]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/dev/memdev.c
xnu-7195.50.7.100.1.tar.gz
[apple/xnu.git] / bsd / dev / memdev.c
index ac6dd485e22781956db844472a85a693f4487af2..fd7e8fa3df0624e32996014851f9739b6852d007 100644 (file)
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2004-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2004-2019 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
@@ -22,7 +22,7 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
@@ -71,7 +71,7 @@
 /*
  * RAM disk driver.
  *
- * Block interface to a ramdisk.  
+ * Block interface to a ramdisk.
  *
  */
 
 #include <miscfs/devfs/devfs.h>
 
 
-void           mdevinit(int the_cnt);
+void            mdevinit(int the_cnt);
 
-static open_close_fcn_t        mdevopen;
-static open_close_fcn_t        mdevclose;
-static psize_fcn_t             mdevsize;
-static strategy_fcn_t  mdevstrategy;
-static int                             mdevbioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
-static int                             mdevcioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
-static int                             mdevrw(dev_t dev, struct uio *uio, int ioflag);
+static open_close_fcn_t mdevopen;
+static open_close_fcn_t mdevclose;
+static psize_fcn_t              mdevsize;
+static strategy_fcn_t   mdevstrategy;
+static int                              mdevbioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
+static int                              mdevcioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
+static int                              mdevrw(dev_t dev, struct uio *uio, int ioflag);
 
 #ifdef CONFIG_MEMDEV_INSECURE
-
-static char *                  nonspace(char *pos, char *end);
-static char *                  getspace(char *pos, char *end);
-static char *                  cvtnum(char *pos, char *end, uint64_t *num);
-
+static char *                   nonspace(char *pos, char *end);
+static char *                   getspace(char *pos, char *end);
+static char *                   cvtnum(char *pos, char *end, uint64_t *num);
 #endif /* CONFIG_MEMDEV_INSECURE */
 
-extern void            bcopy_phys(addr64_t from, addr64_t to, vm_size_t bytes);
-extern void            mapping_set_mod(ppnum_t pn);
-extern ppnum_t         pmap_find_phys(pmap_t pmap, addr64_t va);
+extern void             bcopy_phys(addr64_t from, addr64_t to, vm_size_t bytes);
+extern void             mapping_set_mod(ppnum_t pn);
+extern ppnum_t  pmap_find_phys(pmap_t pmap, addr64_t va);
 
+/*
+ * Maximal number of memory devices.
+ */
+#define NB_MAX_MDEVICES (16)
 
 /*
  * cdevsw
@@ -128,203 +130,212 @@ extern ppnum_t  pmap_find_phys(pmap_t pmap, addr64_t va);
  *     D_CANFREE       We support B_FREEBUF
  */
 
-static struct bdevsw mdevbdevsw = {
-       /* open */      mdevopen,
-       /* close */     mdevclose,
-       /* strategy */  mdevstrategy,
-       /* ioctl */     mdevbioctl,
-       /* dump */      eno_dump,
-       /* psize */     mdevsize,
-       /* flags */     D_DISK,
+static const struct bdevsw mdevbdevsw = {
+       .d_open     = mdevopen,
+       .d_close    = mdevclose,
+       .d_strategy = mdevstrategy,
+       .d_ioctl    = mdevbioctl,
+       .d_dump     = eno_dump,
+       .d_psize    = mdevsize,
+       .d_type     = D_DISK,
 };
 
-static struct cdevsw mdevcdevsw = {
-       /* open */      mdevopen,
-       /* close */     mdevclose,
-       /* read */      mdevrw,
-       /* write */     mdevrw,
-       /* ioctl */     mdevcioctl,
-       /* stop */      eno_stop,
-       /* reset */     eno_reset,
-       /* ttys */      NULL,
-       /* select */    eno_select,
-       /* mmap */      eno_mmap,
-       /* strategy */  eno_strat,
-       /* getc */      eno_getc,
-       /* putc */      eno_putc,
-       /* flags */     D_DISK,
+static const struct cdevsw mdevcdevsw = {
+       .d_open       = mdevopen,
+       .d_close      = mdevclose,
+       .d_read       = mdevrw,
+       .d_write      = mdevrw,
+       .d_ioctl      = mdevcioctl,
+       .d_stop       = eno_stop,
+       .d_reset      = eno_reset,
+       .d_ttys       = NULL,
+       .d_select     = eno_select,
+       .d_mmap       = eno_mmap,
+       .d_strategy   = eno_strat,
+       .d_reserved_1 = eno_getc,
+       .d_reserved_2 = eno_putc,
+       .d_type       = D_DISK,
 };
 
 struct mdev {
-       uint64_t        mdBase;         /* file size in bytes */
-       uint32_t        mdSize;         /* file size in bytes */
-       int                     mdFlags;        /* flags */
-       int                     mdSecsize;      /* sector size */
-       int                     mdBDev;         /* Block device number */
-       int                     mdCDev;         /* Character device number */
-       void *          mdbdevb;
-       void *          mdcdevb;
-} mdev[16];
+       uint64_t        mdBase;         /* file size in bytes */
+       uint32_t        mdSize;         /* file size in bytes */
+       int                     mdFlags;        /* flags */
+       int                     mdSecsize;      /* sector size */
+       int                     mdBDev;         /* Block device number */
+       int                     mdCDev;         /* Character device number */
+       void *          mdbdevb;
+       void *          mdcdevb;
+} mdev[NB_MAX_MDEVICES];
 
 /* mdFlags */
-#define mdInited       0x01    /* This device defined */
-#define        mdRO            0x02    /* This device is read-only */
-#define        mdPhys          0x04    /* This device is in physical memory */
+#define mdInited        0x01    /* This device defined */
+#define mdRO            0x02    /* This device is read-only */
+#define mdPhys          0x04    /* This device is in physical memory */
 
 int mdevBMajor = -1;
 int mdevCMajor = -1;
 
