xref: /freebsd/sys/kern/subr_uio.c (revision 6be3386466ab79a84b48429ae66244f21526d3df) 
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Copyright (c) 2014 The FreeBSD Foundation
13  *
14  * Portions of this software were developed by Konstantin Belousov
15  * under sponsorship from the FreeBSD Foundation.
16  *
17  * Redistribution and use in source and binary forms, with or without
18  * modification, are permitted provided that the following conditions
19  * are met:
20  * 1. Redistributions of source code must retain the above copyright
21  *    notice, this list of conditions and the following disclaimer.
22  * 2. Redistributions in binary form must reproduce the above copyright
23  *    notice, this list of conditions and the following disclaimer in the
24  *    documentation and/or other materials provided with the distribution.
25  * 3. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *	@(#)kern_subr.c	8.3 (Berkeley) 1/21/94
42  */
43 
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/kernel.h>
50 #include <sys/limits.h>
51 #include <sys/lock.h>
52 #include <sys/mman.h>
53 #include <sys/proc.h>
54 #include <sys/resourcevar.h>
55 #include <sys/rwlock.h>
56 #include <sys/sched.h>
57 #include <sys/sysctl.h>
58 #include <sys/vnode.h>
59 
60 #include <vm/vm.h>
61 #include <vm/vm_param.h>
62 #include <vm/vm_extern.h>
63 #include <vm/vm_page.h>
64 #include <vm/vm_pageout.h>
65 #include <vm/vm_map.h>
66 
67 #include <machine/bus.h>
68 
69 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, UIO_MAXIOV,
70 	"Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
71 
72 static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
73 
74 int
75 copyin_nofault(const void *udaddr, void *kaddr, size_t len)
76 {
77 	int error, save;
78 
79 	save = vm_fault_disable_pagefaults();
80 	error = copyin(udaddr, kaddr, len);
81 	vm_fault_enable_pagefaults(save);
82 	return (error);
83 }
84 
85 int
86 copyout_nofault(const void *kaddr, void *udaddr, size_t len)
87 {
88 	int error, save;
89 
90 	save = vm_fault_disable_pagefaults();
91 	error = copyout(kaddr, udaddr, len);
92 	vm_fault_enable_pagefaults(save);
93 	return (error);
94 }
95 
96 #define	PHYS_PAGE_COUNT(len)	(howmany(len, PAGE_SIZE) + 1)
97 
98 int
99 physcopyin(void *src, vm_paddr_t dst, size_t len)
100 {
101 	vm_page_t m[PHYS_PAGE_COUNT(len)];
102 	struct iovec iov[1];
103 	struct uio uio;
104 	int i;
105 
106 	iov[0].iov_base = src;
107 	iov[0].iov_len = len;
108 	uio.uio_iov = iov;
109 	uio.uio_iovcnt = 1;
110 	uio.uio_offset = 0;
111 	uio.uio_resid = len;
112 	uio.uio_segflg = UIO_SYSSPACE;
113 	uio.uio_rw = UIO_WRITE;
114 	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, dst += PAGE_SIZE)
115 		m[i] = PHYS_TO_VM_PAGE(dst);
116 	return (uiomove_fromphys(m, dst & PAGE_MASK, len, &uio));
117 }
118 
119 int
120 physcopyout(vm_paddr_t src, void *dst, size_t len)
121 {
122 	vm_page_t m[PHYS_PAGE_COUNT(len)];
123 	struct iovec iov[1];
124 	struct uio uio;
125 	int i;
126 
127 	iov[0].iov_base = dst;
128 	iov[0].iov_len = len;
129 	uio.uio_iov = iov;
130 	uio.uio_iovcnt = 1;
131 	uio.uio_offset = 0;
132 	uio.uio_resid = len;
133 	uio.uio_segflg = UIO_SYSSPACE;
134 	uio.uio_rw = UIO_READ;
135 	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, src += PAGE_SIZE)
136 		m[i] = PHYS_TO_VM_PAGE(src);
137 	return (uiomove_fromphys(m, src & PAGE_MASK, len, &uio));
138 }
139 
140 #undef PHYS_PAGE_COUNT
141 
142 int
143 physcopyin_vlist(bus_dma_segment_t *src, off_t offset, vm_paddr_t dst,
144     size_t len)
145 {
146 	size_t seg_len;
147 	int error;
148 
149 	error = 0;
150 	while (offset >= src->ds_len) {
151 		offset -= src->ds_len;
152 		src++;
153 	}
154 
155 	while (len > 0 && error == 0) {
