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• 解决的问题是什么

中断抢占

1.实现原理

1/ 禁止 irq与fiq2/ 禁止 中断源 // 与 vic/gic 等 中断控制器 相关	适用于 某个中断源 中断处理过程中,不能接受 来自该中断源的中断

2.1 禁止 irq与fiq

• local_irq_enable

arch/arm/include/asm/irqflags.h 36 #define arch_local_irq_enable arch_local_irq_enable                               37 static inline void arch_local_irq_enable(void)                                    38 {
                                                                                    39     asm volatile(                                                                 40         "   cpsie i         @ arch_local_irq_enable"                              41         :                                                                         42         :                                                                         43         : "memory", "cc");                                                        44 }include/linux/irqflags.h156 #define raw_local_irq_enable()      arch_local_irq_enable()223 #define local_irq_enable()  do {
    raw_local_irq_enable(); } while (0)

• local_irq_disable

arch/arm/include/asm/irqflags.h 46 #define arch_local_irq_disable arch_local_irq_disable                             47 static inline void arch_local_irq_disable(void)                                   48 {
                                                                                    49     asm volatile(                                                                 50         "   cpsid i         @ arch_local_irq_disable"                             51         :                                                                         52         :                                                                         53         : "memory", "cc");                                                        54 }include/linux/irqflags.h155 #define raw_local_irq_disable()     arch_local_irq_disable()224 #define local_irq_disable() do {
    raw_local_irq_disable(); } while (0)

2.2 禁止中断源

• enable_irq

enable_irq																	// kernel/irq/manage.c	__enable_irq 															// kernel/irq/manage.c		irq_startup 														// kernel/irq/chip.c			irq_enable														// kernel/irq/chip.c				unmask_irq 													// kernel/irq/chip.c					desc->irq_data.chip->irq_unmask/vic_unmask_irq 			// drivers/irqchip/irq-vic.c						void __iomem *base = irq_data_get_irq_chip_data(d);						unsigned int irq = d->hwirq;						writel(1 << irq, base + VIC_INT_ENABLE);

• disable_irq

disable_irq 																// kernel/irq/manage.c	__disable_irq_nosync 													// kernel/irq/manage.c		__disable_irq 														// kernel/irq/manage.c			irq_disable 													// kernel/irq/chip.c				__irq_disable 												// kernel/irq/chip.c					mask_irq 												// kernel/irq/chip.c						desc->irq_data.chip->irq_mask(&desc->irq_data);/vic_mask_irq  // drivers/irqchip/irq-vic.c						// desc->irq_data.chip->irq_mask 存在的情况下							void __iomem *base = irq_data_get_irq_chip_data(d);							unsigned int irq = d->hwirq;							writel(1 << irq, base + VIC_INT_ENABLE_CLEAR);					desc->irq_data.chip->irq_disable(&desc->irq_data); 					// desc->irq_data.chip->irq_disable 的情况下

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