From 0185572afc18c8a33df7faecd5aa723e89dca391 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Tue, 27 Jun 2023 20:03:57 -0300
Subject: [PATCH] interrupts: IPL_IGNORE which doesn't raise nor lower the IPL
 on an interrupt

---
 kernel-src/arch/x86-64/apic.c         | 2 +-
 kernel-src/arch/x86-64/idt.c          | 2 +-
 kernel-src/arch/x86-64/mmu.c          | 2 +-
 kernel-src/include/kernel/interrupt.h | 2 +-
 kernel-src/sys/interrupt.c            | 7 +++++--
 5 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/kernel-src/arch/x86-64/apic.c b/kernel-src/arch/x86-64/apic.c
index bbf806c5..741cd950 100644
--- a/kernel-src/arch/x86-64/apic.c
+++ b/kernel-src/arch/x86-64/apic.c
@@ -201,7 +201,7 @@ void arch_apic_initap() {
 	writelapic(APIC_LVT_LINT1, LVT_MASK);
 	writelapic(APIC_LVT_ERROR, LVT_MASK);
 	writelapic(APIC_LVT_TIMER, LVT_MASK);
-	interrupt_register(0xff, spurious, NULL, IPL_MAX); // XXX for now max ipl suffices, however it's likely not the best one
+	interrupt_register(0xff, spurious, NULL, IPL_IGNORE);
 	writelapic(APIC_REG_SPURIOUS, 0x1FF);
 
 	_cpu()->id = readlapic(APIC_REG_ID) >> 24;
diff --git a/kernel-src/arch/x86-64/idt.c b/kernel-src/arch/x86-64/idt.c
index b9219693..f4fb85db 100644
--- a/kernel-src/arch/x86-64/idt.c
+++ b/kernel-src/arch/x86-64/idt.c
@@ -79,7 +79,7 @@ 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, IPL_MAX);
+		interrupt_register(i, exceptisr, NULL, IPL_IGNORE);
 
 	_cpu()->ipl = IPL_NORMAL;
 	interrupt_set(true);
diff --git a/kernel-src/arch/x86-64/mmu.c b/kernel-src/arch/x86-64/mmu.c
index 21cee419..b519508e 100644
--- a/kernel-src/arch/x86-64/mmu.c
+++ b/kernel-src/arch/x86-64/mmu.c
@@ -265,5 +265,5 @@ void arch_mmu_init() {
 	}
 
 	arch_mmu_switch(FROM_HHDM(template));
-	interrupt_register(14, pfisr, NULL, IPL_MAX);
+	interrupt_register(14, pfisr, NULL, IPL_IGNORE);
 }
diff --git a/kernel-src/include/kernel/interrupt.h b/kernel-src/include/kernel/interrupt.h
index 6cb837e7..14627202 100644
--- a/kernel-src/include/kernel/interrupt.h
+++ b/kernel-src/include/kernel/interrupt.h
@@ -11,7 +11,7 @@
 	#error Unsupported architecture!
 #endif
 
-#define IPL_EXCEPT  -1
+#define IPL_IGNORE  -1
 #define IPL_MAX 0
 #define IPL_TIMER 1
 #define IPL_KEYBOARD 2
diff --git a/kernel-src/sys/interrupt.c b/kernel-src/sys/interrupt.c
index 980d54b7..7bfedc54 100644
--- a/kernel-src/sys/interrupt.c
+++ b/kernel-src/sys/interrupt.c
@@ -30,12 +30,15 @@ static void insertinqueue(isr_t *isr) {
 }
 
 static void runisr(isr_t *isr, context_t *ctx) {
-		long oldipl = interrupt_raiseipl(isr->priority);
+		long oldipl = -1;
+		if (isr->priority != IPL_IGNORE)
+			oldipl = interrupt_raiseipl(isr->priority);
 
 		isr->func(isr, ctx);
 		interrupt_set(false);
 
-		interrupt_loweripl(oldipl);
+		if (isr->priority != IPL_IGNORE)
+			interrupt_loweripl(oldipl);
 }
 
 static void dopending(context_t *ctx) {