Nigel
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BarinkOS
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KERNEL: Improved Physical memory allocation code / Code refactor 

* Moved tests to a different folder
* Adjusted the memory map address locations
* Improved readability of `kernel.cpp`
dev
Nigel Barink 2022-09-02 21:09:51 +02:00
parent 13e9beea79
commit 01fcb0aa15
14 changed files with 158 additions and 202 deletions
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35
Makefile
View File

@ -5,7 +5,7 @@ CC = ${HOME}/opt/cross/bin/i686-elf-gcc
CPP = ${HOME}/opt/cross/bin/i686-elf-g++
CFLAGS = -ffreestanding -Og -ggdb -Wall -Wextra
OFILES =$(BUILD_DIR)/boot.o $(BUILD_DIR)/kterm.o $(BUILD_DIR)/kernel.o $(BUILD_DIR)/memory.o $(BUILD_DIR)/paging.o $(BUILD_DIR)/pit.o $(BUILD_DIR)/time.o $(BUILD_DIR)/keyboard.o $(BUILD_DIR)/io.o $(BUILD_DIR)/gdtc.o $(BUILD_DIR)/idt.o $(BUILD_DIR)/pic.o $(BUILD_DIR)/sv-terminal.o $(BUILD_DIR)/string.o $(BUILD_DIR)/prekernel.o $(BUILD_DIR)/cpu.o
OFILES =$(BUILD_DIR)/boot.o $(BUILD_DIR)/kterm.o $(BUILD_DIR)/kernel.o $(BUILD_DIR)/memory.o $(BUILD_DIR)/paging.o $(BUILD_DIR)/pit.o $(BUILD_DIR)/time.o $(BUILD_DIR)/keyboard.o $(BUILD_DIR)/io.o $(BUILD_DIR)/gdtc.o $(BUILD_DIR)/idt.o $(BUILD_DIR)/pic.o $(BUILD_DIR)/sv-terminal.o $(BUILD_DIR)/string.o $(BUILD_DIR)/prekernel.o $(BUILD_DIR)/cpu.o $(BUILD_DIR)/KHeap.o
SRC_DIR = source
BUILD_DIR = build
@ -51,24 +51,15 @@ build_x86_64:
clean:
rm -f $(BUILD_DIR)/myos.bin $(INTERNAL_OBJS)
# C++ definition -> Object files
$(BUILD_DIR)/kernel.o:
$(CPP) -c $(SRC_DIR)/kernel/kernel.cpp -o $(BUILD_DIR)/kernel.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/kterm.o:
$(CPP) -c $(SRC_DIR)/kernel/terminal/kterm.cpp -o $(BUILD_DIR)/kterm.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/boot.o:
$(AS) $(SRC_DIR)/kernel/boot/boot.s -o $(BUILD_DIR)/boot.o
$(BUILD_DIR)/crti.o:
$(AS) $(SRC_DIR)/kernel/crti.s -o $(BUILD_DIR)/crti.o
$(BUILD_DIR)/crtn.o:
$(AS) $(SRC_DIR)/kernel/crtn.s -o $(BUILD_DIR)/crtn.o
$(BUILD_DIR)/io.o:
$(CPP) -c $(SRC_DIR)/kernel/io.cpp -o $(BUILD_DIR)/io.o $(CFLAGS) -fno-exceptions -fno-rtti
$(CPP) -c $(SRC_DIR)/kernel/io.cpp -o $(BUILD_DIR)/io.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/idt.o:
$(CPP) -c $(SRC_DIR)/kernel/interrupts/idt/idt.cpp -o $(BUILD_DIR)/idt.o $(CFLAGS) -fno-exceptions -fno-rtti
@ -76,22 +67,18 @@ $(BUILD_DIR)/idt.o:
$(BUILD_DIR)/gdtc.o:
$(CPP) -c $(SRC_DIR)/kernel/memory/gdt/gdtc.cpp -o $(BUILD_DIR)/gdtc.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/pic.o:
$(CPP) -c $(SRC_DIR)/kernel/drivers/pic/pic.cpp -o $(BUILD_DIR)/pic.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/string.o:
$(CC) -c $(SRC_DIR)/kernel/lib/string.c -o $(BUILD_DIR)/string.o $(CFLAGS) -std=gnu99
$(CPP) -c $(SRC_DIR)/kernel/lib/string.cpp -o $(BUILD_DIR)/string.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/pit.o:
$(CPP) -c $(SRC_DIR)/kernel/drivers/pit/pit.cpp -o $(BUILD_DIR)/pit.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/keyboard.o:
$(CPP) -c $(SRC_DIR)/kernel/drivers/ps-2/keyboard.cpp -o $(BUILD_DIR)/keyboard.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/time.o:
$(CPP) -c $(SRC_DIR)/kernel/time.cpp -o $(BUILD_DIR)/time.o $(CFLAGS) -fno-exceptions -fno-rtti
@ -104,8 +91,22 @@ $(BUILD_DIR)/memory.o:
$(BUILD_DIR)/paging.o:
$(CPP) -c $(SRC_DIR)/kernel/memory/VirtualMemoryManager.cpp -o $(BUILD_DIR)/paging.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/KHeap.o:
$(CPP) -c $(SRC_DIR)/kernel/memory/KernelHeap.cpp -o $(BUILD_DIR)/KHeap.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/prekernel.o:
$(CPP) -c $(SRC_DIR)/kernel/prekernel/prekernel.cpp -o $(BUILD_DIR)/prekernel.o $(CFLAGS) -fno-exceptions -fno-rtti
$(BUILD_DIR)/cpu.o:
$(CPP) -c $(SRC_DIR)/kernel/cpu.cpp -o $(BUILD_DIR)/cpu.o $(CFLAGS) -fno-exceptions -fno-rtti
# Assembly -> Object files
$(BUILD_DIR)/boot.o:
$(AS) $(SRC_DIR)/kernel/boot/boot.s -o $(BUILD_DIR)/boot.o
$(BUILD_DIR)/crti.o:
$(AS) $(SRC_DIR)/kernel/crti.s -o $(BUILD_DIR)/crti.o
$(BUILD_DIR)/crtn.o:
$(AS) $(SRC_DIR)/kernel/crtn.s -o $(BUILD_DIR)/crtn.o

