mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-03-03 18:28:01 +01:00
2066f00e5b
Christian reported that commita430c11f40("intel_idle: Rescan "dead" SMT siblings during initialization") broke the use case in which both 'nosmt' and 'maxcpus' are on the kernel command line because it onlines primary threads, which were offline due to the maxcpus limit. The initially proposed fix to skip primary threads in the loop is inconsistent. While it prevents the primary thread to be onlined, it then onlines the corresponding hyperthread(s), which does not really make sense. The CPU iterator in cpuhp_smt_enable() contains a check which excludes all threads of a core, when the primary thread is offline. The default implementation is a NOOP and therefore not effective on x86. Implement topology_is_core_online() on x86 to address this issue. This makes the behaviour consistent between x86 and PowerPC. Fixes:a430c11f40("intel_idle: Rescan "dead" SMT siblings during initialization") Fixes:f694481b1d("ACPI: processor: Rescan "dead" SMT siblings during initialization") Closes: https://lore.kernel.org/linux-pm/724616a2-6374-4ba3-8ce3-ea9c45e2ae3b@arm.com/ Reported-by: Christian Loehle <christian.loehle@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org> Tested-by: Christian Loehle <christian.loehle@arm.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/12740505.O9o76ZdvQC@rafael.j.wysocki