File: [local] / sys / dev / ramdisk.c (download)
Revision 1.1, Tue Mar 4 16:09:43 2008 UTC (16 years, 1 month ago) by nbrk
Branch point for: MAIN
Initial revision
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/* $OpenBSD: ramdisk.c,v 1.37 2007/06/20 18:15:46 deraadt Exp $ */
/* $NetBSD: ramdisk.c,v 1.8 1996/04/12 08:30:09 leo Exp $ */
/*
* Copyright (c) 1995 Gordon W. Ross, Leo Weppelman.
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
* 4. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by
* Gordon W. Ross and Leo Weppelman.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/*
* This implements a general-purpose RAM-disk.
* See ramdisk.h for notes on the config types.
*
* Note that this driver provides the same functionality
* as the MFS filesystem hack, but this is better because
* you can use this for any filesystem type you'd like!
*
* Credit for most of the kmem ramdisk code goes to:
* Leo Weppelman (atari) and Phil Nelson (pc532)
* Credit for the ideas behind the "user space RAM" code goes
* to the authors of the MFS implementation.
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/device.h>
#include <sys/file.h>
#include <sys/disk.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/disklabel.h>
#include <sys/dkio.h>
#include <uvm/uvm_extern.h>
#include <dev/ramdisk.h>
/*
* By default, include the user-space functionality.
* Use: option RAMDISK_SERVER=0 to turn it off.
*/
#if !defined(RAMDISK_SERVER) && !defined(SMALL_KERNEL)
#define RAMDISK_SERVER 1
#endif
/*
* XXX: the "control" unit is (base unit + 16).
* We should just use the cdev as the "control", but
* that interferes with the security stuff preventing
* simultaneous use of raw and block devices.
*
* XXX Assumption: 16 RAM-disks are enough!
*/
#define RD_MAX_UNITS 0x10
#define RD_IS_CTRL(dev) (DISKPART(dev) == RAW_PART)
/* autoconfig stuff... */
struct rd_softc {
struct device sc_dev; /* REQUIRED first entry */
struct disk sc_dkdev; /* hook for generic disk handling */
struct rd_conf sc_rd;
#if RAMDISK_SERVER
struct buf *sc_buflist;
#endif
};
/* shorthand for fields in sc_rd: */
#define sc_addr sc_rd.rd_addr
#define sc_size sc_rd.rd_size
#define sc_type sc_rd.rd_type
void rdattach(int);
void rd_attach(struct device *, struct device *, void *);
void rdgetdisklabel(dev_t, struct rd_softc *, struct disklabel *, int);
/*
* Some ports (like i386) use a swapgeneric that wants to
* snoop around in this rd_cd structure. It is preserved
* (for now) to remain compatible with such practice.
* XXX - that practice is questionable...
*/
struct cfdriver rd_cd = {
NULL, "rd", DV_DULL
};
void rdstrategy(struct buf *bp);
struct dkdriver rddkdriver = { rdstrategy };
int ramdisk_ndevs;
void *ramdisk_devs[RD_MAX_UNITS];
/*
* This is called if we are configured as a pseudo-device
*/
void
rdattach(n)
int n;
{
struct rd_softc *sc;
int i;
#ifdef DIAGNOSTIC
if (ramdisk_ndevs) {
printf("ramdisk: multiple attach calls?\n");
return;
}
#endif
/* XXX: Are we supposed to provide a default? */
if (n <= 1)
n = 1;
if (n > RD_MAX_UNITS)
n = RD_MAX_UNITS;
ramdisk_ndevs = n;
/* XXX: Fake-up rd_cd (see above) */
rd_cd.cd_ndevs = ramdisk_ndevs;
rd_cd.cd_devs = ramdisk_devs;
/* Attach as if by autoconfig. */
for (i = 0; i < n; i++) {
sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK);
bzero((caddr_t)sc, sizeof(*sc));
if (snprintf(sc->sc_dev.dv_xname, sizeof(sc->sc_dev.dv_xname),
"rd%d", i) >= sizeof(sc->sc_dev.dv_xname)) {
printf("rdattach: device name too long\n");
free(sc, M_DEVBUF);
return;
}
ramdisk_devs[i] = sc;
sc->sc_dev.dv_unit = i;
rd_attach(NULL, &sc->sc_dev, NULL);
}
}
void
rd_attach(parent, self, aux)
struct device *parent, *self;
void *aux;
{
struct rd_softc *sc = (struct rd_softc *)self;
/* XXX - Could accept aux info here to set the config. */
#ifdef RAMDISK_HOOKS
/*
* This external function might setup a pre-loaded disk.
