subr_uio.c revision 292348 
1/*-
2 * Copyright (c) 1982, 1986, 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Copyright (c) 2014 The FreeBSD Foundation
11 *
12 * Portions of this software were developed by Konstantin Belousov
13 * under sponsorship from the FreeBSD Foundation.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 *    notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 *    notice, this list of conditions and the following disclaimer in the
22 *    documentation and/or other materials provided with the distribution.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 *	@(#)kern_subr.c	8.3 (Berkeley) 1/21/94
40 */
41
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD: stable/10/sys/kern/subr_uio.c 292348 2015-12-16 19:01:14Z ken $");
44
45#include <sys/param.h>
46#include <sys/systm.h>
47#include <sys/kernel.h>
48#include <sys/limits.h>
49#include <sys/lock.h>
50#include <sys/mman.h>
51#include <sys/proc.h>
52#include <sys/resourcevar.h>
53#include <sys/rwlock.h>
54#include <sys/sched.h>
55#include <sys/sysctl.h>
56#include <sys/vnode.h>
57
58#include <vm/vm.h>
59#include <vm/vm_param.h>
60#include <vm/vm_extern.h>
61#include <vm/vm_page.h>
62#include <vm/vm_pageout.h>
63#include <vm/vm_map.h>
64
65#include <machine/bus.h>
66
67SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, UIO_MAXIOV,
68	"Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
69
70static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
71
72int
73copyin_nofault(const void *udaddr, void *kaddr, size_t len)
74{
75	int error, save;
76
77	save = vm_fault_disable_pagefaults();
78	error = copyin(udaddr, kaddr, len);
79	vm_fault_enable_pagefaults(save);
80	return (error);
81}
82
83int
84copyout_nofault(const void *kaddr, void *udaddr, size_t len)
85{
86	int error, save;
87
88	save = vm_fault_disable_pagefaults();
89	error = copyout(kaddr, udaddr, len);
90	vm_fault_enable_pagefaults(save);
91	return (error);
92}
93
94#define	PHYS_PAGE_COUNT(len)	(howmany(len, PAGE_SIZE) + 1)
95
96int
97physcopyin(void *src, vm_paddr_t dst, size_t len)
98{
99	vm_page_t m[PHYS_PAGE_COUNT(len)];
100	struct iovec iov[1];
101	struct uio uio;
102	int i;
103
104	iov[0].iov_base = src;
105	iov[0].iov_len = len;
106	uio.uio_iov = iov;
107	uio.uio_iovcnt = 1;
108	uio.uio_offset = 0;
109	uio.uio_resid = len;
110	uio.uio_segflg = UIO_SYSSPACE;
111	uio.uio_rw = UIO_WRITE;
112	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, dst += PAGE_SIZE)
113		m[i] = PHYS_TO_VM_PAGE(dst);
114	return (uiomove_fromphys(m, dst & PAGE_MASK, len, &uio));
115}
116
117int
118physcopyout(vm_paddr_t src, void *dst, size_t len)
119{
120	vm_page_t m[PHYS_PAGE_COUNT(len)];
121	struct iovec iov[1];
122	struct uio uio;
123	int i;
124
125	iov[0].iov_base = dst;
126	iov[0].iov_len = len;
127	uio.uio_iov = iov;
128	uio.uio_iovcnt = 1;
129	uio.uio_offset = 0;
130	uio.uio_resid = len;
131	uio.uio_segflg = UIO_SYSSPACE;
132	uio.uio_rw = UIO_READ;
133	for (i = 0; i < PHYS_PAGE_COUNT(len); i++, src += PAGE_SIZE)
134		m[i] = PHYS_TO_VM_PAGE(src);
135	return (uiomove_fromphys(m, src & PAGE_MASK, len, &uio));
136}
137
138#undef PHYS_PAGE_COUNT
139
140int
141physcopyin_vlist(bus_dma_segment_t *src, off_t offset, vm_paddr_t dst,
142    size_t len)
143{
144	size_t seg_len;
145	int error;
146
147	error = 0;
148	while (offset >= src->ds_len) {
149		offset -= src->ds_len;
150		src++;
151	}
152
153	while (len > 0 && error == 0) {
154		seg_len = MIN(src->ds_len - offset, len);
