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dd403947 DG |
1 | /* |
2 | * Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This software is a component of "386BSD" developed by | |
16 | William F. Jolitz, TeleMuse. | |
17 | * 4. Neither the name of the developer nor the name "386BSD" | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ | |
22 | * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS | |
23 | * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. | |
24 | * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT | |
25 | * NOT MAKE USE THIS WORK. | |
26 | * | |
27 | * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED | |
28 | * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN | |
29 | * REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES | |
30 | * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING | |
31 | * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND | |
32 | * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE | |
33 | * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS | |
34 | * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992. | |
35 | * | |
36 | * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND | |
37 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
38 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
39 | * ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE | |
40 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
41 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
42 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
43 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
44 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
45 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
46 | * SUCH DAMAGE. | |
47 | * | |
7ffbd0e4 | 48 | * $Id: kern_physio.c,v 1.3 1994/03/19 22:13:37 davidg Exp $ |
dd403947 DG |
49 | */ |
50 | ||
51 | #include "param.h" | |
52 | #include "systm.h" | |
53 | #include "buf.h" | |
54 | #include "conf.h" | |
55 | #include "proc.h" | |
56 | #include "malloc.h" | |
57 | #include "vnode.h" | |
58 | #include "vm/vm.h" | |
41aefbec | 59 | #include "vm/vm_page.h" |
dd403947 DG |
60 | #include "specdev.h" |
61 | ||
62 | /* | |
63 | * Driver interface to do "raw" I/O in the address space of a | |
64 | * user process directly for read and write operations.. | |
65 | */ | |
66 | ||
67 | int | |
68 | rawread(dev, uio) | |
69 | dev_t dev; struct uio *uio; | |
70 | { | |
71 | return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy, | |
72 | (caddr_t) (u_long) dev, uio)); | |
73 | } | |
74 | ||
75 | int | |
76 | rawwrite(dev, uio) | |
77 | dev_t dev; struct uio *uio; | |
78 | { | |
79 | return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy, | |
80 | (caddr_t) (u_long) dev, uio)); | |
81 | } | |
82 | ||
83 | ||
84 | int physio(strat, dev, bp, off, rw, base, len, p) | |
85 | d_strategy_t strat; | |
86 | dev_t dev; | |
87 | struct buf *bp; | |
88 | int rw, off; | |
89 | caddr_t base; | |
90 | int *len; | |
91 | struct proc *p; | |
92 | { | |
93 | int amttodo = *len; | |
94 | int error, amtdone; | |
95 | vm_prot_t ftype; | |
41aefbec | 96 | vm_offset_t v, lastv, pa; |
dd403947 DG |
97 | caddr_t adr; |
98 | int oldflags; | |
99 | int s; | |
100 | ||
101 | int bp_alloc = (bp == 0); | |
102 | ||
103 | /* | |
104 | * keep the process from being swapped | |
105 | */ | |
106 | oldflags = p->p_flag; | |
107 | p->p_flag |= SPHYSIO; | |
108 | ||
109 | rw = rw == UIO_READ ? B_READ : 0; | |
110 | ||
111 | /* create and build a buffer header for a transfer */ | |
112 | ||
113 | if (bp_alloc) { | |
114 | bp = (struct buf *)getpbuf(); | |
115 | bzero((char *)bp, sizeof(*bp)); /* 09 Sep 92*/ | |
116 | } else { | |
117 | s = splbio(); | |
118 | while (bp->b_flags & B_BUSY) { | |
119 | bp->b_flags |= B_WANTED; | |
120 | tsleep((caddr_t)bp, PRIBIO, "physbw", 0); | |
121 | } | |
122 | bp->b_flags |= B_BUSY; | |
123 | splx(s); | |
