On 19.04.2022 17:01, David Vrabel wrote:
> From: David Vrabel <[email protected]>
> 
> Heap pages can only be safely allocated and freed with interuupts
> enabled as they may require a TLB flush which will send IPIs.
> 
> Enhance the assertions in alloc_xenheap_pages() and
> alloc_domheap_pages() to check interrupts are enabled. For consistency
> the same asserts are used when freeing heap pages.
> 
> As an exception, during early boot when only 1 PCPU is online,
> allocations are permitted with interrupts disabled.

This exception is tightly coupled with spin lock checking, i.e. the
point in time when spin_debug_enable() is called. I think this wants
making explicit at least in the code comment, but as a result I also
wonder in how far the extended assertions are really worthwhile: Any
violation would be detected in check_lock() anyway. Thoughts?

Furthermore I'm concerned of Arm not using either SYS_STATE_smp_boot
or spin_debug_enable().

Jan


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