diff options
authorMarc Zyngier <marc.zyngier@arm.com>2018-06-22 10:52:54 +0100
committerThomas Gleixner <tglx@linutronix.de>2018-06-22 14:22:02 +0200
commit82f499c8811149069ec958b72a86643a7a289b25 (patch)
parent205e065d91d72e6afad112ea84f0ca60b30bf5ab (diff)
irqchip/gic-v3-its: Fix reprogramming of redistributors on CPU hotplug
Enabling LPIs was made a lot stricter recently, by checking that they are disabled before enabling them. By doing so, the CPU hotplug case was missed altogether, which leaves LPIs enabled on hotplug off (expecting the CPU to eventually come back), and won't write a different value anyway on hotplug on. So skip that check if that particular case is detected Fixes: 6eb486b66a30 ("irqchip/gic-v3: Ensure GICR_CTLR.EnableLPI=0 is observed before enabling") Reported-by: Sumit Garg <sumit.garg@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Sumit Garg <sumit.garg@linaro.org> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Yang Yingliang <yangyingliang@huawei.com> Link: https://lkml.kernel.org/r/20180622095254.5906-8-marc.zyngier@arm.com
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 0269ffb93f6e..d7842d312d3e 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3427,6 +3427,16 @@ static int redist_disable_lpis(void)
u64 timeout = USEC_PER_SEC;
u64 val;
+ /*
+ * If coming via a CPU hotplug event, we don't need to disable
+ * LPIs before trying to re-enable them. They are already
+ * configured and all is well in the world. Detect this case
+ * by checking the allocation of the pending table for the
+ * current CPU.
+ */
+ if (gic_data_rdist()->pend_page)
+ return 0;
if (!gic_rdists_supports_plpis()) {
pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
return -ENXIO;