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KERNEL: Physical Page Frame allocation 

Rewriting the setup to allow for physical memory allocation again to work.
dev
Nigel Barink 2022-09-01 16:11:35 +02:00
parent 59ba41f3d2
commit a5e7fdd07e
7 changed files with 107 additions and 84 deletions
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3
source/kernel/Boot/boot.s
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@ -35,7 +35,7 @@ _start:
/* push the magic value */
pushl %eax
call testLauncher
call prekernelSetup
# Get physical address of the boot_page_table
movl $(boot_page_table - 0xC0000000), %edi
@ -60,7 +60,6 @@ _start:
3: # Map VGA video memory to 0xC03FF00 as "present, writable"
movl $(0x000B8000 | 0x003), boot_page_table - 0xC0000000 + 1023 * 4
# IMPORTANT NOTE FROM WIKI.OSDEV.ORG/HIGHER_HALF_X86_BARE_BONES
# The page table is used at both page directory entry 0 (virtually from 0x0

2
source/kernel/Memory/GDT/gdtc.cpp
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@ -51,7 +51,7 @@ void initGDT(){
gdtDescriptor.limit = ((sizeof(SegmentDescriptor ) * 5 ) - 1);
gdtDescriptor.base = (unsigned int) &GlobalDescriptorTable;
printf("GDT at address 0x%x, with an size of 0x%x bytes\n" , (unsigned int)GlobalDescriptorTable, sizeof(GlobalDescriptorTable));
LoadGlobalDescriptorTable();

82
source/kernel/Memory/PhysicalMemoryManager.cpp
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@ -2,32 +2,61 @@
PhysicalMemoryManagerInfoBlock* PMMInfoBlock;
const uint32_t KERNEL_OFFSET = 0xC0000000;
void SetupPhysicalMemoryManager( BootInfoBlock* Bootinfo) {
void initPMM( MemoryInfo* memory) {
// NOTE: Lets for now puts the Physical memoryManagerBlock at a random address
// We'll think of a more proper solution a bit later
PMMInfoBlock = (PhysicalMemoryManagerInfoBlock*) 0xCC900000;
PMMInfoBlock = (PhysicalMemoryManagerInfoBlock*) ((uint32_t)MemoryMapHeap_pptr + Bootinfo->map_size + 0xC0000000);
/*
Every byte contains 8 pages
A page is 4096 kib
Every block (1 bit) represent an page
*/
// calculate the maximum number of blocks
PMMInfoBlock->max_blocks = KB_TO_BLOCKS(memory->TotalMemory);
PMMInfoBlock->max_blocks =Bootinfo->MemorySize / BLOCK_SIZE / 8;
PMMInfoBlock->used_blocks = 0;
PMMInfoBlock->memoryBitMap = (uint32_t*) 0xCCA00000;
printf("Maximum Number of blocks: 0x%x, Number of bytes for memMap: 0x%x\n", PMMInfoBlock->max_blocks , (PMMInfoBlock->max_blocks/8));
// put the map after the gdt
PMMInfoBlock->memoryBitMap = (uint32_t*) ( 0xC010b100) ;
// // Page in the address space please
// uint32_t PDEI = 0xC020a000 >> 22;
// uint32_t PTEI = (0xC020a000 >> 12) & 0x1FFF;
// printf("PDEI: %d, PTEI: %d\n", PDEI, PTEI);
//Size of memory map
uint32_t memMap_size = (PMMInfoBlock->max_blocks / 8 ) ;
printf("Memory Map size: 0x%x\n", memMap_size );
