Savepoint, trying to implement tasks but it aint workin

Makefile

@@ -25,6 +25,7 @@ kernel/elf.o \
 kernel/syscall.o \
 kernel/io/keyboard.o \
 kernel/heap.o \
+kernel/task.o \
 
 LIB_OBJS=\
 $(ARCHDIR)/bootstrap.o \
@@ -32,6 +33,7 @@ $(ARCHDIR)/tty.o \
 $(ARCHDIR)/strlib.o \
 $(ARCHDIR)/interrupts/idt.o \
 $(ARCHDIR)/interrupts/interrupt.o \
+$(ARCHDIR)/interrupts/irq0.o \
 $(ARCHDIR)/interrupts/syscall.o \
 $(ARCHDIR)/gdt.o \
 $(ARCHDIR)/userland.o \

arch/i686/interrupts/idt.c

@@ -15,6 +15,15 @@
 #define IRQ6 (IRQ0 + 6)
 #define IRQ7 (IRQ0 + 7)
 
+#define IRQ8 0x28
+#define IRQ9  (IRQ8 + 1)
+#define IRQ10 (IRQ8 + 2)
+#define IRQ11 (IRQ8 + 3)
+#define IRQ12 (IRQ8 + 4)
+#define IRQ13 (IRQ8 + 5)
+#define IRQ14 (IRQ8 + 6)
+#define IRQ15 (IRQ8 + 7)
+
 #define NUM_ENTRIES 0x100
 
 struct InterruptDescriptor {
@@ -97,21 +106,20 @@ static void load_idt()
     idt.base = entries;
 
     asm ( "lidt %0" : : "m"(idt) );
-    asm ( "sti" );
 }
 
-struct InterruptDescriptor generate_entry(bool present, void isr(struct interrupt_frame*), uint8_t gate_type, uint8_t ring, uint8_t selector)
+static struct InterruptDescriptor generate_entry(bool present, void isr(struct interrupt_frame*), uint8_t gate_type, uint8_t ring, uint8_t selector)
 {
     struct InterruptDescriptor entry;
     entry.present = present;
-    entry.offset = (uint32_t)isr;
+    entry.offset = (size_t)isr;
     entry.gate_type = gate_type;
     entry.ring = ring;
     entry.selector = selector;
     return entry;
 }
 
-void idt_init()
+static void add_exceptions() 
 {
     struct InterruptDescriptor entry;
 
@@ -130,23 +138,47 @@ void idt_init()
     entry = generate_entry(true, double_fault, 0xF, 0, 0x8);
     add_entry(entry, DoubleFault);
 
-    entry = generate_entry(true, irq, 0xE, 0, 0x8);
+}
+
+static void add_irqs()
+{
+    struct InterruptDescriptor entry;
+    entry = generate_entry(true, irq_1, 0xE, 0, 0x8);
     for (int i = IRQ0; i <= IRQ7; i++)
     {
         add_entry(entry, i);
     }
 
+    entry = generate_entry(true, irq_2, 0xE, 0, 0x8);
+    for (int i = IRQ8; i <= IRQ15; i++)
+    {
+        add_entry(entry, i);
+    }
+
+    entry = generate_entry(true, irq0, 0xE, 0, 0x8);
+    add_entry(entry, IRQ0);
+
     entry = generate_entry(true, keyboard_interrupt, 0xE, 0, 0x8);
     add_entry(entry, IRQ1);
+}
 
+static void add_syscall()
+{
     struct InterruptDescriptor syscall_entry;
     syscall_entry.present = true;
-    syscall_entry.offset = (uint32_t)syscall;
+    syscall_entry.offset = (size_t)syscall;
     syscall_entry.gate_type = 0xE;
     syscall_entry.ring = 3;
     syscall_entry.selector = 0x8;
 
     add_entry(syscall_entry, 0x80);
+}
+
+void idt_init()
+{
+    add_exceptions();
+    add_irqs();
+    add_syscall();
 
     load_idt();
 }

arch/i686/interrupts/interrupt.c

@@ -1,15 +1,11 @@
 #include <kernel/tty.h>
+#include <kernel/task.h>
+#include "interrupt.h" 
 #include <stddef.h>
 #include <debugging.h>
 #include <kernel/io/keyboard.h>
 #include "../io.h"
 
