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edb1942542
LoongArch re-enables interrupts on its idle routine and performs a
TIF_NEED_RESCHED check afterwards before putting the CPU to sleep.
The IRQs firing between the check and the idle instruction may set the
TIF_NEED_RESCHED flag. In order to deal with such a race, IRQs
interrupting __arch_cpu_idle() rollback their return address to the
beginning of __arch_cpu_idle() so that TIF_NEED_RESCHED is checked
again before going back to sleep.
However idle IRQs can also queue timers that may require a tick
reprogramming through a new generic idle loop iteration but those timers
would go unnoticed here because __arch_cpu_idle() only checks
TIF_NEED_RESCHED. It doesn't check for pending timers.
Fix this with fast-forwarding idle IRQs return address to the end of the
idle routine instead of the beginning, so that the generic idle loop can
handle both TIF_NEED_RESCHED and pending timers.
Fixes: 0603839b18f4 ("LoongArch: Add exception/interrupt handling")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
17 lines
325 B
C
17 lines
325 B
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* LoongArch idle loop support.
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*
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* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
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*/
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#include <linux/cpu.h>
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#include <linux/irqflags.h>
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#include <asm/cpu.h>
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#include <asm/idle.h>
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void __cpuidle arch_cpu_idle(void)
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{
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__arch_cpu_idle();
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raw_local_irq_disable();
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}
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