15
source/kernel-test/PhysicalMemoryManagerTest.cpp Normal file
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@ -0,0 +1,15 @@
void PhysicalMemoryAllocatorTest()
{
#ifdef UNIT_TESTS
// 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);
#endif
}

2
source/kernel/boot/boot.s
View File

@ -83,7 +83,7 @@ _start:
# At this point, paging is fully set up and enabled
isPaging:
# Unmap the identity mapping as it is now unnecessary
movl $0, boot_page_directory + 0
//movl $0, boot_page_directory + 0
# Reload cr3 to force tlb flush
movl %cr3, %ecx

185
source/kernel/kernel.cpp
View File

@ -1,122 +1,107 @@
#include "kernel.h"
extern "C" void early_main()
#include "lib/string.h"
#include "definitions.h"
#include "prekernel/bootstructure.h"
#include "drivers/vga/VBE.h"
#include "drivers/pit/pit.h"
#include "memory/PhysicalMemoryManager.h"
#include "memory/VirtualMemoryManager.h"
#include "memory/KernelHeap.h"
#include "memory/gdt/gdtc.h"
#include "interrupts/idt/idt.h"
#include "io.h"
#include "cpu.h"
#include "serial.h"
#include "time.h"
#include "terminal/kterm.h"
#include "supervisorterminal/superVisorTerminal.h"
extern "C" void kernel_main ();
void ProcessBootInfo();
extern "C" void kernel_main ()
{
kterm_init();
initGDT();
init_serial();
print_serial("Hello Higher half kernel!\n");
init_idt();
// Enable interrupts
asm volatile("STI");
/*
* Show a little banner for cuteness
*/
printf("|=== BarinkOS ===|\n");
printf("Kernel End Addr: 0x%x\n" , &kernel_end );
uint32_t PageDirectoryEntryIndex = ((uint32_t)&kernel_end + KERNEL_BASE_ADDR ) >> 22 ;
uint32_t PageTableEntryIndex = (((uint32_t)&kernel_end + KERNEL_BASE_ADDR) >> 12) & 0x1FFF;
printf("Kernel End PDE: %d, PTE: %d\n" , PageDirectoryEntryIndex, PageTableEntryIndex);
uint32_t BootInfoStruct = BootInfoBlock_pptr + 0xC0000000;
printf("Addr BootInfostruct: 0x%x\n", BootInfoStruct);
uint32_t PageDirectoryEntryIndex2 = (BootInfoStruct ) >> 2 ;
uint32_t PageTableEntryIndex2 = (BootInfoStruct >> 12) & 0x1FFF;
printf("PDE: 0x%x, PTE: 0x%x\n", PageDirectoryEntryIndex2 , PageTableEntryIndex2 );
BootInfoBlock* BootInfo = (BootInfoBlock*) ( BootInfoBlock_pptr + 0xC0000000 );
startSuperVisorTerminal();
}
printf("Size of BootInfoBlock: %d bytes\n", sizeof(BootInfoBlock));
printf("Bootloader information:\n");
if( BootInfo->ValidELFHeader )
{
printf("- Valid ELF Header is available!\n");
}
extern "C" void early_main()
{
init_serial();
print_serial("Hello Higher half kernel!\n");
kterm_init();
initGDT();
init_idt();
// Enable interrupts