-static int mdevioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p, int is_char);
-dev_t mdevadd(int devid, uint64_t base, unsigned int size, int phys);
-dev_t mdevlookup(int devid);
-void mdevremoveall(void);
-
-static int mdevclose(__unused dev_t dev, __unused int flags, 
-                                         __unused int devtype, __unused struct proc *p) {
-
-       return (0);
+static int      mdevioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p, int is_char);
+dev_t           mdevadd(int devid, uint64_t base, unsigned int size, int phys);
+dev_t           mdevlookup(int devid);
+void            mdevremoveall(void);
+int             mdevgetrange(int devid, uint64_t *base, uint64_t *size);
+
+static  int
+mdevclose(__unused dev_t dev, __unused int flags,
+    __unused int devtype, __unused struct proc *p)
+{
+       return 0;
 }
 
-static int mdevopen(dev_t dev, int flags, __unused int devtype, __unused struct proc *p) {
-       
+static  int
+mdevopen(dev_t dev, int flags, __unused int devtype, __unused struct proc *p)
+{
        int devid;
 
-       devid = minor(dev);                                                                     /* Get minor device number */
+       devid = minor(dev);                                                                     /* Get minor device number */
 
-       if (devid >= 16) return (ENXIO);                                                /* Not valid */
-
-       if ((flags & FWRITE) && (mdev[devid].mdFlags & mdRO)) return (EACCES);  /* Currently mounted RO */
-
-       return(0);
+       if (devid >= NB_MAX_MDEVICES) {
+               return ENXIO;                                                                 /* Not valid */
+       }
+       if ((flags & FWRITE) && (mdev[devid].mdFlags & mdRO)) {
+               return EACCES;                                                /* Currently mounted RO */
+       }
+       return 0;
 }
 
-static int mdevrw(dev_t dev, struct uio *uio, __unused int ioflag) {
-       int                     status;
-       addr64_t                mdata;
-       int                     devid;
-       enum uio_seg    saveflag;
+static int
+mdevrw(dev_t dev, struct uio *uio, __unused int ioflag)
+{
+       int                     status;
+       addr64_t                mdata;
+       int                     devid;
+       enum uio_seg    saveflag;
 
-       devid = minor(dev);                                                                     /* Get minor device number */
+       devid = minor(dev);                                                                     /* Get minor device number */
 
-       if (devid >= 16) return (ENXIO);                                                /* Not valid */
-       if (!(mdev[devid].mdFlags & mdInited))  return (ENXIO); /* Have we actually been defined yet? */
+       if (devid >= NB_MAX_MDEVICES) {
+               return ENXIO;                                                                 /* Not valid */
+       }
+       if (!(mdev[devid].mdFlags & mdInited)) {
+               return ENXIO;                                 /* Have we actually been defined yet? */
+       }
+       mdata = ((addr64_t)mdev[devid].mdBase << 12) + uio->uio_offset; /* Point to the area in "file" */
 
-       mdata = ((addr64_t)mdev[devid].mdBase << 12) + uio->uio_offset; /* Point to the area in "file" */
-       
-       saveflag = uio->uio_segflg;                                                     /* Remember what the request is */
+       saveflag = uio->uio_segflg;                                                     /* Remember what the request is */
 #if LP64_DEBUG
        if (UIO_IS_USER_SPACE(uio) == 0 && UIO_IS_SYS_SPACE(uio) == 0) {
-         panic("mdevrw - invalid uio_segflg\n"); 
+               panic("mdevrw - invalid uio_segflg\n");
        }
 #endif /* LP64_DEBUG */
        /* Make sure we are moving from physical ram if physical device */
        if (mdev[devid].mdFlags & mdPhys) {
-               if (uio->uio_segflg == UIO_USERSPACE64) 
-                       uio->uio_segflg = UIO_PHYS_USERSPACE64; 
-               else if (uio->uio_segflg == UIO_USERSPACE32)
-                       uio->uio_segflg = UIO_PHYS_USERSPACE32; 
-               else
-                       uio->uio_segflg = UIO_PHYS_USERSPACE;   
+               if (uio->uio_segflg == UIO_USERSPACE64) {
+                       uio->uio_segflg = UIO_PHYS_USERSPACE64;
+               } else if (uio->uio_segflg == UIO_USERSPACE32) {
+                       uio->uio_segflg = UIO_PHYS_USERSPACE32;
+               } else {
+                       uio->uio_segflg = UIO_PHYS_USERSPACE;
+               }
        }
-       status = uiomove64(mdata, uio_resid(uio), uio);         /* Move the data */
-       uio->uio_segflg = saveflag;                                                     /* Restore the flag */
+       status = uiomove64(mdata, (int)uio_resid(uio), uio);    /* Move the data */
+       uio->uio_segflg = saveflag;                                                     /* Restore the flag */
 
-       return (status);
+       return status;
 }
 
-static void mdevstrategy(struct buf *bp) {
+static void
+mdevstrategy(struct buf *bp)
+{
        unsigned int left, lop, csize;
        vm_offset_t vaddr, blkoff;
        int devid;
        addr64_t paddr, fvaddr;
        ppnum_t pp;
 
-       devid = minor(buf_device(bp));                                                  /* Get minor device number */
+       devid = minor(buf_device(bp));                                                  /* Get minor device number */
 
-       if ((mdev[devid].mdFlags & mdInited) == 0) {            /* Have we actually been defined yet? */
-               buf_seterror(bp, ENXIO);
+       if ((mdev[devid].mdFlags & mdInited) == 0) {            /* Have we actually been defined yet? */
+               buf_seterror(bp, ENXIO);
                buf_biodone(bp);
                return;
        }
 
-       buf_setresid(bp, buf_count(bp));                                                /* Set byte count */
-       
-       blkoff = buf_blkno(bp) * mdev[devid].mdSecsize;         /* Get offset into file */
+       buf_setresid(bp, buf_count(bp));                                                /* Set byte count */
+
+       blkoff = buf_blkno(bp) * mdev[devid].mdSecsize;         /* Get offset into file */
 