156 		seg_len = MIN(src->ds_len - offset, len);
157 		error = physcopyin((void *)(uintptr_t)(src->ds_addr + offset),
158 		    dst, seg_len);
159 		offset = 0;
160 		src++;
161 		len -= seg_len;
162 		dst += seg_len;
163 	}
164 
165 	return (error);
166 }
167 
168 int
169 physcopyout_vlist(vm_paddr_t src, bus_dma_segment_t *dst, off_t offset,
170     size_t len)
171 {
172 	size_t seg_len;
173 	int error;
174 
175 	error = 0;
176 	while (offset >= dst->ds_len) {
177 		offset -= dst->ds_len;
178 		dst++;
179 	}
180 
181 	while (len > 0 && error == 0) {
182 		seg_len = MIN(dst->ds_len - offset, len);
183 		error = physcopyout(src, (void *)(uintptr_t)(dst->ds_addr +
184 		    offset), seg_len);
185 		offset = 0;
186 		dst++;
187 		len -= seg_len;
188 		src += seg_len;
189 	}
190 
191 	return (error);
192 }
193 
194 int
195 uiomove(void *cp, int n, struct uio *uio)
196 {
197 
198 	return (uiomove_faultflag(cp, n, uio, 0));
199 }
200 
201 int
202 uiomove_nofault(void *cp, int n, struct uio *uio)
203 {
204 
205 	return (uiomove_faultflag(cp, n, uio, 1));
206 }
207 
208 static int
209 uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
210 {
211 	struct iovec *iov;
212 	size_t cnt;
213 	int error, newflags, save;
214 
215 	save = error = 0;
216 
217 	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
218 	    ("uiomove: mode"));
219 	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
220 	    ("uiomove proc"));
221 
222 	if (uio->uio_segflg == UIO_USERSPACE) {
223 		newflags = TDP_DEADLKTREAT;
224 		if (nofault) {
225 			/*
226 			 * Fail if a non-spurious page fault occurs.
227 			 */
228 			newflags |= TDP_NOFAULTING | TDP_RESETSPUR;
229 		} else {
230 			WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
231 			    "Calling uiomove()");
232 		}
233 		save = curthread_pflags_set(newflags);
234 	} else {
235 		KASSERT(nofault == 0, ("uiomove: nofault"));
236 	}
237 
238 	while (n > 0 && uio->uio_resid) {
239 		iov = uio->uio_iov;
240 		cnt = iov->iov_len;
241 		if (cnt == 0) {
242 			uio->uio_iov++;
243 			uio->uio_iovcnt--;
244 			continue;
245 		}
246 		if (cnt > n)
247 			cnt = n;
248 
249 		switch (uio->uio_segflg) {
250 		case UIO_USERSPACE:
251 			maybe_yield();
252 			if (uio->uio_rw == UIO_READ)
253 				error = copyout(cp, iov->iov_base, cnt);
254 			else
255 				error = copyin(iov->iov_base, cp, cnt);
256 			if (error)
257 				goto out;
258 			break;
259 
260 		case UIO_SYSSPACE:
261 			if (uio->uio_rw == UIO_READ)
262 				bcopy(cp, iov->iov_base, cnt);
263 			else
264 				bcopy(iov->iov_base, cp, cnt);
265 			break;
266 		case UIO_NOCOPY:
267 			break;
268 		}
269 		iov->iov_base = (char *)iov->iov_base + cnt;
270 		iov->iov_len -= cnt;
271 		uio->uio_resid -= cnt;
272 		uio->uio_offset += cnt;
273 		cp = (char *)cp + cnt;
274 		n -= cnt;
275 	}
276 out:
277 	if (save)
278 		curthread_pflags_restore(save);
279 	return (error);
280 }
281 
282 /*
283  * Wrapper for uiomove() that validates the arguments against a known-good
284  * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
285  * is almost definitely a bad thing, so we catch that here as well.  We
286  * return a runtime failure, but it might be desirable to generate a runtime
287  * assertion failure instead.
288  */
289 int
290 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
291 {
292 	size_t offset, n;
293 
294 	if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
295 	    (offset = uio->uio_offset) != uio->uio_offset)
296 		return (EINVAL);
297 	if (buflen <= 0 || offset >= buflen)
298 		return (0);
299 	if ((n = buflen - offset) > IOSIZE_MAX)
300 		return (EINVAL);
301 	return (uiomove((char *)buf + offset, n, uio));
302 }
303 
304 /*
305  * Give next character to user as result of read.