155		error = physcopyin((void *)(uintptr_t)(src->ds_addr + offset),
156		    dst, seg_len);
157		offset = 0;
158		src++;
159		len -= seg_len;
160		dst += seg_len;
161	}
162
163	return (error);
164}
165
166int
167physcopyout_vlist(vm_paddr_t src, bus_dma_segment_t *dst, off_t offset,
168    size_t len)
169{
170	size_t seg_len;
171	int error;
172
173	error = 0;
174	while (offset >= dst->ds_len) {
175		offset -= dst->ds_len;
176		dst++;
177	}
178
179	while (len > 0 && error == 0) {
180		seg_len = MIN(dst->ds_len - offset, len);
181		error = physcopyout(src, (void *)(uintptr_t)(dst->ds_addr +
182		    offset), seg_len);
183		offset = 0;
184		dst++;
185		len -= seg_len;
186		src += seg_len;
187	}
188
189	return (error);
190}
191
192int
193uiomove(void *cp, int n, struct uio *uio)
194{
195
196	return (uiomove_faultflag(cp, n, uio, 0));
197}
198
199int
200uiomove_nofault(void *cp, int n, struct uio *uio)
201{
202
203	return (uiomove_faultflag(cp, n, uio, 1));
204}
205
206static int
207uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
208{
209	struct thread *td;
210	struct iovec *iov;
211	size_t cnt;
212	int error, newflags, save;
213
214	td = curthread;
215	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 == td,
220	    ("uiomove proc"));
221	if (!nofault)
222		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
223		    "Calling uiomove()");
224
225	/* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
226	newflags = TDP_DEADLKTREAT;
227	if (uio->uio_segflg == UIO_USERSPACE && nofault) {
228		/*
229		 * Fail if a non-spurious page fault occurs.
230		 */
231		newflags |= TDP_NOFAULTING | TDP_RESETSPUR;
232	}
233	save = curthread_pflags_set(newflags);
234
235	while (n > 0 && uio->uio_resid) {
236		iov = uio->uio_iov;
237		cnt = iov->iov_len;
238		if (cnt == 0) {
239			uio->uio_iov++;
240			uio->uio_iovcnt--;
241			continue;
242		}
243		if (cnt > n)
244			cnt = n;
245
246		switch (uio->uio_segflg) {
247
248		case UIO_USERSPACE:
249			maybe_yield();
250			if (uio->uio_rw == UIO_READ)
251				error = copyout(cp, iov->iov_base, cnt);
252			else
253				error = copyin(iov->iov_base, cp, cnt);
254			if (error)
255				goto out;
256			break;
257
258		case UIO_SYSSPACE:
259			if (uio->uio_rw == UIO_READ)
260				bcopy(cp, iov->iov_base, cnt);
261			else
262				bcopy(iov->iov_base, cp, cnt);
263			break;
264		case UIO_NOCOPY:
265			break;
266		}
267		iov->iov_base = (char *)iov->iov_base + cnt;
268		iov->iov_len -= cnt;
269		uio->uio_resid -= cnt;
270		uio->uio_offset += cnt;
271		cp = (char *)cp + cnt;
272		n -= cnt;
273	}
274out:
275	curthread_pflags_restore(save);
276	return (error);
277}
278
279/*
280 * Wrapper for uiomove() that validates the arguments against a known-good
281 * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
282 * is almost definitely a bad thing, so we catch that here as well.  We
283 * return a runtime failure, but it might be desirable to generate a runtime
284 * assertion failure instead.
285 */
286int
287uiomove_frombuf(void *buf, int buflen, struct uio *uio)
288{
289	size_t offset, n;
290
291	if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
292	    (offset = uio->uio_offset) != uio->uio_offset)
293		return (EINVAL);
294	if (buflen <= 0 || offset >= buflen)
295		return (0);
296	if ((n = buflen - offset) > IOSIZE_MAX)
297		return (EINVAL);
298	return (uiomove((char *)buf + offset, n, uio));
299}
300
301/*
302 * Give next character to user as result of read.
