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Fixing vm on osf

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 Change: 17343
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David Jones 1997-03-26 13:51:45 +00:00
parent d959f69bc6
commit 132bc4331c
1 changed files with 18 additions and 13 deletions
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31
mps/src/vmo1.c
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@ -1,19 +1,21 @@
/* impl.c.vmso: VIRTUAL MEMORY MAPPING FOR SOLARIS 2.x
/* impl.c.vmo1: VIRTUAL MEMORY MAPPING FOR DIGITAL UNIX
*
* $HopeName$
* $HopeName: MMsrc!vmo1.c(trunk.1) $
* Copyright (C) 1995,1997 Harlequin Group, all rights reserved
*
* Design: design.mps.vm
* Readership: Any MPS developer
*
* Status: er, a bit hacky.
* Design: design.mps.vm, design.mps.vmo1
*
* Status: a bit hacky, but probably working.
*
* This is the implementation of the virtual memory mapping interface
* (vm.h) for DEC UNIX / OSF1 (os.o1).
*
* mmap(2) is used to reserve address space by creating a mapping to
* /etc/passwd with page access none. mmap(2) is used to map pages
* onto store by creating a copy-on-write mapping with the flag
* MAP_ANONYMOUS.
* onto store by creating a copy-on-write (MAP_PRIVATE) mapping with
* the flag MAP_ANONYMOUS.
*
* Experiments have shown that attempting to reserve address space
* by mapping /dev/zero results in swap being reserved. This
@ -29,6 +31,11 @@
* .assume.mmap.err: ENOMEM is the only error we really expect to
* get from mmap. The others are either caused by invalid params
* or features we don't use. See mmap(2) for details.
*
* .assume.off_t: We assume that the Size type (defined by the MM) fits
* in the off_t type (define by the system (POSIX?)). In fact we test
* the more stringent requirement that they are the same size. This
* assumption is made in VMUnmap.
*/
#include "mpm.h"
@ -55,7 +62,7 @@
/* for getpagesize(2),close(2) */
#include <unistd.h>
SRCID(vmo1, "$HopeName$");
SRCID(vmo1, "$HopeName: MMsrc!vmo1.c(trunk.1) $");
/* Fix unprototyped system calls
@ -248,6 +255,7 @@ Res VMMap(Space space, Addr base, Addr limit)
}
/* see design.mps.vmo1.fun.unmap */
void VMUnmap(Space space, Addr base, Addr limit)
{
VM vm = SpaceVM(space);
@ -260,17 +268,14 @@ void VMUnmap(Space space, Addr base, Addr limit)
AVER(limit <= vm->limit);
AVER(AddrIsAligned(base, vm->align));
AVER(AddrIsAligned(limit, vm->align));
/* Map /etc/passwd onto the area, allowing no access. This */
/* effectively depopulates the area from memory, but keeps */
/* it "busy" as far as the OS is concerned, so that it will not */
/* be re-used by other calls to mmap which do not specify MAP_FIXED. */
AVER(sizeof(off_t) == sizeof(Size)); /* .assume.off_t */
size = AddrOffset(base, limit);
/* see design.mps.vmo1.fun.unmap.offset */
addr = mmap((void *)base, (size_t)size,
PROT_NONE, MAP_FILE | MAP_SHARED | MAP_FIXED,
vm->none_fd, 0);
vm->none_fd, (off_t)AddrOffset(vm->base, base));
AVER(addr != (void *)-1);
vm->mapped -= size;