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: 0603839b18 ("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>
79 lines
1.5 KiB
C
79 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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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/kernel.h>
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#include <linux/acpi.h>
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#include <linux/efi.h>
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#include <linux/export.h>
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#include <linux/pm.h>
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#include <linux/types.h>
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#include <linux/reboot.h>
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#include <linux/delay.h>
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#include <linux/console.h>
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#include <acpi/reboot.h>
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#include <asm/idle.h>
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#include <asm/loongarch.h>
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#include <asm/loongson.h>
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void (*pm_power_off)(void);
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EXPORT_SYMBOL(pm_power_off);
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void machine_halt(void)
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{
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#ifdef CONFIG_SMP
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preempt_disable();
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smp_send_stop();
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#endif
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local_irq_disable();
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clear_csr_ecfg(ECFG0_IM);
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pr_notice("\n\n** You can safely turn off the power now **\n\n");
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console_flush_on_panic(CONSOLE_FLUSH_PENDING);
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while (true) {
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__asm__ __volatile__("idle 0" : : : "memory");
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}
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}
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void machine_power_off(void)
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{
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#ifdef CONFIG_SMP
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preempt_disable();
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smp_send_stop();
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#endif
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#ifdef CONFIG_PM
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if (!acpi_disabled)
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enable_pci_wakeup();
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#endif
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do_kernel_power_off();
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#ifdef CONFIG_EFI
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efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL);
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#endif
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while (true) {
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__asm__ __volatile__("idle 0" : : : "memory");
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}
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}
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void machine_restart(char *command)
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{
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#ifdef CONFIG_SMP
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preempt_disable();
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smp_send_stop();
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#endif
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do_kernel_restart(command);
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#ifdef CONFIG_EFI
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if (efi_capsule_pending(NULL))
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efi_reboot(REBOOT_WARM, NULL);
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else
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efi_reboot(REBOOT_COLD, NULL);
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#endif
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if (!acpi_disabled)
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acpi_reboot();
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while (true) {
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__asm__ __volatile__("idle 0" : : : "memory");
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}
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}
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