Patch "LoongArch: Implement constant timer shutdown interface" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    LoongArch: Implement constant timer shutdown interface

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     loongarch-implement-constant-timer-shutdown-interfac.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 17e0ed1640c5a2ada215130d25e51a3d3dd8e1c9
Author: Bibo Mao <maobibo@xxxxxxxxxxx>
Date:   Tue Nov 21 15:03:25 2023 +0800

    LoongArch: Implement constant timer shutdown interface
    
    [ Upstream commit d43f37b73468c172bc89ac4824a1511b411f0778 ]
    
    When a cpu is hot-unplugged, it is put in idle state and the function
    arch_cpu_idle_dead() is called. The timer interrupt for this processor
    should be disabled, otherwise there will be pending timer interrupt for
    the unplugged cpu, so that vcpu is prevented from giving up scheduling
    when system is running in vm mode.
    
    This patch implements the timer shutdown interface so that the constant
    timer will be properly disabled when a CPU is hot-unplugged.
    
    Reviewed-by: WANG Xuerui <git@xxxxxxxxxx>
    Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
    Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
index 3064af94db9c2..e7015f7b70e37 100644
--- a/arch/loongarch/kernel/time.c
+++ b/arch/loongarch/kernel/time.c
@@ -58,14 +58,16 @@ static int constant_set_state_oneshot(struct clock_event_device *evt)
 	return 0;
 }
 
-static int constant_set_state_oneshot_stopped(struct clock_event_device *evt)
+static int constant_set_state_periodic(struct clock_event_device *evt)
 {
+	unsigned long period;
 	unsigned long timer_config;
 
 	raw_spin_lock(&state_lock);
 
-	timer_config = csr_read64(LOONGARCH_CSR_TCFG);
-	timer_config &= ~CSR_TCFG_EN;
+	period = const_clock_freq / HZ;
+	timer_config = period & CSR_TCFG_VAL;
+	timer_config |= (CSR_TCFG_PERIOD | CSR_TCFG_EN);
 	csr_write64(timer_config, LOONGARCH_CSR_TCFG);
 
 	raw_spin_unlock(&state_lock);
@@ -73,16 +75,14 @@ static int constant_set_state_oneshot_stopped(struct clock_event_device *evt)
 	return 0;
 }
 
-static int constant_set_state_periodic(struct clock_event_device *evt)
+static int constant_set_state_shutdown(struct clock_event_device *evt)
 {
-	unsigned long period;
 	unsigned long timer_config;
 
 	raw_spin_lock(&state_lock);
 
-	period = const_clock_freq / HZ;
-	timer_config = period & CSR_TCFG_VAL;
-	timer_config |= (CSR_TCFG_PERIOD | CSR_TCFG_EN);
+	timer_config = csr_read64(LOONGARCH_CSR_TCFG);
+	timer_config &= ~CSR_TCFG_EN;
 	csr_write64(timer_config, LOONGARCH_CSR_TCFG);
 
 	raw_spin_unlock(&state_lock);
@@ -90,11 +90,6 @@ static int constant_set_state_periodic(struct clock_event_device *evt)
 	return 0;
 }
 
-static int constant_set_state_shutdown(struct clock_event_device *evt)
-{
-	return 0;
-}
-
 static int constant_timer_next_event(unsigned long delta, struct clock_event_device *evt)
 {
 	unsigned long timer_config;
@@ -161,7 +156,7 @@ int constant_clockevent_init(void)
 	cd->rating = 320;
 	cd->cpumask = cpumask_of(cpu);
 	cd->set_state_oneshot = constant_set_state_oneshot;
-	cd->set_state_oneshot_stopped = constant_set_state_oneshot_stopped;
+	cd->set_state_oneshot_stopped = constant_set_state_shutdown;
 	cd->set_state_periodic = constant_set_state_periodic;
 	cd->set_state_shutdown = constant_set_state_shutdown;
 	cd->set_next_event = constant_timer_next_event;