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Espresso 0.0.2c

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This commit is contained in:
David Goeke
2026-03-20 16:57:08 -05:00
parent 021fdbbcef
commit 5971218b56
77 changed files with 4538 additions and 518 deletions
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177
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#include <stdio.h>
#include <port_io.h>
#include <drivers/irq.h>
#include <drivers/idt.h>
#define IDT_MAX_DESCRIPTORS 256
#define PIC1_COMMAND 0x20
#define PIC1_DATA 0x21
#define PIC2_COMMAND 0xA0
#define PIC2_DATA 0xA1
/*
Most of the code is this file (and idt.h) are taken from the osdev wiki: https://wiki.osdev.org/Interrupts_Tutorial, though not all of it.
*/
typedef struct {
uint16_t isr_low; // The lower 16 bits of the ISR's address
uint16_t kernel_cs; // The GDT segment selector that the CPU will load into CS before calling the ISR
uint8_t reserved; // Set to zero
uint8_t attributes; // Type and attributes; see the IDT page
uint16_t isr_high; // The higher 16 bits of the ISR's address
} __attribute__((packed)) idt_entry_t;
typedef struct {
uint16_t limit;
uint32_t base;
} __attribute__((packed)) idtr_t;
__attribute__((aligned(0x10)))
static idt_entry_t idt[256]; // Create an array of IDT entries; aligned for performance
static idtr_t idtr;
static bool vectors[IDT_MAX_DESCRIPTORS];
extern void* isr_stub_table[];
void idt_init(void)
{
idtr.base = (uintptr_t)&idt[0];
idtr.limit = (uint16_t)sizeof(idt_entry_t) * IDT_MAX_DESCRIPTORS - 1;
for (uint8_t vector = 0; vector < 32; vector++)
{
idt_set_descriptor(vector, isr_stub_table[vector], 0x8E);
vectors[vector] = true;
}
extern void* irq_stub_table[];
for (uint8_t i = 0; i < 16; i++)
{
idt_set_descriptor(32 + i, irq_stub_table[i], 0x8E);
}
asm volatile ("lidt %0" : : "m"(idtr)); /* load the new IDT */
asm volatile ("sti"); /* set the interrupt flag */
}
void interrupt_dispatcher(registers_t* regs)
{
if (regs->int_no < 32)
{
exception_handler(regs);
}
else if (regs->int_no < 48)
{
uint32_t irq = regs->int_no - 32;
irq_handler(irq, regs);
if (irq >= 8)
{
outb(0xA0, 0x20); /* acknowledge the IRQ to slave PIC */
}
outb(0x20, 0x20); /* acknowledge the IRQ to master PIC */
}
}
__noreturn
void exception_handler(registers_t* regs)
{
uint32_t int_no = regs->int_no;
uint32_t err_code = regs->err_code;
switch (int_no)
{
case 0:
printf("Divide by zero exception (or other division error)\n");
break;
case 2:
printf("NMI encountered\n");
break;
case 6: /* XXX: NOTE: this can be used to emulate instructions that do not exist on the current CPU :NOTE :XXX */
printf("Invalid opcode encountered\n");
break;
case 7: /* XXX: NOTE: use this for FPU emulation and for saving/restoring FPU registers in a multiprocessing enviroment :NOTE :XXX */
printf("FPU instructions used, but FPU is nonexistant/disabled\n");
break;
case 13:
printf("General Protection Fault: err=0x%x at %p\n", err_code, regs->eip);
break;
case 14:
{
uint32_t cr2;
asm volatile ("mov %%cr2, %0" : "=r"(cr2));
printf("Page Fault at address: 0x%x, err=0x%x\n", cr2, err_code);
break;
}
default:
printf("Unhandled exception #%u, err=0x%x at %p\n", int_no, err_code, regs->eip);
break;
}
uint16_t cs, ds, es, ss;
asm volatile ("mov %%cs, %0" : "=r"(cs));
asm volatile ("mov %%ds, %0" : "=r"(ds));
asm volatile ("mov %%es, %0" : "=r"(es));
asm volatile ("mov %%ss, %0" : "=r"(ss));
printf("CS=0x%04x DS=0x%04x ES=0x%04x SS=0x%04x\n", cs, ds, es, ss);
asm volatile ("cli; hlt");
/* Will never be reached */
while (true)
{
asm volatile ("hlt" ::: "memory");
}
}
void idt_set_descriptor(uint8_t vector, void* isr, uint8_t flags)
{
idt_entry_t* descriptor = &idt[vector];
descriptor->isr_low = (uint32_t) isr & 0xFFFF;
descriptor->kernel_cs = 0x08;
descriptor->attributes = flags;
descriptor->isr_high = (uint32_t) isr >> 16;
descriptor->reserved = 0;
}
void pic_remap(void)
{
uint8_t a1, a2;
/* save masks */
a1 = inb(PIC1_DATA);
a2 = inb(PIC2_DATA);
/* start initialization sequence (in cascade mode) */
outb(PIC1_COMMAND, 0x11);
outb(PIC2_COMMAND, 0x11);
/* set vector offset */
outb(PIC1_DATA, 0x20); /* IRQs 0-7 mapped to IDT entries 0x20-0x27 (32–39) */
outb(PIC2_DATA, 0x28); /* IRQs 8-15 mapped to IDT entries 0x28-0x2F (40–47) */
/* tell the master PIC about Slave PIC at IRQ2 (0000 0100) */
outb(PIC1_DATA, 0x04);
/* tell the slave PIC its cascade identity (0000 0010) */
outb(PIC2_DATA, 0x02);
/* set 8086/88 mode */
outb(PIC1_DATA, 0x01);
outb(PIC2_DATA, 0x01);
/* restore saved masks */
outb(PIC1_DATA, a1);
outb(PIC2_DATA, a2);
}