303 */
304int
305ureadc(int c, struct uio *uio)
306{
307	struct iovec *iov;
308	char *iov_base;
309
310	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
311	    "Calling ureadc()");
312
313again:
314	if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
315		panic("ureadc");
316	iov = uio->uio_iov;
317	if (iov->iov_len == 0) {
318		uio->uio_iovcnt--;
319		uio->uio_iov++;
320		goto again;
321	}
322	switch (uio->uio_segflg) {
323
324	case UIO_USERSPACE:
325		if (subyte(iov->iov_base, c) < 0)
326			return (EFAULT);
327		break;
328
329	case UIO_SYSSPACE:
330		iov_base = iov->iov_base;
331		*iov_base = c;
332		break;
333
334	case UIO_NOCOPY:
335		break;
336	}
337	iov->iov_base = (char *)iov->iov_base + 1;
338	iov->iov_len--;
339	uio->uio_resid--;
340	uio->uio_offset++;
341	return (0);
342}
343
344int
345copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
346    int seg)
347{
348	int error = 0;
349
350	switch (seg) {
351	case UIO_USERSPACE:
352		error = copyin(src, dst, len);
353		break;
354	case UIO_SYSSPACE:
355		bcopy(src, dst, len);
356		break;
357	default:
358		panic("copyinfrom: bad seg %d\n", seg);
359	}
360	return (error);
361}
362
363int
364copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
365    size_t * __restrict copied, int seg)
366{
367	int error = 0;
368
369	switch (seg) {
370	case UIO_USERSPACE:
371		error = copyinstr(src, dst, len, copied);
372		break;
373	case UIO_SYSSPACE:
374		error = copystr(src, dst, len, copied);
375		break;
376	default:
377		panic("copyinstrfrom: bad seg %d\n", seg);
378	}
379	return (error);
380}
381
382int
383copyiniov(const struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
384{
385	u_int iovlen;
386
387	*iov = NULL;
388	if (iovcnt > UIO_MAXIOV)
389		return (error);
390	iovlen = iovcnt * sizeof (struct iovec);
391	*iov = malloc(iovlen, M_IOV, M_WAITOK);
392	error = copyin(iovp, *iov, iovlen);
393	if (error) {
394		free(*iov, M_IOV);
395		*iov = NULL;
396	}
397	return (error);
398}
399
400int
401copyinuio(const struct iovec *iovp, u_int iovcnt, struct uio **uiop)
402{
403	struct iovec *iov;
404	struct uio *uio;
405	u_int iovlen;
406	int error, i;
407
408	*uiop = NULL;
409	if (iovcnt > UIO_MAXIOV)
410		return (EINVAL);
411	iovlen = iovcnt * sizeof (struct iovec);
412	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
413	iov = (struct iovec *)(uio + 1);
414	error = copyin(iovp, iov, iovlen);
415	if (error) {
416		free(uio, M_IOV);
417		return (error);
418	}
419	uio->uio_iov = iov;
420	uio->uio_iovcnt = iovcnt;
421	uio->uio_segflg = UIO_USERSPACE;
422	uio->uio_offset = -1;
423	uio->uio_resid = 0;
424	for (i = 0; i < iovcnt; i++) {
425		if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) {
426			free(uio, M_IOV);
427			return (EINVAL);
428		}
429		uio->uio_resid += iov->iov_len;
430		iov++;
431	}
432	*uiop = uio;
433	return (0);
434}
435
436struct uio *
437cloneuio(struct uio *uiop)
438{
439	struct uio *uio;
440	int iovlen;
441
442	iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
443	uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
444	*uio = *uiop;
445	uio->uio_iov = (struct iovec *)(uio + 1);
446	bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
447	return (uio);
448}
449
450/*
451 * Map some anonymous memory in user space of size sz, rounded up to the page
452 * boundary.
