From b51ef52df71cb28e9d90cd1d48b79bf19f0bab06 Mon Sep 17 00:00:00 2001
From: Laura Abbott <labbott@fedoraproject.org>
Date: Mon, 20 Jul 2015 14:47:58 -0700
Subject: 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 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'arch/x86/kernel/cpu/common.c')

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 922c5e0cea4c..fa95bb8829ce 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);
-- 
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