* All it would need to do is setup the rd_conf struct.
* See sys/arch/sun3/dev/rd_root.c for an example.
*/
rd_attach_hook(sc->sc_dev.dv_unit, &sc->sc_rd);
#endif
/*
* Initialize and attach the disk structure.
*/
sc->sc_dkdev.dk_driver = &rddkdriver;
sc->sc_dkdev.dk_name = sc->sc_dev.dv_xname;
disk_attach(&sc->sc_dkdev);
}
/*
* operational routines:
* open, close, read, write, strategy,
* ioctl, dump, size
*/
#if RAMDISK_SERVER
int rd_server_loop(struct rd_softc *sc);
int rd_ioctl_server(struct rd_softc *sc,
struct rd_conf *urd, struct proc *proc);
#endif
int rd_ioctl_kalloc(struct rd_softc *sc,
struct rd_conf *urd, struct proc *proc);
dev_type_open(rdopen);
dev_type_close(rdclose);
dev_type_read(rdread);
dev_type_write(rdwrite);
dev_type_ioctl(rdioctl);
dev_type_size(rdsize);
dev_type_dump(rddump);
int
rddump(dev, blkno, va, size)
dev_t dev;
daddr64_t blkno;
caddr_t va;
size_t size;
{
return ENODEV;
}
daddr64_t
rdsize(dev_t dev)
{
int part, unit;
struct rd_softc *sc;
/* Disallow control units. */
unit = DISKUNIT(dev);
if (unit >= ramdisk_ndevs)
return 0;
sc = ramdisk_devs[unit];
if (sc == NULL)
return 0;
if (sc->sc_type == RD_UNCONFIGURED)
return 0;
rdgetdisklabel(dev, sc, sc->sc_dkdev.dk_label, 0);
part = DISKPART(dev);
if (part >= sc->sc_dkdev.dk_label->d_npartitions)
return 0;
else
return DL_GETPSIZE(&sc->sc_dkdev.dk_label->d_partitions[part]) *
(sc->sc_dkdev.dk_label->d_secsize / DEV_BSIZE);
}
int
rdopen(dev, flag, fmt, proc)
dev_t dev;
int flag, fmt;
struct proc *proc;
{
int unit;
struct rd_softc *sc;
unit = DISKUNIT(dev);
if (unit >= ramdisk_ndevs)
return ENXIO;
sc = ramdisk_devs[unit];
if (sc == NULL)
return ENXIO;
/*
* The control device is not exclusive, and can
* open uninitialized units (so you can setconf).
*/
if (RD_IS_CTRL(dev))
return 0;
#ifdef RAMDISK_HOOKS
/* Call the open hook to allow loading the device. */
rd_open_hook(unit, &sc->sc_rd);
#endif
/*
* This is a normal, "slave" device, so
* enforce initialized, exclusive open.
*/
if (sc->sc_type == RD_UNCONFIGURED)
return ENXIO;
return 0;
}
int
rdclose(dev, flag, fmt, proc)
dev_t dev;
int flag, fmt;
struct proc *proc;
{
return 0;
}
int
rdread(dev, uio, flags)
dev_t dev;
struct uio *uio;
int flags;
{
return (physio(rdstrategy, NULL, dev, B_READ, minphys, uio));
}
int
rdwrite(dev, uio, flags)
dev_t dev;
struct uio *uio;
int flags;
{
return (physio(rdstrategy, NULL, dev, B_WRITE, minphys, uio));
}
/*
* Handle I/O requests, either directly, or
* by passing them to the server process.
