linux/arch/loongarch/kernel/idle.c

// SPDX-License-Identifier: GPL-2.0
/*
 * LoongArch idle loop support.
 *
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */
#include <linux/cpu.h>
#include <linux/irqflags.h>
#include <asm/cpu.h>
#include <asm/idle.h>

void __cpuidle arch_cpu_idle(void)
{
	__arch_cpu_idle();
	raw_local_irq_disable();
}
LoongArch: Add process management Add process management support for LoongArch, including: thread info definition, context switch and process tracing. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-05-31 18:04:11 +08:00			`// SPDX-License-Identifier: GPL-2.0`
			`/*`
			`* LoongArch idle loop support.`
			`*`
			`* Copyright (C) 2020-2022 Loongson Technology Corporation Limited`
			`*/`
			`#include <linux/cpu.h>`
			`#include <linux/irqflags.h>`
			`#include <asm/cpu.h>`
			`#include <asm/idle.h>`

			`void __cpuidle arch_cpu_idle(void)`
			`{`
LoongArch: Fix idle VS timer enqueue 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> 2025-02-13 12:02:35 +08:00			`__arch_cpu_idle();`
arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled Current arch_cpu_idle() is called with IRQs disabled, but will return with IRQs enabled. However, the very first thing the generic code does after calling arch_cpu_idle() is raw_local_irq_disable(). This means that architectures that can idle with IRQs disabled end up doing a pointless 'enable-disable' dance. Therefore, push this IRQ disabling into the idle function, meaning that those architectures can avoid the pointless IRQ state flipping. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64] Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org 2023-01-12 20:43:35 +01:00			`raw_local_irq_disable();`
LoongArch: Add process management Add process management support for LoongArch, including: thread info definition, context switch and process tracing. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-05-31 18:04:11 +08:00			`}`