From patchwork Wed Aug 19 13:36:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 11724191 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 DCA0D14E3 for ; Wed, 19 Aug 2020 13:36:26 +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 B26EB204EC for ; Wed, 19 Aug 2020 13:36:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qTpFAcGW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B26EB204EC 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=JQfmL5pPgdfNec1nRPS8utidYvGaYqu5710wCsGHO3M=; b=qTpFAcGW7I00ESZgs0ive2ket DJeORP98AHjaApJpk0FmCHDQ+sKg29e/XBffjFPE+TvFZgQ2DhZYCBgGuSbMcjbh6r++ML1qHOr/z Vv2KZoXS8rWs2JIE27F1Qo0IHBmnxeJqAT4fp2RGLiFMZTPO9b2djRIX/rIPEj7Zr1CrRfl3PkZbD ogF5MiEqOY+HQ3qsgEF/CnQYJLE0KaCvIUphmZg1YGRSrgFi1ajJYIQGkKm+3iEVPkEu6X6QTuNzH /juWVl05Foyn+WcsW7RuEEIew2RATnDhWEwd/WD6y0CGmENyZ9BOJOYb1+y7ye6EuyJVfX0QhjIGG Le2871zfQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8OGA-0001dt-9e; Wed, 19 Aug 2020 13:36:10 +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 1k8OFi-0001R2-IO for linux-arm-kernel@lists.infradead.org; Wed, 19 Aug 2020 13:35:44 +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 3255C1435; Wed, 19 Aug 2020 06:35:42 -0700 (PDT) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E87BD3F71F; Wed, 19 Aug 2020 06:35:40 -0700 (PDT) From: Alexandru Elisei To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH v2 1/2] irqchip/gicv3: Spell out when pseudo-NMIs are enabled Date: Wed, 19 Aug 2020 14:36:29 +0100 Message-Id: <20200819133630.527243-2-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200819133630.527243-1-alexandru.elisei@arm.com> References: <20200819133630.527243-1-alexandru.elisei@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200819_093542_695131_F284F068 X-CRM114-Status: GOOD ( 13.47 ) 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: jason@lakedaemon.net, maz@kernel.org, catalin.marinas@arm.com, yuzenghui@huawei.com, tglx@linutronix.de, will@kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org When NMIs cannot be enabled, the driver prints a message stating that unambiguously. When they are enabled, the only feedback we get is a message regarding the use of synchronization for ICC_PMR_EL1 writes, which is not as useful for a user who is not intimately familiar with how NMIs are implemented. Let's make it obvious that pseudo-NMIs are enabled. Keep the message about using a barrier for ICC_PMR_EL1 writes, because it has a non-negligible impact on performance. Signed-off-by: Alexandru Elisei --- drivers/irqchip/irq-gic-v3.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index 324f280ff606..ce8944ae1b84 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -1564,8 +1564,8 @@ static void gic_enable_nmi_support(void) if (gic_read_ctlr() & ICC_CTLR_EL1_PMHE_MASK) static_branch_enable(&gic_pmr_sync); - pr_info("%s ICC_PMR_EL1 synchronisation\n", - static_branch_unlikely(&gic_pmr_sync) ? "Forcing" : "Relaxing"); + pr_info("Pseudo-NMIs enabled using %s ICC_PMR_EL1 synchronisation\n", + static_branch_unlikely(&gic_pmr_sync) ? "forced" : "relaxed"); static_branch_enable(&supports_pseudo_nmis); From patchwork Wed Aug 19 13:36:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 11724195 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 08EC014E3 for ; Wed, 19 Aug 2020 13:36:44 +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 C55BF204EC for ; Wed, 19 Aug 2020 13:36:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Z5MxnKkM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C55BF204EC 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=GC/s7iZNsjcboLgsUzsRrkkabY+pw7HVCFtDOq1prNQ=; b=Z5MxnKkM6wBMUoSP03ma5P8jm 5Qiggj0BbQhu6nKi/4KdPdbDZau01EiOc7KaL/y3RyaXcZA89/IbGpYzWKpgEpN7tAlcoVveNau+B imjQfqjw9RIk/0aMwFuhfrD5mGOzQ9nGDxDnQN1kVnd3Ib5zGXeAWT//WyUdTScRJUHLUh+/UTKig lzGI/CVTysUTo8XtymesVy2KE8POAZxKlnYOJsHAIpJgs84l+B3eL71kjnT9M2KeZfyWD425aU4yR l+YBBKusdy1WfFx53IbOidNQ+jtMT9Htls3GcveW5L7qeKeeuFPASDZPHuUCXXThh2gRknYeTbSgF eeE7Lrm0w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8OGP-0001m8-Iz; Wed, 19 Aug 2020 13:36:25 +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 1k8OFk-0001Rz-EP for linux-arm-kernel@lists.infradead.org; Wed, 19 Aug 2020 13:35:46 +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 A4428142F; Wed, 19 Aug 2020 06:35:43 -0700 (PDT) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 660F13F71F; Wed, 19 Aug 2020 06:35:42 -0700 (PDT) From: Alexandru Elisei To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH v2 2/2] irqchip/gic-v3: Support pseudo-NMIs when SCR_EL3.FIQ == 0 Date: Wed, 19 Aug 2020 14:36:30 +0100 Message-Id: <20200819133630.527243-3-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200819133630.527243-1-alexandru.elisei@arm.com> References: <20200819133630.527243-1-alexandru.elisei@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200819_093544_638972_DCECF7E7 X-CRM114-Status: GOOD ( 28.74 ) 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: jason@lakedaemon.net, maz@kernel.org, catalin.marinas@arm.com, yuzenghui@huawei.com, tglx@linutronix.de, will@kernel.org 