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* [PATCHv3] x86, CPU: Restore MSR_IA32_ENERGY_PERF_BIAS after resume
@ 2015-07-20 21:47 Laura Abbott
  2015-07-21  9:36 ` [tip:x86/cpu] x86/cpu: " tip-bot for Laura Abbott
  0 siblings, 1 reply; 2+ messages in thread
From: Laura Abbott @ 2015-07-20 21:47 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, Borislav Petkov
  Cc: Laura Abbott, x86, linux-kernel, Peter Zijlstra, Andy Lutomirski


MSR_IA32_ENERGY_PERF_BIAS is lost after suspend/resume:

x86_energy_perf_policy -r before

cpu0: 0x0000000000000006
cpu1: 0x0000000000000006
cpu2: 0x0000000000000006
cpu3: 0x0000000000000006
cpu4: 0x0000000000000006
cpu5: 0x0000000000000006
cpu6: 0x0000000000000006
cpu7: 0x0000000000000006

after

cpu0: 0x0000000000000000
cpu1: 0x0000000000000006
cpu2: 0x0000000000000006
cpu3: 0x0000000000000006
cpu4: 0x0000000000000006
cpu5: 0x0000000000000006
cpu6: 0x0000000000000006
cpu7: 0x0000000000000006

This register is set via init_intel at bootup. During resume, the
secondary CPUs are brought online again and init_intel is callled which
re-initializes the register. The boot cpu however never reinitializes
the register. Add a syscore callback to reinitialize the register for
the boot CPU.

Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
---
v3: Minor code cleanup in init_intel_energy_perf, added intel_bsp_resume to
make it more obvious what's happening.

v2: Tweaked a few names to be more descriptive
---
 arch/x86/kernel/cpu/common.c | 18 +++++++++++++++++
 arch/x86/kernel/cpu/cpu.h    |  1 +
 arch/x86/kernel/cpu/intel.c  | 47 ++++++++++++++++++++++++++++++--------------
 3 files changed, 51 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 922c5e0..fa95bb8 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -13,6 +13,7 @@
 #include <linux/kgdb.h>
 #include <linux/smp.h>
 #include <linux/io.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/stackprotector.h>
 #include <asm/perf_event.h>
@@ -1488,3 +1489,20 @@ inline bool __static_cpu_has_safe(u16 bit)
 	return boot_cpu_has(bit);
 }
 EXPORT_SYMBOL_GPL(__static_cpu_has_safe);
+
+static void bsp_resume(void)
+{
+	if (this_cpu->c_bsp_resume)
+		this_cpu->c_bsp_resume(&boot_cpu_data);
+}
+
+static struct syscore_ops cpu_syscore_ops = {
+	.resume		= bsp_resume,
+};
+
+static int __init init_cpu_syscore(void)
+{
+	register_syscore_ops(&cpu_syscore_ops);
+	return 0;
+}
+core_initcall(init_cpu_syscore);
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index c37dc37..2584265 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -13,6 +13,7 @@ struct cpu_dev {
 	void		(*c_init)(struct cpuinfo_x86 *);
 	void		(*c_identify)(struct cpuinfo_x86 *);
 	void		(*c_detect_tlb)(struct cpuinfo_x86 *);
+	void		(*c_bsp_resume)(struct cpuinfo_x86 *);
 	int		c_x86_vendor;
 #ifdef CONFIG_X86_32
 	/* Optional vendor specific routine to obtain the cache size. */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 50163fa..4f6758d 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -371,6 +371,36 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 	}
 }
 
+static void init_intel_energy_perf(struct cpuinfo_x86 *c)
+{
+	u64 epb;
+
+	/*
+	 * Initialize MSR_IA32_ENERGY_PERF_BIAS if not already initialized.
+	 * x86_energy_perf_policy(8) is available to change it at run-time
+	 */
+	if (!cpu_has(c, X86_FEATURE_EPB))
+		return;
+
+	rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
+	if ((epb & 0xF) != ENERGY_PERF_BIAS_PERFORMANCE)
+		return;
+
+	pr_warn_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance'\n");
+	pr_warn_once("ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)\n");
+	epb = (epb & ~0xF) | ENERGY_PERF_BIAS_NORMAL;
+	wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
+}
+
+static void intel_bsp_resume(struct cpuinfo_x86 *c)
+{
+	/*
+	 * MSR_IA32_ENERGY_PERF_BIAS is lost across suspend resume
+	 * so treat this as a bootup case to reinitialize it properly.
+	 */
+	init_intel_energy_perf(c);
+}
+
 static void init_intel(struct cpuinfo_x86 *c)
 {
 	unsigned int l2 = 0;
@@ -478,21 +508,7 @@ static void init_intel(struct cpuinfo_x86 *c)
 	if (cpu_has(c, X86_FEATURE_VMX))
 		detect_vmx_virtcap(c);
 