asm volatile("STI");
ProcessBootInfo();
if(BootInfo->EnabledVBE)
{
printf("- VBE graphics mode is available!\n");
}
initHeap();
if(BootInfo->ValidSymbolTable)
{
printf("- Valid Symbol Table available at 0x%x.\n Tab Size: %d, str Size: %d\n", BootInfo->SymbolTableAddr, BootInfo->SymbolTabSize, BootInfo->SymbolStrSize);
}
// test heap allocation
/*
struct KernelInfo {
int bar;
bool foo;
};
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) ;
KernelInfo* MyInfo = (KernelInfo*) malloc(sizeof(KernelInfo));
printf( "Starting address: 0x%x\n", currentBlock);
while( (uint32_t)currentBlock->next != 0x0 )
{
printf("CurrentBlock: 0x%x \n", (uint32_t ) currentBlock );
if(IS_AVAILABLE_MEM(currentBlock->type)){
//printf("AVAILABLE RAM\n");
}
else if(IS_ACPI_MEM(currentBlock->type)){
//printf("ACPI MEMORY\n");
}
else if(IS_RESERVED_MEM(currentBlock->type)){
// printf("RESERVED MEMORY\n");
}
else if(IS_NVS_MEMORY(currentBlock->type)){
// printf("NVS MEMORY \n");
}
else if(IS_BADRAM_MEMORY(currentBlock->type)){
// printf("BADRAM MEMORY \n");
}
else {
// printf("(TYPE 0x%x )TYPE NOT SPECIFIED\n", currentBlock->type);
}
MyInfo->bar = 6;
MyInfo->foo = false;
currentBlock = (MemoryInfoBlock*) ((uint32_t)currentBlock->next + KERNEL_BASE_ADDR );
}
free(MyInfo);
*/
printf("Starting physical memory management setup\n");
// Setup PhysicalMemoryManagement
SetupPhysicalMemoryManager(BootInfo);
}
printf("Enable Protected mode and jump to kernel main\n");
asm volatile("mov %cr0, %eax ");
asm volatile("or $1, %eax");
asm volatile("mov %eax, %cr0"); // re-enable protected mode ?
pit_initialise();
kernel_main();
}
void PhysicalMemoryAllocatorTest(){
#ifdef UNIT_TESTS
// 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);
#endif
void ProcessBootInfo(){
uint32_t BootInfoStruct = BootInfoBlock_pptr + 0xC0000000;
BootInfoBlock* BootInfo = (BootInfoBlock*) ( BootInfoBlock_pptr + 0xC0000000 );
if( BootInfo->ValidELFHeader )
{
// NOTE: Do something with it.. (Store it , process it etc...)
}
if(BootInfo->EnabledVBE)
{
// NOTE: Do something with it.. (Store it , process it etc...)
}
if(BootInfo->ValidSymbolTable)
{
// NOTE: Do something with it.. (Store it , process it etc...)
// printf("- Valid Symbol Table available at 0x%x.\n Tab Size: %d, str Size: %d\n", BootInfo->SymbolTableAddr, BootInfo->SymbolTabSize, BootInfo->SymbolStrSize);
}
if(BootInfo->PhysicalMemoryMapAvailable)
{
SetupPhysicalMemoryManager(BootInfo);
}
}
extern "C" void kernel_main () {
pit_initialise();
startSuperVisorTerminal();
}

