[RFC PATCH v4 5/8] x86/smp native_play_dead: Prefer cpuidle_play_dead() over mwait_play_dead()
From: Patryk Wlazlyn
Date: Mon Nov 25 2024 - 08:22:42 EST
The algorithm based on cpuid leaf 0x5 in the mwait_play_dead(),
for looking up the mwait hint for the deepest cstate may calculate the
wrong hint on recent Intel x86 platforms.
Prefer cpuidle_play_dead() over the generic mwait_play_dead() loop and
only fallback to the later in case of missing appropriate enter_dead()
handler.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/smpboot.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index d0464c7a0af5..2627b56fb9bc 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1413,9 +1413,10 @@ void native_play_dead(void)
play_dead_common();
tboot_shutdown(TB_SHUTDOWN_WFS);
+ /* The first successful play_dead() will not return */
+ cpuidle_play_dead();
mwait_play_dead();
- if (cpuidle_play_dead())
- hlt_play_dead();
+ hlt_play_dead();
}
#else /* ... !CONFIG_HOTPLUG_CPU */
--
2.47.0