interrupts: execute pending interrupts

kernel-src/include/kernel/interrupt.h

@@ -19,6 +19,8 @@
 
 struct _isr_t;
 typedef struct _isr_t {
+	struct _isr_t *next;
+	struct _isr_t *prev;
 	void (*func)(struct _isr_t *self, context_t *ctx);
 	void (*eoi)(struct _isr_t *self);
 	long id;

kernel-src/include/x86-64/arch/cpu.h

@@ -25,6 +25,7 @@ typedef struct cpu_t {
 	thread_t *idlethread;
 	timerentry_t schedtimerentry;
 	void *schedulerstack;
+	isr_t *isrqueue;
 } cpu_t;
 
 #define CPU_HALT() asm volatile("hlt")

kernel-src/sys/interrupt.c

@@ -4,6 +4,92 @@
 #include <arch/context.h>
 #include <panic.h>
 
+void arch_interrupt_disable();
+void arch_interrupt_enable();
+
+#define DOPENDING_SAVE() arch_context_saveandcall(dopending, NULL)
+
+static void removefromqueue(isr_t *isr) {
+	if (isr->prev)
+		isr->prev->next = isr->next;
+	else
+		_cpu()->isrqueue = isr->next;
+
+	if (isr->next)
+		isr->next->prev = isr->prev;
+}
+
+static void insertinqueue(isr_t *isr) {
+	if (isr->pending)
+		return;
+
+	isr->next = _cpu()->isrqueue;
+	if (isr->next)
+		isr->next->prev = isr;
+	_cpu()->isrqueue = isr;
+}
+
+static void dopending(context_t *ctx) {
+	bool entrystatus = _cpu()->intstatus;
+	if (entrystatus) {
+		_cpu()->intstatus = false;
+		arch_interrupt_disable();
+	}
+
+	isr_t *list = NULL;
+	isr_t *iterator = _cpu()->isrqueue;
+
+	// build a list of pending ISRs and remove them from the main queue
+
+	while (iterator) {
+		isr_t *next = iterator->next;
+		if (_cpu()->ipl > iterator->priority) {
+			removefromqueue(iterator);
+
+			if (list)
+				list->prev = iterator;
+			iterator->next = list;
+			iterator->prev = NULL;
+			list = iterator;
+
+			__assert(iterator->pending);
+		}
+
+		iterator = next;
+	}
+
+	if (list == NULL)
+		goto cleanup;
+
+	// run pending ISRs
+
+	while (list) {
+		isr_t *isr = list;
+		list = list->next;
+		if (list)
+			list->prev = NULL;
+		isr->pending = false;
+
+		long oldipl = interrupt_raiseipl(isr->priority);
+
+		isr->func(isr, ctx);
+		interrupt_set(false);
+
+		interrupt_loweripl(oldipl);
+
+		// if any new interrupts are pending, they will be taken care of here
+		// XXX this is kinda hacky could be very very bad if there are a lot of interrupts
+		dopending(ctx);
+	}
+
+	cleanup:
+	if (entrystatus) {
+		_cpu()->intstatus = true;
+		arch_interrupt_enable();
+	}
+}
+
+
 void interrupt_isr(int vec, context_t *ctx) {
 	isr_t *isr = &_cpu()->isr[vec];
 	_cpu()->intstatus = false;
@@ -18,7 +104,9 @@ void interrupt_isr(int vec, context_t *ctx) {
 		interrupt_set(false);
 
 		interrupt_loweripl(oldipl);
+		dopending(ctx);
 	} else {
+		insertinqueue(isr);
 		isr->pending = true;
 	}
 
@@ -58,7 +146,8 @@ long interrupt_loweripl(long ipl) {
 		_cpu()->ipl = ipl;
 	interrupt_set(oldintstatus);
 
-	// TODO do pending interrupts
+	if (oldintstatus)
+		DOPENDING_SAVE();
 
 	return oldipl;
 }
@@ -66,21 +155,26 @@ long interrupt_loweripl(long ipl) {
 long interrupt_raiseipl(long ipl) {
 	bool oldintstatus = interrupt_set(false);
 	long oldipl = _cpu()->ipl;
+
 	if (oldipl > ipl)
 		_cpu()->ipl = ipl;
+
 	interrupt_set(oldintstatus);
+
 	return oldipl;
 }
 
-void arch_interrupt_disable();
-void arch_interrupt_enable();
-
 bool interrupt_set(bool status) {
 	if (status)
 		arch_interrupt_enable();
 	else
 		arch_interrupt_disable();
+
 	bool old = _cpu()->intstatus;
 	_cpu()->intstatus = status;
+
+	if (status)
+		DOPENDING_SAVE();
+
 	return old;
 }