38
source/kernel/kernel.h
View File

@ -1,38 +0,0 @@
#pragma once
extern "C"
{
#include "lib/string.h"
}
#include "definitions.h"
#include "drivers/vga/VBE.h"
#include "terminal/kterm.h"
#include "memory/PhysicalMemoryManager.h"
#include "memory/VirtualMemoryManager.h"
#include "memory/gdt/gdtc.h"
#include "interrupts/idt/idt.h"
#include "drivers/pit/pit.h"
#include "io.h"
#include "cpu.h"
#include "serial.h"
#include "time.h"
#include "supervisorterminal/superVisorTerminal.h"
#include "prekernel/bootstructure.h"
#define CHECK_FLAG(flag, bit) ( flag & (1 << bit ))
#define PANIC(message) {return;}
void map_multiboot_info_structure(unsigned long addr);
extern "C" void kernel_main ();
extern "C" uint32_t boot_page_directory;
extern "C" uint32_t multiboot_page_table;
const uint32_t KERNEL_BASE_ADDR = 0xC0000000;

0
source/kernel/lib/string.c → source/kernel/lib/string.cpp
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9
source/kernel/memory/KernelHeap.cpp
View File

@ -4,7 +4,7 @@
struct heap_block{
uint8_t Used;
uint32_t Size;
}
};
uint32_t heap_size;
heap_block* start ;
@ -17,7 +17,7 @@ void* malloc(size_t size)
// look for a free block
while(current < start + heap_size)
{
if(current->size >= size && current->Used == false )
if(current->Size >= size && current->Used == false )
{
// We found a spot
// Set the spot to in-use
@ -42,11 +42,12 @@ void free(void* addr)
{
// clear the free boolean that corresponds to this adddress
// This should be fairly simple
heap_block* allocatedBlock = addr - sizeof(heap_block);
allocate_block->Used = false;
heap_block* allocatedBlock = (heap_block*)(addr - sizeof(heap_block));
allocatedBlock->Used = false;
}
void initHeap()
{
// NOTE: What to do now??
}

3
source/kernel/memory/KernelHeap.h
View File

@ -1,6 +1,7 @@
#pragma once
#include <stddef.h>
#include <stdint.h>
#include "../terminal/kterm.h"
void initHeap();

45
source/kernel/memory/PhysicalMemoryManager.cpp
View File

@ -1,14 +1,17 @@
#include "./PhysicalMemoryManager.h"
PhysicalMemoryManagerInfoBlock* PMMInfoBlock;
const uint32_t KERNEL_OFFSET = 0xC0000000;
extern uint32_t* boot_page_directory;
extern uint32_t* boot_page_table;
extern uint32_t* multiboot_page_table;
const uint32_t KERNEL_OFFSET = 0xC0000000;
void SetupPhysicalMemoryManager( BootInfoBlock* Bootinfo) {
// NOTE: Physical memory map will override the boot info for now!
PMMInfoBlock = (PhysicalMemoryManagerInfoBlock*) (&BootInfoBlock_pptr + KERNEL_OFFSET );
printf("Setting up physical memory infoblock (0x%x) \n", (uint32_t)&PMMInfoBlock);
PhysicalMemoryManagerInfoBlock* PMMInfoBlock;
void SetupPhysicalMemoryManager( BootInfoBlock* Bootinfo)
{
// NOTE: We should move our bitmap to just after the end of our kernel instead
PMMInfoBlock = (PhysicalMemoryManagerInfoBlock*) ( ((uint32_t)MemoryMapHeap_pptr + 80 ) + KERNEL_OFFSET );
/*
Every byte contains 8 pages
A page is 4096 kib
@ -16,41 +19,33 @@ void SetupPhysicalMemoryManager( BootInfoBlock* Bootinfo) {
*/
// Calculate the maximum number of blocks
printf("Maxblocks at address(0x%x)\n" , (uint32_t)&(PMMInfoBlock->max_blocks));
int maximum_blocks = (uint32_t)Bootinfo->MemorySize / BLOCK_SIZE / 8;
printf("Set bitmap block maximum: %d\n", maximum_blocks);
PMMInfoBlock->max_blocks = maximum_blocks;
printf("Set used blocks to zero\n");
PMMInfoBlock->used_blocks = 0;
printf("Determine memory bit map address");
// put the map after the gdt
PMMInfoBlock->memoryBitMap = (uint32_t*) ( 0xC010b100) ;
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 );
MemoryInfoBlock* currentBlock = (MemoryInfoBlock*) ((uint32_t)Bootinfo->MemoryMap + 0xC0000000) ;
// 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)
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);
printf("skip!\n");
}
else{
printf("allocate region 0x%x of size %d bytes\n", currentBlock->Base_addr, currentBlock->Memory_Size);
// allocate_region( currentBlock->Base_addr, currentBlock->Memory_Size); // allocate region causes #PF Exception
}
currentBlock = (MemoryInfoBlock*) ((uint32_t)currentBlock->next + KERNEL_OFFSET );
currentBlock = (MemoryInfoBlock*) ((uint32_t)currentBlock->next + 0xC0000000 );
}
uint32_t kernel_size = ((uint32_t)&kernel_end - (uint32_t)&kernel_begin ) - KERNEL_OFFSET;

