代码如下图所示，最终操作的是msr daifset, #3 和 msr daifclr, #3 寄存器。

(include/linux/irqflags.h)
#define local_irq_enable()	do { raw_local_irq_enable(); } while (0)
#define local_irq_disable()	do { raw_local_irq_disable(); } while (0)

#define raw_local_irq_disable()		arch_local_irq_disable()
#define raw_local_irq_enable()		arch_local_irq_enable()

static inline void arch_local_irq_disable(void)
{
	if (__irqflags_uses_pmr()) {
		__pmr_local_irq_disable();
	} else {
		__daif_local_irq_disable();
	}
}


static __always_inline void __daif_local_irq_disable(void)
{
	barrier();
	asm volatile("msr daifset, #3");
	barrier();
}

30  static __always_inline void __daif_local_irq_enable(void)
31  {
32  	barrier();
33  	asm volatile("msr daifclr, #3");
34  	barrier();
35  }