*/
void
rdstrategy(bp)
struct buf *bp;
{
int unit, part;
struct rd_softc *sc;
caddr_t addr;
size_t off, xfer;
int s;
unit = DISKUNIT(bp->b_dev);
sc = ramdisk_devs[unit];
/* Sort rogue requests out */
if (sc == NULL || bp->b_blkno < 0 ||
(bp->b_bcount % sc->sc_dkdev.dk_label->d_secsize) != 0) {
bp->b_error = EINVAL;
goto bad;
}
/* Do not write on "no trespassing" areas... */
part = DISKPART(bp->b_dev);
if (part != RAW_PART &&
bounds_check_with_label(bp, sc->sc_dkdev.dk_label, 1) <= 0)
goto bad;
switch (sc->sc_type) {
#if RAMDISK_SERVER
case RD_UMEM_SERVER:
/* Just add this job to the server's queue. */
bp->b_actf = sc->sc_buflist;
sc->sc_buflist = bp;
if (bp->b_actf == NULL) {
/* server queue was empty. */
wakeup((caddr_t)sc);
/* see rd_server_loop() */
}
/* no biodone in this case */
return;
#endif /* RAMDISK_SERVER */
case RD_KMEM_FIXED:
case RD_KMEM_ALLOCATED:
/* These are in kernel space. Access directly. */
bp->b_resid = bp->b_bcount;
off = (bp->b_blkno << DEV_BSHIFT);
xfer = bp->b_bcount;
if (xfer > (sc->sc_size - off))
xfer = (sc->sc_size - off);
addr = sc->sc_addr + off;
if (bp->b_flags & B_READ)
bcopy(addr, bp->b_data, xfer);
else
bcopy(bp->b_data, addr, xfer);
bp->b_resid -= xfer;
break;
default:
bp->b_error = EIO;
bad:
bp->b_flags |= B_ERROR;
bp->b_resid = bp->b_bcount;
break;
}
s = splbio();
biodone(bp);
splx(s);
}
int
rdioctl(dev, cmd, data, flag, proc)
dev_t dev;
u_long cmd;
int flag;
caddr_t data;
struct proc *proc;
{
int unit;
struct disklabel *lp;
struct rd_softc *sc;
struct rd_conf *urd;
int error;
unit = DISKUNIT(dev);
sc = ramdisk_devs[unit];
urd = (struct rd_conf *)data;
switch (cmd) {
case DIOCRLDINFO:
if (sc->sc_type == RD_UNCONFIGURED)
break;
lp = malloc(sizeof(*lp), M_TEMP, M_WAITOK);
rdgetdisklabel(dev, sc, lp, 0);
bcopy(lp, sc->sc_dkdev.dk_label, sizeof(*lp));
free(lp, M_TEMP);
return 0;
case DIOCGPDINFO:
if (sc->sc_type == RD_UNCONFIGURED)
break;
rdgetdisklabel(dev, sc, (struct disklabel *)data, 1);
return 0;
case DIOCGDINFO:
if (sc->sc_type == RD_UNCONFIGURED) {
break;
}
*(struct disklabel *)data = *(sc->sc_dkdev.dk_label);
return 0;
case DIOCGPART:
((struct partinfo *)data)->disklab = sc->sc_dkdev.dk_label;
((struct partinfo *)data)->part =
&sc->sc_dkdev.dk_label->d_partitions[DISKPART(dev)];
return 0;
case DIOCWDINFO:
case DIOCSDINFO:
if (sc->sc_type == RD_UNCONFIGURED) {
break;
}
if ((flag & FWRITE) == 0)
return EBADF;
error = setdisklabel(sc->sc_dkdev.dk_label,
(struct disklabel *)data, /*sd->sc_dk.dk_openmask : */0);
if (error == 0) {
if (cmd == DIOCWDINFO)
error = writedisklabel(DISKLABELDEV(dev),
rdstrategy, sc->sc_dkdev.dk_label);
}
return error;
case DIOCWLABEL:
if (sc->sc_type == RD_UNCONFIGURED) {
break;
}
if ((flag & FWRITE) == 0)
return EBADF;
return 0;
case RD_GETCONF:
/* If this is not the control device, punt! */
if (RD_IS_CTRL(dev) == 0) {
break;
}
*urd = sc->sc_rd;
return 0;
case RD_SETCONF:
/* If this is not the control device, punt! */
if (RD_IS_CTRL(dev) == 0) {
break;
}
/* Can only set it once. */
if (sc->sc_type != RD_UNCONFIGURED) {
break;
}
switch (urd->rd_type) {
case RD_KMEM_ALLOCATED:
return rd_ioctl_kalloc(sc, urd, proc);
#if RAMDISK_SERVER
case RD_UMEM_SERVER:
return rd_ioctl_server(sc, urd, proc);
#endif
default:
break;
}
break;
}
return EINVAL;
}
void
rdgetdisklabel(dev_t dev, struct rd_softc *sc, struct disklabel *lp,
int spoofonly)
{
bzero(lp, sizeof(struct disklabel));
lp->d_secsize = DEV_BSIZE;
lp->d_ntracks = 1;
lp->d_nsectors = sc->sc_size >> DEV_BSHIFT;
lp->d_ncylinders = 1;
lp->d_secpercyl = lp->d_nsectors;
if (lp->d_secpercyl == 0) {
lp->d_secpercyl = 100;
/* as long as it's not 0 - readdisklabel divides by it (?) */
}
strncpy(lp->d_typename, "RAM disk", sizeof(lp->d_typename));
lp->d_type = DTYPE_SCSI;
strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
DL_SETDSIZE(lp, lp->d_nsectors);
lp->d_rpm = 3600;
lp->d_interleave = 1;
lp->d_version = 1;
lp->d_magic = DISKMAGIC;
lp->d_magic2 = DISKMAGIC;
lp->d_checksum = dkcksum(lp);
/*
* Call the generic disklabel extraction routine
*/
readdisklabel(DISKLABELDEV(dev), rdstrategy, lp, spoofonly);
}
/*
* Handle ioctl RD_SETCONF for (sc_type == RD_KMEM_ALLOCATED)
* Just allocate some kernel memory and return.
