Added sequence to remap PIC

Wrote GDT code in C
Added routines to initialize GDT and IDT

src/x86/apic.c

@@ -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);

src/x86/entry.S

@@ -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

src/x86/interrupts.c

@@ -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);
+}

src/x86/interrupts.h

@@ -38,18 +38,6 @@ enum isr_type_t
     INTERRPUT_INT16 = 6
 };
 
-struct interrupt_descriptor_t
+void initialize_gdt();
-{
-    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 lidt(struct interrupt_descriptor_t *idt);
+void initialize_idt();
-
-void create_interrupt_descriptor(struct interrupt_descriptor_t *descriptor, void *isr, enum isr_type_t type, uint32_t privilage);

src/x86/isr.c

@@ -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");
 }
 

src/x86/isr.h

@@ -1,5 +1,8 @@
 #pragma once
 
+__attribute__ ((interrupt))
+void isr_generic(void* frame);
+
 __attribute__ ((interrupt))
 void isr_division_by_zero(void* frame);
 

src/x86/quark_x86.c

@@ -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
 }