sos

commit 0e9bb980e2cbcc7642f51430edb9ac863961c3e4
parent aab5207bbd3c17a735529e96624e47eedfee596f
Author: Stefan <misc@stefan-koch.name>
Date:   Fri, 23 Oct 2015 23:22:20 +0200

added IDT with halting interrupt handler

Diffstat:
M
Makefile
 | 
4
+++-
A
arch/x86/idt.asm
 | 
7
+++++++
A
arch/x86/idt.c
 | 
28
++++++++++++++++++++++++++++
A
arch/x86/idt.h
 | 
26
++++++++++++++++++++++++++
M
kernel.c
 | 
2
++

5 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
@@ -8,9 +8,11 @@ all: image kernel kernel-install
 kernel:
 	$(ASM) arch/x86/boot.asm -o arch/x86/boot.o -f elf
 	$(ASM) arch/x86/gdt.asm -o arch/x86/gdt_asm.o -f elf
+	$(ASM) arch/x86/idt.asm -o arch/x86/idt_asm.o -f elf
 	$(GCC) -c kernel.c -o kernel.o $(GCCFLAGS)
 	$(GCC) -c arch/x86/gdt.c -o arch/x86/gdt.o $(GCCFLAGS)
-	$(GCC) -T kernel.ld -o sos-kernel.img -ffreestanding -O2 -nostdlib arch/x86/boot.o kernel.o arch/x86/gdt_asm.o arch/x86/gdt.o -lgcc
+	$(GCC) -c arch/x86/idt.c -o arch/x86/idt.o $(GCCFLAGS)
+	$(GCC) -T kernel.ld -o sos-kernel.img -ffreestanding -O2 -nostdlib arch/x86/boot.o kernel.o arch/x86/gdt_asm.o arch/x86/gdt.o arch/x86/idt.o arch/x86/idt_asm.o -lgcc
 
 kernel-install:
 	sudo losetup /dev/loop1 sos.img -o 1048576
diff --git a/arch/x86/idt.asm b/arch/x86/idt.asm
@@ -0,0 +1,7 @@
+section .text
+global int_handler
+int_handler:
+    mov ax, 0x10
+    mov gs, ax
+    mov dword [gs:0xB8000],') : '
+    hlt
diff --git a/arch/x86/idt.c b/arch/x86/idt.c
@@ -0,0 +1,28 @@
+#include <stdint.h>
+#include "idt.h"
+
+void idt_set_entry(unsigned int pos, uint32_t base,
+        uint16_t selector, uint8_t type_attributes)
+{
+    idt[pos].base_lower = base & 0xffff;
+    idt[pos].selector = selector;
+    idt[pos].unused = 0x0;
+    idt[pos].type_attributes = type_attributes;
+    idt[pos].base_higher = (base >> 16) & 0xffff;
+}
+
+extern void int_handler();
+void idt_setup()
+{
+    idt_desc.limit = IDT_ENTRIES * sizeof(struct idt_entry) - 1;
+    idt_desc.base = (uint32_t) (uintptr_t) idt;
+
+    // TODO: set some entries
+    for (int i = 0; i < IDT_ENTRIES; i++) {
+        idt_set_entry(i, (uint32_t)(uintptr_t)&int_handler,
+            0x8, 0x8e);
+    }
+
+
+    asm volatile("lidt (%0)" :: "m"(idt_desc));
+}
diff --git a/arch/x86/idt.h b/arch/x86/idt.h
@@ -0,0 +1,26 @@
+#ifndef IDT_H
+#define IDT_H
+
+#include <stdint.h>
+
+#define IDT_ENTRIES 256
+
+struct idt_entry {
+    uint16_t base_lower;
+    uint16_t selector;
+    uint8_t unused;
+    uint8_t type_attributes;
+    uint16_t base_higher;
+} __attribute__((packed));
+
+struct idt_description {
+    uint16_t limit;
+    uint32_t base;
+} __attribute__((packed));
+
+struct idt_description idt_desc;
+struct idt_entry idt[IDT_ENTRIES];
+
+void idt_setup();
+
+#endif
diff --git a/kernel.c b/kernel.c
@@ -1,8 +1,10 @@
+#include "arch/x86/idt.h"
 #include "arch/x86/gdt.h"
 
 void kernel_main()
 {
     gdt_setup();
+    idt_setup();
 
     char *vidmem = (char*) 0xb8000;
     vidmem[0] = 'H';