 /*
  *     Note that reading past end is an error, but reading at end is an EOF.  For these
  *     we just return with resid == count.
  */
 
-       if (blkoff >= (mdev[devid].mdSize << 12)) {                     /* Are they trying to read/write at/after end? */
-               if(blkoff != (mdev[devid].mdSize << 12)) {              /* Are we trying to read after EOF? */
-                       buf_seterror(bp, EINVAL);                                               /* Yeah, this is an error */
+       if (blkoff >= (mdev[devid].mdSize << 12)) {                     /* Are they trying to read/write at/after end? */
+               if (blkoff != (mdev[devid].mdSize << 12)) {              /* Are we trying to read after EOF? */
+                       buf_seterror(bp, EINVAL);                                               /* Yeah, this is an error */
                }
-               buf_biodone(bp);                                                                /* Return */
+               buf_biodone(bp);                                                                /* Return */
                return;
        }
 
-       if ((blkoff + buf_count(bp)) > (mdev[devid].mdSize << 12)) {            /* Will this read go past end? */
-               buf_setcount(bp, ((mdev[devid].mdSize << 12) - blkoff));        /* Yes, trim to max */
+       if ((blkoff + buf_count(bp)) > (mdev[devid].mdSize << 12)) {            /* Will this read go past end? */
+               buf_setcount(bp, (uint32_t)((mdev[devid].mdSize << 12) - blkoff));  /* Yes, trim to max */
        }
        /*
         * make sure the buffer's data area is
         * accessible
         */
-       if (buf_map(bp, (caddr_t *)&vaddr))
-               panic("ramstrategy: buf_map failed\n");
+       if (buf_map(bp, (caddr_t *)&vaddr)) {
+               panic("ramstrategy: buf_map failed\n");
+       }
+
+       fvaddr = (mdev[devid].mdBase << 12) + blkoff;           /* Point to offset into ram disk */
 
-       fvaddr = (mdev[devid].mdBase << 12) + blkoff;           /* Point to offset into ram disk */
-       
-       if (buf_flags(bp) & B_READ) {                                   /* Is this a read? */
-               if(!(mdev[devid].mdFlags & mdPhys)) {                   /* Physical mapped disk? */
+       if (buf_flags(bp) & B_READ) {                                   /* Is this a read? */
+               if (!(mdev[devid].mdFlags & mdPhys)) {                   /* Physical mapped disk? */
                        bcopy((void *)((uintptr_t)fvaddr),
-                               (void *)vaddr, (size_t)buf_count(bp));  /* This is virtual, just get the data */
-               }
-               else {
-                       left = buf_count(bp);                                           /* Init the amount left to copy */
-                       while(left) {                                                           /* Go until it is all copied */
-                               
-                               lop = min((4096 - (vaddr & 4095)), (4096 - (fvaddr & 4095)));   /* Get smallest amount left on sink and source */
-                               csize = min(lop, left);                                 /* Don't move more than we need to */
-                               
-                               pp = pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)vaddr)); /* Get the sink physical address */
-                               if(!pp) {                                                               /* Not found, what gives? */
+                           (void *)vaddr, (size_t)buf_count(bp));      /* This is virtual, just get the data */
+               } else {
+                       left = buf_count(bp);                                           /* Init the amount left to copy */
+                       while (left) {                                                           /* Go until it is all copied */
+                               lop = min((4096 - (vaddr & 4095)), (4096 - (fvaddr & 4095)));   /* Get smallest amount left on sink and source */
+                               csize = min(lop, left);                                 /* Don't move more than we need to */
+
+                               pp = pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)vaddr)); /* Get the sink physical address */
+                               if (!pp) {                                                               /* Not found, what gives? */
                                        panic("mdevstrategy: sink address %016llX not mapped\n", (addr64_t)((uintptr_t)vaddr));
                                }
-                               paddr = (addr64_t)(((addr64_t)pp << 12) | (addr64_t)(vaddr & 4095));    /* Get actual address */
-                               bcopy_phys(fvaddr, paddr, csize);               /* Copy this on in */
-                               mapping_set_mod(paddr >> 12);                   /* Make sure we know that it is modified */
-                               
-                               left = left - csize;                                    /* Calculate what is left */
-                               vaddr = vaddr + csize;                                  /* Move to next sink address */
-                               fvaddr = fvaddr + csize;                                /* Bump to next physical address */
+                               paddr = (addr64_t)(((addr64_t)pp << 12) | (addr64_t)(vaddr & 4095));    /* Get actual address */
+                               bcopy_phys(fvaddr, paddr, csize);               /* Copy this on in */
+                               mapping_set_mod((ppnum_t)(paddr >> 12));        /* Make sure we know that it is modified */
+
+                               left = left - csize;                                    /* Calculate what is left */
+                               vaddr = vaddr + csize;                                  /* Move to next sink address */
+                               fvaddr = fvaddr + csize;                                /* Bump to next physical address */
                        }
                }
-       }
-       else {                                                                                          /* This is a write */
-               if(!(mdev[devid].mdFlags & mdPhys)) {                   /* Physical mapped disk? */
+       } else {                                                                                        /* This is a write */
+               if (!(mdev[devid].mdFlags & mdPhys)) {                   /* Physical mapped disk? */
                        bcopy((void *)vaddr, (void *)((uintptr_t)fvaddr),
-                               (size_t)buf_count(bp));         /* This is virtual, just put the data */
-               }
-               else {
-                       left = buf_count(bp);                                           /* Init the amount left to copy */
-                       while(left) {                                                           /* Go until it is all copied */
-                               
-                               lop = min((4096 - (vaddr & 4095)), (4096 - (fvaddr & 4095)));   /* Get smallest amount left on sink and source */
-                               csize = min(lop, left);                                 /* Don't move more than we need to */
-                               
-                               pp = pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)vaddr)); /* Get the source physical address */
-                               if(!pp) {                                                               /* Not found, what gives? */
+                           (size_t)buf_count(bp));             /* This is virtual, just put the data */
+               } else {
+                       left = buf_count(bp);                                           /* Init the amount left to copy */
+                       while (left) {                                                           /* Go until it is all copied */
+                               lop = min((4096 - (vaddr & 4095)), (4096 - (fvaddr & 4095)));   /* Get smallest amount left on sink and source */
+                               csize = min(lop, left);                                 /* Don't move more than we need to */
+
+                               pp = pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)vaddr)); /* Get the source physical address */
+                               if (!pp) {                                                               /* Not found, what gives? */
                                        panic("mdevstrategy: source address %016llX not mapped\n", (addr64_t)((uintptr_t)vaddr));
                                }
-                               paddr = (addr64_t)(((addr64_t)pp << 12) | (addr64_t)(vaddr & 4095));    /* Get actual address */
-                       
-                               bcopy_phys(paddr, fvaddr, csize);               /* Move this on out */
-                               
-                               left = left - csize;                                    /* Calculate what is left */
-                               vaddr = vaddr + csize;                                  /* Move to next sink address */
-                               fvaddr = fvaddr + csize;                                /* Bump to next physical address */
+                               paddr = (addr64_t)(((addr64_t)pp << 12) | (addr64_t)(vaddr & 4095));    /* Get actual address */
+
+                               bcopy_phys(paddr, fvaddr, csize);               /* Move this on out */
+
+                               left = left - csize;                                    /* Calculate what is left */
+                               vaddr = vaddr + csize;                                  /* Move to next sink address */
+                               fvaddr = fvaddr + csize;                                /* Bump to next physical address */
                        }
                }
        }
@@ -336,115 +347,132 @@ static void mdevstrategy(struct buf *bp) {
         */
        buf_unmap(bp);
 
