xref: /onnv-gate/usr/src/uts/common/os/urw.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28*0Sstevel@tonic-gate /*	  All Rights Reserved   */
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
31*0Sstevel@tonic-gate 
32*0Sstevel@tonic-gate #include <sys/atomic.h>
33*0Sstevel@tonic-gate #include <sys/errno.h>
34*0Sstevel@tonic-gate #include <sys/stat.h>
35*0Sstevel@tonic-gate #include <sys/modctl.h>
36*0Sstevel@tonic-gate #include <sys/conf.h>
37*0Sstevel@tonic-gate #include <sys/systm.h>
38*0Sstevel@tonic-gate #include <sys/ddi.h>
39*0Sstevel@tonic-gate #include <sys/sunddi.h>
40*0Sstevel@tonic-gate #include <sys/cpuvar.h>
41*0Sstevel@tonic-gate #include <sys/kmem.h>
42*0Sstevel@tonic-gate #include <sys/strsubr.h>
43*0Sstevel@tonic-gate #include <sys/sysmacros.h>
44*0Sstevel@tonic-gate #include <sys/frame.h>
45*0Sstevel@tonic-gate #include <sys/stack.h>
46*0Sstevel@tonic-gate #include <sys/proc.h>
47*0Sstevel@tonic-gate #include <sys/priv.h>
48*0Sstevel@tonic-gate #include <sys/policy.h>
49*0Sstevel@tonic-gate #include <sys/ontrap.h>
50*0Sstevel@tonic-gate #include <sys/vmsystm.h>
51*0Sstevel@tonic-gate #include <sys/prsystm.h>
52*0Sstevel@tonic-gate 
53*0Sstevel@tonic-gate #include <vm/as.h>
54*0Sstevel@tonic-gate #include <vm/seg.h>
55*0Sstevel@tonic-gate #include <vm/seg_dev.h>
56*0Sstevel@tonic-gate #include <vm/seg_vn.h>
57*0Sstevel@tonic-gate #include <vm/seg_spt.h>
58*0Sstevel@tonic-gate #include <vm/seg_kmem.h>
59*0Sstevel@tonic-gate 
60*0Sstevel@tonic-gate extern struct seg_ops segdev_ops;	/* needs a header file */
61*0Sstevel@tonic-gate extern struct seg_ops segspt_shmops;	/* needs a header file */
62*0Sstevel@tonic-gate 
63*0Sstevel@tonic-gate static int
64*0Sstevel@tonic-gate page_valid(struct seg *seg, caddr_t addr)
65*0Sstevel@tonic-gate {
66*0Sstevel@tonic-gate 	struct segvn_data *svd;
67*0Sstevel@tonic-gate 	vnode_t *vp;
68*0Sstevel@tonic-gate 	vattr_t vattr;
69*0Sstevel@tonic-gate 
70*0Sstevel@tonic-gate 	/*
71*0Sstevel@tonic-gate 	 * Fail if the page doesn't map to a page in the underlying
72*0Sstevel@tonic-gate 	 * mapped file, if an underlying mapped file exists.
73*0Sstevel@tonic-gate 	 */
74*0Sstevel@tonic-gate 	vattr.va_mask = AT_SIZE;
75*0Sstevel@tonic-gate 	if (seg->s_ops == &segvn_ops &&
76*0Sstevel@tonic-gate 	    SEGOP_GETVP(seg, addr, &vp) == 0 &&
77*0Sstevel@tonic-gate 	    vp != NULL && vp->v_type == VREG &&
78*0Sstevel@tonic-gate 	    VOP_GETATTR(vp, &vattr, 0, CRED()) == 0) {
79*0Sstevel@tonic-gate 		u_offset_t size = roundup(vattr.va_size, (u_offset_t)PAGESIZE);
80*0Sstevel@tonic-gate 		u_offset_t offset = SEGOP_GETOFFSET(seg, addr);
81*0Sstevel@tonic-gate 
82*0Sstevel@tonic-gate 		if (offset >= size)
83*0Sstevel@tonic-gate 			return (0);
84*0Sstevel@tonic-gate 	}
85*0Sstevel@tonic-gate 
86*0Sstevel@tonic-gate 	/*
87*0Sstevel@tonic-gate 	 * Fail if this is an ISM shared segment and the address is
88*0Sstevel@tonic-gate 	 * not within the real size of the spt segment that backs it.