-struct interrupt_frame {
-    uint32_t eflags;
-    uint32_t cs;
-    uint32_t eip;
-};
-
 uint8_t test = 'a';
 
 static void stack_trace() 
@@ -25,40 +21,45 @@ static void stack_trace()
     }
 }
 
-__attribute__((interrupt)) void divide_by_zero(void*) 
+__attribute__((interrupt)) void divide_by_zero(struct interrupt_frame*) 
 {
     terminal_writestring("Yo dude u cant divide by zero yao\n");
     while (1) { }
 }
 
-__attribute__((interrupt)) void general_protection_fault(void*)
+__attribute__((interrupt)) void general_protection_fault(struct interrupt_frame*)
 {
     terminal_writestring("GPF handler called\n");
     while (1) { }
 }
 
-__attribute__((interrupt)) void double_fault(void*) 
+__attribute__((interrupt)) void double_fault(struct interrupt_frame*) 
 {
     stack_trace();
     terminal_writestring("2 Errors in a row, u better behave naughty naughty\n");
     while (1) { }
 }
 
-__attribute__((interrupt)) void exception(void*)
+__attribute__((interrupt)) void exception(struct interrupt_frame*)
 {
     terminal_writestring("Some weird error code stuff\n");
     while (1) { }
 }
 
-__attribute__((interrupt)) void keyboard_interrupt(void*)
+__attribute__((interrupt)) void keyboard_interrupt(struct interrupt_frame*)
 {
     uint8_t scancode = inb(0x60);
     handle_keyboard(scancode);
     outb(0x20, 0x20);
 }
 
-__attribute__((interrupt)) void irq(void*) 
+__attribute__((interrupt)) void irq_1(struct interrupt_frame*) 
 {
     outb(0x20, 0x20);
 }
 
+__attribute__((interrupt)) void irq_2(struct interrupt_frame*) 
+{
+    outb(0xA0, 0x20);
+    outb(0x20, 0x20);
+}

arch/i686/interrupts/interrupt.h

@@ -1,4 +1,12 @@
-struct interrupt_frame;
+#include <stddef.h>
+
+struct interrupt_frame {
+    size_t eip;
+    size_t cs;
+    size_t eflags;
+    size_t ss;
+    size_t esp;
+};
 
 __attribute__((interrupt)) void divide_by_zero(struct interrupt_frame* frame);
 __attribute__((interrupt)) void general_protection_fault(struct interrupt_frame* frame);
@@ -6,7 +14,10 @@ __attribute__((interrupt)) void double_fault(struct interrupt_frame* frame);
 
 __attribute__((interrupt)) void exception(struct interrupt_frame* frame);
 
-__attribute__((interrupt)) void syscall(void*);
+__attribute__((interrupt)) void syscall(struct interrupt_frame* frame);
 
 __attribute__((interrupt)) void keyboard_interrupt(struct interrupt_frame* frame);
-__attribute__((interrupt)) void irq(struct interrupt_frame* frame);
+__attribute__((interrupt)) void irq_1(struct interrupt_frame* frame);
+__attribute__((interrupt)) void irq_2(struct interrupt_frame* frame); 
+
+__attribute__((interrupt)) void irq0(struct interrupt_frame* frame);

arch/i686/interrupts/irq0.s

@@ -0,0 +1,62 @@
+.global irq0
+.extern _switch_task
+
+.global jump_kernel
+.global jump_user
+
+.extern ss
+.extern esp
+.extern eflags
+.extern cs
+.extern eip 
+
+irq0:
+push %esp
+
+push %ebp
+
+push %edx
+push %ecx
+push %ebx
+push %eax
+
+call _switch_task
+
+iret
+
+jump_kernel:
+pop %eax /* pop return instruction */
+
+pop %eax
+pop %ebx
+pop %ecx
+pop %edx
+
+pop %ebp
+pop %esp
+
+push (eflags)
+push (cs)
+push (eip)
+
+iret
+
+jump_user:
+pop %eax /* pop return instruction */
+
+pop %eax
+pop %ebx
+pop %ecx
+pop %edx
+
+pop %ebp
+
+push (ss)
+push (esp)
+push (eflags)
+push (cs)
+push (eip)
+
+iret
+
+