-	/*
-	 * Initialize MSR_IA32_ENERGY_PERF_BIAS if BIOS did not.
-	 * x86_energy_perf_policy(8) is available to change it at run-time
-	 */
-	if (cpu_has(c, X86_FEATURE_EPB)) {
-		u64 epb;
-
-		rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
-		if ((epb & 0xF) == ENERGY_PERF_BIAS_PERFORMANCE) {
-			pr_warn_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance'\n");
-			pr_warn_once("ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)\n");
-			epb = (epb & ~0xF) | ENERGY_PERF_BIAS_NORMAL;
-			wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
-		}
-	}
+	init_intel_energy_perf(c);
 }
 
 #ifdef CONFIG_X86_32
@@ -747,6 +763,7 @@ static const struct cpu_dev intel_cpu_dev = {
 	.c_detect_tlb	= intel_detect_tlb,
 	.c_early_init   = early_init_intel,
 	.c_init		= init_intel,
+	.c_bsp_resume	= intel_bsp_resume,
 	.c_x86_vendor	= X86_VENDOR_INTEL,
 };
 
-- 
2.4.3


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* [tip:x86/cpu] x86/cpu: Restore MSR_IA32_ENERGY_PERF_BIAS after resume
  2015-07-20 21:47 [PATCHv3] x86, CPU: Restore MSR_IA32_ENERGY_PERF_BIAS after resume Laura Abbott
@ 2015-07-21  9:36 ` tip-bot for Laura Abbott
  0 siblings, 0 replies; 2+ messages in thread
From: tip-bot for Laura Abbott @ 2015-07-21  9:36 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: labbott, luto, peterz, linux-kernel, mingo, tglx, torvalds, hpa, bp

Commit-ID:  b51ef52df71cb28e9d90cd1d48b79bf19f0bab06
Gitweb:     http://git.kernel.org/tip/b51ef52df71cb28e9d90cd1d48b79bf19f0bab06
Author:     Laura Abbott <labbott@fedoraproject.org>
AuthorDate: Mon, 20 Jul 2015 14:47:58 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 21 Jul 2015 07:51:38 +0200

x86/cpu: Restore MSR_IA32_ENERGY_PERF_BIAS after resume

MSR_IA32_ENERGY_PERF_BIAS is lost after suspend/resume:

	x86_energy_perf_policy -r before

	cpu0: 0x0000000000000006
	cpu1: 0x0000000000000006
	cpu2: 0x0000000000000006
	cpu3: 0x0000000000000006
	cpu4: 0x0000000000000006
	cpu5: 0x0000000000000006
	cpu6: 0x0000000000000006
	cpu7: 0x0000000000000006

	after

	cpu0: 0x0000000000000000
	cpu1: 0x0000000000000006
	cpu2: 0x0000000000000006
	cpu3: 0x0000000000000006
	cpu4: 0x0000000000000006
	cpu5: 0x0000000000000006
	cpu6: 0x0000000000000006
	cpu7: 0x0000000000000006

Resulting in inconsistent energy policy settings across CPUs.

This register is set via init_intel() at bootup. During resume,
the secondary CPUs are brought online again and init_intel() is
callled which re-initializes the register. The boot CPU however
never reinitializes the register.

Add a syscore callback to reinitialize the register for the boot CPU.

Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437428878-4105-1-git-send-email-labbott@fedoraproject.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/cpu/common.c | 18 +++++++++++++++++
 arch/x86/kernel/cpu/cpu.h    |  1 +
 arch/x86/kernel/cpu/intel.c  | 47 ++++++++++++++++++++++++++++++--------------
 3 files changed, 51 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 922c5e0..fa95bb8 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -13,6 +13,7 @@
 #include <linux/kgdb.h>
 #include <linux/smp.h>
 #include <linux/io.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/stackprotector.h>
 #include <asm/perf_event.h>
@@ -1488,3 +1489,20 @@ inline bool __static_cpu_has_safe(u16 bit)
 	return boot_cpu_has(bit);
 }
 EXPORT_SYMBOL_GPL(__static_cpu_has_safe);
+
+static void bsp_resume(void)
+{
+	if (this_cpu->c_bsp_resume)
+		this_cpu->c_bsp_resume(&boot_cpu_data);
+}
+
+static struct syscore_ops cpu_syscore_ops = {
+	.resume		= bsp_resume,
+};
+
+static int __init init_cpu_syscore(void)
+{
+	register_syscore_ops(&cpu_syscore_ops);
+	return 0;
+}
+core_initcall(init_cpu_syscore);
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index c37dc37..2584265 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -13,6 +13,7 @@ struct cpu_dev {
 	void		(*c_init)(struct cpuinfo_x86 *);
 	void		(*c_identify)(struct cpuinfo_x86 *);
 	void		(*c_detect_tlb)(struct cpuinfo_x86 *);
+	void		(*c_bsp_resume)(struct cpuinfo_x86 *);
 	int		c_x86_vendor;
 #ifdef CONFIG_X86_32
 	/* Optional vendor specific routine to obtain the cache size. */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 50163fa..98a13db 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -371,6 +371,36 @@ static void detect_vmx_virtcap(struct cpuinfo_x86 *c)
 	}
 }
 
+static void init_intel_energy_perf(struct cpuinfo_x86 *c)
+{
+	u64 epb;
+
+	/*
+	 * Initialize MSR_IA32_ENERGY_PERF_BIAS if not already initialized.
+	 * (x86_energy_perf_policy(8) is available to change it at run-time.)
+	 */
+	if (!cpu_has(c, X86_FEATURE_EPB))
+		return;
+
+	rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
+	if ((epb & 0xF) != ENERGY_PERF_BIAS_PERFORMANCE)
+		return;
+
+	pr_warn_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance'\n");
+	pr_warn_once("ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)\n");
+	epb = (epb & ~0xF) | ENERGY_PERF_BIAS_NORMAL;
+	wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
+}
+
+static void intel_bsp_resume(struct cpuinfo_x86 *c)
+{
+	/*
+	 * MSR_IA32_ENERGY_PERF_BIAS is lost across suspend/resume,
+	 * so reinitialize it properly like during bootup:
+	 */
+	init_intel_energy_perf(c);
+}
+
 static void init_intel(struct cpuinfo_x86 *c)
 {
 	unsigned int l2 = 0;
@@ -478,21 +508,7 @@ static void init_intel(struct cpuinfo_x86 *c)
 	if (cpu_has(c, X86_FEATURE_VMX))
 		detect_vmx_virtcap(c);
 
-	/*
-	 * Initialize MSR_IA32_ENERGY_PERF_BIAS if BIOS did not.
-	 * x86_energy_perf_policy(8) is available to change it at run-time
-	 */
-	if (cpu_has(c, X86_FEATURE_EPB)) {
-		u64 epb;
-
-		rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
-		if ((epb & 0xF) == ENERGY_PERF_BIAS_PERFORMANCE) {
-			pr_warn_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance'\n");
-			pr_warn_once("ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)\n");
-			epb = (epb & ~0xF) | ENERGY_PERF_BIAS_NORMAL;
-			wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
-		}
-	}
+	init_intel_energy_perf(c);
 }
 
 #ifdef CONFIG_X86_32
@@ -747,6 +763,7 @@ static const struct cpu_dev intel_cpu_dev = {
 	.c_detect_tlb	= intel_detect_tlb,
 	.c_early_init   = early_init_intel,
 	.c_init		= init_intel,
+	.c_bsp_resume	= intel_bsp_resume,
 	.c_x86_vendor	= X86_VENDOR_INTEL,
 };
 

^ permalink raw reply related	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2015-07-21  9:37 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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2015-07-20 21:47 [PATCHv3] x86, CPU: Restore MSR_IA32_ENERGY_PERF_BIAS after resume Laura Abbott
2015-07-21  9:36 ` [tip:x86/cpu] x86/cpu: " tip-bot for Laura Abbott

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