4
source/kernel/memory/VirtualMemoryManager.cpp
View File

@ -1,6 +1,9 @@
#include "VirtualMemoryManager.h"
extern uint32_t boot_page_directory[1024] ;
extern uint32_t boot_page_table[1024];
void AllocatePage(uint32_t vaddr)
{
uint32_t page_aligned_address = ALIGN(vaddr, 4096);
@ -60,6 +63,7 @@ void Map ( uint32_t vaddr, uint32_t paddr)
// allocate a page at virtual address
int PageDirectoryEntryIndex = vaddr >> 22;
int PageTableEntryIndex = (vaddr >> 12) & 0x1FFF;
}
void Unmap(uint32_t vaddr)

7
source/kernel/prekernel/bootstructure.h
View File

@ -40,6 +40,7 @@ struct BootInfoBlock {
};
// 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);
const uint32_t pke = ((uint32_t)&kernel_end) - 0xC0000000;
const uint32_t BootInfoBlock_pptr = pke + 1000 - sizeof(BootInfoBlock);
const uint32_t MemoryMapHeap_pptr = pke + 0x1;

3
source/kernel/prekernel/prekernel.cpp
View File

@ -99,9 +99,8 @@ if (CHECK_FLAG(mbi->flags, 6))
// continue to the next block
mmap = (multiboot_memory_map_t *) ((unsigned long) mmap + mmap->size + sizeof(mmap->size));
CurrentInfoBlock->next = (MemoryInfoBlock*) ((uint32_t)CurrentInfoBlock) + sizeof(MemoryInfoBlock);
CurrentInfoBlock->next = (MemoryInfoBlock*) CurrentInfoBlock + 16;
CurrentInfoBlock = CurrentInfoBlock->next;
}
CurrentInfoBlock->next = (MemoryInfoBlock*) 0x0;

1
source/kernel/supervisorterminal/superVisorTerminal.h
View File

@ -4,5 +4,6 @@
#include "../drivers/pit/pit.h"
#include "../drivers/ps-2/keyboard.h"
#include "../memory/PhysicalMemoryManager.h"
#include "../lib/string.h"
void startSuperVisorTerminal();

13
source/kernel/terminal/kterm.h
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@ -6,9 +6,8 @@
#include "../drivers/vga/colors.h"
#include "../io.h"
extern "C"{
#include "../lib/string.h"
}
#include "../lib/string.h"
void kterm_init();
@ -35,11 +34,3 @@ int get_cursor_y (uint16_t cursor_pos);
void printf ( const char *format, ...);
//static void itoa (char *buf, int base, int d);
#define KernelTag "[Kernel]: "
#define AS_KERNEL() ( kterm_setcolor(VGA_COLOR_LIGHT_BLUE),\
kterm_write(KernelTag, 10 ), \
kterm_resetcolor())