arch/i686/interrupts/pic.c

@@ -21,9 +21,10 @@
 
 void init_pic() {
     uint8_t a1;
+    uint8_t a2;
     
     a1 = inb(PIC1_DATA);                        // save masks
-    inb(PIC2_DATA);
+    a2 = inb(PIC2_DATA);
 
     outb(PIC1_COMMAND, ICW1_INIT | ICW1_ICW4);  // starts the initialization sequence (in cascade mode)
     io_wait();
@@ -31,7 +32,7 @@ void init_pic() {
     io_wait();
     outb(PIC1_DATA, 0x20);                 // ICW2: Master PIC vector offset
     io_wait();
-    outb(PIC2_DATA, 0xFF);                 // ICW2: Slave PIC vector offset
+    outb(PIC2_DATA, 0x28);                 // ICW2: Slave PIC vector offset
     io_wait();
     outb(PIC1_DATA, 4);                       // ICW3: tell Master PIC that there is a slave PIC at IRQ2 (0000 0100)
     io_wait();
@@ -45,5 +46,5 @@ void init_pic() {
     
     outb(PIC1_DATA, a1);   // restore saved masks.
     // outb(PIC2_DATA, a2);
-    outb(PIC2_DATA, 0xFF);
+    outb(PIC2_DATA, a2);
 }

include/kernel/task.h

@@ -0,0 +1,38 @@
+#include <stdint.h>
+#include <stddef.h>
+
+struct CPUState {
+    size_t eax;
+    size_t ebx;
+    size_t ecx;
+    size_t edx;
+    size_t eip;
+    size_t esp;
+    size_t ebp;
+    size_t cs;
+    size_t ds;
+    size_t eflags;
+};
+
+struct Task {
+    struct CPUState state;
+};
+
+void switch_task(
+    size_t eax, 
+    size_t ebx,
+    size_t ecx,
+    size_t edx,
+
+    size_t ebp,
+
+    size_t esp_real,
+
+    size_t eip,
+    size_t cs,
+    size_t eflags,
+    size_t esp_fake,
+    size_t ds
+);
+void setup_tasks();
+void add_task(struct Task task);

kernel/elf.c

@@ -3,6 +3,7 @@
 #include <debugging.h>
 #include <kernel/tty.h>
 #include <kernel/gdt.h>
+#include <kernel/task.h>
 #include <debugging.h>
 
 static void* memcpy(void* restrict dstptr, const void* restrict srcptr, size_t size) {
@@ -20,5 +21,22 @@ void run_program(uint8_t* program, size_t length)
     uint8_t* userland_code = (uint8_t*) 0x00800000;
     memcpy(userland_code, program, length);
 
-    jump_to_userspace();
+    struct CPUState target = {
+        .eip = (size_t) userland_code,
+        .esp = 0x00c00100,
+        .eax = 0,
+        .ebx = 0,
+        .ecx = 0,
+        .edx = 0,
+        .cs = 0x18 | 0x3,
+        .ds = 0x20 | 0x3,
+        .eflags = 0x0200,
+        .ebp = 0x00c00100,
+    };
+
+    struct Task task = {
+        .state = target,
+    };
+
+    add_task(task);
 }

kernel/kernel.c

@@ -3,6 +3,7 @@
 #include <kernel/elf.h>
 #include <kernel/pic.h>
 #include <kernel/heap.h>
+#include <kernel/task.h>
 
