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os-k/kaleid/kernel/mm/heap.c
2019-03-19 13:37:23 +01:00

130 lines
3.5 KiB
C

//----------------------------------------------------------------------------//
// GNU GPL OS/K //
// //
// Desc: Early and very dumb heap managment //
// //
// //
// Copyright © 2018-2019 The OS/K Team //
// //
// This file is part of OS/K. //
// //
// OS/K is free software: you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation, either version 3 of the License, or //
// any later version. //
// //
// OS/K is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY//without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with OS/K. If not, see <https://www.gnu.org/licenses/>. //
//----------------------------------------------------------------------------//
#include <kernel/heap.h>
// Least address out of the heap
static void *_heap_end;
// Maximal value of the heap
static size_t _heap_max;
// Lock NOT used internally, but used by KalAllocMemory() & co.
static Lock_t _heap_lock = INITLOCK(KLOCK_SPINLOCK);
// Debugging stub
size_t GetAvailZoneSize(void *x) { (void)x; return 8 * MB; }
//
// Initializes heap managment
//
void InitHeap(void)
{
assert(_heap_end == NULL);
_heap_end = (void *)_HEAP_START;
_heap_max = lmin(8 * MB, GetAvailZoneSize((void *)_HEAP_START));
}
//
// Acquires control of the heap's lock
//
void LockHeap(void)
{
AcquireLock(&_heap_lock);
}
//
// Releases control of the heap's lock
//
void UnlockHeap(void)
{
ReleaseLock(&_heap_lock);
}
//
// Returns the heap's current size
//
size_t GetHeapSize(void)
{
return (size_t)_heap_end - _HEAP_START;
}
//
// Returns the heap's maximum size
//
size_t GetMaxHeapSize(void)
{
return _heap_max;
}
//
// Changes the heap's maximal size
//
error_t SetMaxHeapSize(size_t new)
{
if (new > GetAvailZoneSize((void *)_HEAP_START)) {
return ENOMEM;
}
if (new < (size_t)_heap_end - _HEAP_START) {
return EADDRINUSE;
}
_heap_max = new;
return EOK;
}
//
// Extends the heap's size
//
error_t GrowHeap(size_t req)
{
assert(req % alignof(QWORD));
if ((size_t)_heap_end + req > _HEAP_START + _heap_max) {
return ENOMEM;
}
_heap_end += req;
return EOK;
}
//
// Reduces the heap's size
//
error_t ShrinkHeap(size_t req)
{
assert(req % alignof(QWORD));
if (req > (size_t)_heap_end - _HEAP_START) {
return EADDRINUSE;
}
_heap_end -= req;
return EOK;
}