89*0Sstevel@tonic-gate 	 */
90*0Sstevel@tonic-gate 	if (seg->s_ops == &segspt_shmops &&
91*0Sstevel@tonic-gate 	    addr >= seg->s_base + spt_realsize(seg))
92*0Sstevel@tonic-gate 		return (0);
93*0Sstevel@tonic-gate 
94*0Sstevel@tonic-gate 	/*
95*0Sstevel@tonic-gate 	 * Fail if the segment is mapped from /dev/null.
96*0Sstevel@tonic-gate 	 * The key is that the mapping comes from segdev and the
97*0Sstevel@tonic-gate 	 * type is neither MAP_SHARED nor MAP_PRIVATE.
98*0Sstevel@tonic-gate 	 */
99*0Sstevel@tonic-gate 	if (seg->s_ops == &segdev_ops &&
100*0Sstevel@tonic-gate 	    ((SEGOP_GETTYPE(seg, addr) & (MAP_SHARED | MAP_PRIVATE)) == 0))
101*0Sstevel@tonic-gate 		return (0);
102*0Sstevel@tonic-gate 
103*0Sstevel@tonic-gate 	/*
104*0Sstevel@tonic-gate 	 * Fail if the page is a MAP_NORESERVE page that has
105*0Sstevel@tonic-gate 	 * not actually materialized.
106*0Sstevel@tonic-gate 	 * We cheat by knowing that segvn is the only segment
107*0Sstevel@tonic-gate 	 * driver that supports MAP_NORESERVE.
108*0Sstevel@tonic-gate 	 */
109*0Sstevel@tonic-gate 	if (seg->s_ops == &segvn_ops &&
110*0Sstevel@tonic-gate 	    (svd = (struct segvn_data *)seg->s_data) != NULL &&
111*0Sstevel@tonic-gate 	    (svd->vp == NULL || svd->vp->v_type != VREG) &&
112*0Sstevel@tonic-gate 	    (svd->flags & MAP_NORESERVE)) {
113*0Sstevel@tonic-gate 		/*
114*0Sstevel@tonic-gate 		 * Guilty knowledge here.  We know that
115*0Sstevel@tonic-gate 		 * segvn_incore returns more than just the
116*0Sstevel@tonic-gate 		 * low-order bit that indicates the page is
117*0Sstevel@tonic-gate 		 * actually in memory.  If any bits are set,
118*0Sstevel@tonic-gate 		 * then there is backing store for the page.
119*0Sstevel@tonic-gate 		 */
120*0Sstevel@tonic-gate 		char incore = 0;
121*0Sstevel@tonic-gate 		(void) SEGOP_INCORE(seg, addr, PAGESIZE, &incore);
122*0Sstevel@tonic-gate 		if (incore == 0)
123*0Sstevel@tonic-gate 			return (0);
124*0Sstevel@tonic-gate 	}
125*0Sstevel@tonic-gate 	return (1);
126*0Sstevel@tonic-gate }
127*0Sstevel@tonic-gate 
128*0Sstevel@tonic-gate /*
129*0Sstevel@tonic-gate  * Map address "addr" in address space "as" into a kernel virtual address.
130*0Sstevel@tonic-gate  * The memory is guaranteed to be resident and locked down.
131*0Sstevel@tonic-gate  */
132*0Sstevel@tonic-gate static caddr_t
133*0Sstevel@tonic-gate mapin(struct as *as, caddr_t addr, int writing)
134*0Sstevel@tonic-gate {
135*0Sstevel@tonic-gate 	page_t *pp;
136*0Sstevel@tonic-gate 	caddr_t kaddr;
137*0Sstevel@tonic-gate 	pfn_t pfnum;
138*0Sstevel@tonic-gate 
139*0Sstevel@tonic-gate 	/*
140*0Sstevel@tonic-gate 	 * NB: Because of past mistakes, we have bits being returned
141*0Sstevel@tonic-gate 	 * by getpfnum that are actually the page type bits of the pte.
142*0Sstevel@tonic-gate 	 * When the object we are trying to map is a memory page with
143*0Sstevel@tonic-gate 	 * a page structure everything is ok and we can use the optimal
144*0Sstevel@tonic-gate 	 * method, ppmapin.  Otherwise, we have to do something special.
