KERNEL: Implementing VMM & cleaning up

Folders now are alll lower case

Started working on the implementation of the Virtual memory manager. Implemented allocate and free page funtionality for as far as I can atm.

Implemented the
This commit is contained in:
2022-09-01 20:16:16 +02:00
parent 9893a0bd17
commit 13e9beea79
48 changed files with 195 additions and 173 deletions

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.global LoadGlobalDescriptorTable
LoadGlobalDescriptorTable:
lgdt gdtDescriptor
movw $16, %ax
movw %ax, %ds
movw %ax, %es
movw %ax, %fs
movw %ax, %gs
movw %ax, %ss
jmp $8,$flush
flush:
ret

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#include "gdtc.h"
#include "../../terminal/kterm.h"
#define NULL_SEGMENT 0
#define KERNEL_CODE_SEGMENT 1
#define KERNEL_DATA_SEGMENT 2
#define USER_CODE_SEGMENT 3
#define USER_DATA_SEGMENT 4
SegmentDescriptor GlobalDescriptorTable[5];
GlobalDescriptorTableDescriptor gdtDescriptor;
void add_descriptor(int which , unsigned long base, unsigned long limit, unsigned char access, unsigned char granularity ){
GlobalDescriptorTable[which].base_low = (base & 0xFFFF );
GlobalDescriptorTable[which].base_middle = (base >> 6) & 0xFF;
GlobalDescriptorTable[which].base_high = (base >> 24) & 0xFF;
GlobalDescriptorTable[which].limit_low = (limit & 0xFFFF);
GlobalDescriptorTable[which].granularity = ((limit >> 16) & 0x0F);
GlobalDescriptorTable[which].granularity |= (granularity & 0xF0);
GlobalDescriptorTable[which].access = access;
}
void initGDT(){
#ifdef __VERBOSE__
printf("Init GDT!\n");
#endif
// NULL segment
add_descriptor(NULL_SEGMENT, 0,0,0,0);
// Kernel Code Segment
add_descriptor(KERNEL_CODE_SEGMENT, 0, 0xFFFFFFFF, 0x9A, 0xCF);
// Kernel Data Segment
add_descriptor(KERNEL_DATA_SEGMENT, 0, 0xFFFFFFFF, 0x92, 0xCF);
// User Code Segment
// TODO:
// User Data Segement
// TODO:
// init Gdt Descriptor
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();
}

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#include <stdint.h>
struct SegmentDescriptor {
unsigned short limit_low;
unsigned short base_low;
unsigned char base_middle;
unsigned char access;
unsigned char granularity;
unsigned char base_high;
}__attribute__((packed));
struct GlobalDescriptorTableDescriptor{
unsigned short limit;
unsigned int base;
}__attribute__((packed));
extern SegmentDescriptor GlobalDescriptorTable[];
extern GlobalDescriptorTableDescriptor gdtDescriptor;
void add_descriptor(int which , unsigned long base, unsigned long limit, unsigned char access, unsigned char granularity );
extern "C" void LoadGlobalDescriptorTable();
void initGDT();