printf("size of int in bytes: 0x%x \n" , sizeof(int));
printf("Maximum num blocks: %d \n",PMMInfoBlock->max_blocks);
//Size of memory map
uint32_t memMap_size = PMMInfoBlock->max_blocks / 8;
printf("Memory map size: %d\n", memMap_size);
printf("Address of memory map 0x%x\n", PMMInfoBlock->memoryBitMap);
// Set all places in memory as free
memset(PMMInfoBlock->memoryBitMap, 0xFF, memMap_size );
memset(PMMInfoBlock->memoryBitMap, 0xFF, memMap_size );
// Loop over memory map and allocate physical locations
// that are already in use
MemoryInfoBlock* currentBlock = (MemoryInfoBlock*) ((uint32_t)Bootinfo->MemoryMap + KERNEL_OFFSET) ;
printf("Starting address: 0x%x\n", currentBlock);
while( (uint32_t) currentBlock->next != 0x0)
{
if(IS_AVAILABLE_MEM(currentBlock->type)){
printf("skip!\n");
} else {
printf("allocate region 0x%x of size 0x%x\n" , currentBlock->Base_addr, currentBlock->Memory_Size);
allocate_region((uint32_t) currentBlock->Base_addr, currentBlock->Memory_Size);
}
currentBlock = (MemoryInfoBlock*) ((uint32_t)currentBlock->next + KERNEL_OFFSET );
}
uint32_t kernel_size = ((uint32_t)&kernel_end - (uint32_t)&kernel_begin ) - KERNEL_OFFSET;
printf("kernel size in memory: 0x%x\n", kernel_size);
allocate_region((uint32_t)&kernel_begin, kernel_size);
}
// NOTE: this can only give blocks of 4kb at a time!
// NOTE: This can only give blocks of 4kb at a time!
// We might at some point want to allocate multiple blocks at once.
void* allocate_block() {
uint8_t blocks_available = PMMInfoBlock->max_blocks - PMMInfoBlock->used_blocks;
// Are there any blocks available?
@ -38,10 +67,8 @@ void* allocate_block() {
}
// Find 1 free block somewhere
int free_block_index = bitmap_first_unset(PMMInfoBlock->memoryBitMap, (PMMInfoBlock->max_blocks /8) /*memMap Size*/ );
int free_block_index = bitmap_first_unset(PMMInfoBlock->memoryBitMap, PMMInfoBlock->max_blocks / 8 );
if(free_block_index == -1)
{
printf("Could not find a good block!\n");
@ -83,20 +110,27 @@ void allocate_region(uint32_t startAddress, uint32_t size) {
int NumberOfBlocksToAllocate = ( size / 1024) / 4 / 8 + 1;
int startBlock = (startAddress / 1024) / 4 / 8 ;
// printf("NumberOfBlocksToAllocate: 0x%x\n", NumberOfBlocksToAllocate);
//printf( "start block: 0x%x\n" , startBlock);
for( int i = 0; i < NumberOfBlocksToAllocate; i++)
{
//printf("ALLOCATE BLOCK: 0x%x\n" , startBlock + i );
bitmap_unset(PMMInfoBlock->memoryBitMap, startBlock+ i);
PMMInfoBlock->used_blocks++;
}
}
void deallocate_region(uint32_t StartAddress , uint32_t size ) {
// NOT IMPLEMENTED YET
// reverse of what happened in allocate_region
int NumberOfBlocks = (size / 1024) / 4 / 8 + 1;
int startBlock = (StartAddress / 1024) / 4 / 8;
for(int i = 0; i < NumberOfBlocks; i++)
{
bitmap_set(PMMInfoBlock->memoryBitMap, startBlock + i);
PMMInfoBlock->used_blocks --;
}
}