145*0Sstevel@tonic-gate 	 */
146*0Sstevel@tonic-gate 	pfnum = hat_getpfnum(as->a_hat, addr);
147*0Sstevel@tonic-gate 	if (pf_is_memory(pfnum)) {
148*0Sstevel@tonic-gate 		pp = page_numtopp_nolock(pfnum);
149*0Sstevel@tonic-gate 		if (pp != NULL) {
150*0Sstevel@tonic-gate 			ASSERT(PAGE_LOCKED(pp));
151*0Sstevel@tonic-gate 			kaddr = ppmapin(pp, writing ?
152*0Sstevel@tonic-gate 				(PROT_READ | PROT_WRITE) : PROT_READ,
153*0Sstevel@tonic-gate 				(caddr_t)-1);
154*0Sstevel@tonic-gate 			return (kaddr + ((uintptr_t)addr & PAGEOFFSET));
155*0Sstevel@tonic-gate 		}
156*0Sstevel@tonic-gate 	}
157*0Sstevel@tonic-gate 
158*0Sstevel@tonic-gate 	/*
159*0Sstevel@tonic-gate 	 * Oh well, we didn't have a page struct for the object we were
160*0Sstevel@tonic-gate 	 * trying to map in; ppmapin doesn't handle devices, but allocating a
161*0Sstevel@tonic-gate 	 * heap address allows ppmapout to free virutal space when done.
162*0Sstevel@tonic-gate 	 */
163*0Sstevel@tonic-gate 	kaddr = vmem_alloc(heap_arena, PAGESIZE, VM_SLEEP);
164*0Sstevel@tonic-gate 
165*0Sstevel@tonic-gate 	hat_devload(kas.a_hat, kaddr, PAGESIZE, pfnum,
166*0Sstevel@tonic-gate 		writing ? (PROT_READ | PROT_WRITE) : PROT_READ, HAT_LOAD_LOCK);
167*0Sstevel@tonic-gate 
168*0Sstevel@tonic-gate 	return (kaddr + ((uintptr_t)addr & PAGEOFFSET));
169*0Sstevel@tonic-gate }
170*0Sstevel@tonic-gate 
171*0Sstevel@tonic-gate /*ARGSUSED*/
172*0Sstevel@tonic-gate static void
173*0Sstevel@tonic-gate mapout(struct as *as, caddr_t addr, caddr_t vaddr, int writing)
174*0Sstevel@tonic-gate {
175*0Sstevel@tonic-gate 	vaddr = (caddr_t)(uintptr_t)((uintptr_t)vaddr & PAGEMASK);
176*0Sstevel@tonic-gate 	ppmapout(vaddr);
177*0Sstevel@tonic-gate }
178*0Sstevel@tonic-gate 
179*0Sstevel@tonic-gate /*
180*0Sstevel@tonic-gate  * Perform I/O to a given process. This will return EIO if we dectect
181*0Sstevel@tonic-gate  * corrupt memory and ENXIO if there is no such mapped address in the
182*0Sstevel@tonic-gate  * user process's address space.
183*0Sstevel@tonic-gate  */
184*0Sstevel@tonic-gate static int
185*0Sstevel@tonic-gate urw(proc_t *p, int writing, void *buf, size_t len, uintptr_t a)
186*0Sstevel@tonic-gate {
187*0Sstevel@tonic-gate 	caddr_t addr = (caddr_t)a;
188*0Sstevel@tonic-gate 	caddr_t page;
189*0Sstevel@tonic-gate 	caddr_t vaddr;
190*0Sstevel@tonic-gate 	struct seg *seg;
191*0Sstevel@tonic-gate 	int error = 0;
192*0Sstevel@tonic-gate 	int err = 0;
193*0Sstevel@tonic-gate 	uint_t prot;
194*0Sstevel@tonic-gate 	uint_t prot_rw = writing ? PROT_WRITE : PROT_READ;
195*0Sstevel@tonic-gate 	int protchanged;
196*0Sstevel@tonic-gate 	on_trap_data_t otd;
197*0Sstevel@tonic-gate 	int retrycnt;
198*0Sstevel@tonic-gate 	struct as *as = p->p_as;
199*0Sstevel@tonic-gate 	enum seg_rw rw;
200*0Sstevel@tonic-gate 
201*0Sstevel@tonic-gate 	/*
202*0Sstevel@tonic-gate 	 * Locate segment containing address of interest.
