOCK_BACKOFF_MIN; 395 396 KASSERT(ucas_critical_pausing_cpus > 0); 397 atomic_dec_uint(&ucas_critical_pausing_cpus); 398 while (ucas_critical_pausing_cpus != (u_int)-1) { 399 SPINLOCK_BACKOFF(count); 400 } 401 } 402 403 static int 404 ucas_critical_init(void) 405 { 406 ucas_critical_ipi = ipi_register(ucas_critical_cpu_gate, NULL); 407 return 0; 408 } 409 410 static void 411 ucas_critical_wait(void) 412 { 413 int count = SPINLOCK_BACKOFF_MIN; 414 415 while (ucas_critical_pausing_cpus > 0) { 416 SPINLOCK_BACKOFF(count); 417 } 418 } 419 #endif /* ! __HAVE_UCAS_MP && MULTIPROCESSOR */ 420 421 static inline void 422 ucas_critical_enter(lwp_t * const l) 423 { 424 425 #if !defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 426 if (ncpu > 1) { 427 RUN_ONCE(&ucas_critical_init_once, ucas_critical_init); 428 429 /* 430 * Acquire the mutex first, then go to splhigh() and 431 * broadcast the IPI to lock all of the other CPUs 432 * behind the gate. 433 * 434 * N.B. Going to splhigh() implicitly disables preemption, 435 * so there's no need to do it explicitly. 436 */ 437 mutex_enter(&cpu_lock); 438 ucas_critical_splcookie = splhigh(); 439 ucas_critical_pausing_cpus = ncpu - 1; 440 membar_enter(); 441 442 ipi_trigger_broadcast(ucas_critical_ipi, true); 443 ucas_critical_wait(); 444 return; 445 } 446 #endif /* ! __HAVE_UCAS_MP && MULTIPROCESSOR */ 447 448 KPREEMPT_DISABLE(l); 449 } 450 451 static inline void 452 ucas_critical_exit(lwp_t * const l) 453 { 454 455 #if !defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 456 if (ncpu > 1) { 457 membar_exit(); 458 ucas_critical_pausing_cpus = (u_int)-1; 459 splx(ucas_critical_splcookie); 460 mutex_exit(&cpu_lock); 461 return; 462 } 463 #endif /* ! __HAVE_UCAS_MP && MULTIPROCESSOR */ 464 465 KPREEMPT_ENABLE(l); 466 } 467 468 int 469 _ucas_32(volatile uint32_t *uaddr, uint32_t old, uint32_t new, uint32_t *ret) 470 { 471 lwp_t * const l = curlwp; 472 uint32_t *uva = ((void *)(uintptr_t)uaddr); 473 int error; 474 475 /* 476 * Wire the user address down to avoid taking a page fault during 477 * the critical section. 478 */ 479 error = uvm_vslock(l->l_proc->p_vmspace, uva, sizeof(*uaddr), 480 VM_PROT_READ | VM_PROT_WRITE); 481 if (error) 482 return error; 483 484 ucas_critical_enter(l); 485 error = _ufetch_32(uva, ret); 486 if (error == 0 && *ret == old) { 487 error = _ustore_32(uva, new); 488 } 489 ucas_critical_exit(l); 490 491 uvm_vsunlock(l->l_proc->p_vmspace, uva, sizeof(*uaddr)); 492 493 return error; 494 } 495 496 #ifdef _LP64 497 int 498 _ucas_64(volatile uint64_t *uaddr, uint64_t old, uint64_t new, uint64_t *ret) 499 { 500 lwp_t * const l = curlwp; 501 uint64_t *uva = ((void *)(uintptr_t)uaddr); 502 int error; 503 504 /* 505 * Wire the user address down to avoid taking a page fault during 506 * the critical section. 