tree ca7ad7e935411e3c9142e9dedbe3f655be0f8cfb
parent 506a66f374891ff08e064a058c446b336c5ac760
author Thomas Gleixner <tglx@linutronix.de> 1530281148 +0200
committer Thomas Gleixner <tglx@linutronix.de> 1530523529 +0200

cpu/hotplug: Boot HT siblings at least once

Due to the way Machine Check Exceptions work on X86 hyperthreads it's
required to boot up _all_ logical cores at least once in order to set the
CR4.MCE bit.

So instead of ignoring the sibling threads right away, let them boot up
once so they can configure themselves. After they came out of the initial
boot stage check whether its a "secondary" sibling and cancel the operation
which puts the CPU back into offline state.

Reported-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tony Luck <tony.luck@intel.com>