203*0Sstevel@tonic-gate 	 */
204*0Sstevel@tonic-gate 	page = (caddr_t)(uintptr_t)((uintptr_t)addr & PAGEMASK);
205*0Sstevel@tonic-gate 	retrycnt = 0;
206*0Sstevel@tonic-gate 	AS_LOCK_ENTER(as, &as->a_lock, RW_WRITER);
207*0Sstevel@tonic-gate retry:
208*0Sstevel@tonic-gate 	if ((seg = as_segat(as, page)) == NULL ||
209*0Sstevel@tonic-gate 	    !page_valid(seg, page)) {
210*0Sstevel@tonic-gate 		AS_LOCK_EXIT(as, &as->a_lock);
211*0Sstevel@tonic-gate 		return (ENXIO);
212*0Sstevel@tonic-gate 	}
213*0Sstevel@tonic-gate 	SEGOP_GETPROT(seg, page, 0, &prot);
214*0Sstevel@tonic-gate 
215*0Sstevel@tonic-gate 	protchanged = 0;
216*0Sstevel@tonic-gate 	if ((prot & prot_rw) == 0) {
217*0Sstevel@tonic-gate 		protchanged = 1;
218*0Sstevel@tonic-gate 		err = SEGOP_SETPROT(seg, page, PAGESIZE, prot | prot_rw);
219*0Sstevel@tonic-gate 
220*0Sstevel@tonic-gate 		if (err == IE_RETRY) {
221*0Sstevel@tonic-gate 			protchanged = 0;
222*0Sstevel@tonic-gate 			ASSERT(retrycnt == 0);
223*0Sstevel@tonic-gate 			retrycnt++;
224*0Sstevel@tonic-gate 			goto retry;
225*0Sstevel@tonic-gate 		}
226*0Sstevel@tonic-gate 
227*0Sstevel@tonic-gate 		if (err != 0) {
228*0Sstevel@tonic-gate 			AS_LOCK_EXIT(as, &as->a_lock);
229*0Sstevel@tonic-gate 			return (ENXIO);
230*0Sstevel@tonic-gate 		}
231*0Sstevel@tonic-gate 	}
232*0Sstevel@tonic-gate 
233*0Sstevel@tonic-gate 	/*
234*0Sstevel@tonic-gate 	 * segvn may do a copy-on-write for F_SOFTLOCK/S_READ case to break
235*0Sstevel@tonic-gate 	 * sharing to avoid a copy on write of a softlocked page by another
236*0Sstevel@tonic-gate 	 * thread. But since we locked the address space as a writer no other
237*0Sstevel@tonic-gate 	 * thread can cause a copy on write. S_READ_NOCOW is passed as the
238*0Sstevel@tonic-gate 	 * access type to tell segvn that it's ok not to do a copy-on-write
239*0Sstevel@tonic-gate 	 * for this SOFTLOCK fault.
240*0Sstevel@tonic-gate 	 */
241*0Sstevel@tonic-gate 	if (writing)
242*0Sstevel@tonic-gate 		rw = S_WRITE;
243*0Sstevel@tonic-gate 	else if (seg->s_ops == &segvn_ops)
244*0Sstevel@tonic-gate 		rw = S_READ_NOCOW;
245*0Sstevel@tonic-gate 	else
246*0Sstevel@tonic-gate 		rw = S_READ;
247*0Sstevel@tonic-gate 
248*0Sstevel@tonic-gate 	if (SEGOP_FAULT(as->a_hat, seg, page, PAGESIZE, F_SOFTLOCK, rw)) {
249*0Sstevel@tonic-gate 		if (protchanged)
250*0Sstevel@tonic-gate 			(void) SEGOP_SETPROT(seg, page, PAGESIZE, prot);
251*0Sstevel@tonic-gate 		AS_LOCK_EXIT(as, &as->a_lock);
252*0Sstevel@tonic-gate 		return (ENXIO);
253*0Sstevel@tonic-gate 	}
254*0Sstevel@tonic-gate 	CPU_STATS_ADD_K(vm, softlock, 1);
255*0Sstevel@tonic-gate 
256*0Sstevel@tonic-gate 	/*
257*0Sstevel@tonic-gate 	 * Make sure we're not trying to read or write off the end of the page.
258*0Sstevel@tonic-gate 	 */
259*0Sstevel@tonic-gate 	ASSERT(len <= page + PAGESIZE - addr);
260*0Sstevel@tonic-gate 
261*0Sstevel@tonic-gate 	/*
262*0Sstevel@tonic-gate 	 * Map in the locked page, copy to our local buffer,
263*0Sstevel@tonic-gate 	 * then map the page out and unlock it.
