From 5f84cdec3cb4b33bccb57794089762f23ca27285 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Sun, 23 Apr 2023 15:42:08 -0300
Subject: [PATCH] interrupt: basic ipl handling

---
 kernel-src/arch/x86-64/idt.c          |  2 +-
 kernel-src/include/kernel/interrupt.h |  8 ++++++--
 kernel-src/include/x86-64/arch/cpu.h  |  1 +
 kernel-src/sys/interrupt.c            | 28 +++++++++++++++++++--------
 4 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/kernel-src/arch/x86-64/idt.c b/kernel-src/arch/x86-64/idt.c
index 3d48ac88..d343d6bc 100644
--- a/kernel-src/arch/x86-64/idt.c
+++ b/kernel-src/arch/x86-64/idt.c
@@ -78,7 +78,7 @@ void arch_idt_reload() {
 
 	// make sure to reserve the first 32 isrs for exceptions with a dummy panic isr
 	for (int i = 0; i < 32; ++i)
-		interrupt_register(i, exceptisr, NULL, 0); // TODO assign priority
+		interrupt_register(i, exceptisr, NULL, IPL_MAX);
 }
 
 void arch_interrupt_disable() {
diff --git a/kernel-src/include/kernel/interrupt.h b/kernel-src/include/kernel/interrupt.h
index b0481e85..7eac1dbb 100644
--- a/kernel-src/include/kernel/interrupt.h
+++ b/kernel-src/include/kernel/interrupt.h
@@ -11,6 +11,11 @@
 	#error Unsupported architecture!
 #endif
 
+#define IPL_MAX  -1
+#define IPL_NONE 0
+#define IPL_TIMER 1
+#define IPL_BASE 1000
+
 struct _isr_t;
 typedef struct _isr_t {
 	void (*func)(struct _isr_t *self, context_t *ctx);
@@ -22,8 +27,7 @@ typedef struct _isr_t {
 
 void interrupt_register(int vector, void (*func)(isr_t *self, context_t *ctx), void (*eoi)(isr_t *self), long priority);
 isr_t *interrupt_allocate(void (*func)(isr_t *self, context_t *ctx), void (*eoi)(isr_t *self), long priority);
-void interrupt_raiseipl(long newipl);
-void interrupt_loweripl(long newipl);
+long interrupt_setipl(long newipl);
 bool interrupt_set(bool status);
 
 #endif
diff --git a/kernel-src/include/x86-64/arch/cpu.h b/kernel-src/include/x86-64/arch/cpu.h
index 20931605..3890a86b 100644
--- a/kernel-src/include/x86-64/arch/cpu.h
+++ b/kernel-src/include/x86-64/arch/cpu.h
@@ -20,6 +20,7 @@ typedef struct {
 	int acpiid;
 	timer_t *timer;
 	bool intstatus;
+	long ipl;
 } cpu_t;
 
 static inline cpu_t *_cpu() {
diff --git a/kernel-src/sys/interrupt.c b/kernel-src/sys/interrupt.c
index 07b47ef4..fbe57dc2 100644
--- a/kernel-src/sys/interrupt.c
+++ b/kernel-src/sys/interrupt.c
@@ -9,8 +9,18 @@ void interrupt_isr(int vec, context_t *ctx) {
 	if (isr->func == NULL)
 		_panic("Unregistered interrupt", ctx);
 
-	// TODO ipl check
-	isr->func(isr, ctx);
+	if (_cpu()->ipl < isr->priority) {
+		long oldipl = interrupt_setipl(isr->priority);
+
+		bool oldint = interrupt_set(true);
+		isr->func(isr, ctx);
+		interrupt_set(false);
+
+		_cpu()->intstatus = oldint;
+		interrupt_setipl(oldipl);
+	} else {
+		isr->pending = true;
+	}
 
 	if (isr->eoi)
 		isr->eoi(isr);
@@ -22,6 +32,7 @@ void interrupt_register(int vector, void (*func)(isr_t *self, context_t *ctx), v
 	isr->eoi = eoi;
 	isr->id = (uint64_t)_cpu()->id << 32 | vector;
 	isr->priority = priority;
+	isr->pending = false;
 }
 
 isr_t *interrupt_allocate(void (*func)(isr_t *self, context_t *ctx), void (*eoi)(isr_t *self), long priority) {
@@ -38,14 +49,15 @@ isr_t *interrupt_allocate(void (*func)(isr_t *self, context_t *ctx), void (*eoi)
 	return isr;
 }
 
-// TODO ipl is thread level, write these when the scheduler is written
+long interrupt_setipl(long ipl) {
+	bool oldintstatus = interrupt_set(false);
+	long oldipl = _cpu()->ipl;
+	_cpu()->ipl = ipl;
+	interrupt_set(oldintstatus);
 
-void interrupt_raiseipl(long newipl) {
-	__assert(!"Unimplemented");
-}
+	// TODO do pending interrupts
 
-void interrupt_loweripl(long newipl) {
-	__assert(!"Unimplemented");
+	return oldipl;
 }
 
 void arch_interrupt_disable();