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Added sequence to remap PIC

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Wrote GDT code in C
Added routines to initialize GDT and IDT
This commit is contained in:
ngiddings
2021-04-16 01:45:40 -05:00
parent 8e6589b472
commit 6138766c49
7 changed files with 223 additions and 74 deletions
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22
src/x86/apic.c
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@@ -1,12 +1,34 @@
#include "mmgr.h"
#include "apic.h"
#include "msr.h"
#include "stdio.h"
#include <stddef.h>
extern int _kernel_end;
void apic_enable(struct page_stact_t *page_stack)
{
// Remap and mask 8259 PIC
asm volatile(
"mov $0x11, %%al;"
"outb %%al, $0x20;"
"outb %%al, $0xA0;"
"mov $0x20, %%al;"
"outb %%al, $0x21;"
"mov $0x28, %%al;"
"outb %%al, $0xA1;"
"mov $4, %%al;"
"outb %%al, $0x21;"
"mov $2, %%al;"
"outb %%al, $0xA1;"
"mov $0x01, %%al;"
"outb %%al, $0x21;"
"outb %%al, $0xA1;"
"mov $0xFF, %%al;"
"outb %%al, $0xA1;"
"outb %%al, $0x21;"
::: "al"
);
struct msr_apic_base_t msr;
read_msr(MSR_APIC_BASE, (uint64_t*)&msr);
map_page(page_stack, &_kernel_end, msr.apic_base << 12, 0);

34
src/x86/entry.S
View File

@@ -93,23 +93,6 @@ _multibootInfoTagEnd:
.long 8
_multibootHeaderEnd:
.section .rodata
gdt:
.long 0, 0
.short 0xFFFF
.short 0x0000
.short 0x9A00
.short 0x00CF
.short 0xFFFF
.short 0x0000
.short 0x9200
.short 0x00CF
gdt_info:
.short 23
.long gdt
.section .bss
@@ -170,7 +153,7 @@ _start:
push %eax
# Load physical address of startPaging()
mov $startPaging, %eax
mov $start_paging, %eax
sub $BASE_DIFF, %eax
# Initialize paging
@@ -180,8 +163,6 @@ _start:
lea 1f, %eax
jmp *%eax
1:
# Delete PDE corresponding to identity map. We shouldn't need it anymore.
movl $0, (_tempIdentityMap)
# Flush TLB
mov %cr3, %eax
@@ -190,19 +171,6 @@ _start:
# Initialize stack in virtual memory
mov $stackTop, %esp
# Load GPT
lgdt gdt_info
# Load segment registers
jmp $8, $.ldcs
.ldcs:
mov $16, %ax
mov %ax, %ds
mov %ax, %es
mov %ax, %gs
mov %ax, %fs
mov %ax, %ss
# Change EBX to point to the virtual address of the multiboot info
# If the new pointer is out-of-bounds, error
add $0xFF800000, %ebx