 #include <debugging.h>
 
@@ -17,6 +18,7 @@ uint8_t program[] = {
     0xcd, 0x80, // int 0x80
     0xba, 0x00, 0x00, 0x00, 0x00, // mov 0, %edx
     0xcd, 0x80, // int 0x80
+    0xcd, 0x20, // int 0x20
     0xb9, 0x00, 0x00, 0x80, 0x00, // mov $start, %ecx
     0xff, 0xe1, // jmp *%ecx
 };
@@ -26,9 +28,18 @@ void kernel_main(void)
     /* Initialize terminal interface */
     terminal_initialize();
 
-    init_pic();
     idt_init();
+    init_pic();
     heap_init();
 
+    setup_tasks();
+
+    asm("sti");
+
     run_program(program, sizeof(program));
+
+    while (true) {
+        asm("hlt");
+    }
+
 }

kernel/task.c

@@ -0,0 +1,141 @@
+#include <kernel/task.h>
+#include <kernel/heap.h>
+
+struct Task* tasks;
+size_t tasks_capacity;
+size_t num_tasks;
+
+size_t current_task = 0;
+
+void setup_tasks()
+{
+    tasks = malloc(sizeof(*tasks));
+    tasks_capacity = 1;
+    num_tasks = 1;
+}
+
+void add_task(struct Task task)
+{
+    if (num_tasks == tasks_capacity) {
+        struct Task* temp = malloc(sizeof(*tasks) * tasks_capacity * 2);
+
+        for (size_t i = 0; i < num_tasks; i++) {
+            temp[i] = tasks[i];
+        }
+        
+        tasks_capacity *= 2;
+
+        free(tasks);
+        tasks = temp;
+    }
+
+    tasks[num_tasks] = task;
+    num_tasks++;
+}
+
+size_t ss;
+size_t esp;
+size_t eflags;
+size_t cs;
+size_t eip;
+
+void jump_kernel(size_t eax, size_t ebx, size_t ecx, size_t edx, size_t ebp, size_t esp);
+void jump_user(size_t eax, size_t ebx, size_t ecx, size_t edx, size_t ebp);
+
+static void save_state(
+    size_t eax,
+    size_t ebx,
+    size_t ecx,
+    size_t edx,
+
+    size_t esp,
+    size_t ebp,
+
+    size_t eip,
+
+    size_t cs,
+    size_t ds,
+
+    size_t eflags
+) {
+    struct CPUState state = {
+        .eax = eax,
+        .ebx = ebx,
+        .ecx = ecx,
+        .edx = edx,
+
+        .esp = esp,
+        .ebp = ebp,
+
+        .eip = eip,
+
+        .cs = cs,
+        .ds = ds,
+
+        .eflags = eflags,
+    };
+    
+    tasks[current_task].state = state;
+    
+    current_task++;
+    current_task %= num_tasks;
+}
+
+void next_task() {
+    struct CPUState s = tasks[current_task].state;
+
+    ss = s.ds;
+    esp = s.esp;
+    eflags = s.eflags;
+    cs = s.cs;
+    eip = s.eip;
+
+    if ((cs & 3) == 0) {
+        jump_kernel(s.eax, s.ebx, s.ecx, s.edx, s.ebp, s.esp);
+    } else {
+        jump_user(s.eax, s.ebx, s.ecx, s.edx, s.ebp);
+    }
+}
+
+void _switch_task(
+    size_t eax, 
+    size_t ebx,
+    size_t ecx,
+    size_t edx,
+
+    size_t ebp,
+
+    size_t esp_current,
+
+    size_t eip_passed,
+    size_t cs_passed,
+    size_t eflags_passed,
+    size_t esp_passed,
+    size_t ds_passed
+) 
+{
+    if (num_tasks == 0) {
+        return;
+    };
+    
+    size_t ds;
+    if ((cs & 3) == 0) {
+        ds = 0x10;
+        esp_current = esp_current + sizeof(size_t) * 3;
+    } else {
+        ds = ds_passed;
+        esp_current = esp_passed;
+    }
+
+    ss = ds_passed;
+    esp = esp_passed;
+    eflags = eflags_passed;
+    cs = cs_passed;
+    eip = eip_passed;
+
+    save_state(eax, ebx, ecx, edx, esp, ebp, eip_passed, cs_passed, ds, eflags_passed);
+
+    next_task();
+}
+
+