3 files changed, 51 insertions, 15 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index b128808853a2..07ce52c22ec8 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 c37dc37e8317..2584265d4745 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 50163fa9034f..98a13db5f4be 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,
 };