306  */
307 int
308 ureadc(int c, struct uio *uio)
309 {
310 	struct iovec *iov;
311 	char *iov_base;
312 
313 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
314 	    "Calling ureadc()");
315 
316 again:
317 	if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
318 		panic("ureadc");
319 	iov = uio->uio_iov;
320 	if (iov->iov_len == 0) {
321 		uio->uio_iovcnt--;
322 		uio->uio_iov++;
323 		goto again;
324 	}
325 	switch (uio->uio_segflg) {
326 	case UIO_USERSPACE:
327 		if (subyte(iov->iov_base, c) < 0)
328 			return (EFAULT);
329 		break;
330 
331 	case UIO_SYSSPACE:
332 		iov_base = iov->iov_base;
333 		*iov_base = c;
334 		break;
335 
336 	case UIO_NOCOPY:
337 		break;
338 	}
339 	iov->iov_base = (char *)iov->iov_base + 1;
340 	iov->iov_len--;
341 	uio->uio_resid--;
342 	uio->uio_offset++;
343 	return (0);
344 }
345 
346 int
347 copyiniov(const struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
348 {
349 	u_int iovlen;
350 
351 	*iov = NULL;
352 	if (iovcnt > UIO_MAXIOV)
353 		return (error);
354 	iovlen = iovcnt * sizeof (struct iovec);
355 	*iov = malloc(iovlen, M_IOV, M_WAITOK);
356 	error = copyin(iovp, *iov, iovlen);
357 	if (error) {
358 		free(*iov, M_IOV);
359 		*iov = NULL;
360 	}
361 	return (error);
362 }
363 
364 int
365 copyinuio(const struct iovec *iovp, u_int iovcnt, struct uio **uiop)
366 {
367 	struct iovec *iov;
368 	struct uio *uio;
369 	u_int iovlen;
370 	int error, i;
371 
372 	*uiop = NULL;
373 	if (iovcnt > UIO_MAXIOV)
374 		return (EINVAL);
375 	iovlen = iovcnt * sizeof (struct iovec);
376 	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
377 	iov = (struct iovec *)(uio + 1);
378 	error = copyin(iovp, iov, iovlen);
379 	if (error) {
380 		free(uio, M_IOV);
381 		return (error);
382 	}
383 	uio->uio_iov = iov;
384 	uio->uio_iovcnt = iovcnt;
385 	uio->uio_segflg = UIO_USERSPACE;
386 	uio->uio_offset = -1;
387 	uio->uio_resid = 0;
388 	for (i = 0; i < iovcnt; i++) {
389 		if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) {
390 			free(uio, M_IOV);
391 			return (EINVAL);
392 		}
393 		uio->uio_resid += iov->iov_len;
394 		iov++;
395 	}
396 	*uiop = uio;
397 	return (0);
398 }
399 
400 struct uio *
401 cloneuio(struct uio *uiop)
402 {
403 	struct uio *uio;
404 	int iovlen;
405 
406 	iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
407 	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
408 	*uio = *uiop;
409 	uio->uio_iov = (struct iovec *)(uio + 1);
410 	bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
411 	return (uio);
412 }
413 
414 /*
415  * Map some anonymous memory in user space of size sz, rounded up to the page
416  * boundary.
417  */
418 int
419 copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
420 {
421 	struct vmspace *vms;
422 	int error;
423 	vm_size_t size;
424 
425 	vms = td->td_proc->p_vmspace;
426 
427 	/*
428 	 * Map somewhere after heap in process memory.
429 	 */
430 	*addr = round_page((vm_offset_t)vms->vm_daddr +
431 	    lim_max(td, RLIMIT_DATA));
432 
433 	/* round size up to page boundary */
434 	size = (vm_size_t)round_page(sz);
435 	if (size == 0)
436 		return (EINVAL);
437 	error = vm_mmap_object(&vms->vm_map, addr, size, VM_PROT_READ |
438 	    VM_PROT_WRITE, VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, NULL, 0,
439 	    FALSE, td);
440 	return (error);
441 }
442 
443 /*
444  * Unmap memory in user space.
445  */
446 int
447 copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
448 {
449 	vm_map_t map;
450 	vm_size_t size;
451 
452 	if (sz == 0)
453 		return (0);
454 
455 	map = &td->td_proc->p_vmspace->vm_map;
456 	size = (vm_size_t)round_page(sz);
457 
458 	if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
459 		return (EINVAL);
460 
461 	return (0);
462 }
463 
464 int32_t
465 fuword32(volatile const void *addr)
466 {
467 	int rv;
468 	int32_t val;
469 
470 	rv = fueword32(addr, &val);
471 	return (rv == -1 ? -1 : val);
472 }
473 
474 #ifdef _LP64
475 int64_t
476 fuword64(volatile const void *addr)
477 {
478 	int rv;
479 	int64_t val;
480 
481 	rv = fueword64(addr, &val);
482 	return (rv == -1 ? -1 : val);
483 }
484 #endif /* _LP64 */
485 
486 long
487 fuword(volatile const void *addr)
488 {
489 	long val;
490 	int rv;
491 
492 	rv = fueword(addr, &val);
493 	return (rv == -1 ? -1 : val);
494 }
495 
496 uint32_t
497 casuword32(volatile uint32_t *addr, uint32_t old, uint32_t new)
498 {
499 	int rv;
500 	uint32_t val;
501 
502 	rv = casueword32(addr, old, &val, new);
503 	return (rv == -1 ? -1 : val);
504 }
505 
506 u_long
507 casuword(volatile u_long *addr, u_long old, u_long new)
508 {
509 	int rv;
510 	u_long val;
511 
512 	rv = casueword(addr, old, &val, new);
513 	return (rv == -1 ? -1 : val);
514 }
515