lkl: enable HIGH_RES_TIMERS (hrtimer) for the arch

thehajime · thehajime · commit 85b1276e5fab · 2017-02-09T21:22:22.000+09:00
This enables us to grow the goodput with tcp-bbr cc.
It also required to change irq handler since tick_sched_timer()
needs a valid register pointer in irq_regs to call update_process_time().

Signed-off-by: Hajime Tazaki &lt;thehajime@gmail.com&gt;
diff --git a/arch/lkl/Kconfig b/arch/lkl/Kconfig
@@ -24,6 +24,7 @@ config LKL
        select IP_PNP
        select IP_PNP_DHCP
        select TCP_CONG_BBR
+       select HIGH_RES_TIMERS
 
 config OUTPUTFORMAT
        string
diff --git a/arch/lkl/kernel/irq.c b/arch/lkl/kernel/irq.c
@@ -52,15 +52,19 @@ static struct irq_info {
 
 static bool irqs_enabled;
 
+static struct pt_regs dummy;
+
 static void run_irq(int irq)
 {
 	unsigned long flags;
+	struct pt_regs *old_regs = set_irq_regs((struct pt_regs *)&dummy);
 
 	/* interrupt handlers need to run with interrupts disabled */
 	local_irq_save(flags);
 	irq_enter();
 	generic_handle_irq(irq);
 	irq_exit();
+	set_irq_regs(old_regs);
 	local_irq_restore(flags);
 }
 
