arch/arm/armv8-r: fix multicore gicv3 init issue #16892
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arch/arm/src/armv8-r/arm_doirq.c
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| /* Initialize the Generic Interrupt Controller (GIC) for CPU0 */ | ||
| while (gicd_ready == 0) |
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but why the secondary cpu start without waiting the primary cpu command?
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Some SoC may release all the cpus simultaneously after power on, while let the software to do the synchronization.
By the way, gic init is called by nuttx kernel in nx_start, which is also probably called by some cpus simultaneously while cpu0 is doing it, because cpu0 tend to do more stuff in initialization after releasing other cpus.
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Ok, this is a general problem. not only GIC need this special process, but also the global variables and other shared resource need finish the initialization in the boot cpu before other cpu boot.
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Yes, for this general problem, I think, on the one hand, app should take care of the app specific global variable and shared resource init sequence and sync in multicore system.
On the other hand, for other global variables or shared resource in multicore system, i would call them default one, not app specific, they should be initialzed by system, before any app starts, like bss clear or data copy, and it is the system that should take care of their initialzaiton sequence or sync . I think GIC is this kind of shared resource
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The coordination of initialization should be done in the common layer, not specific in GIC, so all system components could get sync. @hujun260 will provide a similar patch for review.
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Got it, I removed the sync in gic init
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In multicore situation, it is cpu0 to call arm_gic_initialize to init global GICD and percpu GICRD/GIC cpu interface; other cpus only need to call arm_gic_secondary_init to int percpu GICRD/GIC cpu interface. The current code may int GICD multiple times in multicore situation which is a bug.
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| arm_gic_initialize(); /* Initialization common to all CPUs */ | ||
| arm_gic_secondary_init(); |
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but up_irqinitialize is designed to be called on primary cpu, other cpu should call arm_gic_secondary_init directly. Please search how arm64_gic_secondary_init get called.
In multicore situation, it is cpu0 to call arm_gic_initialize to init global GICD and percpu GICRD/GIC cpu interface; other cpus only need to call arm_gic_secondary_init to int percpu GICRD/GIC cpu interface. The current code may int GICD multiple times in multicore situation which is a bug.
Note: Please adhere to Contributing Guidelines.
Summary
Cpu0 call arm_gic_initialize, other Cpus call arm_gic_secondary_init
Impact
Fix bugs about GIC initialization in multicore situation
Testing
This was tested in our own multicore arm cortex-r52 board