lx_emul: track irq state changes

To be able to check for interrupts being on or off,
the enabling and disabling is tracked in lx_emul.
When interrupts get received, they have to be turned off.

Ref genodelabs/genode#4778

repos/dde_linux/lib/import/import-lx_emul_common.inc

@@ -16,6 +16,7 @@ SRC_CC  += lx_emul/log.cc
 SRC_CC  += lx_emul/page_virt.cc
 SRC_CC  += lx_emul/task.cc
 SRC_CC  += lx_emul/time.cc
+SRC_CC  += lx_emul/irq_flags.cc
 
 SRC_C   += lx_emul/clocksource.c
 SRC_C   += lx_emul/shadow/fs/exec.c

repos/dde_linux/src/include/lx_emul/irq.h

@@ -34,6 +34,12 @@ extern void * lx_emul_irq_task_struct;
 unsigned int lx_emul_irq_last(void);
 
 int lx_emul_irq_init(struct device_node *node, struct device_node *parent);
+
+unsigned long lx_emul_irq_enable(void);
+unsigned long lx_emul_irq_disable(void);
+unsigned long lx_emul_irq_state(void);
+void          lx_emul_irq_restore(unsigned long);
+
 #ifdef __cplusplus
 }
 #endif

repos/dde_linux/src/include/lx_emul/shadow/arch/arm/include/asm/irqflags.h

@@ -14,14 +14,25 @@
 #ifndef __ASM_IRQFLAGS_H
 #define __ASM_IRQFLAGS_H
 
-static inline unsigned long arch_local_save_flags(void) {
+#include <lx_emul/irq.h>
-	return 1; }
 
-static inline void arch_local_irq_restore(unsigned long flags) { }
+#define arch_local_save_flags arch_local_save_flags
+static inline unsigned long arch_local_save_flags(void)
+{
+	return lx_emul_irq_state();
+}
+
+#define arch_local_irq_restore arch_local_irq_restore
+static inline void arch_local_irq_restore(unsigned long flags)
+{
+	lx_emul_irq_restore(flags);
+}
 
 #define arch_irqs_disabled_flags arch_irqs_disabled_flags
-static inline int arch_irqs_disabled_flags(unsigned long flags) {
+static inline int arch_irqs_disabled_flags(unsigned long flags)
-	return 1; }
+{
+	return flags & 1;
+}
 
 #define local_fiq_enable() ({})
 #define local_fiq_disable() ({})

repos/dde_linux/src/include/lx_emul/shadow/arch/arm64/include/asm/irqflags.h

@@ -14,19 +14,36 @@
 #ifndef __ASM_IRQFLAGS_H
 #define __ASM_IRQFLAGS_H
 
-static inline void arch_local_irq_enable(void) { }
+#include <lx_emul/irq.h>
 
-static inline void arch_local_irq_disable(void) { }
+static inline void arch_local_irq_enable(void)
+{
+	lx_emul_irq_enable();
+}
 
-static inline unsigned long arch_local_save_flags(void) {
+static inline void arch_local_irq_disable(void)
-	return 1; }
+{
+	lx_emul_irq_disable();
+}
 
-static inline int arch_irqs_disabled_flags(unsigned long flags) {
+static inline unsigned long arch_local_save_flags(void)
-	return flags; }
+{
+	return lx_emul_irq_state();
+}
 
-static inline unsigned long arch_local_irq_save(void) {
+static inline int arch_irqs_disabled_flags(unsigned long flags)
-	return 1; }
+{
+	return flags & 1;
+}
 
-static inline void arch_local_irq_restore(unsigned long flags) { }
+static inline unsigned long arch_local_irq_save(void)
+{
+	return lx_emul_irq_disable();
+}
+
+static inline void arch_local_irq_restore(unsigned long flags)
+{
+	lx_emul_irq_restore(flags);
+}
 