507 */ 508 error = uvm_vslock(l->l_proc->p_vmspace, uva, sizeof(*uaddr), 509 VM_PROT_READ | VM_PROT_WRITE); 510 if (error) 511 return error; 512 513 ucas_critical_enter(l); 514 error = _ufetch_64(uva, ret); 515 if (error == 0 && *ret == old) { 516 error = _ustore_64(uva, new); 517 } 518 ucas_critical_exit(l); 519 520 uvm_vsunlock(l->l_proc->p_vmspace, uva, sizeof(*uaddr)); 521 522 return error; 523 } 524 #endif /* _LP64 */ 525 #endif /* ! __HAVE_UCAS_FULL */ 526 527 int 528 ucas_32(volatile uint32_t *uaddr, uint32_t old, uint32_t new, uint32_t *ret) 529 { 530 531 ASSERT_SLEEPABLE(); 532 CHECK_ALIGNMENT(); 533 #if defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 534 if (ncpu > 1) { 535 return _ucas_32_mp(uaddr, old, new, ret); 536 } 537 #endif /* __HAVE_UCAS_MP && MULTIPROCESSOR */ 538 return _ucas_32(uaddr, old, new, ret); 539 } 540 541 #ifdef _LP64 542 int 543 ucas_64(volatile uint64_t *uaddr, uint64_t old, uint64_t new, uint64_t *ret) 544 { 545 546 ASSERT_SLEEPABLE(); 547 CHECK_ALIGNMENT(); 548 #if defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 549 if (ncpu > 1) { 550 return _ucas_64_mp(uaddr, old, new, ret); 551 } 552 #endif /* __HAVE_UCAS_MP && MULTIPROCESSOR */ 553 return _ucas_64(uaddr, old, new, ret); 554 } 555 #endif /* _LP64 */ 556 557 __strong_alias(ucas_int,ucas_32); 558 #ifdef _LP64 559 __strong_alias(ucas_ptr,ucas_64); 560 #else 561 __strong_alias(ucas_ptr,ucas_32); 562 #endif /* _LP64 */ 563 564 int 565 ufetch_8(const uint8_t *uaddr, uint8_t *valp) 566 { 567 568 ASSERT_SLEEPABLE(); 569 CHECK_ALIGNMENT(); 570 return _ufetch_8(uaddr, valp); 571 } 572 573 int 574 ufetch_16(const uint16_t *uaddr, uint16_t *valp) 575 { 576 577 ASSERT_SLEEPABLE(); 578 CHECK_ALIGNMENT(); 579 return _ufetch_16(uaddr, valp); 580 } 581 582 int 583 ufetch_32(const uint32_t *uaddr, uint32_t *valp) 584 { 585 586 ASSERT_SLEEPABLE(); 587 CHECK_ALIGNMENT(); 588 return _ufetch_32(uaddr, valp); 589 } 590 591 #ifdef _LP64 592 int 593 ufetch_64(const uint64_t *uaddr, uint64_t *valp) 594 { 595 596 ASSERT_SLEEPABLE(); 597 CHECK_ALIGNMENT(); 598 return _ufetch_64(uaddr, valp); 599 } 600 #endif /* _LP64 */ 601 602 __strong_alias(ufetch_char,ufetch_8); 603 __strong_alias(ufetch_short,ufetch_16); 604 __strong_alias(ufetch_int,ufetch_32); 605 #ifdef _LP64 606 __strong_alias(ufetch_long,ufetch_64); 607 __strong_alias(ufetch_ptr,ufetch_64); 608 #else 609 __strong_alias(ufetch_long,ufetch_32); 610 __strong_alias(ufetch_ptr,ufetch_32); 611 #endif /* _LP64 */ 612 613 int 614 ustore_8(uint8_t *uaddr, uint8_t val) 615 { 616 617 ASSERT_SLEEPABLE(); 618 CHECK_ALIGNMENT(); 619 return _ustore_8(uaddr, val); 620 } 621 622 int 623 ustore_16(uint16_t *uaddr, uint16_t val) 624 { 625 626 ASSERT_SLEEPABLE(); 627 CHECK_ALIGNMENT(); 628 return _ustore_16(uaddr, val); 629 } 630 631 int 632 ustore_32(uint32_t *uaddr, uint32_t val) 633 { 634 635 ASSERT_SLEEPABLE(); 636 CHECK_ALIGNMENT(); 637 return _ustore_32(uaddr, val); 638 } 639 640 #ifdef _LP64 641 int 642 ustore_64(uint64_t *uaddr, uint64_t val) 643 { 644 645 ASSERT_SLEEPABLE(); 646 CHECK_ALIGNMENT(); 647 return _ustore_64(uaddr, val); 648 } 649 #endif /* _LP64 */ 650 651 __strong_alias(ustore_char,ustore_8); 652 __strong_alias(ustore_short,ustore_16); 653 __strong_alias(ustore_int,ustore_32); 654 #ifdef _LP64 655 __strong_alias(ustore_long,ustore_64); 656 __strong_alias(ustore_ptr,ustore_64); 657 #else 658 __strong_alias(ustore_long,ustore_32); 659 __strong_alias(ustore_ptr,ustore_32); 660 #endif /* _LP64 */ 661
Indexes created Mon Sep 22 05:09:51 GMT 2025