From patchwork Tue Feb 3 19:06:54 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 5771351 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C8EB5BF440 for ; Tue, 3 Feb 2015 19:13:23 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7BCD22021A for ; Tue, 3 Feb 2015 19:13:22 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 333B1201FB for ; Tue, 3 Feb 2015 19:13:21 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YIisM-0003Ha-Ou; Tue, 03 Feb 2015 19:11:06 +0000 Received: from mail-wi0-f175.google.com ([209.85.212.175]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YIisA-0002xL-9u for linux-arm-kernel@lists.infradead.org; Tue, 03 Feb 2015 19:10:55 +0000 Received: by mail-wi0-f175.google.com with SMTP id fb4so26825238wid.2 for ; Tue, 03 Feb 2015 11:10:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=FmkwMTJy+NylLcvUXsyJzmKdsqUKiujlXQqX7t1jyN0=; b=EMbB5AUBXiPk7t4bJm8rYvLWjQF/Gb4rOut4RWMG/VSKVj22eOynYpdXSO4xmksG4t qaRvtkh2e6nT1QdiaOXUcQvUNXMhtGPqhISLqybfqLDbEbeAKEbdQP4e1sa9v8h0d8yz 3AkUHB6UF3fj3cRN/I8lPtMYFV4mc+rchJYcahMCQMoX97hj5tk1aTiN+vmU5qcK1Wb7 Oa9ckvJqf1/nZqeSAU2SMBtveZTgWvJOexgtmATYdOD1ReS4LqnlstXSA3K8qV779QSv 2jaMLME2xWIoCNKhL8JZKzlFNh77MY0qvYWX1ydFdaXBgGK9xg8GI94b/eogrMsw87oE Z4VQ== X-Gm-Message-State: ALoCoQnr9Hbx0LMoxGSunnT397W+Lb05UkmrD7z/QC1Vo4v5E/Sb4KkAtGyHn8gEUsg8MMZF7z6X X-Received: by 10.194.189.77 with SMTP id gg13mr57659661wjc.81.1422990631932; Tue, 03 Feb 2015 11:10:31 -0800 (PST) Received: from sundance.lan (cpc4-aztw19-0-0-cust157.18-1.cable.virginm.net. [82.33.25.158]) by mx.google.com with ESMTPSA id bi9sm12603663wib.18.2015.02.03.11.10.28 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Feb 2015 11:10:31 -0800 (PST) From: Daniel Thompson To: Thomas Gleixner Subject: [PATCH 3.19-rc6 v16 3/6] irqchip: gic: Introduce plumbing for IPI FIQ Date: Tue, 3 Feb 2015 19:06:54 +0000 Message-Id: <1422990417-1783-4-git-send-email-daniel.thompson@linaro.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1422990417-1783-1-git-send-email-daniel.thompson@linaro.org> References: <1422022952-31552-1-git-send-email-daniel.thompson@linaro.org> <1422990417-1783-1-git-send-email-daniel.thompson@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150203_111054_674337_202A4095 X-CRM114-Status: GOOD ( 32.26 ) X-Spam-Score: -0.7 (/) Cc: Daniel Thompson , linaro-kernel@lists.linaro.org, Russell King , Jason Cooper , patches@linaro.org, Marc Zyngier , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Steven Rostedt , Sumit Semwal , Dmitry Pervushin , Dirk Behme , John Stultz , Tim Sander , Daniel Drake , Stephen Boyd , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently it is not possible to exploit FIQ for systems with a GIC, even if the systems are otherwise capable of it. This patch makes it possible for IPIs to be delivered using FIQ. To do so it modifies the register state so that normal interrupts are placed in group 1 and specific IPIs are placed into group 0. It also configures the controller to raise group 0 interrupts using the FIQ signal. It provides a means for architecture code to define which IPIs shall use FIQ and to acknowledge any IPIs that are raised. All GIC hardware except GICv1-without-TrustZone support provides a means to group exceptions into group 0 and group 1 but the hardware functionality is unavailable to the kernel when a secure monitor is present because access to the grouping registers are prohibited outside "secure world". However when grouping is not available (or in the case of early GICv1 implementations is very hard to configure) the code to change groups does not deploy and all IPIs will be raised via IRQ. It has been tested and shown working on two systems capable of supporting grouping (Freescale i.MX6 and STiH416). It has also been tested for boot regressions on two systems that do not support grouping (vexpress-a9 and Qualcomm Snapdragon 600). Signed-off-by: Daniel Thompson Cc: Thomas Gleixner Cc: Jason Cooper Cc: Russell King Cc: Marc Zyngier Tested-by: Jon Medhurst --- arch/arm/kernel/traps.c | 5 +- drivers/irqchip/irq-gic.c | 151 +++++++++++++++++++++++++++++++++++++--- include/linux/irqchip/arm-gic.h | 8 +++ 3 files changed, 153 insertions(+), 11 deletions(-) diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 788e23fe64d8..b35e220ae1b1 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include @@ -479,7 +480,9 @@ asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) nmi_enter(); - /* nop. FIQ handlers for special arch/arm features can be added here. */ +#ifdef CONFIG_ARM_GIC + gic_handle_fiq_ipi(); +#endif nmi_exit(); diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index c172176499f6..c4f4a8827ed8 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -39,6 +39,7 @@ #include #include #include +#include #include #include @@ -48,6 +49,10 @@ #include "irq-gic-common.h" #include "irqchip.h" +#ifndef SMP_IPI_FIQ_MASK +#define SMP_IPI_FIQ_MASK 0 +#endif + union gic_base { void __iomem *common_base; void __percpu * __iomem *percpu_base; @@ -65,6 +70,7 @@ struct gic_chip_data { #endif struct irq_domain *domain; unsigned int gic_irqs; + u32 igroup0_shadow; #ifdef CONFIG_GIC_NON_BANKED void __iomem *(*get_base)(union gic_base *); #endif @@ -348,6 +354,83 @@ static struct irq_chip gic_chip = { .irq_set_wake = gic_set_wake, }; +/* + * Shift an interrupt between Group 0 and Group 1. + * + * In addition to changing the group we also modify the priority to + * match what "ARM strongly recommends" for a system where no Group 1 + * interrupt must ever preempt a Group 0 interrupt. + * + * If is safe to call this function on systems which do not support + * grouping (it will have no effect). + */ +static void gic_set_group_irq(struct gic_chip_data *gic, unsigned int hwirq, + int group) +{ + void __iomem *base = gic_data_dist_base(gic); + unsigned int grp_reg = hwirq / 32 * 4; + u32 grp_mask = BIT(hwirq % 32); + u32 grp_val; + + unsigned int pri_reg = (hwirq / 4) * 4; + u32 pri_mask = BIT(7 + ((hwirq % 4) * 8)); + u32 pri_val; + + /* + * Systems which do not support grouping will have not have + * the EnableGrp1 bit set. + */ + if (!(GICD_ENABLE_GRP1 & readl_relaxed(base + GIC_DIST_CTRL))) + return; + + raw_spin_lock(&irq_controller_lock); + + grp_val = readl_relaxed(base + GIC_DIST_IGROUP + grp_reg); + pri_val = readl_relaxed(base + GIC_DIST_PRI + pri_reg); + + if (group) { + grp_val |= grp_mask; + pri_val |= pri_mask; + } else { + grp_val &= ~grp_mask; + pri_val &= ~pri_mask; + } + + writel_relaxed(grp_val, base + GIC_DIST_IGROUP + grp_reg); + if (grp_reg == 0) + gic->igroup0_shadow = grp_val; + + writel_relaxed(pri_val, base + GIC_DIST_PRI + pri_reg); + + raw_spin_unlock(&irq_controller_lock); +} + + +/* + * Fully acknowledge (both ack and eoi) any outstanding FIQ-based IPI, + * otherwise do nothing. + */ +void gic_handle_fiq_ipi(void) +{ + struct gic_chip_data *gic = &gic_data[0]; + void __iomem *cpu_base = gic_data_cpu_base(gic); + unsigned long irqstat, irqnr; + + if (WARN_ON(!in_nmi())) + return; + + while ((1u << readl_relaxed(cpu_base + GIC_CPU_HIGHPRI)) & + SMP_IPI_FIQ_MASK) { + irqstat = readl_relaxed(cpu_base + GIC_CPU_INTACK); + writel_relaxed(irqstat, cpu_base + GIC_CPU_EOI); + + irqnr = irqstat & GICC_IAR_INT_ID_MASK; + WARN_RATELIMIT(irqnr > 16, + "Unexpected irqnr %lu (bad prioritization?)\n", + irqnr); + } +} + void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq) { if (gic_nr >= MAX_GIC_NR) @@ -379,15 +462,24 @@ static u8 gic_get_cpumask(struct gic_chip_data *gic) static void gic_cpu_if_up(void) { void __iomem *cpu_base = gic_data_cpu_base(&gic_data[0]); - u32 bypass = 0; + void __iomem *dist_base = gic_data_dist_base(&gic_data[0]); + u32 ctrl = 0; /* - * Preserve bypass disable bits to be written back later - */ - bypass = readl(cpu_base + GIC_CPU_CTRL); - bypass &= GICC_DIS_BYPASS_MASK; + * Preserve bypass disable bits to be written back later + */ + ctrl = readl(cpu_base + GIC_CPU_CTRL); + ctrl &= GICC_DIS_BYPASS_MASK; - writel_relaxed(bypass | GICC_ENABLE, cpu_base + GIC_CPU_CTRL); + /* + * If EnableGrp1 is set in the distributor then enable