-       buf_setresid(bp, 0);                                                                    /* Nothing more to do */        
-       buf_biodone(bp);                                                                        /* Say we've finished */
+       buf_setresid(bp, 0);                                                                    /* Nothing more to do */
+       buf_biodone(bp);                                                                        /* Say we've finished */
 }
 
-static int mdevbioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p) {
-       return (mdevioctl(dev, cmd, data, flag, p, 0));
+static int
+mdevbioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
+{
+       return mdevioctl(dev, cmd, data, flag, p, 0);
 }
 
-static int mdevcioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p) {
-       return (mdevioctl(dev, cmd, data, flag, p, 1));
+static int
+mdevcioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
+{
+       return mdevioctl(dev, cmd, data, flag, p, 1);
 }
 
-static int mdevioctl(dev_t dev, u_long cmd, caddr_t data, __unused int flag, 
-                                        struct proc *p, int is_char) {
+static int
+mdevioctl(dev_t dev, u_long cmd, caddr_t data, __unused int flag,
+    struct proc *p, int is_char)
+{
        int error;
        u_int32_t *f;
        u_int64_t *o;
        int devid;
        dk_memdev_info_t * memdev_info;
 
-       devid = minor(dev);                                                                     /* Get minor device number */
-
-       if (devid >= 16) return (ENXIO);                                                /* Not valid */
-
-       error = proc_suser(p);                  /* Are we superman? */
-       if (error) return (error);                                                      /* Nope... */
+       devid = minor(dev);                                                                     /* Get minor device number */
 
+       if (devid >= NB_MAX_MDEVICES) {
+               return ENXIO;                                                                 /* Not valid */
+       }
+       error = proc_suser(p);                  /* Are we superman? */
+       if (error) {
+               return error;                                                         /* Nope... */
+       }
        f = (u_int32_t*)data;
        o = (u_int64_t *)data;
        memdev_info = (dk_memdev_info_t *) data;
 
        switch (cmd) {
+       case DKIOCGETMAXBLOCKCOUNTREAD:
+               *o = 32;
+               break;
 
-               case DKIOCGETMAXBLOCKCOUNTREAD:
-                       *o = 32;
-                       break;
-               
-               case DKIOCGETMAXBLOCKCOUNTWRITE:
-                       *o = 32;
-                       break;
-               
-               case DKIOCGETMAXSEGMENTCOUNTREAD:
-                       *o = 32;
-                       break;
-               
-               case DKIOCGETMAXSEGMENTCOUNTWRITE:
-                       *o = 32;
-                       break;
-               
-               case DKIOCGETBLOCKSIZE:
-                       *f = mdev[devid].mdSecsize;
-                       break;
-               
-               case DKIOCSETBLOCKSIZE:
-                       if (is_char) return (ENODEV);                           /* We can only do this for a block */
-
-                       if (*f < DEV_BSIZE) return (EINVAL);            /* Too short? */
-
-                       mdev[devid].mdSecsize = *f;                                     /* set the new block size */
-                       break;
-                       
-               case DKIOCISWRITABLE:
-                       *f = 1;
-                       break;
-                       
-               case DKIOCGETBLOCKCOUNT:
-                       if(!(mdev[devid].mdFlags & mdInited)) return (ENXIO);
-                       *o = ((mdev[devid].mdSize << 12) + mdev[devid].mdSecsize - 1) / mdev[devid].mdSecsize;
-                       break;
-
-               /*
-                * We're interested in the following bits of information:
-                *   Are you a memory-backed device (always yes, in this case)?
-                *   Physical memory (mdPhys)?
-                *   What is your base page?
-                *   What is your size?
-                */
-               case DKIOCGETMEMDEVINFO:
-                       if (!(mdev[devid].mdFlags & mdInited)) return (ENXIO);
-                       memdev_info->mi_mdev = TRUE;
-                       memdev_info->mi_phys = (mdev[devid].mdFlags & mdPhys) ? TRUE : FALSE;
-                       memdev_info->mi_base = mdev[devid].mdBase;
-                       memdev_info->mi_size = mdev[devid].mdSize;
-                       break;
-
-               default:
-                       error = ENOTTY;
-                       break;
-       }
-       return(error);
-}
+       case DKIOCGETMAXBLOCKCOUNTWRITE:
+               *o = 32;
+               break;
 
