Commit-ID: b51ef52df71cb28e9d90cd1d48b79bf19f0bab06
Gitweb: http://git.kernel.org/tip/b51ef52df71cb28e9d90cd1d48b79bf19f0bab06
Author: Laura Abbott <labbott@xxxxxxxxxxxxxxxxx>
AuthorDate: Mon, 20 Jul 2015 14:47:58 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1437428878-4105-1-git-send-email-labbott@xxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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,
};
--
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