Re: [PATCH v3 0/3] SRF: Fix offline CPU preventing pc6 entry

[Patryk Wlazlyn]

> There's a comment there that explains why this is done. If you don't
> understand this, then please don't touch this code.

/*
 * Kexec is about to happen. Don't go back into mwait() as
 * the kexec kernel might overwrite text and data including
 * page tables and stack. So mwait() would resume when the
 * monitor cache line is written to and then the CPU goes
 * south due to overwritten text, page tables and stack.
 *
 * Note: This does _NOT_ protect against a stray MCE, NMI,
 * SMI. They will resume execution at the instruction
 * following the HLT instruction and run into the problem
 * which this is trying to prevent.
 */

If you are referring to this comment above, I do understand the need to
enter hlt loop before the kexec happens. I thought that I could bring
all of the offlined CPUs back online, effectively getting them out of
the mwait loop.