Nigel/BarinkOS
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Divided the kernel into seperate distinct phases

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The first stage after GRUB will be Pre-Kernel. This stage will organize the
information we receive from the bootloader. (in our case that will be grub)

The second stage is for now called early_main. The program will at this
point already be running in virtual higher-half / higher-quarter address space.
The goal of the second stage is to set up the kernel in such a way that we are
ready to jump in to usermode.

The third stage is for now called kernel_main. This stage will jump us into
usermode and load the startup programs.

- Added a GRUB entry for tests
- Started writing the pre-kernel stage
- Removed knowledge of multiboot from early_main
- Edited the linkerscript to link variables in pre-kernel to
	lower address space. ( from 1MB and up)
This commit is contained in:
Nigel Barink
2022-08-22 21:16:34 +02:00
parent 0f0fc9f252
commit 5051b8903c
16 changed files with 206 additions and 253 deletions
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145
source/kernel/kernel.cpp
View File

@ -1,15 +1,13 @@
#include "kernel.h"
extern "C" void early_main(unsigned long magic, unsigned long addr){
// Convert MBI address to higher quarter kernel space
addr += KERNEL_BASE_ADDR;
/**
extern "C" void early_main()
{
/*
* Initialize terminal interface
* NOTE: This should be done later on , the magic value should be checked first.
*/
initGDT();
kterm_init();
init_serial();
print_serial("Hello Higher half kernel!\n");
@ -17,110 +15,38 @@ extern "C" void early_main(unsigned long magic, unsigned long addr){
// Enable interrupts
asm volatile("STI");
printf("DEBUG:\n Magic: 0x%x\n MBT_addr: 0x%x\n", magic, addr);
/**
* Check Multiboot magic number
* NOTE: Printf call should not be a thing this early on ...
*/
if (magic != MULTIBOOT_BOOTLOADER_MAGIC){
printf("Invalid magic number: 0x%x\n", magic);
return;
}
/**
/*
* Show a little banner for cuteness
*/
printf("|=== BarinkOS ===|\n");
/**
* Use the address given as an argument as the pointer
* to a Multiboot information structure.
*/
multiboot_info_t* mbt = (multiboot_info_t*) (addr );
/**
* Construct our own bootInfo structure
*/
BootInfo bootinfo = {};
/*
If we got a memory map from our bootloader we
should be parsing it to find out the memory regions available.
*/
if (CHECK_FLAG(mbt->flags, 6))
{
/*
Setup Physical memory managment
*/
MemoryInfo meminfo = {};
bootinfo.memory = &meminfo;
///mapMultibootMemoryMap(bootinfo.memory , mbt);
printf("Memory size: 0x%x bytes\n", bootinfo.memory->TotalMemory );
BootInfoBlock* BootInfo = (BootInfoBlock*) ( BootInfoBlock_pptr + 0xC0000000 );
/*
PhysicalMemory memAlloc = PhysicalMemory{};
memAlloc.setup(bootinfo.memory );
*/
printf("Bootloader information:\n");
if( BootInfo->ValidELFHeader )
{
printf("- Valid ELF Header is available!\n");
}
// TODO: FIX physical allocator
/*
Mark already in use sections
*/
// Mark kernel memory as used
printf("Kernel Begin Pointer: 0x%x, Kernel end pointer: 0x%x\n", &kernel_begin , &kernel_end );
multiboot_memory_map_t *mmap = (multiboot_memory_map_t*) (mbt->mmap_addr + KERNEL_BASE_ADDR) ;
if(BootInfo->EnabledVBE)
{
printf("- VBE graphics mode is available!\n");
}
for (; (unsigned long) mmap < mbt->mmap_addr + mbt->mmap_length; mmap = (multiboot_memory_map_t *) ((unsigned long) mmap + mmap->size + sizeof(mmap->size))){
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);
}
if ( mmap->type == MULTIBOOT_MEMORY_AVAILABLE){
} else{
printf("allocate region: 0x%x, size : 0x%x bytes\n", (unsigned) mmap->addr,(unsigned) mmap->len );
// memAlloc.allocate_region((unsigned)mmap->addr , (unsigned)mmap->len);
}
}
printf("allocate region: 0x%x, size : 0x%x bytes\n", &kernel_begin, &kernel_end - &kernel_begin );
//memAlloc.allocate_region(kernel_end, kernel_end - kernel_begin);
// test alloc_block
/*
uint8_t* memory = (uint8_t*) memAlloc.allocate_block();
printf("Got a new pointer: 0x%x\n", memory);
uint8_t* memory2 = (uint8_t*) memAlloc.allocate_block();
printf("Got a new pointer: 0x%x\n", memory2);
memAlloc.free_block((void*) memory);
uint8_t* newBlockPlse = (uint8_t*) memAlloc.allocate_block();
*/
//memAlloc.free_block((void*) memory);
//InitializePaging();
//IdentityMap();
//Enable();
} else{
printf("memory flag not set!");
if(BootInfo->PhysicalMemoryMapAvailable)
{
printf("- Physical Memory Map available!\n");
}
CheckMBT( (multiboot_info_t *) addr);
asm volatile("mov %cr0, %eax ");
asm volatile("or $1, %eax");
asm volatile("mov %eax, %cr0");
kernel_main(&bootinfo);
kernel_main();
}
@ -151,9 +77,28 @@ void map_multiboot_info_structure(unsigned long addr){
asm("movl %cr3, %ecx;" "movl %ecx, %cr3" );
}
extern "C" void kernel_main (BootInfo* bootinfo) {
void PhysicalMemoryAllocatorTest(){
#ifdef UNIT_TESTS
// test alloc_block
uint8_t* memory = (uint8_t*) memAlloc.allocate_block();
printf("Got a new pointer: 0x%x\n", memory);
uint8_t* memory2 = (uint8_t*) memAlloc.allocate_block();
printf("Got a new pointer: 0x%x\n", memory2);
memAlloc.free_block((void*) memory);
uint8_t* newBlockPlse = (uint8_t*) memAlloc.allocate_block();
#endif
}
extern "C" void kernel_main () {
pit_initialise();
// Create a dummy BootInfo object
// TODO: This should be done properly or the dependency should
// be removed from the SuperVisorTerminal.
BootInfo* bootinfo = {};
startSuperVisorTerminal(bootinfo);
}