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#ifndef _IDT_H
#define _IDT_H
#include <drivers/irq.h>
#include <types.h>
void idt_init(void);
void pic_remap(void);
void idt_set_descriptor(uint8_t vector, void* isr, uint8_t flags);
void exception_handler(registers_t* regs);
#endif

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#include <stdio.h>
#include <drivers/ps2_keyboard.h>
#include <drivers/pit.h>
#include <port_io.h>
#include <drivers/irq.h>
#define MAX_IRQ_HANDLERS 128 /* the maximum number of irq handlers */
typedef struct {
uint32_t irq_no;
irq_func_t func;
} irq_handler_t;
uint32_t num_irq_handlers = 0;
irq_handler_t handler_list[MAX_IRQ_HANDLERS];
static volatile uint32_t num_irqs_missed = 0;
void irq_init(void)
{
for (int i = 0; i < MAX_IRQ_HANDLERS; i++)
{
handler_list[i].irq_no = 0;
handler_list[i].func = NULL;
}
set_irq_handler(0, (irq_func_t) pit_handler);
set_irq_handler(1, (irq_func_t) ps2_keyboard_handler);
}
void irq_handler(uint32_t irq, registers_t* regs)
{
uint8_t funcs_called = 0;
if (num_irq_handlers > 0)
{
for (unsigned int i = 0; i < num_irq_handlers; i++)
{
if (handler_list[i].irq_no == irq && handler_list[i].func != NULL)
{
handler_list[i].func(regs);
funcs_called++;
/* PIC IRQ acknowledgement happens in idt.c */
}
}
}
if (funcs_called == 0)
{
num_irqs_missed++;
}
}
uint32_t get_interrupts_missed(void)
{
return num_irqs_missed;
}
void set_irq_handler(uint32_t num, irq_func_t handler)
{
if (num < MAX_IRQ_HANDLERS)
{
handler_list[num].irq_no = num;
handler_list[num].func = handler;
num_irq_handlers++;
}
}

