[unix-history] / sys / kern / kern_physio.c

/*
 * Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This software is a component of "386BSD" developed by 
	William F. Jolitz, TeleMuse.
 * 4. Neither the name of the developer nor the name "386BSD"
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ 
 * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS 
 * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. 
 * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT 
 * NOT MAKE USE THIS WORK.
 *
 * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
 * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN 
 * REFERENCES SUCH AS THE  "PORTING UNIX TO THE 386" SERIES 
 * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING 
 * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND 
 * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE 
 * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS 
 * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE DEVELOPER BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	$Id: kern_physio.c,v 1.3 1994/03/19 22:13:37 davidg Exp $
 */

#include "param.h"
#include "systm.h"
#include "buf.h"
#include "conf.h"
#include "proc.h"
#include "malloc.h"
#include "vnode.h"
#include "vm/vm.h"
#include "vm/vm_page.h"
#include "specdev.h"

/*
 * Driver interface to do "raw" I/O in the address space of a
 * user process directly for read and write operations..
 */

int
rawread(dev, uio)
	dev_t dev; struct uio *uio;
{
	return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy,
				 (caddr_t) (u_long) dev, uio));
}

int
rawwrite(dev, uio)
	dev_t dev; struct uio *uio;
{
	return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy,
				(caddr_t) (u_long) dev, uio));
}


int physio(strat, dev, bp, off, rw, base, len, p)
	d_strategy_t strat; 
	dev_t dev;
	struct buf *bp;
	int rw, off;
	caddr_t base;
	int *len;
	struct proc *p;
{
	int amttodo = *len;
	int error, amtdone;
	vm_prot_t ftype;
	vm_offset_t v, lastv, pa;
	caddr_t adr;
	int oldflags;
	int s;
	
	int bp_alloc = (bp == 0);

/*
 * keep the process from being swapped
 */
	oldflags = p->p_flag;
	p->p_flag |= SPHYSIO;

	rw = rw == UIO_READ ? B_READ : 0;

	/* create and build a buffer header for a transfer */

	if (bp_alloc) {
		bp = (struct buf *)getpbuf();
		bzero((char *)bp, sizeof(*bp));			/* 09 Sep 92*/
	} else {
		s = splbio();
		while (bp->b_flags & B_BUSY) {
			bp->b_flags |= B_WANTED;
			tsleep((caddr_t)bp, PRIBIO, "physbw", 0);
		}
		bp->b_flags |= B_BUSY;
		splx(s);
	}

	bp->b_flags = B_BUSY | B_PHYS | rw;
	bp->b_proc = p;
	bp->b_dev = dev;
	bp->b_error = 0;
	bp->b_blkno = off/DEV_BSIZE;
	amtdone = 0;

	/* iteratively do I/O on as large a chunk as possible */
	do {
		bp->b_flags &= ~B_DONE;
		bp->b_un.b_addr = base;
		/* XXX limit */
		bp->b_bcount = min (256*1024, amttodo);

		/* first, check if accessible */
		if (rw == B_READ && !useracc(base, bp->b_bcount, B_WRITE)) {
			error = EFAULT;
			goto errrtn;
		}
		if (rw == B_WRITE && !useracc(base, bp->b_bcount, B_READ)) {
			error = EFAULT;
			goto errrtn;
		}

		/* update referenced and dirty bits, handle copy objects */
		if (rw == B_READ)
			ftype = VM_PROT_READ | VM_PROT_WRITE;
		else
			ftype = VM_PROT_READ;

		lastv = 0;
		for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount;
			adr += NBPG) {
	
/*
 * make sure that the pde is valid and held
 */
			v = trunc_page(((vm_offset_t)vtopte(adr)));
			if (v != lastv) {
				
				*(volatile int *)v += 0;
				pa = pmap_extract(&p->p_vmspace->vm_pmap, v);
				vm_page_hold(PHYS_TO_VM_PAGE(pa));
				lastv = v;
			}

/*
 * do the vm_fault if needed, do the copy-on-write thing when
 * reading stuff off device into memory.
 */
			if (ftype & VM_PROT_WRITE) {
				/*
				 * properly handle copy-on-write
				 */
				*(volatile int *) adr += 0;
			} 
#if defined(HOLD_WORKS_FOR_SHARING)
			else {
				*(volatile int *) adr;
			}
			pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr);
/*
 * hold the data page
 */
			vm_page_hold(PHYS_TO_VM_PAGE(pa));
#endif
		}

#if !defined(HOLD_WORKS_FOR_SHARING)
		vslock(base, bp->b_bcount);
#endif
		/* perform transfer */
		physstrat(bp, strat, PRIBIO);
#if !defined(HOLD_WORKS_FOR_SHARING)
		vsunlock(base, bp->b_bcount);
#endif

/*
 * unhold the pde, and data pages
 */
		lastv = 0;
		for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount;
			adr += NBPG) {
			v = trunc_page(((vm_offset_t)vtopte(adr)));
			if (v != lastv) {
				pa = pmap_extract(&p->p_vmspace->vm_pmap, v);
				vm_page_unhold(PHYS_TO_VM_PAGE(pa));
				lastv = v;
			}
#if defined(HOLD_WORKS_FOR_SHARING)
			pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr);
			vm_page_unhold(PHYS_TO_VM_PAGE(pa));
#endif
		}
			

		amtdone = bp->b_bcount - bp->b_resid;
		amttodo -= amtdone;
		base += amtdone;
		bp->b_blkno += amtdone/DEV_BSIZE;
	} while (amttodo && (bp->b_flags & B_ERROR) == 0 && amtdone > 0);

	error = bp->b_error;
errrtn:
	if (bp_alloc) {
		relpbuf(bp);
	} else {
		bp->b_flags &= ~B_BUSY;
		wakeup((caddr_t)bp);
	}
	*len = amttodo;

/*
 * allow the process to be swapped
 */
	p->p_flag &= ~SPHYSIO;
	p->p_flag |= (oldflags & SPHYSIO);

	return (error);
}
Commit	Line	Data
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;
dd403947 DG	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 */
dd403947 DG	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);
41aefbec DG	212	vm_page_unhold(PHYS_TO_VM_PAGE(pa));
dd403947 DG	213	lastv = v;
dd403947 DG	214	}
6232f830	215	#if defined(HOLD_WORKS_FOR_SHARING)
41aefbec DG	216	pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr);
41aefbec DG	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	}