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x86/AMD: Fix erratum 1076 (CPB bit)

PATCH New Borislav Petkov 2 participants 3 messages Sep 7, 2017 – Sep 15, 2017 x86

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Borislav Petkov

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#0 lore raw

PATCH 1/1 x86/AMD: Fix erratum 1076 (CPB bit)

From: Borislav Petkov <[email protected]>

CPUID Fn8000_0007_EDX[CPB] is wrongly 0 on models up to B1. But they do support CPB so fix that.

Signed-off-by Borislav Petkov <[email protected]>
---
 arch/x86/kernel/cpu/amd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
arch/x86/kernel/cpu/amd.c +11 -0
index 9862e2cd6d93..d58184b7cd44 100644
@@ -763,6 +763,16 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
 	}
 }
 
+static void init_amd_zn(struct cpuinfo_x86 *c)
+{
+	/*
+	 * 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_mask <= 1)
+		set_cpu_cap(c, X86_FEATURE_CPB);
+}
+
 static void init_amd(struct cpuinfo_x86 *c)
 {
 	early_init_amd(c);

@@ -791,6 +801,7 @@ static void init_amd(struct cpuinfo_x86 *c)
 	case 0x10: init_amd_gh(c); break;
 	case 0x12: init_amd_ln(c); break;
 	case 0x15: init_amd_bd(c); break;
+	case 0x17: init_amd_zn(c); break;
 	}
 
 	/* Enable workaround for FXSAVE leak */
Signature · 1 line
2.13.0
merge bot
#1 lore raw

[tip:x86/urgent] x86/cpu/AMD: Fix erratum 1076 (CPB bit)

x86/cpu/AMD: Fix erratum 1076 (CPB bit)
Commit-ID:  6a707c0e451cb8d86943b840939e2ed881b8023e
Gitweb:     http://git.kernel.org/tip/6a707c0e451cb8d86943b840939e2ed881b8023e
Author:     Borislav Petkov <[email protected]>
AuthorDate: Thu, 7 Sep 2017 19:08:21 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 15 Sep 2017 07:44:50 +0200

x86/cpu/AMD: Fix erratum 1076 (CPB bit)

CPUID Fn8000_0007_EDX[CPB] is wrongly 0 on models up to B1. But they do support CPB (AMD's Core Performance Boosting cpufreq CPU feature), so fix that.

Signed-off-by Borislav Petkov <[email protected]>
Reviewed-by Don Zickus <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Sherry Hurwitz <[email protected]>
Cc Thomas Gleixner <[email protected]>
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Ingo Molnar <[email protected]>
---
 arch/x86/kernel/cpu/amd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
arch/x86/kernel/cpu/amd.c +11 -0
index 9862e2c..d58184b 100644
@@ -763,6 +763,16 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
 	}
 }
 
+static void init_amd_zn(struct cpuinfo_x86 *c)
+{
+	/*
+	 * 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_mask <= 1)
+		set_cpu_cap(c, X86_FEATURE_CPB);
+}
+
 static void init_amd(struct cpuinfo_x86 *c)
 {
 	early_init_amd(c);

@@ -791,6 +801,7 @@ static void init_amd(struct cpuinfo_x86 *c)
 	case 0x10: init_amd_gh(c); break;
 	case 0x12: init_amd_ln(c); break;
 	case 0x15: init_amd_bd(c); break;
+	case 0x17: init_amd_zn(c); break;
 	}
 
 	/* Enable workaround for FXSAVE leak */
merge bot
#2 lore raw

[tip:x86/urgent] x86/cpu/AMD: Fix erratum 1076 (CPB bit)

In reply to Borislav Petkov
x86/cpu/AMD: Fix erratum 1076 (CPB bit)
Commit-ID:  f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9
Gitweb:     http://git.kernel.org/tip/f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9
Author:     Borislav Petkov <[email protected]>
AuthorDate: Thu, 7 Sep 2017 19:08:21 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 15 Sep 2017 11:30:53 +0200

x86/cpu/AMD: Fix erratum 1076 (CPB bit)

CPUID Fn8000_0007_EDX[CPB] is wrongly 0 on models up to B1. But they do support CPB (AMD's Core Performance Boosting cpufreq CPU feature), so fix that.

Signed-off-by Borislav Petkov <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Sherry Hurwitz <[email protected]>
Cc Thomas Gleixner <[email protected]>
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Ingo Molnar <[email protected]>
---
 arch/x86/kernel/cpu/amd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
arch/x86/kernel/cpu/amd.c +11 -0
index 9862e2c..d58184b 100644
@@ -763,6 +763,16 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
 	}
 }
 
+static void init_amd_zn(struct cpuinfo_x86 *c)
+{
+	/*
+	 * 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_mask <= 1)
+		set_cpu_cap(c, X86_FEATURE_CPB);
+}
+
 static void init_amd(struct cpuinfo_x86 *c)
 {
 	early_init_amd(c);

@@ -791,6 +801,7 @@ static void init_amd(struct cpuinfo_x86 *c)
 	case 0x10: init_amd_gh(c); break;
 	case 0x12: init_amd_ln(c); break;
 	case 0x15: init_amd_bd(c); break;
+	case 0x17: init_amd_zn(c); break;
 	}
 
 	/* Enable workaround for FXSAVE leak */