264*0Sstevel@tonic-gate 	 */
265*0Sstevel@tonic-gate 	vaddr = mapin(as, addr, writing);
266*0Sstevel@tonic-gate 
267*0Sstevel@tonic-gate 	/*
268*0Sstevel@tonic-gate 	 * Since we are copying memory on behalf of the user process,
269*0Sstevel@tonic-gate 	 * protect against memory error correction faults.
270*0Sstevel@tonic-gate 	 */
271*0Sstevel@tonic-gate 	if (!on_trap(&otd, OT_DATA_EC)) {
272*0Sstevel@tonic-gate 		if (seg->s_ops == &segdev_ops) {
273*0Sstevel@tonic-gate 			/*
274*0Sstevel@tonic-gate 			 * Device memory can behave strangely; invoke
275*0Sstevel@tonic-gate 			 * a segdev-specific copy operation instead.
276*0Sstevel@tonic-gate 			 */
277*0Sstevel@tonic-gate 			if (writing) {
278*0Sstevel@tonic-gate 				if (segdev_copyto(seg, addr, buf, vaddr, len))
279*0Sstevel@tonic-gate 					error = ENXIO;
280*0Sstevel@tonic-gate 			} else {
281*0Sstevel@tonic-gate 				if (segdev_copyfrom(seg, addr, vaddr, buf, len))
282*0Sstevel@tonic-gate 					error = ENXIO;
283*0Sstevel@tonic-gate 			}
284*0Sstevel@tonic-gate 		} else {
285*0Sstevel@tonic-gate 			if (writing)
286*0Sstevel@tonic-gate 				bcopy(buf, vaddr, len);
287*0Sstevel@tonic-gate 			else
288*0Sstevel@tonic-gate 				bcopy(vaddr, buf, len);
289*0Sstevel@tonic-gate 		}
290*0Sstevel@tonic-gate 	} else {
291*0Sstevel@tonic-gate 		error = EIO;
292*0Sstevel@tonic-gate 	}
293*0Sstevel@tonic-gate 	no_trap();
294*0Sstevel@tonic-gate 
295*0Sstevel@tonic-gate 	/*
296*0Sstevel@tonic-gate 	 * If we're writing to an executable page, we may need to sychronize
297*0Sstevel@tonic-gate 	 * the I$ with the modifications we made through the D$.
298*0Sstevel@tonic-gate 	 */
299*0Sstevel@tonic-gate 	if (writing && (prot & PROT_EXEC))
300*0Sstevel@tonic-gate 		sync_icache(vaddr, (uint_t)len);
301*0Sstevel@tonic-gate 
302*0Sstevel@tonic-gate 	mapout(as, addr, vaddr, writing);
303*0Sstevel@tonic-gate 
304*0Sstevel@tonic-gate 	if (rw == S_READ_NOCOW)
305*0Sstevel@tonic-gate 		rw = S_READ;
306*0Sstevel@tonic-gate 
307*0Sstevel@tonic-gate 	(void) SEGOP_FAULT(as->a_hat, seg, page, PAGESIZE, F_SOFTUNLOCK, rw);
308*0Sstevel@tonic-gate 
309*0Sstevel@tonic-gate 	if (protchanged)
310*0Sstevel@tonic-gate 		(void) SEGOP_SETPROT(seg, page, PAGESIZE, prot);
311*0Sstevel@tonic-gate 
312*0Sstevel@tonic-gate 	AS_LOCK_EXIT(as, &as->a_lock);
313*0Sstevel@tonic-gate 
314*0Sstevel@tonic-gate 	return (error);
315*0Sstevel@tonic-gate }
316*0Sstevel@tonic-gate 
317*0Sstevel@tonic-gate int
318*0Sstevel@tonic-gate uread(proc_t *p, void *buf, size_t len, uintptr_t a)
319*0Sstevel@tonic-gate {
320*0Sstevel@tonic-gate 	return (urw(p, 0, buf, len, a));
321*0Sstevel@tonic-gate }
322*0Sstevel@tonic-gate 
323*0Sstevel@tonic-gate int
324*0Sstevel@tonic-gate uwrite(proc_t *p, void *buf, size_t len, uintptr_t a)
325*0Sstevel@tonic-gate {
326*0Sstevel@tonic-gate 	return (urw(p, 1, buf, len, a));
327*0Sstevel@tonic-gate }
328