subr_copy.c revision 1.13
1 /* $NetBSD: subr_copy.c,v 1.13 2020/03/14 18:08:39 ad 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 1.13 2020/03/14 18:08:39 ad 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 preempt_point(); 127 } 128 129 if (uio->uio_rw == UIO_READ) { 130 error = copyout_vmspace(vm, cp, iov->iov_base, 131 cnt); 132 } else { 133 error = copyin_vmspace(vm, iov->iov_base, cp, 134 cnt); 135 } 136 if (error) { 137 break; 138 } 139 iov->iov_base = (char *)iov->iov_base + cnt; 140 iov->iov_len -= cnt; 141 uio->uio_resid -= cnt; 142 uio->uio_offset += cnt; 143 cp += cnt; 144 KDASSERT(cnt <= n); 145 n -= cnt; 146 } 147 148 return (error); 149 } 150 151 /* 152 * Wrapper for uiomove() that validates the arguments against a known-good 153 * kernel buffer. 154 */ 155 int 156 uiomove_frombuf(void *buf, size_t buflen, struct uio *uio) 157 { 158 size_t offset; 159 160 if (uio->uio_offset < 0 || /* uio->uio_resid < 0 || */ 161 (offset = uio->uio_offset) != uio->uio_offset) 162 return (EINVAL); 163 if (offset >= buflen) 164 return (0); 165 return (uiomove((char *)buf + offset, buflen - offset, uio)); 166 } 167 168 /* 169 * Give next character to user as result of read. 170 */ 171 int 172 ureadc(int c, struct uio *uio) 173 { 174 struct iovec *iov; 175 176 if (uio->uio_resid <= 0) 177 panic("ureadc: non-positive resid"); 178 again: 179 if (uio->uio_iovcnt <= 0) 180 panic("ureadc: non-positive iovcnt"); 181 iov = uio->uio_iov; 182 if (iov->iov_len <= 0) { 183 uio->uio_iovcnt--; 184 uio->uio_iov++; 185 goto again; 186 } 187 if (!VMSPACE_IS_KERNEL_P(uio->uio_vmspace)) { 188 int error; 189 if ((error = ustore_char(iov->iov_base, c)) != 0) 190 return (error); 191 } else { 192 *(char *)iov->iov_base = c; 193 } 194 iov->iov_base = (char *)iov->iov_base + 1; 195 iov->iov_len--; 196 uio->uio_resid--; 197 uio->uio_offset++; 198 return (0); 199 } 200 201 /* 202 * Like copyin(), but operates on an arbitrary vmspace. 203 */ 204 int 205 copyin_vmspace(struct vmspace *vm, const void *uaddr, void *kaddr, size_t len) 206 { 207 struct iovec iov; 208 struct uio uio; 209 int error; 210 211 if (len == 0) 212 return (0); 213 214 if (VMSPACE_IS_KERNEL_P(vm)) { 215 return kcopy(uaddr, kaddr, len); 216 } 217 if (__predict_true(vm == curproc->p_vmspace)) { 218 return copyin(uaddr, kaddr, len); 219 } 220 221 iov.iov_base = kaddr; 222 iov.iov_len = len; 223 uio.uio_iov = &iov; 224 uio.uio_iovcnt = 1; 225 uio.uio_offset = (off_t)(uintptr_t)uaddr; 226 uio.uio_resid = len; 227 uio.uio_rw = UIO_READ; 228 UIO_SETUP_SYSSPACE(&uio); 229 error = uvm_io(&vm->vm_map, &uio, 0); 230 231 return (error); 232 } 233 234 /* 235 * Like copyout(), but operates on an arbitrary vmspace. 236 */ 237 int 238 copyout_vmspace(struct vmspace *vm, const void *kaddr, void *uaddr, size_t len) 239 { 240 struct iovec iov; 241 struct uio uio; 242 int error; 243 244 if (len == 0) 245 return (0); 246 247 if (VMSPACE_IS_KERNEL_P(vm)) { 248 return kcopy(kaddr, uaddr, len); 249 } 250 if (__predict_true(vm == curproc->p_vmspace)) { 251 return copyout(kaddr, uaddr, len); 252 } 253 254 iov.iov_base = __UNCONST(kaddr); /* XXXUNCONST cast away const */ 255 iov.iov_len = len; 256 uio.uio_iov = &iov; 257 uio.uio_iovcnt = 1; 258 uio.uio_offset = (off_t)(uintptr_t)uaddr; 259 uio.uio_resid = len; 260 uio.uio_rw = UIO_WRITE; 261 UIO_SETUP_SYSSPACE(&uio); 262 error = uvm_io(&vm->vm_map, &uio, 0); 263 264 return (error); 265 } 266 267 /* 268 * Like copyin(), but operates on an arbitrary process. 