12
source/kernel/Memory/PhysicalMemoryManager.h
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@ -1,17 +1,13 @@
#pragma once
#include <stddef.h>
#include "memoryinfo.h"
#include "../PreKernel/bootstructure.h"
#include "../Terminal/kterm.h"
#include "../Lib/mem.h"
#include "../bitmap.h"
// Asumming 32 bit x86 for now!
#define BLOCK_SIZE 4092
#define WORD_SIZE 2
#define BLOCKS_PER_WORD 32
// Asumming i386 for now!
#define BLOCK_SIZE 4092
#define KB_TO_BLOCKS(x) (x / BLOCK_SIZE)
#define IS_ALIGNED(addr, align) !((addr) & ~((align) - 1))
#define ALIGN(addr, align) (((addr) & ~((align) - 1 )) + (align))
@ -23,7 +19,7 @@ struct PhysicalMemoryManagerInfoBlock
int used_blocks;
};
void initPMM(MemoryInfo* memory);
void SetupPhysicalMemoryManager(BootInfoBlock* memory);
void free_block(void* ptr);
void* allocate_block();
void allocate_region(uint32_t, uint32_t);

12
source/kernel/PreKernel/bootstructure.h
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@ -2,17 +2,12 @@
#include <stddef.h>
#include <stdint.h>
extern "C" const uint32_t kernel_begin;
extern "C" const uint32_t kernel_end;
// Put the BootInfoBlock 1MB above the kernel.
const uint32_t BootInfoBlock_pptr = (uint32_t)&kernel_end - 0xC0000000 + 0x1;
const uint32_t MemoryMapHeap_pptr = BootInfoBlock_pptr + 0x1;
#define IS_AVAILABLE_MEM(MEM_TYPE) MEM_TYPE & 0x1
#define IS_ACPI_MEM(MEM_TYPE) MEM_TYPE & 0x2
#define IS_RESERVED_MEM(MEM_TYPE) MEM_TYPE & 0x3
#define IS_RESERVED_MEM(MEM_TYPE) MEM_TYPE & 0x4
#define IS_NVS_MEMORY(MEM_TYPE) MEM_TYPE & 0x8
#define IS_BADRAM_MEMORY(MEM_TYPE) MEM_TYPE & 0x10
@ -40,6 +35,11 @@ struct BootInfoBlock {
bool PhysicalMemoryMapAvailable;
MemoryInfoBlock* MemoryMap;
uint32_t map_size;
uint32_t MemorySize ;
};
// TODO Put the BootInfoBlock 1MB above the kernel.
const uint32_t BootInfoBlock_pptr = (uint32_t)&kernel_end - 0xC0000000 + 0x1;
const uint32_t MemoryMapHeap_pptr = BootInfoBlock_pptr + sizeof(BootInfoBlock);

20
source/kernel/PreKernel/prekernel.cpp
View File

@ -5,7 +5,7 @@
#define CHECK_FLAG(flags, bit) ((flags) & (1 <<(bit)))
extern "C" void testLauncher ( unsigned long magic, multiboot_info_t* mbi) {
extern "C" void prekernelSetup ( unsigned long magic, multiboot_info_t* mbi) {
// Create the bootInfoBlock at its location
BootInfoBlock* BIB = (BootInfoBlock*) BootInfoBlock_pptr;
@ -74,23 +74,25 @@ if (CHECK_FLAG(mbi->flags, 6))
auto CurrentInfoBlock = BIB->MemoryMap;
while((unsigned long) mmap < MemoryMapEnd){
uint32_t RAM_size = 0;
while((unsigned long) mmap < MemoryMapEnd){
BIB->map_size += sizeof(MemoryInfoBlock);
CurrentInfoBlock->Base_addr = mmap->addr;
CurrentInfoBlock->Memory_Size = mmap->len;
if(mmap->type == MULTIBOOT_MEMORY_AVAILABLE)
CurrentInfoBlock->type &= 0x1;
CurrentInfoBlock->type |= 0x1;
RAM_size += mmap->len;
if(mmap->type == MULTIBOOT_MEMORY_ACPI_RECLAIMABLE)
CurrentInfoBlock->type &= 0x2;
CurrentInfoBlock->type |= 0x2;
if(mmap->type == MULTIBOOT_MEMORY_RESERVED)
CurrentInfoBlock->type &= 0x4;
CurrentInfoBlock->type |= 0x4;
if(mmap->type == MULTIBOOT_MEMORY_NVS)
CurrentInfoBlock->type &= 0x8;
CurrentInfoBlock->type |= 0x8;
if(mmap->type == MULTIBOOT_MEMORY_BADRAM)
CurrentInfoBlock->type &= 0x10;
CurrentInfoBlock->type |= 0x10;
// continue to the next block
@ -102,7 +104,7 @@ if (CHECK_FLAG(mbi->flags, 6))
}
CurrentInfoBlock->next = (MemoryInfoBlock*) 0x0;
BIB->MemorySize = RAM_size;
} else
{
BIB->PhysicalMemoryMapAvailable = false;