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#ifndef _IRQ_H
#define _IRQ_H
#include <types.h>
/*
typedef struct registers {
uint32_t ds, es, fs, gs;
uint32_t edi, esi, ebp, esp, ebx, edx, ecx, eax;
uint32_t int_no;
uint32_t err_code;
uint32_t eip, cs, eflags;
} registers_t;
*/
typedef struct {
uint32_t ds, es, fs, gs;
uint32_t eax, ecx, edx, ebx;
uint32_t esp, ebp, esi, edi;
uint32_t int_no;
uint32_t err_code;
uint32_t eip, cs, eflags;
} registers_t;
typedef void (*irq_func_t)(registers_t*);
void irq_init(void);
void irq_handler(uint32_t irq, registers_t* regs);
void set_irq_handler(uint32_t num, irq_func_t handler);
/*void add_irq_handler(uint32_t num, irq_func_t* handler);*/
uint32_t get_interrupts_missed(void);
#endif

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[BITS 32]
[GLOBAL isr_stub_table]
[GLOBAL irq_stub_table]
[GLOBAL interrupt_entry]
extern interrupt_dispatcher
section .text
; ============================================================
; COMMON INTERRUPT ENTRY
; ============================================================
interrupt_entry:
; Stack already contains:
; err_code
; int_no
; eip
; cs
; eflags
pusha ; eax, ecx, edx, ebx, esp, ebp, esi, edi
;push ds
;push es
;push fs
;push gs
push gs
push fs
push es
push ds
mov ax, 0x10 ; load kernel data selector
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
push esp ; pass pointer to registers_t
call interrupt_dispatcher
add esp, 4
pop gs
pop fs
pop es
pop ds
popa
add esp, 8 ; remove int_no + err_code
iret
; ============================================================
; IRQ STUBS
; ============================================================
%macro IRQ 1
irq_stub_%+%1:
push dword 0 ; fake error code
push dword (32 + %1) ; vector number
jmp interrupt_entry
%endmacro
IRQ 0
IRQ 1
IRQ 2
IRQ 3
IRQ 4
IRQ 5
IRQ 6
IRQ 7
IRQ 8
IRQ 9
IRQ 10
IRQ 11
IRQ 12
IRQ 13
IRQ 14
IRQ 15
irq_stub_table:
%assign i 0
%rep 16
dd irq_stub_%+i
%assign i i+1
%endrep
; ============================================================
; EXCEPTION STUBS
; ============================================================
%macro ISR_NOERR 1
isr_stub_%+%1:
push dword 0 ; fake error code
push dword %1 ; interrupt number
jmp interrupt_entry
%endmacro
%macro ISR_ERR 1
isr_stub_%+%1:
push dword %1 ; interrupt number
jmp interrupt_entry
%endmacro
; Exceptions 0–31
ISR_NOERR 0
ISR_NOERR 1
ISR_NOERR 2
ISR_NOERR 3
ISR_NOERR 4
ISR_NOERR 5
ISR_NOERR 6
ISR_NOERR 7
ISR_ERR 8
ISR_NOERR 9
ISR_ERR 10
ISR_ERR 11
ISR_ERR 12
ISR_ERR 13
ISR_ERR 14
ISR_NOERR 15
ISR_NOERR 16
ISR_ERR 17
ISR_NOERR 18
ISR_NOERR 19
ISR_NOERR 20
ISR_NOERR 21
ISR_NOERR 22
ISR_NOERR 23
ISR_NOERR 24
ISR_NOERR 25
ISR_NOERR 26
ISR_NOERR 27
ISR_NOERR 28
ISR_NOERR 29
ISR_ERR 30
ISR_NOERR 31
isr_stub_table:
%assign i 0
%rep 32
dd isr_stub_%+i
%assign i i+1
%endrep