178
src/x86/interrupts.c
View File

@@ -1,14 +1,85 @@
#include "interrupts.h"
#include "isr.h"
#include "string.h"
#include <stddef.h>
struct idt_info_t
#define idt_size 256
#define gdt_size 6
enum segment_type_t
{
SEGMENT_KERNEL_CODE,
SEGMENT_KERNEL_DATA,
SEGMENT_USER_CODE,
SEGMENT_USER_DATA,
SEGMENT_TSS
};
struct gdt_entry_t
{
unsigned int limit_low : 16;
unsigned int base_low : 24;
unsigned int accessed : 1;
unsigned int read_write : 1;
unsigned int conforming_expand_down : 1;
unsigned int code : 1;
unsigned int code_data_segment : 1;
unsigned int dpl : 2;
unsigned int present : 1;
unsigned int limit_high : 4;
unsigned int available : 1;
unsigned int long_mode : 1;
unsigned int big : 1;
unsigned int gran : 1;
unsigned int base_high : 8;
} __attribute__ ((packed));
struct tss_t
{
};
struct interrupt_descriptor_t
{
uint16_t offset_1;
uint16_t selector;
uint16_t zero : 8;
uint16_t type : 4;
uint16_t storage : 1;
uint16_t dpl : 2;
uint16_t present : 1;
uint16_t offset_2;
};
struct descriptor_table_info_t
{
uint16_t size;
void *location;
} __attribute__ ((packed));
void lidt(struct interrupt_descriptor_t *idt)
struct tss_t tss;
void load_gdt(struct gdt_entry_t *gdt)
{
struct idt_info_t idt_info;
struct descriptor_table_info_t gdt_info;
gdt_info.size = sizeof(struct gdt_entry_t) * 6 - 1;
gdt_info.location = (void *)gdt;
asm("lgdt (%0);"
"jmp $8, $.ldcs;"
".ldcs:;"
"mov $16, %%ax;"
"mov %%ax, %%ds;"
"mov %%ax, %%es;"
"mov %%ax, %%gs;"
"mov %%ax, %%fs;"
"mov %%ax, %%ss;"
:
: "r"(&gdt_info));
}
void load_idt(struct interrupt_descriptor_t *idt)
{
struct descriptor_table_info_t idt_info;
idt_info.size = sizeof(struct interrupt_descriptor_t) * 256 - 1;
idt_info.location = (void *)idt;
asm("lidt (%0)"
@@ -27,3 +98,104 @@ void create_interrupt_descriptor(struct interrupt_descriptor_t *descriptor, void
descriptor->dpl = privilage;
descriptor->present = 1;
}
void create_segment_descriptor(struct gdt_entry_t *descriptor, size_t base, size_t limit, enum segment_type_t type)
{
descriptor->limit_low = limit;
descriptor->limit_high = (limit & (0xf << 16)) >> 16;
descriptor->base_low = base;
descriptor->base_high = (base & (0xff << 24)) >> 24;
descriptor->present = 1;
switch(type)
{
case SEGMENT_KERNEL_CODE:
descriptor->accessed = 0;
descriptor->read_write = 1;
descriptor->conforming_expand_down = 0;
descriptor->code = 1;
descriptor->code_data_segment = 1;
descriptor->dpl = 0;
descriptor->available = 0;
descriptor->long_mode = 0;
descriptor->big = 1;
descriptor->gran = 1;
break;
case SEGMENT_KERNEL_DATA:
descriptor->accessed = 0;
descriptor->read_write = 1;
descriptor->conforming_expand_down = 0;
descriptor->code = 0;
descriptor->code_data_segment = 1;
descriptor->dpl = 0;
descriptor->available = 0;
descriptor->long_mode = 0;
descriptor->big = 1;
descriptor->gran = 1;
break;
case SEGMENT_USER_CODE:
descriptor->accessed = 0;
descriptor->read_write = 1;
descriptor->conforming_expand_down = 0;
descriptor->code = 1;
descriptor->code_data_segment = 1;
descriptor->dpl = 3;
descriptor->available = 0;
descriptor->long_mode = 0;
descriptor->big = 1;
descriptor->gran = 1;
break;
case SEGMENT_USER_DATA:
descriptor->accessed = 0;
descriptor->read_write = 1;
descriptor->conforming_expand_down = 0;
descriptor->code = 0;
descriptor->code_data_segment = 1;
descriptor->dpl = 3;
descriptor->available = 0;
descriptor->long_mode = 0;
descriptor->big = 1;
descriptor->gran = 1;
break;
case SEGMENT_TSS:
descriptor->accessed = 1;
descriptor->read_write = 0;
descriptor->conforming_expand_down = 0;
descriptor->code = 1;
descriptor->code_data_segment = 0;
descriptor->dpl = 3;
descriptor->available = 0;
descriptor->long_mode = 0;
descriptor->big = 0;
descriptor->gran = 0;
}
}
void initialize_gdt()
{
static struct gdt_entry_t gdt[gdt_size];
memset(gdt, 0, sizeof(struct gdt_entry_t) * gdt_size);
create_segment_descriptor(&gdt[1], 0, 0xFFFFF, SEGMENT_KERNEL_CODE);
create_segment_descriptor(&gdt[2], 0, 0xFFFFF, SEGMENT_KERNEL_DATA);
create_segment_descriptor(&gdt[3], 0, 0xFFFFF, SEGMENT_USER_CODE);
create_segment_descriptor(&gdt[4], 0, 0xFFFFF, SEGMENT_USER_DATA);
//create_segment_descriptor(&gdt[5], (size_t)&tss, sizeof(struct tss_t), SEGMENT_TSS);
load_gdt(gdt);
}
void initialize_idt()
{
static struct interrupt_descriptor_t idt[idt_size];
memset(idt, 0, sizeof(struct interrupt_descriptor_t) * idt_size);
for(int i = 0; i < idt_size; i++)
{
create_interrupt_descriptor(&idt[i], (void*)isr_generic, INTERRPUT_INT32, 0);
}
create_interrupt_descriptor(&idt[EXCEPTION_DIV_BY_0], (void*)isr_division_by_zero, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[EXCEPTION_GPF], (void*)isr_gp_fault, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[EXCEPTION_PAGE_FAULT], (void*)isr_page_fault, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[EXCEPTION_DOUBLE_FAULT], (void*)isr_double_fault, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[ISR_APIC_TIMER], (void*)isr_timer, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[ISR_AP_START], (void*)isr_ap_start, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[ISR_SYSCALL], (void*)isr_syscall, INTERRPUT_INT32, 0);
load_idt(idt);
}