60
source/kernel/kernel.cpp
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@ -4,9 +4,11 @@ extern "C" void early_main()
/*
* Initialize terminal interface
*/
initGDT();
kterm_init();
initGDT();
init_serial();
print_serial("Hello Higher half kernel!\n");
@ -21,7 +23,7 @@ extern "C" void early_main()
printf("|=== BarinkOS ===|\n");
printf("Kernel End Addr: 0x%x\n" , &kernel_end + KERNEL_BASE_ADDR);
uint32_t PageDirectoryEntryIndex = ((uint32_t)&kernel_end + KERNEL_BASE_ADDR ) >> 2 ;
uint32_t PageDirectoryEntryIndex = ((uint32_t)&kernel_end + KERNEL_BASE_ADDR ) >> 22 ;
uint32_t PageTableEntryIndex = (((uint32_t)&kernel_end + KERNEL_BASE_ADDR) >> 12) & 0x1FFF;
@ -38,6 +40,8 @@ extern "C" void early_main()
BootInfoBlock* BootInfo = (BootInfoBlock*) ( BootInfoBlock_pptr + 0xC0000000 );
printf("Size of BootInfoBlock: %d bytes\n", sizeof(BootInfoBlock));
printf("Bootloader information:\n");
if( BootInfo->ValidELFHeader )
{
@ -57,71 +61,58 @@ extern "C" void early_main()
if(BootInfo->PhysicalMemoryMapAvailable)
{
printf("- Physical Memory Map available!\n");
printf("MemoryInfoheap size : %d bytes\n", BootInfo->map_size);
// Print the memory regions
MemoryInfoBlock* currentBlock = (MemoryInfoBlock*) ((uint32_t)BootInfo->MemoryMap + KERNEL_BASE_ADDR) ;
kterm_setcolor(VGA_COLOR_RED);
printf("size of MemoryInfoBlock: 0x%x\n", sizeof(MemoryInfoBlock));
kterm_setcolor(VGA_COLOR_CYAN);
printf("Kernel End is at address: 0x%x\n", &kernel_end);
printf("BootInfo is at address: 0x%x\n", BootInfo);
printf("map is at address: 0x%x\n", currentBlock + KERNEL_BASE_ADDR);
kterm_setcolor(VGA_COLOR_WHITE);
printf( "Starting address: 0x%x\n", currentBlock);
while( (uint32_t)currentBlock->next != 0x0 )
{
kterm_setcolor(VGA_COLOR_CYAN);
printf("map is at address: 0x%x\n", ( (uint32_t)currentBlock ));
kterm_setcolor(VGA_COLOR_WHITE);
/*
uint32_t pageDirectoryIndex = ((uint32_t)&currentBlock ) >> 22;
printf("pageDirectoryIndex: %d\n", pageDirectoryIndex);
uint32_t pageTableIndex = ((uint32_t)&currentBlock >> 12) & 0x1FFF;
printf("PagTableIndex: %d\n", pageTableIndex);
*/
//printf("boot_page_directory addr: 0x%x\n", &boot_page_directory);
//printf("boot_page_table addr: 0x%x\n", &multiboot_page_table);
printf("Memory Region: \n");
if(IS_AVAILABLE_MEM(currentBlock->type)){
//printf("AVAILABLE RAM\n");
}
else if(IS_ACPI_MEM(currentBlock->type)){
printf("ACPI MEMORY\n");
//printf("ACPI MEMORY\n");
}
else if(IS_RESERVED_MEM(currentBlock->type)){
printf("RESERVED MEMORY\n");
// printf("RESERVED MEMORY\n");
}
else if(IS_NVS_MEMORY(currentBlock->type)){
printf("NVS MEMORY \n");
// printf("NVS MEMORY \n");
}
else if(IS_BADRAM_MEMORY(currentBlock->type)){
printf("BADRAM MEMORY \n");
// printf("BADRAM MEMORY \n");
}
else {
// printf("(TYPE 0x%x )TYPE NOT SPECIFIED\n", currentBlock->type);
}
// printf("Base address: 0x%x, Memory size: 0x%x\n", currentBlock->Base_addr, currentBlock->Memory_Size);
currentBlock = (MemoryInfoBlock*) ((uint32_t)currentBlock->next + KERNEL_BASE_ADDR );
}
// Setup PhysicalMemoryManagement
SetupPhysicalMemoryManager(BootInfo);
// Small test!
void* block = allocate_block();
void* block2 = allocate_block();
printf("Allocated addresss 1: 0x%x 2: 0x%x\n", (uint32_t)block ,(uint32_t)block2);
free_block(block);
free_block(block2);
void* block3 = allocate_block();
printf("Allocated addresss 3: 0x%x\n", (uint32_t)block3);
free_block(block3);
}
asm volatile("mov %cr0, %eax ");
asm volatile("or $1, %eax");
asm volatile("mov %eax, %cr0");
asm volatile("mov %eax, %cr0"); // re-enable protected mode ?
kernel_main();
}
void map_multiboot_info_structure(unsigned long addr){
// map the multiboot structure into virtual memory
// so we can gather the necessary data from it.
@ -150,6 +141,7 @@ void map_multiboot_info_structure(unsigned long addr){
}
void PhysicalMemoryAllocatorTest(){
#ifdef UNIT_TESTS
// test alloc_block
uint8_t* memory = (uint8_t*) memAlloc.allocate_block();