Kernel/Core/Memory/ProgramBreak.cpp
2023-08-22 06:21:17 +03:00

99 lines
2.3 KiB
C++

/*
This file is part of Fennix Kernel.
Fennix Kernel 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 (at your option) any later version.
Fennix Kernel 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 Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
*/
#include <memory.hpp>
#include <assert.h>
#include <errno.h>
#include <debug.h>
namespace Memory
{
void *ProgramBreak::brk(void *Address)
{
if (HeapStart == 0x0 || Break == 0x0)
{
error("HeapStart or Break is 0x0");
return (void *)-EAGAIN;
}
/* Get the current program break. */
if (Address == nullptr)
return (void *)Break;
/* Check if the address is valid. */
if (Address < (void *)HeapStart)
return (void *)-ENOMEM;
Virtual vmm = Virtual(this->Table);
if (Address > (void *)Break)
{
/* Allocate more memory. */
size_t Pages = TO_PAGES(uintptr_t(Address) - Break);
void *Allocated = mm->RequestPages(Pages);
if (Allocated == nullptr)
return (void *)-ENOMEM;
/* Map the allocated pages. */
for (size_t i = 0; i < Pages; i++)
{
void *VirtAddr = (void *)(Break + (i * PAGE_SIZE));
void *PhysAddr = (void *)(uintptr_t(Allocated) + (i * PAGE_SIZE));
vmm.Map(VirtAddr, PhysAddr, RW | US);
}
Break = (uint64_t)Address;
return (void *)Break;
}
else if (Address < (void *)Break)
{
/* Free memory. */
size_t Pages = TO_PAGES(uintptr_t(Address) - Break);
mm->FreePages((void *)Break, Pages);
/* Unmap the freed pages. */
for (size_t i = 0; i < Pages; i++)
{
uint64_t Page = Break - (i * 0x1000);
vmm.Unmap((void *)Page);
}
Break = (uint64_t)Address;
return (void *)Break;
}
assert(false);
}
ProgramBreak::ProgramBreak(PageTable *Table, MemMgr *mm)
{
assert(Table != nullptr);
assert(mm != nullptr);
this->Table = Table;
this->mm = mm;
}
ProgramBreak::~ProgramBreak()
{
/* Do nothing because MemMgr
will be destroyed later. */
}
}