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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-03-26 17:36:06 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-03-28 13:34:58 +0100 |
| commit | bebd024e4815b1a170fcd21ead9c2222b23ce9e6 (patch) | |
| tree | eef0ad5f1eee35a03c4cd224824f0910d3e0fc5b /arch | |
| parent | 206b92353c839c0b27a0b9bec24195f93fd6cf7a (diff) | |
| download | linux-bebd024e4815b1a170fcd21ead9c2222b23ce9e6.tar.gz | |
x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y
The SMT disable 'nosmt' command line argument is not working properly when CONFIG_HOTPLUG_CPU is disabled. The teardown of the sibling CPUs which are required to be brought up due to the MCE issues, cannot work. The CPUs are then kept in a half dead state. As the 'nosmt' functionality has become popular due to the speculative hardware vulnerabilities, the half torn down state is not a proper solution to the problem. Enforce CONFIG_HOTPLUG_CPU=y when SMP is enabled so the full operation is possible. Reported-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Konrad Wilk <konrad.wilk@oracle.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Mukesh Ojha <mojha@codeaurora.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Rik van Riel <riel@surriel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Micheal Kelley <michael.h.kelley@microsoft.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190326163811.598166056@linutronix.de
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/Kconfig | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c1f9b3cf437c..5ad92419be19 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2217,14 +2217,8 @@ config RANDOMIZE_MEMORY_PHYSICAL_PADDING If unsure, leave at the default value. config HOTPLUG_CPU - bool "Support for hot-pluggable CPUs" + def_bool y depends on SMP - ---help--- - Say Y here to allow turning CPUs off and on. CPUs can be - controlled through /sys/devices/system/cpu. - ( Note: power management support will enable this option - automatically on SMP systems. ) - Say N if you want to disable CPU hotplug. config BOOTPARAM_HOTPLUG_CPU0 bool "Set default setting of cpu0_hotpluggable" |