Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756907AbaFYN4t (ORCPT ); Wed, 25 Jun 2014 09:56:49 -0400 Received: from mail-ve0-f178.google.com ([209.85.128.178]:47557 "EHLO mail-ve0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756382AbaFYN4s (ORCPT ); Wed, 25 Jun 2014 09:56:48 -0400 MIME-Version: 1.0 X-Originating-IP: [42.104.12.237] In-Reply-To: <1403688530-23273-4-git-send-email-marc.zyngier@arm.com> References: <1403688530-23273-1-git-send-email-marc.zyngier@arm.com> <1403688530-23273-4-git-send-email-marc.zyngier@arm.com> Date: Wed, 25 Jun 2014 19:26:47 +0530 Message-ID: Subject: Re: [RFC PATCH 3/9] irqchip: GIC: Convert to EOImode == 1 From: Anup Patel To: Marc Zyngier Cc: "kvmarm@lists.cs.columbia.edu" , linux-arm-kernel , "linux-kernel@vger.kernel.org List" , Catalin Marinas , Thomas Gleixner , Will Deacon , Christoffer Dall , Eric Auger , Ian Campbell , Stefano Stabellini Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Marc, On Wed, Jun 25, 2014 at 2:58 PM, Marc Zyngier wrote: > So far, GICv2 has been used in with EOImode == 0. The effect of this > mode is to perform the priority drop and the deactivation of the > interrupt at the same time. > > While this works perfectly for Linux (we only have a single priority), > it causes issues when an interrupt is forwarded to a guest, and when > we want the guest to perform the EOI itself. > > For this case, the GIC architecture provides EOImode == 1, where: > - A write to the EOI register drops the priority of the interrupt and leaves > it active. Other interrupts at the same priority level can now be taken, > but the active interrupt cannot be taken again > - A write to the DIR marks the interrupt as inactive, meaning it can > now be taken again. > > We only enable this feature when booted in HYP mode. Also, as most device > trees are broken (they report the CPU interface size to be 4kB, while > the GICv2 CPU interface size is 8kB), output a warning if we're booted > in HYP mode, and disable the feature. > > Signed-off-by: Marc Zyngier > --- > drivers/irqchip/irq-gic.c | 61 +++++++++++++++++++++++++++++++++++++---- > include/linux/irqchip/arm-gic.h | 4 +++ > 2 files changed, 59 insertions(+), 6 deletions(-) > > diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c > index 508b815..9295bf2 100644 > --- a/drivers/irqchip/irq-gic.c > +++ b/drivers/irqchip/irq-gic.c > @@ -45,6 +45,7 @@ > #include > #include > #include > +#include > > #include "irq-gic-common.h" > #include "irqchip.h" > @@ -94,6 +95,10 @@ struct irq_chip gic_arch_extn = { > .irq_set_wake = NULL, > }; > > +static struct irq_chip *gic_chip; > + > +static bool supports_deactivate = false; > + > #ifndef MAX_GIC_NR > #define MAX_GIC_NR 1 > #endif > @@ -185,6 +190,12 @@ static void gic_eoi_irq(struct irq_data *d) > writel_relaxed(gic_irq(d), gic_cpu_base(d) + GIC_CPU_EOI); > } > > +static void gic_eoi_dir_irq(struct irq_data *d) > +{ > + gic_eoi_irq(d); > + writel_relaxed(gic_irq(d), gic_cpu_base(d) + GIC_CPU_DEACTIVATE); > +} > + > static int gic_set_type(struct irq_data *d, unsigned int type) > { > void __iomem *base = gic_dist_base(d); > @@ -277,6 +288,7 @@ static void __exception_irq_entry gic_handle_irq(struct pt_regs *regs) > } > if (irqnr < 16) { > writel_relaxed(irqstat, cpu_base + GIC_CPU_EOI); > + writel_relaxed(irqstat, cpu_base + GIC_CPU_DEACTIVATE); > #ifdef CONFIG_SMP > handle_IPI(irqnr, regs); > #endif > @@ -313,7 +325,7 @@ static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc) > chained_irq_exit(chip, desc); > } > > -static struct irq_chip gic_chip = { > +static struct irq_chip gicv1_chip = { > .name = "GIC", > .irq_mask = gic_mask_irq, > .irq_unmask = gic_unmask_irq, > @@ -326,6 +338,19 @@ static struct irq_chip gic_chip = { > .irq_set_wake = gic_set_wake, > }; > > +static struct irq_chip gicv2_chip = { > + .name = "GIC", > + .irq_mask = gic_mask_irq, > + .irq_unmask = gic_unmask_irq, > + .irq_eoi = gic_eoi_dir_irq, > + .irq_set_type = gic_set_type, > + .irq_retrigger = gic_retrigger, > +#ifdef CONFIG_SMP > + .irq_set_affinity = gic_set_affinity, > +#endif > + .irq_set_wake = gic_set_wake, > +}; > + > void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq) > { > if (gic_nr >= MAX_GIC_NR) > @@ -377,6 +402,16 @@ static void __init gic_dist_init(struct gic_chip_data *gic) > writel_relaxed(1, base + GIC_DIST_CTRL); > } > > +static void gic_cpu_if_up(void) > +{ > + void __iomem *cpu_base = gic_data_cpu_base(&gic_data[0]); > + u32 val = 0; > + > + if (supports_deactivate) > + val = GIC_CPU_CTRL_EOImodeNS; > + writel_relaxed(val | 1, cpu_base + GIC_CPU_CTRL); > +} > + > static void gic_cpu_init(struct gic_chip_data *gic) > { > void __iomem *dist_base = gic_data_dist_base(gic); > @@ -402,7 +437,7 @@ static void gic_cpu_init(struct gic_chip_data *gic) > gic_cpu_config(dist_base, NULL); > > writel_relaxed(0xf0, base + GIC_CPU_PRIMASK); > - writel_relaxed(1, base + GIC_CPU_CTRL); > + gic_cpu_if_up(); > } > > void gic_cpu_if_down(void) > @@ -543,7 +578,7 @@ static void gic_cpu_restore(unsigned int gic_nr) > writel_relaxed(0xa0a0a0a0, dist_base + GIC_DIST_PRI + i * 4); > > writel_relaxed(0xf0, cpu_base + GIC_CPU_PRIMASK); > - writel_relaxed(1, cpu_base + GIC_CPU_CTRL); > + gic_cpu_if_up(); > } > > static int gic_notifier(struct notifier_block *self, unsigned long cmd, void *v) > @@ -770,11 +805,11 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq, > { > if (hw < 32) { > irq_set_percpu_devid(irq); > - irq_set_chip_and_handler(irq, &gic_chip, > + irq_set_chip_and_handler(irq, gic_chip, > handle_percpu_devid_irq); > set_irq_flags(irq, IRQF_VALID | IRQF_NOAUTOEN); > } else { > - irq_set_chip_and_handler(irq, &gic_chip, > + irq_set_chip_and_handler(irq, gic_chip, > handle_fasteoi_irq); > set_irq_flags(irq, IRQF_VALID | IRQF_PROBE); > > @@ -951,6 +986,11 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start, > > gic_irqs -= hwirq_base; /* calculate # of irqs to allocate */ > > + if (!supports_deactivate) > + gic_chip = &gicv1_chip; > + else > + gic_chip = &gicv2_chip; > + > if (of_property_read_u32(node, "arm,routable-irqs", > &nr_routable_irqs)) { > irq_base = irq_alloc_descs(irq_start, 16, gic_irqs, > @@ -980,7 +1020,7 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start, > set_handle_irq(gic_handle_irq); > } > > - gic_chip.flags |= gic_arch_extn.flags; > + gic_chip->flags |= gic_arch_extn.flags; > gic_dist_init(gic); > gic_cpu_init(gic); > gic_pm_init(gic); > @@ -994,6 +1034,7 @@ gic_of_init(struct device_node *node, struct device_node *parent) > { > void __iomem *cpu_base; > void __iomem *dist_base; > + struct resource cu_res; > u32 percpu_offset; > int irq; > > @@ -1006,6 +1047,14 @@ gic_of_init(struct device_node *node, struct device_node *parent) > cpu_base = of_iomap(node, 1); > WARN(!cpu_base, "unable to map gic cpu registers\n"); > > + of_address_to_resource(node, 1, &cpu_res); > + if (is_hyp_mode_available()) { Interrupt deactivation feature is not dependent on whether hyp-mode is available or not. We can use GICC_DIR even if CPU does not have virtualization extension. Also, we can use GICV_DIR when running as Guest or VM. I think "supports_deactivate" should depend on the GIC compatible string. > + if (resource_size(&cpu_res) >= SZ_8K) > + supports_deactivate = true; > + else > + pr_warn("GIC: CPU interface size is %x, DT is probably wrong\n", (int)resource_size(&cpu_res)); This will not work on APM X-Gene because, for X-Gene first CPU page is at 0x78020000 and second CPU page is at 0x78030000. Ian had send-out a patch long time back to extend GIC dt-bindings for addressing this issue. (http://www.spinics.net/lists/arm-kernel/msg283767.html) Regards, Anup > + } > + > if (of_property_read_u32(node, "cpu-offset", &percpu_offset)) > percpu_offset = 0; > > diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h > index 45e2d8c..ffe3911 100644 > --- a/include/linux/irqchip/arm-gic.h > +++ b/include/linux/irqchip/arm-gic.h > @@ -21,6 +21,10 @@ > #define GIC_CPU_ACTIVEPRIO 0xd0 > #define GIC_CPU_IDENT 0xfc > > +#define GIC_CPU_DEACTIVATE 0x1000 > + > +#define GIC_CPU_CTRL_EOImodeNS (1 << 9) > + > #define GICC_IAR_INT_ID_MASK 0x3ff > > #define GIC_DIST_CTRL 0x000 > -- > 1.8.3.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/