269 */ 270 int 271 copyin_proc(struct proc *p, const void *uaddr, void *kaddr, size_t len) 272 { 273 struct vmspace *vm; 274 int error; 275 276 error = proc_vmspace_getref(p, &vm); 277 if (error) { 278 return error; 279 } 280 error = copyin_vmspace(vm, uaddr, kaddr, len); 281 uvmspace_free(vm); 282 283 return error; 284 } 285 286 /* 287 * Like copyout(), but operates on an arbitrary process. 288 */ 289 int 290 copyout_proc(struct proc *p, const void *kaddr, void *uaddr, size_t len) 291 { 292 struct vmspace *vm; 293 int error; 294 295 error = proc_vmspace_getref(p, &vm); 296 if (error) { 297 return error; 298 } 299 error = copyout_vmspace(vm, kaddr, uaddr, len); 300 uvmspace_free(vm); 301 302 return error; 303 } 304 305 /* 306 * Like copyin(), but operates on an arbitrary pid. 307 */ 308 int 309 copyin_pid(pid_t pid, const void *uaddr, void *kaddr, size_t len) 310 { 311 struct proc *p; 312 struct vmspace *vm; 313 int error; 314 315 mutex_enter(proc_lock); 316 p = proc_find(pid); 317 if (p == NULL) { 318 mutex_exit(proc_lock); 319 return ESRCH; 320 } 321 mutex_enter(p->p_lock); 322 error = proc_vmspace_getref(p, &vm); 323 mutex_exit(p->p_lock); 324 mutex_exit(proc_lock); 325 326 if (error == 0) { 327 error = copyin_vmspace(vm, uaddr, kaddr, len); 328 uvmspace_free(vm); 329 } 330 return error; 331 } 332 333 /* 334 * Like copyin(), except it operates on kernel addresses when the FKIOCTL 335 * flag is passed in `ioctlflags' from the ioctl call. 336 */ 337 int 338 ioctl_copyin(int ioctlflags, const void *src, void *dst, size_t len) 339 { 340 if (ioctlflags & FKIOCTL) 341 return kcopy(src, dst, len); 342 return copyin(src, dst, len); 343 } 344 345 /* 346 * Like copyout(), except it operates on kernel addresses when the FKIOCTL 347 * flag is passed in `ioctlflags' from the ioctl call. 348 */ 349 int 350 ioctl_copyout(int ioctlflags, const void *src, void *dst, size_t len) 351 { 352 if (ioctlflags & FKIOCTL) 353 return kcopy(src, dst, len); 354 return copyout(src, dst, len); 355 } 356 357 /* 358 * User-space CAS / fetch / store 359 */ 360 361 #ifdef __NO_STRICT_ALIGNMENT 362 #define CHECK_ALIGNMENT(x) __nothing 363 #else /* ! __NO_STRICT_ALIGNMENT */ 364 static bool 365 ufetchstore_aligned(uintptr_t uaddr, size_t size) 366 { 367 return (uaddr & (size - 1)) == 0; 368 } 369 370 #define CHECK_ALIGNMENT() \ 371 do { \ 372 if (!ufetchstore_aligned((uintptr_t)uaddr, sizeof(*uaddr))) \ 373 return EFAULT; \ 374 } while (/*CONSTCOND*/0) 375 #endif /* __NO_STRICT_ALIGNMENT */ 376 377 /* 378 * __HAVE_UCAS_FULL platforms provide _ucas_32() and _ucas_64() themselves. 379 * _RUMPKERNEL also provides it's own _ucas_32() and _ucas_64(). 380 * 381 * In all other cases, we provide generic implementations that work on 382 * all platforms. 