[tip: x86/urgent] x86/cpu: Add Lunar Lake to list of CPUs with a broken MONITOR implementation
From: tip-bot2 for Len Brown
Date: Wed Dec 04 2024 - 15:39:48 EST
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: c9a4b55431e5220347881e148725bed69c84e037
Gitweb: https://git.kernel.org/tip/c9a4b55431e5220347881e148725bed69c84e037
Author: Len Brown <len.brown@xxxxxxxxx>
AuthorDate: Tue, 12 Nov 2024 21:07:00 -05:00
Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Wed, 04 Dec 2024 12:30:14 -08:00
x86/cpu: Add Lunar Lake to list of CPUs with a broken MONITOR implementation
Under some conditions, MONITOR wakeups on Lunar Lake processors
can be lost, resulting in significant user-visible delays.
Add Lunar Lake to X86_BUG_MONITOR so that wake_up_idle_cpu()
always sends an IPI, avoiding this potential delay.
Reported originally here:
https://bugzilla.kernel.org/show_bug.cgi?id=219364
[ dhansen: tweak subject ]
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc:stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/all/a4aa8842a3c3bfdb7fe9807710eef159cbf0e705.1731463305.git.len.brown%40intel.com
---
arch/x86/kernel/cpu/intel.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index d1de300..8ded9f8 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -555,7 +555,9 @@ static void init_intel(struct cpuinfo_x86 *c)
c->x86_vfm == INTEL_WESTMERE_EX))
set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR);
- if (boot_cpu_has(X86_FEATURE_MWAIT) && c->x86_vfm == INTEL_ATOM_GOLDMONT)
+ if (boot_cpu_has(X86_FEATURE_MWAIT) &&
+ (c->x86_vfm == INTEL_ATOM_GOLDMONT ||
+ c->x86_vfm == INTEL_LUNARLAKE_M))
set_cpu_bug(c, X86_BUG_MONITOR);
#ifdef CONFIG_X86_64