[PATCH 3/4] x86/fpu: Prepare AMX state for CPU idle

From: Chang S. Bae
Date: Thu Nov 04 2021 - 19:00:05 EST


Before entering CPU idle, make sure large registers such as AMX TILE are
initialized. Otherwise, non-initialized register states may prevent a CPU
from entering a deeper low-power state.

Suggested-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
arch/x86/kernel/process.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index eb470be0e5ae..7044ba276064 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -707,6 +707,7 @@ static inline void play_dead(void)

void arch_cpu_idle_enter(void)
{
+ fpu_idle_fpregs();
tsc_verify_tsc_adjust(false);
local_touch_nmi();
}
--
2.17.1