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/* Check if the compiler thinks you are targeting the wrong operating system. */
#if defined(__linux__)
#error "You are not using a cross-compiler, you will most certainly run into trouble"
#endif
/* This tutorial will only work for the 32-bit ix86 targets. */
#if !defined(__i386__)
#error "This kernel needs to be compiled with a ix86-elf compiler"
#endif
#include <types.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <kernel/boot.h>
#include <kernel/kshell.h>
#include <kdebug.h>
#include <gdt.h>
#include <drivers/idt.h>
#include <drivers/irq.h>
#include <scheduler.h>
#include <multiboot.h>
#include <drivers/pci.h>
#include <drivers/ps2_keyboard.h>
#include <drivers/pit.h>
/*#include <drivers/ahci.h>*/
#include <drivers/ide.h>
#include <mm/mm.h>
#include <fs/fat32.h>
/*#include <fs/duckfs.h>*/
#include <fs/vfs.h>
#include <fs/sfs.h>
#include <vector_extensions/sse.h>
#include <kernel/intro.h>
#include <builtin_games/miner.h>
#include <fs/ssfs.h>
extern void _hang_asm(void);
extern void _sti_asm(void);
void idle_task(void)
{
while (1)
asm volatile("hlt");
}
void kernel_main(multiboot_info_t* mbd, uint32_t magic)
{
/* --- BEGIN INITIALIZATION SECTION --- */
/* We need to initialize the terminal so that any error/debugging messages show. */
terminal_initialize();
printf("Loading Espresso %s... ", KERNEL_VERSION);
#ifdef _DEBUG
printf("[ DEBUG BUILD ]");
#endif
printf("\n");
terminal_setcolor(VGA_COLOR_RED);
/* Make sure the magic number matches for memory mapping */
if(magic != MULTIBOOT_BOOTLOADER_MAGIC)
{
printf("[ ERROR ] invalid magic number!\n");
_hang_asm();
}
/* Check bit 6 to see if we have a valid memory map */
if(!(mbd->flags >> 6 & 0x1))
{
printf("[ ERROR ] invalid memory map given by GRUB bootloader\n");
_hang_asm();
}
gdt_install(false);
pic_remap(); /* must be done before idt_init() */
idt_init();
_sti_asm();
irq_init(); /* MUST be done after pic_remap() and idt_init() */
terminal_setcolor(VGA_COLOR_GREEN);
pmm_init(mbd);
paging_init();
heap_init(0xC2000000, 0x80000);
#ifdef _DEBUG
printd("Testing SSE...\n");
#endif
int32_t sse_test_result = test_sse();
if (sse_test_result != 0)
{
printf("[ SSE ] SSE test failed with RV %d\n", sse_test_result);
}
else
{
#ifdef _DEBUG
printd("SSE test passed\n");
#endif
}
pit_init();
keyboard_init();
ide_initialize();
pci_init();
scheduler_init();
/* --- END INITIALIZATION SECTION --- */
terminal_setcolor(VGA_COLOR_LIGHT_GREEN);
printf("Guten tag and welcome to Espresso %s\n", KERNEL_VERSION);
//terminal_clear();
create_task(kshell_start);
create_task(idle_task);
extern task_t* task_list;
extern task_t* current_task;
current_task = task_list;
printf("in kernel_main\n");
/*extern void terminal_clear(void);
terminal_clear();
kshell_start(1, NULL);*/
for(;;) /* Loop infinitely. We only do something when an interrupt/syscall happens now. */
{
asm volatile("hlt" ::: "memory");
}
}

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#include <types.h>
#include <port_io.h>
#include <stdio.h>
#include <scheduler.h>
#include <drivers/pit.h>
#define PIT_CHANNEL0 0x40
#define PIT_COMMAND 0x43
#define PIT_IRQ_LINE 0
#define PIT_FREQUENCY_BASE 1193182
volatile uint64_t pit_ticks = 0;
bool pit_initialized = false;
void pit_init(void)
{
#ifdef _DEBUG
printf("[ PIT ] Initializing the PIT...\n");
#endif
uint16_t divisor = (uint16_t) 1193;
/* Send command byte */
outb(PIT_COMMAND, 0x36); /* Channel 0, low/high byte, mode 3 (square wave), binary */
/* Send divisor low and high byte */
outb(PIT_CHANNEL0, (uint8_t)(divisor & 0xFF)); /* Low byte */
outb(PIT_CHANNEL0, (uint8_t)((divisor >> 8) & 0xFF)); /* High byte */
pit_initialized = true;
#ifdef _DEBUG
printf("[ PIT ] PIT Initialized\n");
#endif
}
void pit_handler(void)
{
pit_ticks++;
}
/*void pit_sleep(uint64_t ms)
{
uint64_t target = pit_ticks + ms;
while (pit_ticks < target)
{
asm volatile ("hlt");
}
}*/
void pit_sleep(uint64_t ms)
{
extern task_t* current_task;
current_task->wakeup_tick = pit_ticks + ms;
current_task->state = TASK_SLEEPING;
asm volatile("int $32"); /* force reschedule immediately */
}

