https://android.googlesource.com/platform/hardware/bsp/kernel/freescale/+/247271e59c76fe57d70f00f926f0d2e7c77567b8/kernel/softirq.c
kernel/softirq.c - platform/hardware/bsp/kernel/freescale - Git at Google
kernelcplatformhardwarebsp
https://lwn.net/Articles/780980/
softirq: Per vector masking v3 [LWN.net]
pervectormaskinglwn