+       case DKIOCGETMAXSEGMENTCOUNTREAD:
+               *o = 32;
+               break;
 
-static int mdevsize(dev_t dev) {
+       case DKIOCGETMAXSEGMENTCOUNTWRITE:
+               *o = 32;
+               break;
 
-       int devid;
+       case DKIOCGETBLOCKSIZE:
+               *f = mdev[devid].mdSecsize;
+               break;
 
-       devid = minor(dev);                                                                     /* Get minor device number */
-       if (devid >= 16) return (ENXIO);                                                /* Not valid */
+       case DKIOCSETBLOCKSIZE:
+               if (is_char) {
+                       return ENODEV;                                        /* We can only do this for a block */
+               }
+               if (*f < DEV_BSIZE) {
+                       return EINVAL;                                /* Too short? */
+               }
+               mdev[devid].mdSecsize = *f;                                             /* set the new block size */
+               break;
 
-       if ((mdev[devid].mdFlags & mdInited) == 0) return(-1);          /* Not inited yet */
+       case DKIOCISWRITABLE:
+               *f = 1;
+               break;
 
-       return(mdev[devid].mdSecsize);
+       case DKIOCGETBLOCKCOUNT:
+               if (!(mdev[devid].mdFlags & mdInited)) {
+                       return ENXIO;
+               }
+               *o = ((mdev[devid].mdSize << 12) + mdev[devid].mdSecsize - 1) / mdev[devid].mdSecsize;
+               break;
+
+       /*
+        * We're interested in the following bits of information:
+        *   Are you a memory-backed device (always yes, in this case)?
+        *   Physical memory (mdPhys)?
+        *   What is your base page?
+        *   What is your size?
+        */
+       case DKIOCGETMEMDEVINFO:
+               if (!(mdev[devid].mdFlags & mdInited)) {
+                       return ENXIO;
+               }
+               memdev_info->mi_mdev = TRUE;
+               memdev_info->mi_phys = (mdev[devid].mdFlags & mdPhys) ? TRUE : FALSE;
+               memdev_info->mi_base = (uint32_t)mdev[devid].mdBase;
+               memdev_info->mi_size = mdev[devid].mdSize;
+               break;
+
+       default:
+               error = ENOTTY;
+               break;
+       }
+       return error;
 }
 
-#include <pexpert/pexpert.h>
 
-void mdevinit(__unused int the_cnt) {
+static  int
+mdevsize(dev_t dev)
+{
+       int devid;
+
+       devid = minor(dev);                                                                     /* Get minor device number */
+       if (devid >= NB_MAX_MDEVICES) {
+               return ENXIO;                                                                 /* Not valid */
+       }
+       if ((mdev[devid].mdFlags & mdInited) == 0) {
+               return -1;                                            /* Not inited yet */
+       }
+       return mdev[devid].mdSecsize;
+}
+
+#include <pexpert/pexpert.h>
 
+void
+mdevinit(__unused int the_cnt)
+{
 #ifdef CONFIG_MEMDEV_INSECURE
 
        int devid, phys;
@@ -452,201 +480,250 @@ void mdevinit(__unused int the_cnt) {
        uint64_t size;
        char *ba, *lp;
        dev_t dev;
-       
-       
-       ba = PE_boot_args();                                                            /* Get the boot arguments */
-       lp = ba + 256;                                                                          /* Point to the end */
-               
-       while(1) {                                                                                      /* Step through, looking for our keywords */
-               phys = 0;                                                                               /* Assume virtual memory device */
-               ba = nonspace(ba, lp);                                                  /* Find non-space */
-               if(ba >= lp) return;                                                    /* We are done if no more... */
-               if(((ba[0] != 'v') && (ba[0] != 'p'))  
-                 || (ba[1] != 'm') || (ba[2] != 'd') || (ba[4] != '=')
-                 || (ba[3] < '0') || (ba[3] > 'f') 
-                 || ((ba[3] > '9') && (ba[3] < 'a'))) {                /* Is this of form "vmdx=" or "pmdx=" where x is hex digit? */
-                       
-                       ba = getspace(ba, lp);                                          /* Find next white space or end */
-                       continue;                                                                       /* Start looking for the next one */
-               }
-               
-               if(ba[0] == 'p') phys = 1;                                              /* Set physical memory disk */
-               
-               devid = ba[3] & 0xF;                                                    /* Assume digit */
-               if(ba[3] > '9') devid += 9;                                             /* Adjust for hex digits */
-       
-               ba = &ba[5];                                                                    /* Step past keyword */
-               ba = cvtnum(ba, lp, &base);                                             /* Convert base of memory disk */
-               if(ba >= lp) return;                                                    /* Malformed one at the end, leave */
-               if(ba[0] != '.') continue;                                              /* If not length separater, try next... */
-               if(base & 0xFFF) continue;                                              /* Only allow page aligned stuff */
-       
-               ba++;                                                                                   /* Step past '.' */
-               ba = cvtnum(ba, lp, &size);                                             /* Try to convert it */
-               if(!size || (size & 0xFFF)) continue;                   /* Allow only non-zer page size multiples */
-               if(ba < lp) {                                                                   /* If we are not at end, check end character */
-                       if((ba[0] != ' ') && (ba[0] != 0)) continue;    /* End must be null or space */
-               }
-               
-               dev = mdevadd(devid, base >> 12, (unsigned)size >> 12, phys);   /* Go add the device */ 
+
+
+       ba = PE_boot_args();                                                            /* Get the boot arguments */
+       lp = ba + 256;                                                                          /* Point to the end */
+
+       while (1) {                                                                                      /* Step through, looking for our keywords */
+               phys = 0;                                                                               /* Assume virtual memory device */
+               ba = nonspace(ba, lp);                                                  /* Find non-space */
+               if (ba >= lp) {
+                       return;                                                         /* We are done if no more... */
+               }
+               if (((ba[0] != 'v') && (ba[0] != 'p'))
+                   || (ba[1] != 'm') || (ba[2] != 'd') || (ba[4] != '=')
+                   || (ba[3] < '0') || (ba[3] > 'f')
+                   || ((ba[3] > '9') && (ba[3] < 'a'))) {              /* Is this of form "vmdx=" or "pmdx=" where x is hex digit? */
+                       ba = getspace(ba, lp);                                          /* Find next white space or end */
+                       continue;                                                                       /* Start looking for the next one */
+               }
+
+               if (ba[0] == 'p') {
+                       phys = 1;                                                       /* Set physical memory disk */
+               }
+               devid = ba[3] & 0xF;                                                    /* Assume digit */
+               if (ba[3] > '9') {
+                       devid += 9;                                                     /* Adjust for hex digits */
+               }
+               ba = &ba[5];                                                                    /* Step past keyword */
+               ba = cvtnum(ba, lp, &base);                                             /* Convert base of memory disk */
+               if (ba >= lp) {
+                       return;                                                         /* Malformed one at the end, leave */
+               }
+               if (ba[0] != '.') {
+                       continue;                                                       /* If not length separater, try next... */
+               }
+               if (base & 0xFFF) {
+                       continue;                                                       /* Only allow page aligned stuff */
+               }
+               ba++;                                                                                   /* Step past '.' */
+               ba = cvtnum(ba, lp, &size);                                             /* Try to convert it */
+               if (!size || (size & 0xFFF)) {
+                       continue;                                       /* Allow only non-zer page size multiples */
+               }
+               if (ba < lp) {                                                                   /* If we are not at end, check end character */
+                       if ((ba[0] != ' ') && (ba[0] != 0)) {
+                               continue;                               /* End must be null or space */
+                       }
+               }
+
+               dev = mdevadd(devid, base >> 12, (unsigned)size >> 12, phys);   /* Go add the device */
        }
 