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#include <stdlib.h>
#include <string.h>
#include <drivers/irq.h>
#include <scheduler.h>
#define STACK_SIZE 4096
task_t* task_list = NULL;
task_t* current_task = NULL;
uint32_t next_task_id = 1;
static void schedule(void);
/* scheduler init */
void scheduler_init(void)
{
set_irq_handler(0, (irq_func_t) scheduler_tick);
}
static void schedule(void)
{
if (!task_list)
{
return;
}
/* wake sleeping tasks */
task_t* t = task_list;
extern uint64_t pit_ticks;
do
{
if (t->state == TASK_SLEEPING && pit_ticks >= t->wakeup_tick)
{
t->state = TASK_READY;
}
t = t->next;
}
while (t != task_list);
/* find next ready task */
task_t* start = current_task;
do
{
current_task = current_task->next;
if (current_task->state == TASK_READY)
{
return;
}
}
while (current_task != start);
}
/* tick handler */
void scheduler_tick(registers_t* regs)
{
if (!task_list)
{
printf("!task_list\n");
return;
}
if (!current_task)
{
printf("!current_task\n");
current_task = task_list;
}
/* save current task state */
*(current_task->regs) = *regs;
/* pick next */
schedule();
/* load next task state */
*regs = *(current_task->regs);
}
/* task creation */
task_t* create_task(void (*entry)())
{
task_t* task = malloc(sizeof(task_t));
if (!task)
{
return NULL;
}
memset(task, 0, sizeof(task_t));
/* allocate stack */
uint8_t* stack = malloc(STACK_SIZE);
if (!stack)
{
free(task);
return NULL;
}
printf("Creating task %i @ %p\n", next_task_id, entry);
/*
align stack to 16 bytes for safety (SSE friendly).
stack grows downward.
*/
uintptr_t stack_top = (uintptr_t)(stack + STACK_SIZE);
stack_top &= ~0xF;
registers_t* regs = (registers_t*) (stack_top - sizeof(registers_t));
memset(regs, 0, sizeof(registers_t));
/* initialize register frame */
regs->eip = (uint32_t) entry;
regs->cs = 0x08; /* Kernel code segment */
regs->eflags = 0x202; /* IF=1 */
task->id = next_task_id++;
task->regs = regs;
task->stack_base = (uint32_t*) stack;
task->state = TASK_READY;
/* insert into circular list */
if (!task_list)
{
task_list = task;
task->next = task;
}
else
{
task_t* last = task_list;
while (last->next != task_list)
{
last = last->next;
}
last->next = task;
task->next = task_list;
}
printf("Task %i @ %p created successfully\n", next_task_id - 1, entry);
return task;
}
/* task destruction */
void destroy_task(task_t* task)
{
free(task->stack_base);
free(task);
}

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#ifndef _SCHEDULER_H
#define _SCHEDULER_H
#include <drivers/irq.h>
#include <types.h>
typedef enum {
TASK_READY,
TASK_RUNNING,
TASK_SLEEPING,
TASK_BLOCKED,
TASK_TERMINATED,
} task_state_t;
typedef struct task {
uint32_t id;
registers_t* regs; /* pointer to saved register frame */
uint32_t* stack_base; /* original malloc() pointer */
task_state_t state;
struct task* next;
uint64_t wakeup_tick;
} task_t;
void scheduler_init(void);
task_t* create_task(void (*entry)());
void scheduler_tick(registers_t* regs);
#endif