Karina
131 lines
4.5 KiB
C
131 lines
4.5 KiB
C
// SPDX-License-Identifier: GPL-3.0-or-later
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// Copyright (c) 2026 0xKarinyash
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#include <VM/PMM.h>
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#include <VM/VMM.h>
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#include <lib/String.h>
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#include <lib/Math.h>
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#include <OS/OSPanic.h>
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#include <OS/OSSpinlock.h>
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#include <types.h>
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#include "bootinfo.h"
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UInt8* gVMPhycalMemoryBitmap = nullptr;
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UInt64 gVMPhycalMemoryBitmapSize = 0;
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UInt64 gVMPhycalMemoryTotalMemorySize = 0;
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static OSSpinlock sVMPMMLock = {0};
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extern UInt64 _kernel_start;
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extern UInt64 _kernel_end;
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UInt64 VMPhysicalMemoryGetTotalMemorySize() {
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return gVMPhycalMemoryTotalMemorySize;
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}
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void VMPhysicalMemoryInitialize(BIMemoryMap *memoryMap) {
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UInt64 descriptorCount = memoryMap->mapSize / memoryMap->descriptorSize;
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UInt64 maxPhysicalAddress = 0;
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for (UInt64 i = 0; i < descriptorCount; i++) {
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OSMemoryDescriptor* descriptor = (OSMemoryDescriptor*)((UInt8*)memoryMap->map + (i * memoryMap->descriptorSize));
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if (descriptor->type == kOSMemoryTypeMappedIO ||
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descriptor->type == kOSMemoryTypeMappedIOPortSpace ||
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descriptor->type == kOSMemoryTypeUnusable ||
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descriptor->type == kOSMemoryTypeReserved ||
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descriptor->type == kOSMemoryTypePalCode) {
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continue;
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}
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UInt64 nominee = descriptor->physicalStart + (descriptor->pageCount * kVMPageSize);
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if (nominee > maxPhysicalAddress) {
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maxPhysicalAddress = nominee;
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}
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}
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gVMPhycalMemoryTotalMemorySize = maxPhysicalAddress;
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UInt64 totalPageCount = maxPhysicalAddress / kVMPageSize;
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UInt64 bitmapSize = (totalPageCount + 7) / 8;
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OSMemoryDescriptor *bitmapHostDescriptor = nullptr;
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for (UInt64 i = 0; i < descriptorCount; i++) {
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OSMemoryDescriptor *descriptor = (OSMemoryDescriptor*)((UInt8*)memoryMap->map + (i * memoryMap->descriptorSize));
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if ((descriptor->type == kOSMemoryTypeConventional) &&
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((descriptor->pageCount * kVMPageSize) >= bitmapSize) &&
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(descriptor->physicalStart >= kVMSafeSpaceStartAddress)) {
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bitmapHostDescriptor = descriptor;
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break;
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}
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}
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if (bitmapHostDescriptor == nullptr) {
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OSPanic("PMM: Not enough RAM for memory bitmap!");
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}
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gVMPhycalMemoryBitmap = (UInt8*)bitmapHostDescriptor->physicalStart;
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gVMPhycalMemoryBitmapSize = bitmapSize;
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MemorySet(gVMPhycalMemoryBitmap, 0xFF, bitmapSize);
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for (UInt64 i = 0; i < descriptorCount; i++) {
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OSMemoryDescriptor *descriptor = (OSMemoryDescriptor*)((UInt8*)memoryMap->map + (i * memoryMap->descriptorSize));
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if (descriptor->type != kOSMemoryTypeConventional) {
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continue;
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}
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UInt64 startAddress = descriptor->physicalStart;
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UInt64 endAddress = startAddress + (descriptor->pageCount * kVMPageSize);
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for (UInt64 addr = startAddress; addr < endAddress; addr += kVMPageSize) {
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BITMAP_UNSET(gVMPhycalMemoryBitmap, addr);
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}
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}
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UInt64 kernelStart = KERNEL_VIRT_TO_PHYS((UInt64)&_kernel_start);
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UInt64 kernelEnd = KERNEL_VIRT_TO_PHYS((UInt64)&_kernel_end);
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UInt64 bitmapStart = (UInt64)gVMPhycalMemoryBitmap;
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UInt64 bitmapEnd = bitmapStart + gVMPhycalMemoryBitmapSize;
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for (UInt64 addr = 0; addr < kVMSafeSpaceStartAddress; addr += kVMPageSize) BITMAP_SET(gVMPhycalMemoryBitmap, addr);
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for (UInt64 addr = kernelStart; addr < kernelEnd; addr += kVMPageSize) BITMAP_SET(gVMPhycalMemoryBitmap, addr);
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for (UInt64 addr = bitmapStart; addr < bitmapEnd; addr += kVMPageSize) BITMAP_SET(gVMPhycalMemoryBitmap, addr);
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}
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void* VMPhysicalMemoryAllocatePage() {
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OSSpinlockState state;
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OSSpinlockLockIRQ(&sVMPMMLock, &state);
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for (UInt64 i = 0; i < gVMPhycalMemoryBitmapSize; i++) {
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if (gVMPhycalMemoryBitmap[i] == 0xFF) continue;
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for (UInt64 bit = 0; bit < 8; bit++) {
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if ((gVMPhycalMemoryBitmap[i] & (1 << bit)) == 0) {
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UInt64 address = (i * 8 + bit) * kVMPageSize;
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BITMAP_SET(gVMPhycalMemoryBitmap, address);
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OSSpinlockUnlockIRQ(&sVMPMMLock, &state);
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return (void*)address;
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}
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}
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}
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OSSpinlockUnlockIRQ(&sVMPMMLock, &state);
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return nullptr; // Out of memory
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}
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void VMPhysicalMemoryFreePage(void* address) {
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OSSpinlockState state;
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OSSpinlockLockIRQ(&sVMPMMLock, &state);
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BITMAP_UNSET(gVMPhycalMemoryBitmap, (UInt64)address);
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OSSpinlockUnlockIRQ(&sVMPMMLock, &state);
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} |