 #endif /* CONFIG_MEMDEV_INSECURE */
 
        return;
-
 }
 
 #ifdef CONFIG_MEMDEV_INSECURE
 
-char *nonspace(char *pos, char *end) {                                 /* Find next non-space in string */
-
-       if(pos >= end) return end;                                                      /* Don't go past end */
-       if(pos[0] == 0) return end;                                                     /* If at null, make end */
-       
-       while(1) {                                                                                      /* Keep going */
-               if(pos[0] != ' ') return pos;                                   /* Leave if we found one */
-               pos++;                                                                                  /* Stop */
-               if(pos >= end) return end;                                              /* Quit if we run off end */
+char *
+nonspace(char *pos, char *end)                                          /* Find next non-space in string */
+{
+       if (pos >= end) {
+               return end;                                                             /* Don't go past end */
+       }
+       if (pos[0] == 0) {
+               return end;                                                             /* If at null, make end */
+       }
+       while (1) {                                                                                      /* Keep going */
+               if (pos[0] != ' ') {
+                       return pos;                                             /* Leave if we found one */
+               }
+               pos++;                                                                                  /* Stop */
+               if (pos >= end) {
+                       return end;                                                     /* Quit if we run off end */
+               }
        }
 }
 
-char *getspace(char *pos, char *end) {                                 /* Find next non-space in string */
-
-       while(1) {                                                                                      /* Keep going */
-               if(pos >= end) return end;                                              /* Don't go past end */
-               if(pos[0] == 0) return end;                                             /* Leave if we hit null */
-               if(pos[0] == ' ') return pos;                                   /* Leave if we found one */
-               pos++;                                                                                  /* Stop */
+char *
+getspace(char *pos, char *end)                                          /* Find next non-space in string */
+{
+       while (1) {                                                                                      /* Keep going */
+               if (pos >= end) {
+                       return end;                                                     /* Don't go past end */
+               }
+               if (pos[0] == 0) {
+                       return end;                                                     /* Leave if we hit null */
+               }
+               if (pos[0] == ' ') {
+                       return pos;                                             /* Leave if we found one */
+               }
+               pos++;                                                                                  /* Stop */
        }
 }
 
-char *cvtnum(char *pos, char *end, uint64_t *num) {            /* Convert to a number */
-
+char *
+cvtnum(char *pos, char *end, uint64_t *num)                     /* Convert to a number */
+{
        int rad, dig;
-       
-       *num = 0;                                                                                       /* Set answer to 0 to start */  
+
+       *num = 0;                                                                                       /* Set answer to 0 to start */
        rad = 10;
 
