From a9f490b4313c629af74838cda065e67ef58dbd16 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Sat, 8 Apr 2023 20:13:51 -0300
Subject: [PATCH] kernel: initial interrupt abstraction implementation

---
 kernel-src/include/kernel/interrupt.h | 26 +++++++++++++++
 kernel-src/include/x86-64/arch/cpu.h  |  4 ++-
 kernel-src/sys/interrupt.c            | 47 +++++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 1 deletion(-)
 create mode 100644 kernel-src/include/kernel/interrupt.h
 create mode 100644 kernel-src/sys/interrupt.c

diff --git a/kernel-src/include/kernel/interrupt.h b/kernel-src/include/kernel/interrupt.h
new file mode 100644
index 00000000..9db5eff4
--- /dev/null
+++ b/kernel-src/include/kernel/interrupt.h
@@ -0,0 +1,26 @@
+#ifndef _INTERRUPT_H
+#define _INTERRUPT_H
+
+#include <stdbool.h>
+
+#ifdef __x86_64__
+	#define MAX_ISR_COUNT 256
+#else
+	#error Unsupported architecture!
+#endif
+
+struct _isr_t;
+typedef struct _isr_t {
+	void (*func)(struct _isr_t *self); // TODO pass register context as argument as well.
+	void (*eoi)(struct _isr_t *self);
+	long id;
+	long priority;
+	bool pending;
+} isr_t;
+
+void interrupt_register(int vector, void (*func)(isr_t *self), void (*eoi)(isr_t *self), long priority); // TODO pass register context as well.
+isr_t *interrupt_allocate(void (*func)(isr_t *self), void (*eoi)(isr_t *self), long priority); // TODO pass register context as well.
+void interrupt_raiseipl(long newipl);
+void interrupt_loweripl(long newipl);
+
+#endif
diff --git a/kernel-src/include/x86-64/arch/cpu.h b/kernel-src/include/x86-64/arch/cpu.h
index 470ca745..1c3bdae8 100644
--- a/kernel-src/include/x86-64/arch/cpu.h
+++ b/kernel-src/include/x86-64/arch/cpu.h
@@ -6,11 +6,13 @@
 
 #include <arch/msr.h>
 #include <arch/ist.h>
+#include <kernel/interrupt.h>
 
 typedef struct {
 	uint64_t gdt[7];
 	ist_t ist;
-	int lapicid;
+	long id;
+	isr_t isr[MAX_ISR_COUNT];
 } cpu_t;
 
 static inline cpu_t *_cpu() {
diff --git a/kernel-src/sys/interrupt.c b/kernel-src/sys/interrupt.c
new file mode 100644
index 00000000..a9dc3add
--- /dev/null
+++ b/kernel-src/sys/interrupt.c
@@ -0,0 +1,47 @@
+#include <kernel/interrupt.h>
+#include <logging.h>
+#include <arch/cpu.h>
+
+// TODO pass register context as well
+void interrupt_isr(int vec) {
+	isr_t *isr = &_cpu()->isr[vec];
+	// TODO ipl check
+	isr->func(isr); // TODO pass context
+
+	if (isr->eoi)
+		isr->eoi(isr);
+}
+
+// TODO pass register context as well.
+void interrupt_register(int vector, void (*func)(isr_t *self), void (*eoi)(isr_t *self), long priority) {
+	isr_t *isr = &_cpu()->isr[vector];
+	isr->func = func;
+	isr->eoi = eoi;
+	isr->id = _cpu()->id << 32 | vector;
+	isr->priority = priority;
+}
+
+// TODO pass register context as well.
+isr_t *interrupt_allocate(void (*func)(isr_t *self), void (*eoi)(isr_t *self), long priority) {
+	isr_t *isr = NULL;
+
+	for (int i = 0; i < MAX_ISR_COUNT; ++i) {
+		if (_cpu()->isr[i].func == NULL) {
+			isr = &_cpu()->isr[i];
+			interrupt_register(i, func, eoi, priority);
+			break;
+		}
+	}
+
+	return isr;
+}
+
+// TODO ipl is thread level, write these when the scheduler is written
+
+void interrupt_raiseipl(long newipl) {
+	__assert(!"Unimplemented");
+}
+
+void interrupt_loweripl(long newipl) {
+	__assert(!"Unimplemented");
+}