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From 114e0a684753516ef4b71ccb55a8ebcfa8735edb Mon Sep 17 00:00:00 2001 |
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From: Mark Rutland <mark.rutland@arm.com> |
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Date: Mon, 30 Nov 2020 11:59:41 +0000 |
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Subject: [PATCH 124/150] arm64: mark idle code as noinstr |
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|
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Core code disables RCU when calling arch_cpu_idle(), so it's not safe |
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for arch_cpu_idle() or its calees to be instrumented, as the |
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instrumentation callbacks may attempt to use RCU or other features which |
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are unsafe to use in this context. |
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|
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Mark them noinstr to prevent issues. |
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|
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The use of local_irq_enable() in arch_cpu_idle() is similarly |
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problematic, and the "sched/idle: Fix arch_cpu_idle() vs tracing" patch |
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queued in the tip tree addresses that case. |
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|
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Reported-by: Marco Elver <elver@google.com> |
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Signed-off-by: Mark Rutland <mark.rutland@arm.com> |
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Cc: Catalin Marinas <catalin.marinas@arm.com> |
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Cc: James Morse <james.morse@arm.com> |
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Cc: Will Deacon <will@kernel.org> |
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Link: https://lore.kernel.org/r/20201130115950.22492-3-mark.rutland@arm.com |
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Signed-off-by: Will Deacon <will@kernel.org> |
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--- |
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arch/arm64/kernel/process.c | 8 ++++---- |
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1 file changed, 4 insertions(+), 4 deletions(-) |
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|
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diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c |
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index a47a40ec6ad9..0c65a91f8f53 100644 |
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--- a/arch/arm64/kernel/process.c |
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+++ b/arch/arm64/kernel/process.c |
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@@ -72,13 +72,13 @@ EXPORT_SYMBOL_GPL(pm_power_off); |
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|
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void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); |
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|
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-static void __cpu_do_idle(void) |
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+static void noinstr __cpu_do_idle(void) |
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{ |
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dsb(sy); |
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wfi(); |
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} |
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|
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-static void __cpu_do_idle_irqprio(void) |
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+static void noinstr __cpu_do_idle_irqprio(void) |
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{ |
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unsigned long pmr; |
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unsigned long daif_bits; |
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@@ -108,7 +108,7 @@ static void __cpu_do_idle_irqprio(void) |
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* ensure that interrupts are not masked at the PMR (because the core will |
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* not wake up if we block the wake up signal in the interrupt controller). |
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*/ |
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-void cpu_do_idle(void) |
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+void noinstr cpu_do_idle(void) |
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{ |
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if (system_uses_irq_prio_masking()) |
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__cpu_do_idle_irqprio(); |
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@@ -119,7 +119,7 @@ void cpu_do_idle(void) |
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/* |
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* This is our default idle handler. |
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*/ |
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-void arch_cpu_idle(void) |
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+void noinstr arch_cpu_idle(void) |
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{ |
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/* |
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* This should do all the clock switching and wait for interrupt |
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-- |
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2.29.2 |
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