*/
int
rd_ioctl_kalloc(sc, urd, proc)
struct rd_softc *sc;
struct rd_conf *urd;
struct proc *proc;
{
vaddr_t addr;
vsize_t size;
/* Sanity check the size. */
size = urd->rd_size;
addr = uvm_km_zalloc(kernel_map, size);
if (!addr)
return ENOMEM;
/* This unit is now configured. */
sc->sc_addr = (caddr_t)addr; /* kernel space */
sc->sc_size = (size_t)size;
sc->sc_type = RD_KMEM_ALLOCATED;
return 0;
}
#if RAMDISK_SERVER
/*
* Handle ioctl RD_SETCONF for (sc_type == RD_UMEM_SERVER)
* Set config, then become the I/O server for this unit.
*/
int
rd_ioctl_server(sc, urd, proc)
struct rd_softc *sc;
struct rd_conf *urd;
struct proc *proc;
{
vaddr_t end;
int error;
/* Sanity check addr, size. */
end = (vaddr_t) (urd->rd_addr + urd->rd_size);
if ((end >= VM_MAXUSER_ADDRESS) || (end < ((vaddr_t) urd->rd_addr)) )
return EINVAL;
/* This unit is now configured. */
sc->sc_addr = urd->rd_addr; /* user space */
sc->sc_size = urd->rd_size;
sc->sc_type = RD_UMEM_SERVER;
/* Become the server daemon */
error = rd_server_loop(sc);
/* This server is now going away! */
sc->sc_type = RD_UNCONFIGURED;
sc->sc_addr = 0;
sc->sc_size = 0;
return (error);
}
int rd_sleep_pri = PWAIT | PCATCH;
int
rd_server_loop(sc)
struct rd_softc *sc;
{
struct buf *bp;
caddr_t addr; /* user space address */
size_t off; /* offset into "device" */
size_t xfer; /* amount to transfer */
int error;
int s;
for (;;) {
/* Wait for some work to arrive. */
while (sc->sc_buflist == NULL) {
error = tsleep((caddr_t)sc, rd_sleep_pri, "rd_idle", 0);
if (error)
return error;
}
/* Unlink buf from head of list. */
bp = sc->sc_buflist;
sc->sc_buflist = bp->b_actf;
bp->b_actf = NULL;
/* Do the transfer to/from user space. */
error = 0;
bp->b_resid = bp->b_bcount;
off = (bp->b_blkno << DEV_BSHIFT);
if (off >= sc->sc_size) {
if (bp->b_flags & B_READ)
goto done; /* EOF (not an error) */
error = EIO;
goto done;
}
xfer = bp->b_resid;
if (xfer > (sc->sc_size - off))
xfer = (sc->sc_size - off);
addr = sc->sc_addr + off;
if (bp->b_flags & B_READ)
error = copyin(addr, bp->b_data, xfer);
else
error = copyout(bp->b_data, addr, xfer);
if (!error)
bp->b_resid -= xfer;
done:
if (error) {
bp->b_error = error;
bp->b_flags |= B_ERROR;
}
s = splbio();
biodone(bp);
splx(s);
}
}
#endif /* RAMDISK_SERVER */
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