From: Pu Wen <puwen@hygon.cn>
Date: Sun, 23 Sep 2018 17:34:32 +0800
Subject: x86/smpboot: Do not use BSP INIT delay and MWAIT to idle on Dhyana
Git-commit: 0b13bec787dccca96f8c431da732657ae01baf9a
Patch-mainline: v4.20-rc1
References: fate#327735

The Hygon Dhyana CPU uses no delay in smp_quirk_init_udelay(), and does
HLT on idle just like AMD does.

Signed-off-by: Pu Wen <puwen@hygon.cn>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: bp@alien8.de
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: x86@kernel.org
Cc: thomas.lendacky@amd.com
Link: https://lkml.kernel.org/r/87000fa82e273f5967c908448414228faf61e077.1537533369.git.puwen@hygon.cn
---
 arch/x86/kernel/smpboot.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index f02ecaf97904..5369d7fac797 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -676,6 +676,7 @@ static void __init smp_quirk_init_udelay(void)
 
 	/* if modern processor, use no delay */
 	if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||
+	    ((boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) && (boot_cpu_data.x86 >= 0x18)) ||
 	    ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {
 		init_udelay = 0;
 		return;
@@ -1592,7 +1593,8 @@ static inline void mwait_play_dead(void)
 	void *mwait_ptr;
 	int i;
 
-	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+	    boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
 		return;
 	if (!this_cpu_has(X86_FEATURE_MWAIT))
 		return;