453 */
454int
455copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
456{
457	struct vmspace *vms;
458	int error;
459	vm_size_t size;
460
461	vms = td->td_proc->p_vmspace;
462
463	/*
464	 * Map somewhere after heap in process memory.
465	 */
466	PROC_LOCK(td->td_proc);
467	*addr = round_page((vm_offset_t)vms->vm_daddr +
468	    lim_max(td->td_proc, RLIMIT_DATA));
469	PROC_UNLOCK(td->td_proc);
470
471	/* round size up to page boundry */
472	size = (vm_size_t)round_page(sz);
473
474	error = vm_mmap(&vms->vm_map, addr, size, PROT_READ | PROT_WRITE,
475	    VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0);
476
477	return (error);
478}
479
480/*
481 * Unmap memory in user space.
482 */
483int
484copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
485{
486	vm_map_t map;
487	vm_size_t size;
488
489	if (sz == 0)
490		return (0);
491
492	map = &td->td_proc->p_vmspace->vm_map;
493	size = (vm_size_t)round_page(sz);
494
495	if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
496		return (EINVAL);
497
498	return (0);
499}
500
501#ifdef NO_FUEWORD
502/*
503 * XXXKIB The temporal implementation of fue*() functions which do not
504 * handle usermode -1 properly, mixing it with the fault code.  Keep
505 * this until MD code is written.  Currently sparc64, mips and arm do
506 * not have proper implementation.
507 */
508
509int
510fueword(volatile const void *base, long *val)
511{
512	long res;
513
514	res = fuword(base);
515	if (res == -1)
516		return (-1);
517	*val = res;
518	return (0);
519}
520
521int
522fueword32(volatile const void *base, int32_t *val)
523{
524	int32_t res;
525
526	res = fuword32(base);
527	if (res == -1)
528		return (-1);
529	*val = res;
530	return (0);
531}
532
533#ifdef _LP64
534int
535fueword64(volatile const void *base, int64_t *val)
536{
537	int32_t res;
538
539	res = fuword64(base);
540	if (res == -1)
541		return (-1);
542	*val = res;
543	return (0);
544}
545#endif
546
547int
548casueword32(volatile uint32_t *base, uint32_t oldval, uint32_t *oldvalp,
549    uint32_t newval)
550{
551	int32_t ov;
552
553	ov = casuword32(base, oldval, newval);
554	if (ov == -1)
555		return (-1);
556	*oldvalp = ov;
557	return (0);
558}
559
560int
561casueword(volatile u_long *p, u_long oldval, u_long *oldvalp, u_long newval)
562{
563	u_long ov;
564
565	ov = casuword(p, oldval, newval);
566	if (ov == -1)
567		return (-1);
568	*oldvalp = ov;
569	return (0);
570}
571#else /* NO_FUEWORD */
572int32_t
573fuword32(volatile const void *addr)
574{
575	int rv;
576	int32_t val;
577
578	rv = fueword32(addr, &val);
579	return (rv == -1 ? -1 : val);
580}
581
582#ifdef _LP64
583int64_t
584fuword64(volatile const void *addr)
585{
586	int rv;
587	int64_t val;
588
589	rv = fueword64(addr, &val);
590	return (rv == -1 ? -1 : val);
591}
592#endif /* _LP64 */
593
594long
595fuword(volatile const void *addr)
596{
597	long val;
598	int rv;
599
600	rv = fueword(addr, &val);
601	return (rv == -1 ? -1 : val);
602}
603
604uint32_t
605casuword32(volatile uint32_t *addr, uint32_t old, uint32_t new)
606{
607	int rv;
608	uint32_t val;
609
610	rv = casueword32(addr, old, &val, new);
611	return (rv == -1 ? -1 : val);
612}
613
614u_long
615casuword(volatile u_long *addr, u_long old, u_long new)
616{
617	int rv;
618	u_long val;
619
620	rv = casueword(addr, old, &val, new);
621	return (rv == -1 ? -1 : val);
622}
623
624#endif /* NO_FUEWORD */
625