kernel: interrupt: create a generic interrupt API

Create a generic interface for drivers to make use of interrupt vectors.
This API should be platform-agnostic enough to allow any driver to make
use of virtually any interrupt vector on any CPU. On x86, the first 32
interrupts are set aside for CPU exceptions, and interrupt 128 is set
aside for system calls.

Signed-off-by: Danny Holman <dholman@gymli.org>

2 files changed, 13 insertions, 16 deletions

diff --git a/arch/i386/kernel/idt.c b/arch/i386/kernel/idt.c
index 1a06631..a178801 100644
--- a/arch/i386/kernel/idt.c
+++ b/arch/i386/kernel/idt.c
@@ -1,4 +1,5 @@
 #include <kernel/idt.h>
+#include <kernel/interrupt.h>
 #include <kernel/syscall.h>
 #include <kernel/panic.h>
 #include <kernel/gdt.h>
@@ -67,20 +68,10 @@ void exception_handler(struct isr_frame *frame) {
         }
 }
 
-void interrupt_handler(struct isr_frame frame) {
-        if (frame.isr_vector < 32) {
-                exception_handler(&frame);
-        } else if (frame.isr_vector < 48) {
-                irq_dispatch(&frame);
-        } else {
-                switch (frame.isr_vector) {
-                        case 0x80:
-                                handle_syscall(&frame);
-                                break;
-                        default:
-                                panic("Unmapped interrupt");
-                }
-        }
+void generic_handler(struct isr_frame *frame) {
+        kprintf("No handler registered for IRQ %d\n", frame->isr_vector);
+        if (frame->isr_vector > 32 && frame->isr_vector < 48)
+                pic_eoi(frame->isr_vector-32);
 }
 
 void idt_set_gate(uint8_t num, void (*handler)(void), uint16_t cs, uint8_t flags) {
@@ -96,6 +87,12 @@ void idt_install(void) {
         idtr.limit = (uint16_t)sizeof(struct idt_entry) * 256 - 1;
         idtr.base = (uint32_t)idt;
 
+        for (int i = 0; i < 32; i++)
+                register_isr_handler(i, exception_handler);
+        for (int i = 32; i < 224; i++)
+                register_isr_handler(i, generic_handler);
+        register_isr_handler(0x80, handle_syscall);
+
         idt_set_gate(0x0, isr_stub_0, 0x08, IDT_EXCEPTION);
         idt_set_gate(0x1, isr_stub_1, 0x08, IDT_EXCEPTION);
         idt_set_gate(0x2, isr_stub_2, 0x08, IDT_EXCEPTION);
@@ -146,7 +143,7 @@ void idt_install(void) {
         idt_set_gate(0x2E, irq_stub_14, 0x08, IDT_INTERRUPT);
         idt_set_gate(0x2F, irq_stub_15, 0x08, IDT_INTERRUPT);
 
-        idt_set_gate(0x80, syscall_stub, 0x08, IDT_INTERRUPT);
+        idt_set_gate(0x80, isr_stub_128, 0x08, IDT_INTERRUPT);
 
         __asm__ volatile("lidt %0" : : "memory"(idtr));
 }
diff --git a/arch/i386/kernel/syscall.c b/arch/i386/kernel/syscall.c
index e8b69a2..200af4f 100644
--- a/arch/i386/kernel/syscall.c
+++ b/arch/i386/kernel/syscall.c
@@ -10,7 +10,7 @@ void sys_read(struct isr_frame *frame) {
 void sys_write(struct isr_frame *frame) {
 }
 
-int handle_syscall(struct isr_frame *frame) {
+void handle_syscall(struct isr_frame *frame) {
         switch (frame->eax) {
                 case SYS_READ:
                         sys_read(frame);