according to manual:
The FPU is not affected by any security configuration.
Thus, it appears as not present in PERIPHID[n].PERM
register located in the SPU
Purpose: make the the os crash when busyloop with interrupt disable
Follow the arm gicv2 spec, if we want to use the IRQ and FIQ
simultaneously when not using the processor Security Externsions.
We should:
1. IRQ to Group 1 and FIQ to Group 0;
2. Set CICC_CTLR.FIQEn to 1;
Then in NuttX:
1. implement the arm_decodefiq and directly crash in it;
2. provide interface to change the IRQ to FIQ, e.g. change the
watchdog IRQ to FIQ, so the watchdog can trigger even with the
interrupt disabled (up_irq_save() called);
Signed-off-by: wangbowen6 <wangbowen6@xiaomi.com>
Signed-off-by: zhangyuan21 <zhangyuan21@xiaomi.com>
Signed-off-by: ligd <liguiding1@xiaomi.com>
