From: Julien Thierry <julien.thierry@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, daniel.thompson@linaro.org,
joel@joelfernandes.org, marc.zyngier@arm.com,
christoffer.dall@arm.com, james.morse@arm.com,
catalin.marinas@arm.com, will.deacon@arm.com,
mark.rutland@arm.com, Julien Thierry <julien.thierry@arm.com>
Subject: [PATCH v10 23/25] arm64: Skip preemption when exiting an NMI
Date: Thu, 31 Jan 2019 14:59:01 +0000 [thread overview]
Message-ID: <1548946743-38979-24-git-send-email-julien.thierry@arm.com> (raw)
In-Reply-To: <1548946743-38979-1-git-send-email-julien.thierry@arm.com>
Handling of an NMI should not set any TIF flags. For NMIs received from
EL0 the current exit path is safe to use.
However, an NMI received at EL1 could have interrupted some task context
that has set the TIF_NEED_RESCHED flag. Preempting a task should not
happen as a result of an NMI.
Skip preemption after handling an NMI from EL1.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kernel/entry.S | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 35a47f6..acf1250 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -624,7 +624,15 @@ el1_irq:
#ifdef CONFIG_PREEMPT
ldr x24, [tsk, #TSK_TI_PREEMPT] // get preempt count
- cbnz x24, 1f // preempt count != 0
+alternative_if ARM64_HAS_IRQ_PRIO_MASKING
+ /*
+ * DA_F were cleared at start of handling. If anything is set in DAIF,
+ * we come back from an NMI, so skip preemption
+ */
+ mrs x0, daif
+ orr x24, x24, x0
+alternative_else_nop_endif
+ cbnz x24, 1f // preempt count != 0 || NMI return path
bl el1_preempt
1:
#endif
--
1.9.1
next prev parent reply other threads:[~2019-01-31 15:00 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-31 14:58 [PATCH v10 00/25] arm64: provide pseudo NMI with GICv3 Julien Thierry
2019-01-31 14:58 ` [PATCH v10 01/25] arm64: Fix HCR.TGE status for NMI contexts Julien Thierry
2019-01-31 14:58 ` [PATCH v10 02/25] arm64: Remove unused daif related functions/macros Julien Thierry
2019-01-31 14:58 ` [PATCH v10 03/25] arm64: cpufeature: Set SYSREG_GIC_CPUIF as a boot system feature Julien Thierry
2019-01-31 14:58 ` [PATCH v10 04/25] arm64: cpufeature: Add cpufeature for IRQ priority masking Julien Thierry
2019-01-31 14:58 ` [PATCH v10 05/25] arm/arm64: gic-v3: Add PMR and RPR accessors Julien Thierry
2019-01-31 14:58 ` [PATCH v10 06/25] irqchip/gic-v3: Switch to PMR masking before calling IRQ handler Julien Thierry
2019-01-31 14:58 ` [PATCH v10 07/25] arm64: ptrace: Provide definitions for PMR values Julien Thierry
2019-01-31 14:58 ` [PATCH v10 08/25] arm64: Make PMR part of task context Julien Thierry
2019-01-31 14:58 ` [PATCH v10 09/25] arm64: Unmask PMR before going idle Julien Thierry
2019-01-31 14:58 ` [PATCH v10 10/25] arm64: kvm: Unmask PMR before entering guest Julien Thierry
2019-01-31 14:58 ` [PATCH v10 11/25] efi: Let architectures decide the flags that should be saved/restored Julien Thierry
2019-01-31 14:58 ` [PATCH v10 12/25] arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking Julien Thierry
2019-02-08 4:35 ` Nathan Chancellor
2019-02-08 9:36 ` Julien Thierry
2019-02-08 16:00 ` Nathan Chancellor
2019-02-08 16:16 ` Catalin Marinas
2019-01-31 14:58 ` [PATCH v10 13/25] arm64: daifflags: Include PMR in daifflags restore operations Julien Thierry
2019-01-31 14:58 ` [PATCH v10 14/25] arm64: alternative: Allow alternative status checking per cpufeature Julien Thierry
2019-01-31 14:58 ` [PATCH v10 15/25] arm64: alternative: Apply alternatives early in boot process Julien Thierry
2019-01-31 14:58 ` [PATCH v10 16/25] irqchip/gic-v3: Factor group0 detection into functions Julien Thierry
2019-01-31 14:58 ` [PATCH v10 17/25] arm64: Switch to PMR masking when starting CPUs Julien Thierry
2019-01-31 14:58 ` [PATCH v10 18/25] arm64: gic-v3: Implement arch support for priority masking Julien Thierry
2019-01-31 14:58 ` [PATCH v10 19/25] irqchip/gic-v3: Detect if GIC can support pseudo-NMIs Julien Thierry
2019-01-31 14:58 ` [PATCH v10 20/25] irqchip/gic-v3: Handle pseudo-NMIs Julien Thierry
2019-01-31 14:58 ` [PATCH v10 21/25] irqchip/gic-v3: Allow interrupts to be set as pseudo-NMI Julien Thierry
2019-01-31 14:59 ` [PATCH v10 22/25] arm64: Handle serror in NMI context Julien Thierry
2019-01-31 14:59 ` Julien Thierry [this message]
2019-01-31 14:59 ` [PATCH v10 24/25] arm64: Skip irqflags tracing for NMI in IRQs disabled context Julien Thierry
2019-01-31 14:59 ` [PATCH v10 25/25] arm64: Enable the support of pseudo-NMIs Julien Thierry
2019-02-06 10:27 ` [PATCH v10 00/25] arm64: provide pseudo NMI with GICv3 Catalin Marinas
2019-02-07 14:21 ` Daniel Thompson
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