linux-kernel - [tip:x86/cpu] x86/smpboot: Do not use BSP INIT delay and MWAIT to idle on Dhyana

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Message-ID: <tip-0b13bec787dccca96f8c431da732657ae01baf9a@git.kernel.org>
Date:   Thu, 27 Sep 2018 10:02:42 -0700
From:   tip-bot for Pu Wen <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     bp@...e.de, tglx@...utronix.de, linux-kernel@...r.kernel.org,
        hpa@...or.com, puwen@...on.cn, mingo@...nel.org
Subject: [tip:x86/cpu] x86/smpboot: Do not use BSP INIT delay and MWAIT to
 idle on Dhyana

Commit-ID:  0b13bec787dccca96f8c431da732657ae01baf9a
Gitweb:     https://git.kernel.org/tip/0b13bec787dccca96f8c431da732657ae01baf9a
Author:     Pu Wen <puwen@...on.cn>
AuthorDate: Sun, 23 Sep 2018 17:34:32 +0800
Committer:  Borislav Petkov <bp@...e.de>
CommitDate: Thu, 27 Sep 2018 18:28:57 +0200

x86/smpboot: Do not use BSP INIT delay and MWAIT to idle on Dhyana

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@...on.cn>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Borislav Petkov <bp@...e.de>
Cc: bp@...en8.de
Cc: tglx@...utronix.de
Cc: mingo@...hat.com
Cc: hpa@...or.com
Cc: x86@...nel.org
Cc: thomas.lendacky@....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;