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/* vman.c: ANSI VM: MALLOC-BASED PSEUDO MEMORY MAPPING
*
* $Id$
* Copyright (c) 2001-2020 Ravenbrook Limited. See end of file for license.
*/
#include "mpm.h"
#include "vm.h"
#include <stdlib.h> /* for malloc and free */
SRCID(vman, "$Id$");
/* PageSize -- return the page size */
Size PageSize(void)
{
return VMAN_PAGE_SIZE;
}
Res VMParamFromArgs(void *params, size_t paramSize, ArgList args)
{
AVER(params != NULL);
AVERT(ArgList, args);
UNUSED(paramSize);
return ResOK;
}
/* VMInit -- reserve some virtual address space, and create a VM structure */
Res VMInit(VM vm, Size size, Size grainSize, void *params)
{
void *vbase;
Size pageSize, reserved;
AVER(vm != NULL);
AVERT(ArenaGrainSize, grainSize);
AVER(size > 0);
AVER(params != NULL);
pageSize = PageSize();
/* Grains must consist of whole pages. */
AVER(grainSize % pageSize == 0);
/* Check that the rounded-up sizes will fit in a Size. */
size = SizeRoundUp(size, grainSize);
if (size < grainSize || size > (Size)(size_t)-1)
return ResRESOURCE;
/* Note that because we add a whole grainSize here (not grainSize -
* pageSize), we are not in danger of overflowing vm->limit even if
* malloc were perverse enough to give us a block at the end of
* memory. Compare vmix.c#.assume.not-last. */
reserved = size + grainSize;
if (reserved < grainSize || reserved > (Size)(size_t)-1)
return ResRESOURCE;
vbase = malloc((size_t)reserved);
if (vbase == NULL)
return ResMEMORY;
(void)mps_lib_memset(vbase, VMJunkBYTE, reserved);
vm->pageSize = pageSize;
vm->block = vbase;
vm->base = AddrAlignUp(vbase, grainSize);
vm->limit = AddrAdd(vm->base, size);
AVER(vm->base < vm->limit); /* can't overflow, as discussed above */
AVER(vm->limit < AddrAdd((Addr)vm->block, reserved));
vm->reserved = reserved;
vm->mapped = (Size)0;
vm->sig = VMSig;
AVERT(VM, vm);
EVENT3(VMInit, vm, VMBase(vm), VMLimit(vm));
return ResOK;
}
/* VMFinish -- release all address space and finish VM structure */
void VMFinish(VM vm)
{
AVERT(VM, vm);
/* Descriptor must not be stored inside its own VM at this point. */
AVER(PointerAdd(vm, sizeof *vm) <= vm->block
|| PointerAdd(vm->block, VMReserved(vm)) <= (Pointer)vm);
/* All address space must have been unmapped. */
AVER(VMMapped(vm) == (Size)0);
EVENT1(VMFinish, vm);
vm->sig = SigInvalid;
(void)mps_lib_memset(vm->block, VMJunkBYTE, vm->reserved);
free(vm->block);
}
/* VMMap -- map the given range of memory */
Res VMMap(VM vm, Addr base, Addr limit)
{
Size size;
AVER(base != (Addr)0);
AVER(VMBase(vm) <= base);
AVER(base < limit);
AVER(limit <= VMLimit(vm));
AVER(AddrIsAligned(base, vm->pageSize));
AVER(AddrIsAligned(limit, vm->pageSize));
size = AddrOffset(base, limit);
(void)mps_lib_memset((void *)base, VMJunkBYTE, size);
vm->mapped += size;
AVER(VMMapped(vm) <= VMReserved(vm));
EVENT3(VMMap, vm, base, limit);
return ResOK;
}
/* VMUnmap -- unmap the given range of memory */
void VMUnmap(VM vm, Addr base, Addr limit)
{
Size size;
AVER(base != (Addr)0);
AVER(VMBase(vm) <= base);
AVER(base < limit);
AVER(limit <= VMLimit(vm));
AVER(AddrIsAligned(base, vm->pageSize));
AVER(AddrIsAligned(limit, vm->pageSize));
size = AddrOffset(base, limit);
AVER(VMMapped(vm) >= size);
(void)mps_lib_memset((void *)base, VMJunkBYTE, size);
vm->mapped -= size;
EVENT3(VMUnmap, vm, base, limit);
}
/* C. COPYRIGHT AND LICENSE
*
* Copyright (C) 2001-2020 Ravenbrook Limited <https://www.ravenbrook.com/>.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT
* HOLDER OR CONTRIBUTORS 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.
*/
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