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/daifflags.h | 4 +-- arch/arm64/include/asm/irqflags.h | 18 ++++++---- arch/arm64/include/asm/ptrace.h | 12 +++++++ arch/arm64/kernel/entry.S | 2 +- arch/arm64/kernel/image-vars.h | 2 ++ arch/arm64/kvm/hyp/nvhe/switch.c | 2 +- drivers/irqchip/irq-gic-v3.c | 52 ++++++++++++++++++++++------- 8 files changed, 77 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h index 6647ae4f0231..908152e8659b 100644 --- a/arch/arm64/include/asm/arch_gicv3.h +++ b/arch/arm64/include/asm/arch_gicv3.h @@ -162,7 +162,13 @@ 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); - gic_write_pmr(GIC_PRIO_IRQOFF); + /* + * 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()); } static inline void gic_arch_enable_irqs(void) diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h index ec213b4a1650..3efa240a6c48 100644 --- a/arch/arm64/include/asm/daifflags.h +++ b/arch/arm64/include/asm/daifflags.h @@ -22,7 +22,7 @@ static inline void local_daif_mask(void) { WARN_ON(system_has_prio_mask_debugging() && - (read_sysreg_s(SYS_ICC_PMR_EL1) == (GIC_PRIO_IRQOFF | + (read_sysreg_s(SYS_ICC_PMR_EL1) == (gic_prio_irqoff() | GIC_PRIO_PSR_I_SET))); asm volatile( @@ -87,7 +87,7 @@ static inline void local_daif_restore(unsigned long flags) * asynchronous errors, we can take NMIs */ flags &= ~PSR_I_BIT; - pmr = GIC_PRIO_IRQOFF; + pmr = gic_prio_irqoff(); } else { pmr = GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET; } diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h index aa4b6521ef14..af353c78d5f8 100644 --- a/arch/arm64/include/asm/irqflags.h +++ b/arch/arm64/include/asm/irqflags.h @@ -28,10 +28,13 @@ */ static inline void arch_local_irq_enable(void) { + u64 pmr_irqon = GIC_PRIO_IRQON; + if (system_has_prio_mask_debugging()) { - u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1); + u64 pmr = read_sysreg_s(SYS_ICC_PMR_EL1); + u64 pmr_irqoff = gic_prio_irqoff(); - WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF); + WARN_ON_ONCE(pmr != pmr_irqon && pmr != pmr_irqoff); } asm volatile(ALTERNATIVE( @@ -39,7 +42,7 @@ static inline void arch_local_irq_enable(void) __msr_s(SYS_ICC_PMR_EL1, "%0"), ARM64_HAS_IRQ_PRIO_MASKING) : - : "r" ((unsigned long) GIC_PRIO_IRQON) + : "r" (pmr_irqon) : "memory"); pmr_sync(); @@ -47,10 +50,13 @@ static inline void arch_local_irq_enable(void) static inline void arch_local_irq_disable(void) { + u64 pmr_irqoff = gic_prio_irqoff(); + if (system_has_prio_mask_debugging()) { - u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1); + u64 pmr = read_sysreg_s(SYS_ICC_PMR_EL1); + u64 pmr_irqon = GIC_PRIO_IRQON; - WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF); + WARN_ON_ONCE(pmr != pmr_irqon && pmr != pmr_irqoff); } asm volatile(ALTERNATIVE( @@ -58,7 +64,7 @@ static inline void arch_local_irq_disable(void) __msr_s(SYS_ICC_PMR_EL1, "%0"), ARM64_HAS_IRQ_PRIO_MASKING) : - : "r" ((unsigned long) GIC_PRIO_IRQOFF) + : "r" (pmr_irqoff) : "memory"); } diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index 966ed30ed5f7..a19cd6ff4d1b 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -32,6 +32,7 @@ */ #define GIC_PRIO_IRQON 0xe0 #define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80) +#define GIC_PRIO_IRQOFF_NS 0xa0 #define GIC_PRIO_PSR_I_SET (1 << 4) /* Additional SPSR bits not exposed in the UABI */ @@ -129,6 +130,17 @@ #define compat_sp_fiq regs[29] #define compat_lr_fiq regs[30] +#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; \ + }) + static inline unsigned long compat_psr_to_pstate(const unsigned long psr) { unsigned long pstate; diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 2646178c8329..e4fa944dbf1d 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -653,7 +653,7 @@ alternative_else_nop_endif #ifdef CONFIG_ARM64_PSEUDO_NMI /* * When using IRQ priority masking, we can get spurious interrupts while - * PMR is set to GIC_PRIO_IRQOFF. An NMI might also have occurred in a + * PMR is set to mask interrupts. An NMI might also have occurred in a * section with interrupts disabled. Skip tracing in those cases. */ test_irqs_unmasked res=x0, pmr=x20 diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 9e897c500237..c4476a99dee8 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 #endif /* CONFIG_KVM */ diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 341be2f2f312..729a3a59ad6a 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -237,7 +237,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu) /* Returning to host will clear PSR.I, remask PMR if needed */ if (system_uses_irq_prio_masking()) - gic_write_pmr(GIC_PRIO_IRQOFF); + gic_write_pmr(gic_prio_irqoff()); return exit_code; } diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index ce8944ae1b84..19e52c025c59 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 +933,16 @@ 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 */ - 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 +1547,6 @@ 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 +1565,36 @@ 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))