linux-kernel - [tip:x86/cpu] x86/CPU/AMD: Set the CPB bit unconditionally on F17h

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Date:   Fri, 18 Jan 2019 07:48:59 -0800
From:   tip-bot for Jiaxun Yang <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     suravee.suthikulpanit@....com, jiaxun.yang@...goat.com,
        tglx@...utronix.de, x86@...nel.org, linux-kernel@...r.kernel.org,
        sherry.hurwitz@....com, mingo@...hat.com, bp@...e.de,
        mingo@...nel.org, thomas.lendacky@....com, hpa@...or.com
Subject: [tip:x86/cpu] x86/CPU/AMD: Set the CPB bit unconditionally on F17h

Commit-ID:  0237199186e7a4aa5310741f0a6498a20c820fd7
Gitweb:     https://git.kernel.org/tip/0237199186e7a4aa5310741f0a6498a20c820fd7
Author:     Jiaxun Yang <jiaxun.yang@...goat.com>
AuthorDate: Tue, 20 Nov 2018 11:00:18 +0800
Committer:  Borislav Petkov <bp@...e.de>
CommitDate: Fri, 18 Jan 2019 16:44:03 +0100

x86/CPU/AMD: Set the CPB bit unconditionally on F17h

Some F17h models do not have CPB set in CPUID even though the CPU
supports it. Set the feature bit unconditionally on all F17h.

 [ bp: Rewrite commit message and patch. ]

Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Acked-by: Tom Lendacky <thomas.lendacky@....com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Sherry Hurwitz <sherry.hurwitz@....com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: x86-ml <x86@...nel.org>
Link: https://lkml.kernel.org/r/20181120030018.5185-1-jiaxun.yang@flygoat.com
---
 arch/x86/kernel/cpu/amd.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 69f6bbb41be0..01004bfb1a1b 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -819,11 +819,9 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
 static void init_amd_zn(struct cpuinfo_x86 *c)
 {
 	set_cpu_cap(c, X86_FEATURE_ZEN);
-	/*
-	 * Fix erratum 1076: CPB feature bit not being set in CPUID. It affects
-	 * all up to and including B1.
-	 */
-	if (c->x86_model <= 1 && c->x86_stepping <= 1)
+
+	/* Fix erratum 1076: CPB feature bit not being set in CPUID. */
+	if (!cpu_has(c, X86_FEATURE_CPB))
 		set_cpu_cap(c, X86_FEATURE_CPB);
 }