-       if(pos >= end) return end;                                                      /* Don't go past end */
-       if(pos[0] == 0) return end;                                                     /* If at null, make end */
-       
-       if(pos[0] == '0' && ((pos[1] == 'x') || (pos[1] == 'x'))) {     /* A hex constant? */
+       if (pos >= end) {
+               return end;                                                             /* Don't go past end */
+       }
+       if (pos[0] == 0) {
+               return end;                                                             /* If at null, make end */
+       }
+       if (pos[0] == '0' && ((pos[1] == 'x') || (pos[1] == 'x'))) {     /* A hex constant? */
                rad = 16;
-               pos += 2;                                                                               /* Point to the number */
-       }
-       
-       while(1) {                                                                                      /* Convert it */
-               
-               if(pos >= end) return end;                                              /* Don't go past end */
-               if(pos[0] == 0) return end;                                             /* If at null, make end */
-               if(pos[0] < '0') return pos;                                    /* Leave if non-digit */
-               dig = pos[0] & 0xF;                                                             /* Extract digit */
-               if(pos[0] > '9') {                                                              /* Is it bigger than 9? */
-                       if(rad == 10) return pos;                                       /* Leave if not base 10 */
-                       if(!(((pos[0] >= 'A') && (pos[0] <= 'F')) 
-                         || ((pos[0] >= 'a') && (pos[0] <= 'f')))) return pos; /* Leave if bogus char */
-                        dig = dig + 9;                                                         /* Adjust for character */
-               }
-               *num = (*num * rad) + dig;                                              /* Accumulate the number */
-               pos++;                                                                                  /* Step on */
+               pos += 2;                                                                               /* Point to the number */
+       }
+
+       while (1) {                                                                                      /* Convert it */
+               if (pos >= end) {
+                       return end;                                                     /* Don't go past end */
+               }
+               if (pos[0] == 0) {
+                       return end;                                                     /* If at null, make end */
+               }
+               if (pos[0] < '0') {
+                       return pos;                                             /* Leave if non-digit */
+               }
+               dig = pos[0] & 0xF;                                                             /* Extract digit */
+               if (pos[0] > '9') {                                                              /* Is it bigger than 9? */
+                       if (rad == 10) {
+                               return pos;                                             /* Leave if not base 10 */
+                       }
+                       if (!(((pos[0] >= 'A') && (pos[0] <= 'F'))
+                           || ((pos[0] >= 'a') && (pos[0] <= 'f')))) {
+                               return pos;                                     /* Leave if bogus char */
+                       }
+                       dig = dig + 9;                                                          /* Adjust for character */
+               }
+               *num = (*num * rad) + dig;                                              /* Accumulate the number */
+               pos++;                                                                                  /* Step on */
        }
 }
 
 #endif /* CONFIG_MEMDEV_INSECURE */
 
-dev_t mdevadd(int devid, uint64_t base, unsigned int size, int phys) {
-       
+dev_t
+mdevadd(int devid, uint64_t base, unsigned int size, int phys)
+{
        int i;
-       
-       if(devid < 0) {
 
+       if (devid < 0) {
                devid = -1;
-               for(i = 0; i < 16; i++) {                                               /* Search all known memory devices */
-                       if(!(mdev[i].mdFlags & mdInited)) {                     /* Is this a free one? */
-                               if(devid < 0)devid = i;                                 /* Remember first free one */
-                               continue;                                                               /* Skip check */
+               for (i = 0; i < NB_MAX_MDEVICES; i++) {                                          /* Search all known memory devices */
+                       if (!(mdev[i].mdFlags & mdInited)) {                     /* Is this a free one? */
+                               if (devid < 0) {
+                                       devid = i;                                      /* Remember first free one */
+                               }
+                               continue;                                                               /* Skip check */
                        }
-                       if(!(((base + size -1 ) < mdev[i].mdBase) || ((mdev[i].mdBase + mdev[i].mdSize - 1) < base))) { /* Is there any overlap? */
+                       if (!(((base + size - 1) < mdev[i].mdBase) || ((mdev[i].mdBase + mdev[i].mdSize - 1) < base))) { /* Is there any overlap? */
                                panic("mdevadd: attempt to add overlapping memory device at %016llX-%016llX\n", mdev[i].mdBase, mdev[i].mdBase + mdev[i].mdSize - 1);
                        }
                }
-               if(devid < 0) {                                                                 /* Do we have free slots? */
-                       panic("mdevadd: attempt to add more than 16 memory devices\n");
+               if (devid < 0) {                                                                 /* Do we have free slots? */
+                       panic("mdevadd: attempt to add more than %d memory devices\n", NB_MAX_MDEVICES);
                }
-       }
-       else {
-               if(devid >= 16) {                                                               /* Giving us something bogus? */
+       } else {
+               if (devid >= NB_MAX_MDEVICES) {                                                          /* Giving us something bogus? */
                        panic("mdevadd: attempt to explicitly add a bogus memory device: %08X\n", devid);
                }
-               if(mdev[devid].mdFlags & mdInited) {                    /* Already there? */
+               if (mdev[devid].mdFlags & mdInited) {                    /* Already there? */
                        panic("mdevadd: attempt to explicitly add a previously defined memory device: %08X\n", devid);
                }
        }
-       
-       if(mdevBMajor < 0) {                                                            /* Have we gotten a major number yet? */
-               mdevBMajor = bdevsw_add(-1, &mdevbdevsw);               /* Add to the table and figure out a major number */
+
+       if (mdevBMajor < 0) {                                                            /* Have we gotten a major number yet? */
+               mdevBMajor = bdevsw_add(-1, &mdevbdevsw);               /* Add to the table and figure out a major number */
                if (mdevBMajor < 0) {
                        printf("mdevadd: error - bdevsw_add() returned %d\n", mdevBMajor);
                        return -1;
                }
        }
-       
-       if(mdevCMajor < 0) {                                                            /* Have we gotten a major number yet? */
-               mdevCMajor = cdevsw_add_with_bdev(-1, &mdevcdevsw, mdevBMajor);         /* Add to the table and figure out a major number */
+
+       if (mdevCMajor < 0) {                                                            /* Have we gotten a major number yet? */
+               mdevCMajor = cdevsw_add_with_bdev(-1, &mdevcdevsw, mdevBMajor);         /* Add to the table and figure out a major number */
                if (mdevCMajor < 0) {
                        printf("ramdevice_init: error - cdevsw_add() returned %d\n", mdevCMajor);
                        return -1;
                }
        }
 