383 */ 384 385 #if !defined(__HAVE_UCAS_FULL) && !defined(_RUMPKERNEL) 386 #if !defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 387 #include <sys/atomic.h> 388 #include <sys/cpu.h> 389 #include <sys/once.h> 390 #include <sys/mutex.h> 391 #include <sys/ipi.h> 392 393 static int ucas_critical_splcookie; 394 static volatile u_int ucas_critical_pausing_cpus; 395 static u_int ucas_critical_ipi; 396 static ONCE_DECL(ucas_critical_init_once) 397 398 static void 399 ucas_critical_cpu_gate(void *arg __unused) 400 { 401 int count = SPINLOCK_BACKOFF_MIN; 402 403 KASSERT(ucas_critical_pausing_cpus > 0); 404 atomic_dec_uint(&ucas_critical_pausing_cpus); 405 while (ucas_critical_pausing_cpus != (u_int)-1) { 406 SPINLOCK_BACKOFF(count); 407 } 408 } 409 410 static int 411 ucas_critical_init(void) 412 { 413 ucas_critical_ipi = ipi_register(ucas_critical_cpu_gate, NULL); 414 return 0; 415 } 416 417 static void 418 ucas_critical_wait(void) 419 { 420 int count = SPINLOCK_BACKOFF_MIN; 421 422 while (ucas_critical_pausing_cpus > 0) { 423 SPINLOCK_BACKOFF(count); 424 } 425 } 426 #endif /* ! __HAVE_UCAS_MP && MULTIPROCESSOR */ 427 428 static inline void 429 ucas_critical_enter(lwp_t * const l) 430 { 431 432 #if !defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 433 if (ncpu > 1) { 434 RUN_ONCE(&ucas_critical_init_once, ucas_critical_init); 435 436 /* 437 * Acquire the mutex first, then go to splhigh() and 438 * broadcast the IPI to lock all of the other CPUs 439 * behind the gate. 440 * 441 * N.B. Going to splhigh() implicitly disables preemption, 442 * so there's no need to do it explicitly. 443 */ 444 mutex_enter(&cpu_lock); 445 ucas_critical_splcookie = splhigh(); 446 ucas_critical_pausing_cpus = ncpu - 1; 447 membar_enter(); 448 449 ipi_trigger_broadcast(ucas_critical_ipi, true); 450 ucas_critical_wait(); 451 return; 452 } 453 #endif /* ! __HAVE_UCAS_MP && MULTIPROCESSOR */ 454 455 KPREEMPT_DISABLE(l); 456 } 457 458 static inline void 459 ucas_critical_exit(lwp_t * const l) 460 { 461 462 #if !defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR) 463 if (ncpu > 1) { 464 membar_exit(); 465 ucas_critical_pausing_cpus = (u_int)-1; 466 splx(ucas_critical_splcookie); 467 mutex_exit(&cpu_lock); 468 return; 469 } 470 #endif /* ! __HAVE_UCAS_MP && MULTIPROCESSOR */ 471 472 KPREEMPT_ENABLE(l); 473 } 474 475 int 476 _ucas_32(volatile uint32_t *uaddr, uint32_t old, uint32_t new, uint32_t *ret) 477 { 478 lwp_t * const l = curlwp; 479 uint32_t *uva = ((void *)(uintptr_t)uaddr); 480 int error; 481 482 /* 483 * Wire the user address down to avoid taking a page fault during 484 * the critical section. 485 */ 486 error = uvm_vslock(l->l_proc->p_vmspace, uva, sizeof(*uaddr), 487 VM_PROT_READ | VM_PROT_WRITE); 488 if (error) 489 return error; 490 491 ucas_critical_enter(l); 492 error = _ufetch_32(uva, ret); 493 if (error == 0 && *ret == old) { 494 error = _ustore_32(uva, new); 495 } 496 ucas_critical_exit(l); 497 498 uvm_vsunlock(l->l_proc->p_vmspace, uva, sizeof(*uaddr)); 499 500 return error; 501 } 502 503 #ifdef _LP64 504 int 505 _ucas_64(volatile uint64_t *uaddr, uint64_t old, uint64_t new, uint64_t *ret) 506 { 507 lwp_t * const l = curlwp; 508 uint64_t *uva = ((void *)(uintptr_t)uaddr); 509 int error; 510 511 /* 512 * Wire the user address down to avoid taking a page fault during 513 * the critical section. 