From b8604932ebae3c63538d2e104f5d5d21d5e839de Mon Sep 17 00:00:00 2001
From: Alexander Myltsev <a.myltsev@gmail.com>
Date: Sun, 20 Nov 2022 19:48:55 +0300
Subject: [PATCH] Load kernel with a .data segment.

---
 Makefile       |  4 ++--
 cpu/idt.c      |  8 ++++++--
 cpu/vectors.S  |  2 +-
 drivers/port.h | 10 +++++-----
 kernel.c       | 10 ++++++++--
 mbr.S          | 12 +++++++++++-
 6 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/Makefile b/Makefile
index bda8f47..42bb9ac 100644
--- a/Makefile
+++ b/Makefile
@@ -25,11 +25,11 @@ fs.img: kernel.bin tools/mkfs
 image.bin: mbr.bin fs.img
 	cat $^ >$@
 
-kernel.bin: kernel.o console.o drivers/vga.o string.o drivers/ata.o cpu/vectors.o cpu/idt.o
+kernel.bin: kernel.o console.o drivers/vga.o drivers/keyboard.o string.o drivers/ata.o cpu/vectors.o cpu/idt.o
 	$(LD) -m elf_i386 -o $@ -Ttext 0x1000 $^
 
 %.o: %.c
-	$(CC) -m32 -ffreestanding -c -g $< -o $@
+	$(CC) -m32 -ffreestanding -Wall -Werror -c -g $< -o $@
 
 %.o: %.S
 	$(AS) --32 -g $^ -o $@
diff --git a/cpu/idt.c b/cpu/idt.c
index 715580a..7b2f41b 100644
--- a/cpu/idt.c
+++ b/cpu/idt.c
@@ -30,7 +30,7 @@ void set_idt_gate(int n, uint32_t handler) {
 }
 
 // defined in vectors.S
-extern uint32_t default_handlers[IDT_HANDLERS];
+extern uint32_t default_handlers[];
 
 void init_idt() {
     for (int i = 0; i < IDT_HANDLERS; i++) {
@@ -64,7 +64,11 @@ const char *exception_messages[] = {
 
 #define ARRLEN(a) (sizeof(a) / sizeof(a[0]))
 
-isr_t interrupt_handlers[IDT_HANDLERS];
+static isr_t interrupt_handlers[IDT_HANDLERS];
+
+void register_interrupt_handler(uint8_t i, isr_t handler) {
+    interrupt_handlers[i] = handler;
+}
 
 void trap(registers_t *r) {
     if (r->int_no < 32) {
diff --git a/cpu/vectors.S b/cpu/vectors.S
index 9fd80ed..ef92bfc 100644
--- a/cpu/vectors.S
+++ b/cpu/vectors.S
@@ -45,7 +45,7 @@ vector\i :
 .global default_handlers
 default_handlers:
 .set i,0
-.rept 256
+.rept 40
     irq_insertX %i
     .set i, i+1
 .endr
diff --git a/drivers/port.h b/drivers/port.h
index 283418b..380272a 100644
--- a/drivers/port.h
+++ b/drivers/port.h
@@ -1,25 +1,25 @@
 #pragma once
 
-static unsigned char port_byte_in(unsigned short port) {
+static inline unsigned char port_byte_in(unsigned short port) {
     unsigned char result;
     __asm__("in %%dx, %%al" : "=a" (result) : "d" (port));
     return result;
 }
 
-static unsigned short port_word_in(unsigned short port) {
+static inline unsigned short port_word_in(unsigned short port) {
     unsigned short result;
     __asm__("in %%dx, %%ax" : "=a" (result) : "d" (port));
     return result;
 }
 
-static void port_byte_out(unsigned short port, unsigned char data) {
+static inline void port_byte_out(unsigned short port, unsigned char data) {
     __asm__("outb %%al, %%dx" : : "a" (data), "d" (port));
 }
 
-static void port_word_out(unsigned short port, unsigned short data) {
+static inline void port_word_out(unsigned short port, unsigned short data) {
     __asm__("outw %%ax, %%dx" : : "a" (data), "d" (port));
 }
 
-static void port_long_out(unsigned short port, unsigned int data) {
+static inline void port_long_out(unsigned short port, unsigned int data) {
     __asm__("outl %%eax, %%dx" : : "a" (data), "d" (port));
 }
diff --git a/kernel.c b/kernel.c
index 80ca3a3..35cb1af 100644
--- a/kernel.c
+++ b/kernel.c
@@ -1,21 +1,27 @@
 asm(".asciz \"kernel start\"");
 
+#include "console.h"
 #include "cpu/isr.h"
+#include "drivers/keyboard.h"
 #include "drivers/vga.h"
 #include "drivers/ata.h"
 #include "drivers/misc.h"
 
 void _start() {
+    init_keyboard();
     load_idt();
     sti();
     char buf[512];
 
     vga_clear_screen();
-    vga_print_string("YABLOKO\n");
+    printk("YABLOKO\n");
 
     read_sectors_ATA_PIO((uint32_t)buf, 10, 1);
-    vga_print_string(buf);
+    printk(buf);
 
+    while (1) {
+        asm("pause");
+    }
     asm("hlt");
     qemu_shutdown();
 }
diff --git a/mbr.S b/mbr.S
index 6471c95..9b1b007 100644
--- a/mbr.S
+++ b/mbr.S
@@ -13,6 +13,9 @@ _start:
 
 .equ ELF32_ENTRY_OFFSET, 0x18
 .equ ELF32_PHDR_OFFSET, 0x1c
+.equ ELF32_PHENTSIZE_OFFSET, ELF32_PHDR_OFFSET + 14
+.equ ELF32_PHNUM_OFFSET, ELF32_PHENTSIZE_OFFSET + 2
+.equ ELF32_PHDR_P_OFFSET, 4
 .equ ELF32_PHDR_FILESZ_OFFSET, 4*4
 .equ KERNEL_OFFSET, 0x1000
 
@@ -31,8 +34,15 @@ load_kernel:
     mov KERNEL_OFFSET + ELF32_ENTRY_OFFSET, %si
     mov %si, entry // store entry point
 
-    mov KERNEL_OFFSET + ELF32_PHDR_OFFSET, %di
+    mov KERNEL_OFFSET + ELF32_PHNUM_OFFSET, %ax
+    dec %ax  // no offset to the first entry
+    mulb KERNEL_OFFSET + ELF32_PHENTSIZE_OFFSET
+    mov %ax, %di
+
+    add KERNEL_OFFSET + ELF32_PHDR_OFFSET, %di
+    // now di holds offset to the last phentry
     mov KERNEL_OFFSET + ELF32_PHDR_FILESZ_OFFSET(%di), %ax
+    add KERNEL_OFFSET + ELF32_PHDR_P_OFFSET(%di), %ax
     sub $0x1000, %ax // we won't load the header
     add $SECTOR_SIZE - 1, %ax
     shr $SECTOR_SHIFT, %ax // round up to sector count