Add first C user program

src/kernel/kernel.c

@@ -0,0 +1,77 @@
+#include "src/kernel/fs.h"
+#include "src/kernel/gdt.h"
+#include "src/kernel/idt.h"
+#include "src/kernel/keyboard.h"
+#include "src/kernel/panic.h"
+#include "src/kernel/path.h"
+#include "src/kernel/pic.h"
+#include "src/kernel/process.h"
+#include "src/kernel/syscall.h"
+#include "src/kernel/util.h"
+#include "src/kernel/vga.h"
+#include "src/lib/memory.h"
+
+__attribute__((interrupt)) void isr_divide_by_zero(__attribute__((unused)) struct interrupt_frame *frame) {
+  vga_set_string(VGA_HEIGHT - 1, 0, "EXCEPTION: divide by zero", 0x4F);
+  while (1)
+    ;
+}
+
+__attribute__((interrupt)) void isr_page_fault(__attribute__((unused)) struct interrupt_frame *frame) {
+  vga_set_string(VGA_HEIGHT - 1, 0, "EXCEPTION: page fault", 0x4F);
+  while (1)
+    ;
+}
+
+__attribute__((interrupt)) void isr_general_violation(__attribute__((unused)) struct interrupt_frame *frame) {
+  vga_set_string(VGA_HEIGHT - 1, 0, "EXCEPTION: general violation", 0x4F);
+  while (1)
+    ;
+}
+
+__attribute__((interrupt)) void isr_ata_primary(__attribute__((unused)) struct interrupt_frame *frame) {
+  outb(0x20, 0x20);
+  outb(0xA0, 0x20);
+}
+
+void kernel_main() {
+  pic_init();
+  idt_init();
+  outb(0x21, inb(0x21) | 0x01); // mask out timer interrupt
+  idt_set_entry(0, isr_divide_by_zero, 0x8E);
+  idt_set_entry(0x0E, isr_page_fault, 0x8E);
+  idt_set_entry(0x0D, isr_general_violation, 0x8E);
+  idt_set_entry(46, isr_ata_primary, 0x8E);
+  __asm__ volatile("sti");
+
+  gdt_init();
+  syscall_init();
+
+  process_t *kp = memory_allocate(sizeof(process_t));
+  kp->root = fs_mount();
+  kp->cwd = memory_allocate(sizeof(path_t));
+  kp->stdin = keyboard_init();
+  kp->stdout = vga_init();
+
+  fs_node_t *hello = fs_open_by(kp->root, "HELLO.BIN");
+
+  ASSERT(hello, "kernel: hello.bin not found");
+
+  uint8_t *hello_code = memory_allocate(hello->size);
+  fs_read(hello, 0, hello->size, hello_code);
+
+  process_t *proc = process_create(kp, hello_code, hello->size);
+
+  memory_free(hello_code);
+  fs_close(hello);
+
+  process_run(proc);
+
+  while (1)
+    ;
+
+  fs_unmount(kp->root);
+
+  outw(0x604, 0x2000); // TODO: parse ACPI tables for real hardware
+  __asm__ volatile("cli; hlt");
+}