From 25ac19e1b076e52c41d713138cb21d6dd2339440 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Tue, 31 Oct 2017 09:41:46 -0700 Subject: irqchip: mips-gic: Mask local interrupts when CPUs come online We currently walk through the range 0..gic_vpes-1, expecting these values all to be valid Linux CPU numbers to provide to mips_cm_vp_id(), and masking all routable local interrupts during boot. This approach has a few drawbacks: - In multi-cluster systems we won't have access to all CPU's GIC local registers when the driver is probed, since clusters (and their GICs) may be powered down at this point & only brought online later. - In multi-cluster systems we may power down clusters at runtime, for example if we offline all CPUs within it via hotplug, and the cluster's GIC may lose state. We therefore need to reinitialise it when powering back up, which this approach does not take into account. - The range 0..gic_vpes-1 may not all be valid Linux CPU numbers, for example if we run a kernel configured to support fewer CPUs than the system it is running on actually has. In this case we'll get garbage values from mips_cm_vp_id() as we read past the end of the cpu_data array. Fix this and simplify the code somewhat by writing an all-bits-set value to the VP-local reset mask register when a CPU is brought online, before any local interrupts are configured for it. This removes the need for us to access all CPUs during driver probe, removing all of the problems described above. In the name of simplicity we drop the checks for routability of interrupts and simply clear the mask bits for all interrupts. Bits for non-routable local interrupts will have no effect so there's no point performing extra work to avoid modifying them. Signed-off-by: Paul Burton Cc: Jason Cooper Cc: Marc Zyngier Cc: Thomas Gleixner Cc: linux-mips@linux-mips.org Signed-off-by: Marc Zyngier --- drivers/irqchip/irq-mips-gic.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'drivers/irqchip') diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c index 60f644279803..bd732b256f67 100644 --- a/drivers/irqchip/irq-mips-gic.c +++ b/drivers/irqchip/irq-mips-gic.c @@ -655,6 +655,9 @@ static const struct irq_domain_ops gic_ipi_domain_ops = { static int gic_cpu_startup(unsigned int cpu) { + /* Clear all local IRQ masks (ie. disable all local interrupts) */ + write_gic_vl_rmask(~0); + /* Invoke irq_cpu_online callbacks to enable desired interrupts */ irq_cpu_online(); @@ -664,7 +667,7 @@ static int gic_cpu_startup(unsigned int cpu) static int __init gic_of_init(struct device_node *node, struct device_node *parent) { - unsigned int cpu_vec, i, j, gicconfig, cpu, v[2]; + unsigned int cpu_vec, i, gicconfig, cpu, v[2]; unsigned long reserved; phys_addr_t gic_base; struct resource res; @@ -797,15 +800,6 @@ static int __init gic_of_init(struct device_node *node, write_gic_rmask(i); } - for (i = 0; i < gic_vpes; i++) { - write_gic_vl_other(mips_cm_vp_id(i)); - for (j = 0; j < GIC_NUM_LOCAL_INTRS; j++) { - if (!gic_local_irq_is_routable(j)) - continue; - write_gic_vo_rmask(BIT(j)); - } - } - return cpuhp_setup_state(CPUHP_AP_IRQ_MIPS_GIC_STARTING, "irqchip/mips/gic:starting", gic_cpu_startup, NULL); -- cgit v1.2.3