group 1 + * support for this CPU (and route group 0 interrupts to FIQ). + */ + if (GICD_ENABLE_GRP1 & readl_relaxed(dist_base + GIC_DIST_CTRL)) + ctrl |= GICC_COMMON_BPR | GICC_FIQ_EN | GICC_ACK_CTL | + GICC_ENABLE_GRP1; + + writel_relaxed(ctrl | GICC_ENABLE, cpu_base + GIC_CPU_CTRL); } @@ -411,7 +503,23 @@ static void __init gic_dist_init(struct gic_chip_data *gic) gic_dist_config(base, gic_irqs, NULL); - writel_relaxed(GICD_ENABLE, base + GIC_DIST_CTRL); + /* + * Set EnableGrp1/EnableGrp0 (bit 1 and 0) or EnableGrp (bit 0 only, + * bit 1 ignored) depending on current mode. + */ + writel_relaxed(GICD_ENABLE_GRP1 | GICD_ENABLE, base + GIC_DIST_CTRL); + + /* + * Set all global interrupts to be group 1 if (and only if) it + * is possible to enable group 1 interrupts. This register is RAZ/WI + * if not accessible or not implemented, however some GICv1 devices + * do not implement the EnableGrp1 bit making it unsafe to set + * this register unconditionally. + */ + if (GICD_ENABLE_GRP1 & readl_relaxed(base + GIC_DIST_CTRL)) + for (i = 32; i < gic_irqs; i += 32) + writel_relaxed(0xffffffff, + base + GIC_DIST_IGROUP + i * 4 / 32); } static void gic_cpu_init(struct gic_chip_data *gic) @@ -420,6 +528,7 @@ static void gic_cpu_init(struct gic_chip_data *gic) void __iomem *base = gic_data_cpu_base(gic); unsigned int cpu_mask, cpu = smp_processor_id(); int i; + unsigned long secure_irqs, secure_irq; /* * Get what the GIC says our CPU mask is. @@ -438,6 +547,20 @@ static void gic_cpu_init(struct gic_chip_data *gic) gic_cpu_config(dist_base, NULL); + /* + * If the distributor is configured to support interrupt grouping + * then set any PPI and SGI interrupts not set in SMP_IPI_FIQ_MASK + * to be group1 and ensure any remaining group 0 interrupts have + * the right priority. + */ + if (GICD_ENABLE_GRP1 & readl_relaxed(dist_base + GIC_DIST_CTRL)) { + secure_irqs = SMP_IPI_FIQ_MASK; + writel_relaxed(~secure_irqs, dist_base + GIC_DIST_IGROUP + 0); + gic->igroup0_shadow = ~secure_irqs; + for_each_set_bit(secure_irq, &secure_irqs, 16) + gic_set_group_irq(gic, secure_irq, 0); + } + writel_relaxed(GICC_INT_PRI_THRESHOLD, base + GIC_CPU_PRIMASK); gic_cpu_if_up(); } @@ -527,7 +650,8 @@ static void gic_dist_restore(unsigned int gic_nr) writel_relaxed(gic_data[gic_nr].saved_spi_enable[i], dist_base + GIC_DIST_ENABLE_SET + i * 4); - writel_relaxed(GICD_ENABLE, dist_base + GIC_DIST_CTRL); + writel_relaxed(GICD_ENABLE_GRP1 | GICD_ENABLE, + dist_base + GIC_DIST_CTRL); } static void gic_cpu_save(unsigned int gic_nr) @@ -655,6 +779,7 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq) { int cpu; unsigned long map = 0; + unsigned long softint; bl_migration_lock(); @@ -668,8 +793,14 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq) */ dmb(ishst); - /* this always happens on GIC0 */ - writel_relaxed(map << 16 | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT); + /* We avoid a readl here by using the shadow copy of IGROUP[0] */ + softint = map << 16 | irq; + if (gic_data[0].igroup0_shadow & BIT(irq)) + softint |= 0x8000; + + /* This always happens on GIC0 */ + writel_relaxed(softint, + gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT); bl_migration_unlock(); } diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h index 71d706d5f169..7690f70049a3 100644 --- a/include/linux/irqchip/arm-gic.h +++ b/include/linux/irqchip/arm-gic.h @@ -22,6 +22,10 @@ #define GIC_CPU_IDENT 0xfc #define GICC_ENABLE 0x1 +#define GICC_ENABLE_GRP1 0x2 +#define GICC_ACK_CTL 0x4 +#define GICC_FIQ_EN 0x8 +#define GICC_COMMON_BPR 0x10 #define GICC_INT_PRI_THRESHOLD 0xf0 #define GICC_IAR_INT_ID_MASK 0x3ff #define GICC_INT_SPURIOUS 1023 @@ -44,6 +48,7 @@ #define GIC_DIST_SGI_PENDING_SET 0xf20 #define GICD_ENABLE 0x1 +#define GICD_ENABLE_GRP1 0x2 #define GICD_DISABLE 0x0 #define GICD_INT_ACTLOW_LVLTRIG 0x0 #define GICD_INT_EN_CLR_X32 0xffffffff @@ -121,5 +126,8 @@ static inline void __init register_routable_domain_ops { gic_routable_irq_domain_ops = ops; } + +void gic_handle_fiq_ipi(void); + #endif /* __ASSEMBLY */ #endif