1
0
Fork 0
mirror of https://gitlab.com/sortix/sortix.git synced 2023-02-13 20:55:38 -05:00
sortix--sortix/kernel/addralloc.cpp

129 lines
3.7 KiB
C++
Raw Normal View History

/*
* Copyright (c) 2013, 2014 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* addralloc.cpp
* Class to keep track of mount points.
*/
#include <assert.h>
#include <errno.h>
#include <stddef.h>
#include <sortix/kernel/addralloc.h>
2013-10-26 20:42:10 -04:00
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/kthread.h>
#include <sortix/kernel/memorymanagement.h>
namespace Sortix {
size_t aux_allocated = 0;
size_t heap_allocated = 0;
kthread_mutex_t alloc_lock = KTHREAD_MUTEX_INITIALIZER;
// TODO: Kernel address space is allocated simply by increasing the pointer,
// with no support for freeing it. This is not that big a problem at this point,
// since address space is consumed at boot and then used forever. When it
// becomes normal for devices to come and go, just recode these functions and
// everyone should do the right thing.
bool AllocateKernelAddress(addralloc_t* ret, size_t size)
{
size = Page::AlignUp(size);
ScopedLock lock(&alloc_lock);
addr_t kmem_from;
size_t kmem_size;
Memory::GetKernelVirtualArea(&kmem_from, &kmem_size);
addr_t aux_reached = kmem_from + kmem_size - aux_allocated;
size_t heap_reached = kmem_from + heap_allocated;
size_t unused_left = aux_reached - heap_reached;
if ( unused_left < size )
return errno = ENOMEM, false;
aux_allocated += size;
ret->from = kmem_from + kmem_size - aux_allocated;
ret->size = size;
return true;
}
// TODO: Proper deallocation support!
void FreeKernelAddress(addralloc_t* alloc)
{
if ( !alloc->from )
return;
ScopedLock lock(&alloc_lock);
addr_t kmem_from;
size_t kmem_size;
Memory::GetKernelVirtualArea(&kmem_from, &kmem_size);
addr_t aux_reached = kmem_from + kmem_size - aux_allocated;
if ( alloc->from == aux_reached )
aux_allocated -= alloc->size;
alloc->from = 0;
alloc->size = 0;
}
size_t ExpandHeap(size_t increase)
{
increase = Page::AlignUp(increase);
ScopedLock lock(&alloc_lock);
addr_t kmem_from;
size_t kmem_size;
Memory::GetKernelVirtualArea(&kmem_from, &kmem_size);
addr_t aux_reached = kmem_from + kmem_size - aux_allocated;
size_t heap_reached = kmem_from + heap_allocated;
size_t unused_left = aux_reached - heap_reached;
if ( unused_left < increase )
return errno = ENOMEM, 0;
heap_allocated += increase;
return increase;
}
void ShrinkHeap(size_t decrease)
{
assert(decrease == Page::AlignUp(decrease));
ScopedLock lock(&alloc_lock);
assert(decrease <= heap_allocated);
heap_allocated -= decrease;
}
// No need for locks in these three functions, since only the heap calls these
// and it already uses an internal lock, and heap_allocated will not change
// unless the heap calls ExpandHeap.
addr_t GetHeapLower()
{
addr_t kmem_from;
size_t kmem_size;
Memory::GetKernelVirtualArea(&kmem_from, &kmem_size);
(void) kmem_size;
return kmem_from;
}
addr_t GetHeapUpper()
{
addr_t kmem_from;
size_t kmem_size;
Memory::GetKernelVirtualArea(&kmem_from, &kmem_size);
(void) kmem_size;
return kmem_from + heap_allocated;
}
size_t GetHeapSize()
{
return heap_allocated;
}
} // namespace Sortix