From patchwork Sat Sep 12 15:37:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 11771941 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 611C059D for ; Sat, 12 Sep 2020 15:36:37 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C488B20796 for ; Sat, 12 Sep 2020 15:36:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="fqA2gEvn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C488B20796 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=SrWpHcmO7bWNXd+XYH2gQ1I0k/5SksgmNbFdCfqBI9A=; b=fqA2gEvnwW1aHMArSJ9vbN3Eg Ug8E/xmupuSPOUtXXGosvvo8+a7iHoDBSZdaz5YMuah3oczRGkjlZE3YBIVh671Jovf7kBRrx4e9q OWQKhbfDP29cn5WAmAftmge3m57cJKR7u0Iw2DEPKvmEpQu0AXQSZKjJINjgGK7FGmVtYZmGZ7SK0 neW5qNdWZf5CaLqGYtscWF4K/kDQBEdbvHu7+yd17KzKaKa3VnIROWx8jJuKHCHhQArIgQZM04XYo HrEVmk1zjEsDLnR1W2r3csfZQ414kq5l4tViutsg5dRRrCMxqaQctvTBgEKOPzGMHedtzu5f4nEDX Db9mq7BVg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kH7Ze-000581-M7; Sat, 12 Sep 2020 15:36:22 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kH7ZX-000576-9e for linux-arm-kernel@lists.infradead.org; Sat, 12 Sep 2020 15:36:16 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 802C51396; Sat, 12 Sep 2020 08:36:12 -0700 (PDT) Received: from monolith.localdoman (unknown [10.37.8.20]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 208663F68F; Sat, 12 Sep 2020 08:36:10 -0700 (PDT) From: Alexandru Elisei To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH v3 2/2] irqchip/gic-v3: Support pseudo-NMIs when SCR_EL3.FIQ == 0 Date: Sat, 12 Sep 2020 16:37:07 +0100 Message-Id: <20200912153707.667731-3-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200912153707.667731-1-alexandru.elisei@arm.com> References: <20200912153707.667731-1-alexandru.elisei@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200912_113615_457154_31BFAD11 X-CRM114-Status: GOOD ( 26.21 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: maz@kernel.org, tglx@linutronix.de, will@kernel.org, jason@lakedaemon.net, catalin.marinas@arm.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The GIC's internal view of the priority mask register and the assigned interrupt priorities are based on whether GIC security is enabled and whether firmware routes Group 0 interrupts to EL3. At the moment, we support priority masking when ICC_PMR_EL1 and interrupt priorities are either both modified by the GIC, or both left unchanged. Trusted Firmware-A's default interrupt routing model allows Group 0 interrupts to be delivered to the non-secure world (SCR_EL3.FIQ == 0). Unfortunately, this is precisely the case that the GIC driver doesn't support: ICC_PMR_EL1 remains unchanged, but the GIC's view of interrupt priorities is different from the software programmed values. Support pseudo-NMIs when SCR_EL3.FIQ == 0 by using a different value to mask regular interrupts. All the other values remain the same. Signed-off-by: Alexandru Elisei --- arch/arm64/include/asm/arch_gicv3.h | 8 ++++- arch/arm64/include/asm/ptrace.h | 14 +++++++- arch/arm64/kernel/image-vars.h | 2 ++ drivers/irqchip/irq-gic-v3.c | 56 ++++++++++++++++++++++------- 4 files changed, 66 insertions(+), 14 deletions(-) diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h index 6647ae4f0231..880b9054d75c 100644 --- a/arch/arm64/include/asm/arch_gicv3.h +++ b/arch/arm64/include/asm/arch_gicv3.h @@ -153,7 +153,7 @@ static inline bool gic_prio_masking_enabled(void) static inline void gic_pmr_mask_irqs(void) { - BUILD_BUG_ON(GICD_INT_DEF_PRI < (GIC_PRIO_IRQOFF | + BUILD_BUG_ON(GICD_INT_DEF_PRI < (__GIC_PRIO_IRQOFF | GIC_PRIO_PSR_I_SET)); BUILD_BUG_ON(GICD_INT_DEF_PRI >= GIC_PRIO_IRQON); /* @@ -162,6 +162,12 @@ static inline void gic_pmr_mask_irqs(void) * are applied to IRQ priorities */ BUILD_BUG_ON((0x80 | (GICD_INT_DEF_PRI >> 1)) >= GIC_PRIO_IRQON); + /* + * Same situation as above, but now we make sure that we can mask + * regular interrupts. + */ + BUILD_BUG_ON((0x80 | (GICD_INT_DEF_PRI >> 1)) < (__GIC_PRIO_IRQOFF_NS | + GIC_PRIO_PSR_I_SET)); gic_write_pmr(GIC_PRIO_IRQOFF); } diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index 966ed30ed5f7..997cf8c8cd52 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -31,9 +31,21 @@ * interrupt disabling temporarily does not rely on IRQ priorities. */ #define GIC_PRIO_IRQON 0xe0 -#define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80) +#define __GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80) +#define __GIC_PRIO_IRQOFF_NS 0xa0 #define GIC_PRIO_PSR_I_SET (1 << 4) +#define GIC_PRIO_IRQOFF \ + ({ \ + extern struct static_key_false gic_nonsecure_priorities;\ + u8 __prio = __GIC_PRIO_IRQOFF; \ + \ + if (static_branch_unlikely(&gic_nonsecure_priorities)) \ + __prio = __GIC_PRIO_IRQOFF_NS; \ + \ + __prio; \ + }) + /* Additional SPSR bits not exposed in the UABI */ #define PSR_MODE_THREAD_BIT (1 << 0) #define PSR_IL_BIT (1 << 20) diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 8982b68289b7..98a5215c1598 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -101,6 +101,8 @@ KVM_NVHE_ALIAS(vgic_v3_cpuif_trap); /* Static key checked in pmr_sync(). */ #ifdef CONFIG_ARM64_PSEUDO_NMI KVM_NVHE_ALIAS(gic_pmr_sync); +/* Static key checked in GIC_PRIO_IRQOFF. */ +KVM_NVHE_ALIAS(gic_nonsecure_priorities); #endif /* EL2 exception handling */ diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index aa9b43d412b2..bb55d89d7d49 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -75,16 +75,14 @@ static DEFINE_STATIC_KEY_TRUE(supports_deactivate_key); * * If SCR_EL3.FIQ == 1, the values writen to/read from PMR and RPR at non-secure * EL1 are subject to a similar operation thus matching the priorities presented - * from the (re)distributor when security is enabled. + * from the (re)distributor when security is enabled. When SCR_EL3.FIQ == 0, + * these values are unchanched by the GIC. * * see GICv3/GICv4 Architecture Specification (IHI0069D): * - section 4.8.1 Non-secure accesses to register fields for Secure interrupt * priorities. * - Figure 4-7 Secure read of the priority field for a Non-secure Group 1 * interrupt. - * - * For now, we only support pseudo-NMIs if we have non-secure view of - * priorities. */ static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis); @@ -97,6 +95,9 @@ static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis); DEFINE_STATIC_KEY_FALSE(gic_pmr_sync); EXPORT_SYMBOL(gic_pmr_sync); +DEFINE_STATIC_KEY_FALSE(gic_nonsecure_priorities); +EXPORT_SYMBOL(gic_nonsecure_priorities); + /* ppi_nmi_refs[n] == number of cpus having ppi[n + 16] set as NMI */ static refcount_t *ppi_nmi_refs; @@ -932,14 +933,20 @@ static void gic_cpu_sys_reg_init(void) /* Set priority mask register */ if (!gic_prio_masking_enabled()) { write_gicreg(DEFAULT_PMR_VALUE, ICC_PMR_EL1); - } else { + } else if (gic_supports_nmi()) { /* * Mismatch configuration with boot CPU, the system is likely * to die as interrupt masking will not work properly on all * CPUs + * + * The boot CPU calls this function before enabling NMI support, + * and as a result we'll never see this warning in the boot path + * for that CPU. */ - WARN_ON(gic_supports_nmi() && group0 && - !gic_dist_security_disabled()); + if (static_branch_unlikely(&gic_nonsecure_priorities)) + WARN_ON(!group0 || gic_dist_security_disabled()); + else + WARN_ON(group0 && !gic_dist_security_disabled()); } /* @@ -1544,11 +1551,6 @@ static void gic_enable_nmi_support(void) if (!gic_prio_masking_enabled()) return; - if (gic_has_group0() && !gic_dist_security_disabled()) { - pr_warn("SCR_EL3.FIQ is cleared, cannot enable use of pseudo-NMIs\n"); - return; - } - ppi_nmi_refs = kcalloc(gic_data.ppi_nr, sizeof(*ppi_nmi_refs), GFP_KERNEL); if (!ppi_nmi_refs) return; @@ -1567,6 +1569,36 @@ static void gic_enable_nmi_support(void) pr_info("Pseudo-NMIs enabled using %s ICC_PMR_EL1 synchronisation\n", static_branch_unlikely(&gic_pmr_sync) ? "forced" : "relaxed"); + /* + * How priority values are used by the GIC depends on two things: + * the security state of the GIC (controlled by the GICD_CTRL.DS bit) + * and if Group 0 interrupts can be delivered to Linux in the non-secure + * world as FIQs (controlled by the SCR_EL3.FIQ bit). These affect the + * the ICC_PMR_EL1 register and the priority that software assigns to + * interrupts: + * + * GICD_CTRL.DS | SCR_EL3.FIQ | ICC_PMR_EL1 | Group 1 priority + * ----------------------------------------------------------- + * 1 | - | unchanged | unchanged + * ----------------------------------------------------------- + * 0 | 1 | non-secure | non-secure + * ----------------------------------------------------------- + * 0 | 0 | unchanged | non-secure + * + * where non-secure means that the value is right-shifted by one and the + * MSB bit set, to make it fit in the non-secure priority range. + * + * In the first two cases, where ICC_PMR_EL1 and the interrupt priority + * are both either modified or unchanged, we can use the same set of + * priorities. + * + * In the last case, where only the interrupt priorities are modified to + * be in the non-secure range, we use a different PMR value to mask IRQs + * and the rest of the values that we use remain unchanged. + */ + if (gic_has_group0() && !gic_dist_security_disabled()) + static_branch_enable(&gic_nonsecure_priorities); + static_branch_enable(&supports_pseudo_nmis); if (static_branch_likely(&supports_deactivate_key))