16
src/x86/interrupts.h
View File

@@ -38,18 +38,6 @@ enum isr_type_t
INTERRPUT_INT16 = 6
};
struct interrupt_descriptor_t
{
uint16_t offset_1;
uint16_t selector;
uint16_t zero : 8;
uint16_t type : 4;
uint16_t storage : 1;
uint16_t dpl : 2;
uint16_t present : 1;
uint16_t offset_2;
};
void initialize_gdt();
void lidt(struct interrupt_descriptor_t *idt);
void create_interrupt_descriptor(struct interrupt_descriptor_t *descriptor, void *isr, enum isr_type_t type, uint32_t privilage);
void initialize_idt();

14
src/x86/isr.c
View File

@@ -2,6 +2,12 @@
#include "stdio.h"
#include "apic.h"
__attribute__ ((interrupt))
void isr_generic(void* frame)
{
printf("Generic interrupt.\n");
}
__attribute__ ((interrupt))
void isr_division_by_zero(void* frame)
{
@@ -11,18 +17,22 @@ void isr_division_by_zero(void* frame)
__attribute__ ((interrupt))
void isr_gp_fault(void* frame, unsigned int error)
{
asm("cli");
printf("Exception: GP fault, code %08x\n", error);
asm("hlt");
}
__attribute__ ((interrupt))
void isr_page_fault(void* frame, unsigned int error)
{
printf("Exception: Page fault\n");
}
__attribute__ ((interrupt))
void isr_double_fault(void* frame, unsigned int error)
{
asm("cli");
printf("Exception: Double fault (!!), code %08x\n", error);
asm("hlt");
}

3
src/x86/isr.h
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@@ -1,5 +1,8 @@
#pragma once
__attribute__ ((interrupt))
void isr_generic(void* frame);
__attribute__ ((interrupt))
void isr_division_by_zero(void* frame);

30
src/x86/quark_x86.c
View File

@@ -17,7 +17,7 @@ extern int _kernel_end;
struct apic_registers_t volatile *apic_registers;
int startPaging(uint32_t *directory, uint32_t *table, uint32_t *identityTable)
int start_paging(uint32_t *directory, uint32_t *table, uint32_t *identityTable)
{
for (int i = 0; i < 1024; i++)
{
@@ -42,8 +42,9 @@ int startPaging(uint32_t *directory, uint32_t *table, uint32_t *identityTable)
int initialize(void *multiboot_info)
{
initialize_gdt();
initialize_idt();
printf("***%s***\n", PACKAGE_STRING);
static struct interrupt_descriptor_t idt[256];
static struct page_stack_t page_stack;
static struct kernel_t kernel;
struct memory_region_t map_array[16];
@@ -76,33 +77,18 @@ int initialize(void *multiboot_info)
{
load_module(&kernel, &boot_info.modules[i]);
}
memset(idt, 0, sizeof(struct interrupt_descriptor_t) * 256);
create_interrupt_descriptor(&idt[EXCEPTION_DIV_BY_0], (void*)isr_division_by_zero, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[EXCEPTION_GPF], (void*)isr_gp_fault, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[EXCEPTION_PAGE_FAULT], (void*)isr_page_fault, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[EXCEPTION_DOUBLE_FAULT], (void*)isr_double_fault, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[ISR_APIC_TIMER], (void*)isr_timer, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[ISR_AP_START], (void*)isr_ap_start, INTERRPUT_INT32, 0);
create_interrupt_descriptor(&idt[ISR_SYSCALL], (void*)isr_syscall, INTERRPUT_INT32, 0);
lidt(idt);
asm volatile(
"mov $0xFF, %%al;"
"outb %%al, $0xA1;"
"outb %%al, $0x21;"
::: "al"
);
apic_enable(page_stack);
printf("spurious_interrupt_vector: %08x\n", *((uint32_t*) &apic_registers->spurious_iv));
printf("lvt_timer_vector: %08x\n", *((uint32_t*) &apic_registers->lvt_timer));
apic_registers->divide_config.value = APIC_DIVIDE_128;
apic_registers->lvt_timer.vector = ISR_APIC_TIMER;
apic_registers->lvt_timer.timer_mode = APIC_TIMER_PERIODIC;
apic_registers->initial_count.value = 1024*1024*512;
apic_registers->initial_count.value = 1024*1024*1024;
apic_registers->lvt_timer.mask = 0;
printf("spurious_interrupt_vector: %08x\n", *((uint32_t*) &apic_registers->spurious_iv));
printf("lvt_timer_vector: %08x\n", *((uint32_t*) &apic_registers->lvt_timer));
asm("sti");
while(1) asm("hlt");
while(1)
{
asm("hlt");
}
// TODO: enter first process
}