From 7e2c546d8e5fc5113bf6b12b8e4a76a4f487c787 Mon Sep 17 00:00:00 2001
From: Stefan Kalkowski <stefan.kalkowski@genode-labs.com>
Date: Thu, 2 Mar 2023 13:08:27 +0100
Subject: [PATCH] lx_emul: update jiffies during schedule

Whenever a new schedule decision is made in the Linux emulation layer,
we try to update the jiffies counter.

Ref genodelabs/genode#4778
---
 repos/dde_linux/src/include/lx_emul/time.h    |  2 ++
 repos/dde_linux/src/lib/lx_emul/clocksource.c | 20 +++++++++++++++++++
 .../lib/lx_emul/shadow/kernel/sched/core.c    | 10 +++++-----
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/repos/dde_linux/src/include/lx_emul/time.h b/repos/dde_linux/src/include/lx_emul/time.h
index 7f560b75c0..dabd2e43df 100644
--- a/repos/dde_linux/src/include/lx_emul/time.h
+++ b/repos/dde_linux/src/include/lx_emul/time.h
@@ -28,6 +28,8 @@ unsigned long long lx_emul_time_counter(void);
 
 void lx_emul_time_handle(void);
 
+void lx_emul_time_update_jiffies(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/repos/dde_linux/src/lib/lx_emul/clocksource.c b/repos/dde_linux/src/lib/lx_emul/clocksource.c
index fe6cbedcc2..5ddc520d8a 100644
--- a/repos/dde_linux/src/lib/lx_emul/clocksource.c
+++ b/repos/dde_linux/src/lib/lx_emul/clocksource.c
@@ -17,6 +17,8 @@
 #include <linux/sched_clock.h>
 #include <linux/smp.h>
 #include <linux/of_clk.h>
+#include <linux/tick.h>
+#include <linux/interrupt.h>
 #include <lx_emul/debug.h>
 #include <lx_emul/time.h>
 #include <lx_emul/init.h>
@@ -109,6 +111,24 @@ void lx_emul_time_handle(void)
 }
 
 
+extern ktime_t tick_next_period;
+void lx_emul_time_update_jiffies(void)
+{
+	/* check if jiffies need an update */
+	if (ktime_before(ktime_get(), tick_next_period))
+		return;
+
+	/* tick_nohz_idle_stop_tick breaks with error if softirq is pending */
+	if (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)
+		return;
+
+	tick_nohz_idle_enter();
+	tick_nohz_idle_stop_tick();
+	tick_nohz_idle_restart_tick();
+	tick_nohz_idle_exit();
+}
+
+
 enum { LX_EMUL_MAX_OF_CLOCK_PROVIDERS = 256 };
 
 
diff --git a/repos/dde_linux/src/lib/lx_emul/shadow/kernel/sched/core.c b/repos/dde_linux/src/lib/lx_emul/shadow/kernel/sched/core.c
index 8ea839d7d3..a9ee03858a 100644
--- a/repos/dde_linux/src/lib/lx_emul/shadow/kernel/sched/core.c
+++ b/repos/dde_linux/src/lib/lx_emul/shadow/kernel/sched/core.c
@@ -103,14 +103,12 @@ static void __schedule(void)
 
 asmlinkage __visible void __sched schedule(void)
 {
+	lx_emul_time_update_jiffies();
+
 	if (current->__state) {
 		unsigned int task_flags = current->flags;
-		if (task_flags & PF_WQ_WORKER) {
-			tick_nohz_idle_enter();
-			lx_emul_time_handle();
-			tick_nohz_idle_exit();
+		if (task_flags & PF_WQ_WORKER)
 			wq_worker_sleeping(current);
-		}
 	}
 
 	__schedule();
@@ -141,6 +139,7 @@ asmlinkage __visible void __sched notrace preempt_schedule(void)
 	if (likely(!preemptible()))
 		return;
 
+	lx_emul_time_update_jiffies();
 	__schedule();
 }
 
@@ -150,6 +149,7 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
 	if (likely(!preemptible()))
 		return;
 
+	lx_emul_time_update_jiffies();
 	__schedule();
 }