 #endif

repos/dde_linux/src/include/lx_emul/shadow/arch/x86/include/asm/irqflags.h

@@ -14,19 +14,36 @@
 #ifndef __ASM_IRQFLAGS_H
 #define __ASM_IRQFLAGS_H
 
-static inline void arch_local_irq_enable(void) { }
+#include <lx_emul/irq.h>
 
-static inline void arch_local_irq_disable(void) { }
+static inline void arch_local_irq_enable(void)
+{
+	lx_emul_irq_enable();
+}
 
-static inline unsigned long arch_local_save_flags(void) {
+static inline void arch_local_irq_disable(void)
-	return 1; }
+{
+	lx_emul_irq_disable();
+}
 
-static inline int arch_irqs_disabled_flags(unsigned long flags) {
+static inline unsigned long arch_local_save_flags(void)
-	return flags; }
+{
+	return lx_emul_irq_state();
+}
 
-static inline unsigned long arch_local_irq_save(void) {
+static inline int arch_irqs_disabled_flags(unsigned long flags)
-	return 1; }
+{
+	return flags & 1;
+}
 
-static inline void arch_local_irq_restore(unsigned long flags) { }
+static inline unsigned long arch_local_irq_save(void)
+{
+	return lx_emul_irq_disable();
+}
+
+static inline void arch_local_irq_restore(unsigned long flags)
+{
+	lx_emul_irq_restore(flags);
+}
 
 #endif

repos/dde_linux/src/lib/lx_emul/irq_flags.cc

@@ -0,0 +1,45 @@
+/*
+ * \brief  Lx_emul backend for interrupts
+ * \author Stefan Kalkowski
+ * \date   2021-04-22
+ */
+
+/*
+ * Copyright (C) 2021 Genode Labs GmbH
+ *
+ * This file is distributed under the terms of the GNU General Public License
+ * version 2.
+ */
+
+#include <lx_emul/irq.h>
+
+static unsigned long cpu_local_irq_flags = 0;
+
+
+extern "C" unsigned long lx_emul_irq_enable(void)
+{
+	unsigned long ret = cpu_local_irq_flags;
+	cpu_local_irq_flags = 0;
+	return ret;
+}
+
+
+extern "C" unsigned long lx_emul_irq_disable(void)
+{
+	unsigned long ret = cpu_local_irq_flags;
+	cpu_local_irq_flags = 1;
+	return ret;
+}
+
+
+extern "C" unsigned long lx_emul_irq_state(void)
+{
+	return cpu_local_irq_flags;
+}
+
+
+extern "C" void lx_emul_irq_restore(unsigned long flags)
+{
+	cpu_local_irq_flags = flags;
+}
+

repos/dde_linux/src/lib/lx_emul/spec/arm/irqchip.c

@@ -165,6 +165,7 @@ IRQCHIP_DECLARE(dde_gic_400, "arm,gic-400",       lx_emul_irq_init);
 int lx_emul_irq_task_function(void * data)
 {
 	int irq;
+	unsigned long flags;
 
 	for (;;) {
 		lx_emul_task_schedule(true);
@@ -172,6 +173,7 @@ int lx_emul_irq_task_function(void * data)
 		if (!dde_irq_domain)
 			continue;
 
+		local_irq_save(flags);
 		irq_enter();
 
 		irq = irq_find_mapping(dde_irq_domain, lx_emul_irq_last());
@@ -184,6 +186,7 @@ int lx_emul_irq_task_function(void * data)
 		}
 
 		irq_exit();
+		local_irq_restore(flags);
 	}
 
 	return 0;

repos/dde_linux/src/lib/lx_emul/spec/x86/irqchip.c

@@ -47,11 +47,13 @@ struct irq_chip dde_irqchip_data_chip = {
 
 int lx_emul_irq_task_function(void * data)
 {
+	unsigned long flags;
 	int irq;
 
 	for (;;) {
 		lx_emul_task_schedule(true);
 
+		local_irq_save(flags);
 		irq_enter();
 
 		irq = lx_emul_irq_last();
@@ -66,6 +68,7 @@ int lx_emul_irq_task_function(void * data)
 		}
 
 		irq_exit();
+		local_irq_restore(flags);
 	}
 
 	return 0;