124 | } | |
125 | ||
126 | bp->b_flags = B_BUSY | B_PHYS | rw; | |
127 | bp->b_proc = p; | |
128 | bp->b_dev = dev; | |
129 | bp->b_error = 0; | |
130 | bp->b_blkno = off/DEV_BSIZE; | |
131 | amtdone = 0; | |
132 | ||
133 | /* iteratively do I/O on as large a chunk as possible */ | |
134 | do { | |
135 | bp->b_flags &= ~B_DONE; | |
136 | bp->b_un.b_addr = base; | |
137 | /* XXX limit */ | |
138 | bp->b_bcount = min (256*1024, amttodo); | |
139 | ||
140 | /* first, check if accessible */ | |
141 | if (rw == B_READ && !useracc(base, bp->b_bcount, B_WRITE)) { | |
142 | error = EFAULT; | |
143 | goto errrtn; | |
144 | } | |
145 | if (rw == B_WRITE && !useracc(base, bp->b_bcount, B_READ)) { | |
146 | error = EFAULT; | |
147 | goto errrtn; | |
148 | } | |
149 | ||
150 | /* update referenced and dirty bits, handle copy objects */ | |
151 | if (rw == B_READ) | |
152 | ftype = VM_PROT_READ | VM_PROT_WRITE; | |
153 | else | |
154 | ftype = VM_PROT_READ; | |
155 | ||
156 | lastv = 0; | |
157 | for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount; | |
158 | adr += NBPG) { | |
159 | ||
160 | /* | |
41aefbec | 161 | * make sure that the pde is valid and held |
dd403947 DG |
162 | */ |
163 | v = trunc_page(((vm_offset_t)vtopte(adr))); | |
164 | if (v != lastv) { | |
41aefbec DG |
165 | |
166 | *(volatile int *)v += 0; | |
167 | pa = pmap_extract(&p->p_vmspace->vm_pmap, v); | |
168 | vm_page_hold(PHYS_TO_VM_PAGE(pa)); | |
dd403947 DG |
169 | lastv = v; |
170 | } | |
171 | ||
172 | /* | |
173 | * do the vm_fault if needed, do the copy-on-write thing when | |
174 | * reading stuff off device into memory. | |
175 | */ | |
176 | if (ftype & VM_PROT_WRITE) { | |
177 | /* | |
178 | * properly handle copy-on-write | |
179 | */ | |
180 | *(volatile int *) adr += 0; | |
6232f830 DG |
181 | } |
182 | #if defined(HOLD_WORKS_FOR_SHARING) | |
183 | else { | |
dd403947 DG |
184 | *(volatile int *) adr; |
185 | } | |
41aefbec | 186 | pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr); |
dd403947 | 187 | /* |
41aefbec | 188 | * hold the data page |
dd403947 | 189 | */ |
41aefbec | 190 | vm_page_hold(PHYS_TO_VM_PAGE(pa)); |
6232f830 | 191 | #endif |
41aefbec | 192 | } |
dd403947 | 193 | |
6232f830 DG |
194 | #if !defined(HOLD_WORKS_FOR_SHARING) |
195 | vslock(base, bp->b_bcount); | |
196 | #endif | |
dd403947 DG |
197 | /* perform transfer */ |
198 | physstrat(bp, strat, PRIBIO); | |
6232f830 DG |
199 | #if !defined(HOLD_WORKS_FOR_SHARING) |
200 | vsunlock(base, bp->b_bcount); | |
201 | #endif | |
dd403947 | 202 | |
dd403947 | 203 | /* |
41aefbec | 204 | * unhold the pde, and data pages |
dd403947 | 205 | */ |
41aefbec | 206 | lastv = 0; |
dd403947 DG |
207 | for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount; |
208 | adr += NBPG) { | |
209 | v = trunc_page(((vm_offset_t)vtopte(adr))); | |
210 | if (v != lastv) { | |
41aefbec DG |
211 | pa = pmap_extract(&p->p_vmspace->vm_pmap, v); |
212 | vm_page_unhold(PHYS_TO_VM_PAGE(pa)); | |
dd403947 DG |
213 | lastv = v; |
214 | } | |
6232f830 | 215 | #if defined(HOLD_WORKS_FOR_SHARING) |
41aefbec DG |
216 | pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr); |
217 | vm_page_unhold(PHYS_TO_VM_PAGE(pa)); | |
6232f830 | 218 | #endif |
dd403947 DG |
219 | } |
220 | ||
221 | ||
222 | amtdone = bp->b_bcount - bp->b_resid; | |
223 | amttodo -= amtdone; | |
224 | base += amtdone; | |
225 | bp->b_blkno += amtdone/DEV_BSIZE; | |
226 | } while (amttodo && (bp->b_flags & B_ERROR) == 0 && amtdone > 0); | |
227 | ||
228 | error = bp->b_error; | |
229 | errrtn: | |
230 | if (bp_alloc) { | |
231 | relpbuf(bp); | |
232 | } else { | |
233 | bp->b_flags &= ~B_BUSY; | |
234 | wakeup((caddr_t)bp); | |
235 | } | |
236 | *len = amttodo; | |
237 | ||
238 | /* | |
239 | * allow the process to be swapped | |
240 | */ | |
241 | p->p_flag &= ~SPHYSIO; | |
242 | p->p_flag |= (oldflags & SPHYSIO); | |
243 | ||
244 | return (error); | |
245 | } |