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| author |   Jiri Kosina <jkosina@suse.cz> | 2019-05-30 00:09:39 +0200 |
|---|---|---|
| committer |   Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-06-03 12:02:03 +0200 |
| commit | ec527c318036a65a083ef68d8ba95789d2212246 (patch) | |
| tree | 175e0ca9ba0d214c469b7f03aa2baa567d99be7b /include/linux/cpu.h | |
| parent | x86: intel_epb: Do not build when CONFIG_PM is unset (diff) | |
| download | wireguard-linux-ec527c318036a65a083ef68d8ba95789d2212246.tar.xz wireguard-linux-ec527c318036a65a083ef68d8ba95789d2212246.zip | |
x86/power: Fix 'nosmt' vs hibernation triple fault during resume
As explained in
0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once")
we always, no matter what, have to bring up x86 HT siblings during boot at
least once in order to avoid first MCE bringing the system to its knees.
That means that whenever 'nosmt' is supplied on the kernel command-line,
all the HT siblings are as a result sitting in mwait or cpudile after
going through the online-offline cycle at least once.
This causes a serious issue though when a kernel, which saw 'nosmt' on its
commandline, is going to perform resume from hibernation: if the resume
from the hibernated image is successful, cr3 is flipped in order to point
to the address space of the kernel that is being resumed, which in turn
means that all the HT siblings are all of a sudden mwaiting on address
which is no longer valid.
That results in triple fault shortly after cr3 is switched, and machine
reboots.
Fix this by always waking up all the SMT siblings before initiating the
'restore from hibernation' process; this guarantees that all the HT
siblings will be properly carried over to the resumed kernel waiting in
resume_play_dead(), and acted upon accordingly afterwards, based on the
target kernel configuration.
Symmetricaly, the resumed kernel has to push the SMT siblings to mwait
again in case it has SMT disabled; this means it has to online all
the siblings when resuming (so that they come out of hlt) and offline
them again to let them reach mwait.
Cc: 4.19+ <stable@vger.kernel.org> # v4.19+
Debugged-by: Thomas Gleixner <tglx@linutronix.de>
Fixes: 0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/linux/cpu.h')
| -rw-r--r-- | include/linux/cpu.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 3813fe45effd..fcb1386bb0d4 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -201,10 +201,14 @@ enum cpuhp_smt_control { extern enum cpuhp_smt_control cpu_smt_control; extern void cpu_smt_disable(bool force); extern void cpu_smt_check_topology(void); +extern int cpuhp_smt_enable(void); +extern int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval); #else # define cpu_smt_control (CPU_SMT_NOT_IMPLEMENTED) static inline void cpu_smt_disable(bool force) { } static inline void cpu_smt_check_topology(void) { } +static inline int cpuhp_smt_enable(void) { return 0; } +static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; } #endif /* |