-       mdev[devid].mdBDev = makedev(mdevBMajor, devid);        /* Get the device number */
-       mdev[devid].mdbdevb = devfs_make_node(mdev[devid].mdBDev, DEVFS_BLOCK,  /* Make the node */
-                                                 UID_ROOT, GID_OPERATOR, 
-                                                 0600, "md%d", devid);
-       if (mdev[devid].mdbdevb == NULL) {                                      /* Did we make one? */
+       mdev[devid].mdBDev = makedev(mdevBMajor, devid);        /* Get the device number */
+       mdev[devid].mdbdevb = devfs_make_node(mdev[devid].mdBDev, DEVFS_BLOCK,  /* Make the node */
+           UID_ROOT, GID_OPERATOR,
+           0600, "md%d", devid);
+       if (mdev[devid].mdbdevb == NULL) {                                      /* Did we make one? */
                printf("mdevadd: devfs_make_node for block failed!\n");
-               return -1;                                                                              /* Nope... */
+               return -1;                                                                              /* Nope... */
        }
 
-       mdev[devid].mdCDev = makedev(mdevCMajor, devid);        /* Get the device number */
-       mdev[devid].mdcdevb = devfs_make_node(mdev[devid].mdCDev, DEVFS_CHAR,           /* Make the node */
-                                                 UID_ROOT, GID_OPERATOR, 
-                                                 0600, "rmd%d", devid);
-       if (mdev[devid].mdcdevb == NULL) {                                      /* Did we make one? */
+       mdev[devid].mdCDev = makedev(mdevCMajor, devid);        /* Get the device number */
+       mdev[devid].mdcdevb = devfs_make_node(mdev[devid].mdCDev, DEVFS_CHAR,           /* Make the node */
+           UID_ROOT, GID_OPERATOR,
+           0600, "rmd%d", devid);
+       if (mdev[devid].mdcdevb == NULL) {                                      /* Did we make one? */
                printf("mdevadd: devfs_make_node for character failed!\n");
-               return -1;                                                                              /* Nope... */
-       }
-       
-       mdev[devid].mdBase = base;                                                      /* Set the base address of ram disk */
-       mdev[devid].mdSize = size;                                                      /* Set the length of the ram disk */
-       mdev[devid].mdSecsize = DEV_BSIZE;                                      /* Set starting block size */
-       if(phys) mdev[devid].mdFlags |= mdPhys;                         /* Show that we are in physical memory */
-       mdev[devid].mdFlags |= mdInited;                                        /* Show we are all set up */
-       printf("Added memory device md%x/rmd%x (%08X/%08X) at %016llX for %016llX\n", 
-                  devid, devid, mdev[devid].mdBDev, mdev[devid].mdCDev, base << 12, (uint64_t)size << 12);
+               return -1;                                                                              /* Nope... */
+       }
+
+       mdev[devid].mdBase = base;                                                      /* Set the base address of ram disk */
+       mdev[devid].mdSize = size;                                                      /* Set the length of the ram disk */
+       mdev[devid].mdSecsize = DEV_BSIZE;                                      /* Set starting block size */
+       if (phys) {
+               mdev[devid].mdFlags |= mdPhys;                          /* Show that we are in physical memory */
+       }
+       mdev[devid].mdFlags |= mdInited;                                        /* Show we are all set up */
+       printf("Added memory device md%x/rmd%x (%08X/%08X) at %016llX for %016llX\n",
+           devid, devid, mdev[devid].mdBDev, mdev[devid].mdCDev, base << 12, (uint64_t)size << 12);
        return mdev[devid].mdBDev;
 }
 
 
-dev_t mdevlookup(int devid) {
-       
-       if((devid < 0) || (devid > 15)) return -1;                      /* Filter any bogus requests */
-       if(!(mdev[devid].mdFlags & mdInited)) return -1;        /* This one hasn't been defined */
-       return mdev[devid].mdBDev;                                                      /* Return the device number */
+dev_t
+mdevlookup(int devid)
+{
+       if ((devid < 0) || (devid >= NB_MAX_MDEVICES)) {
+               return -1;                                                              /* Filter any bogus requests */
+       }
+       if (!(mdev[devid].mdFlags & mdInited)) {
+               return -1;                                      /* This one hasn't been defined */
+       }
+       return mdev[devid].mdBDev;                                                      /* Return the device number */
 }
 
-void mdevremoveall(void) {
-
+void
+mdevremoveall(void)
+{
        int i;
 
-       for(i = 0; i < 16; i++) {
-               if(!(mdev[i].mdFlags & mdInited)) continue;     /* Ignore unused mdevs */
-
-               devfs_remove(mdev[i].mdbdevb);                  /* Remove the block device */
-               devfs_remove(mdev[i].mdcdevb);                  /* Remove the character device */
+       for (i = 0; i < NB_MAX_MDEVICES; i++) {
+               if (!(mdev[i].mdFlags & mdInited)) {
+                       continue;                               /* Ignore unused mdevs */
+               }
+               devfs_remove(mdev[i].mdbdevb);                  /* Remove the block device */
+               devfs_remove(mdev[i].mdcdevb);                  /* Remove the character device */
 
-               mdev[i].mdBase = 0;                             /* Clear the mdev's storage */
+               mdev[i].mdBase = 0;                             /* Clear the mdev's storage */
                mdev[i].mdSize = 0;
                mdev[i].mdSecsize = 0;
                mdev[i].mdFlags = 0;
@@ -656,3 +733,28 @@ void mdevremoveall(void) {
                mdev[i].mdcdevb = 0;
        }
 }
+
+int
+mdevgetrange(int devid, uint64_t *base, uint64_t *size)
+{
+       assert(base);
+       assert(size);
+
+       /* filter invalid request */
+       if ((devid < 0) || (devid >= NB_MAX_MDEVICES)) {
+               return -1;
+       }
+
+       /* filter non-initialized memory devices */
+       if ((mdev[devid].mdFlags & mdInited) == 0) {
+               return -1;
+       }
+
+       *base = mdev[devid].mdBase << 12;
+       *size = mdev[devid].mdSize << 12;
+
+       /* make sure (base, size) is a valid range and will not overflow */
+       assert(*size < (UINT64_MAX - *base));
+
+       return 0;
+}