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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-03-26 17:36:06 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-03 06:27:38 +0200 |
| commit | 8c0823aa123b7b4cd5ebc9fbed324dbe4a37755d (patch) | |
| tree | cb61413f493f611e443fce8a6bd589f6d7335f44 | |
| parent | c3bcf031466592a5d58eafae1d8df5bc4448122c (diff) | |
| download | blackbird-obmc-linux-8c0823aa123b7b4cd5ebc9fbed324dbe4a37755d.tar.gz blackbird-obmc-linux-8c0823aa123b7b4cd5ebc9fbed324dbe4a37755d.zip | |
x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y
commit bebd024e4815b1a170fcd21ead9c2222b23ce9e6 upstream.
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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 68261430fe6e..64d5a3327030 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2221,14 +2221,8 @@ 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" |