514 */ 515 error = uvm_vslock(l->l_proc->p_vmspace, uva, sizeof(*uaddr), 516 VM_PROT_READ | VM_PROT_WRITE); 517 if (error) 518 return error; 519 520 ucas_critical_enter(l); 521 error = _ufetch_64(uva, ret); 522 if (error == 0 && *ret == old) { 523 error = _ustore_64(uva, new); 524 } 525 ucas_critical_exit(l); 526 527 uvm_vsunlock(l->l_proc->p_vmspace, uva, sizeof(*uaddr)); 528 529 return error; 530 } 531 #endif /* _LP64 */ 532 #endif /* ! __HAVE_UCAS_FULL && ! _RUMPKERNEL */ 533 534 int 535 ucas_32(volatile uint32_t *uaddr, uint32_t old, uint32_t new, uint32_t *ret) 536 { 537 538 ASSERT_SLEEPABLE(); 539 CHECK_ALIGNMENT(); 540 #if (defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR)) && \ 541 !defined(_RUMPKERNEL) 542 if (ncpu > 1) { 543 return _ucas_32_mp(uaddr, old, new, ret); 544 } 545 #endif /* __HAVE_UCAS_MP && MULTIPROCESSOR */ 546 return _ucas_32(uaddr, old, new, ret); 547 } 548 549 #ifdef _LP64 550 int 551 ucas_64(volatile uint64_t *uaddr, uint64_t old, uint64_t new, uint64_t *ret) 552 { 553 554 ASSERT_SLEEPABLE(); 555 CHECK_ALIGNMENT(); 556 #if (defined(__HAVE_UCAS_MP) && defined(MULTIPROCESSOR)) && \ 557 !defined(_RUMPKERNEL) 558 if (ncpu > 1) { 559 return _ucas_64_mp(uaddr, old, new, ret); 560 } 561 #endif /* __HAVE_UCAS_MP && MULTIPROCESSOR */ 562 return _ucas_64(uaddr, old, new, ret); 563 } 564 #endif /* _LP64 */ 565 566 __strong_alias(ucas_int,ucas_32); 567 #ifdef _LP64 568 __strong_alias(ucas_ptr,ucas_64); 569 #else 570 __strong_alias(ucas_ptr,ucas_32); 571 #endif /* _LP64 */ 572 573 int 574 ufetch_8(const uint8_t *uaddr, uint8_t *valp) 575 { 576 577 ASSERT_SLEEPABLE(); 578 CHECK_ALIGNMENT(); 579 return _ufetch_8(uaddr, valp); 580 } 581 582 int 583 ufetch_16(const uint16_t *uaddr, uint16_t *valp) 584 { 585 586 ASSERT_SLEEPABLE(); 587 CHECK_ALIGNMENT(); 588 return _ufetch_16(uaddr, valp); 589 } 590 591 int 592 ufetch_32(const uint32_t *uaddr, uint32_t *valp) 593 { 594 595 ASSERT_SLEEPABLE(); 596 CHECK_ALIGNMENT(); 597 return _ufetch_32(uaddr, valp); 598 } 599 600 #ifdef _LP64 601 int 602 ufetch_64(const uint64_t *uaddr, uint64_t *valp) 603 { 604 605 ASSERT_SLEEPABLE(); 606 CHECK_ALIGNMENT(); 607 return _ufetch_64(uaddr, valp); 608 } 609 #endif /* _LP64 */ 610 611 __strong_alias(ufetch_char,ufetch_8); 612 __strong_alias(ufetch_short,ufetch_16); 613 __strong_alias(ufetch_int,ufetch_32); 614 #ifdef _LP64 615 __strong_alias(ufetch_long,ufetch_64); 616 __strong_alias(ufetch_ptr,ufetch_64); 617 #else 618 __strong_alias(ufetch_long,ufetch_32); 619 __strong_alias(ufetch_ptr,ufetch_32); 620 #endif /* _LP64 */ 621 622 int 623 ustore_8(uint8_t *uaddr, uint8_t val) 624 { 625 626 ASSERT_SLEEPABLE(); 627 CHECK_ALIGNMENT(); 628 return _ustore_8(uaddr, val); 629 } 630 631 int 632 ustore_16(uint16_t *uaddr, uint16_t val) 633 { 634 635 ASSERT_SLEEPABLE(); 636 CHECK_ALIGNMENT(); 637 return _ustore_16(uaddr, val); 638 } 639 640 int 641 ustore_32(uint32_t *uaddr, uint32_t val) 642 { 643 644 ASSERT_SLEEPABLE(); 645 CHECK_ALIGNMENT(); 646 return _ustore_32(uaddr, val); 647 } 648 649 #ifdef _LP64 650 int 651 ustore_64(uint64_t *uaddr, uint64_t val) 652 { 653 654 ASSERT_SLEEPABLE(); 655 CHECK_ALIGNMENT(); 656 return _ustore_64(uaddr, val); 657 } 658 #endif /* _LP64 */ 659 660 __strong_alias(ustore_char,ustore_8); 661 __strong_alias(ustore_short,ustore_16); 662 __strong_alias(ustore_int,ustore_32); 663 #ifdef _LP64 664 __strong_alias(ustore_long,ustore_64); 665 __strong_alias(ustore_ptr,ustore_64); 666 #else 667 __strong_alias(ustore_long,ustore_32); 668 __strong_alias(ustore_ptr,ustore_32); 669 #endif /* _LP64 */ 670
Indexes created Wed Sep 24 05:09:52 GMT 2025