Merge branch 'pm-x86'

* pm-x86:
  x86/power: Fix 'nosmt' vs hibernation triple fault during resume
  x86: intel_epb: Do not build when CONFIG_PM is unset

arch/x86/kernel/cpu/Makefile

@@ -28,7 +28,10 @@ obj-y			+= cpuid-deps.o
 obj-$(CONFIG_PROC_FS)	+= proc.o
 obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o
 
-obj-$(CONFIG_CPU_SUP_INTEL)		+= intel.o intel_pconfig.o intel_epb.o
+ifdef CONFIG_CPU_SUP_INTEL
+obj-y			+= intel.o intel_pconfig.o
+obj-$(CONFIG_PM)	+= intel_epb.o
+endif
 obj-$(CONFIG_CPU_SUP_AMD)		+= amd.o
 obj-$(CONFIG_CPU_SUP_HYGON)		+= hygon.o
 obj-$(CONFIG_CPU_SUP_CYRIX_32)		+= cyrix.o

arch/x86/kernel/cpu/intel_epb.c

@@ -97,7 +97,6 @@ static void intel_epb_restore(void)
 	wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, (epb & ~EPB_MASK) | val);
 }
 
-#ifdef CONFIG_PM
 static struct syscore_ops intel_epb_syscore_ops = {
 	.suspend = intel_epb_save,
 	.resume = intel_epb_restore,
@@ -194,25 +193,6 @@ static int intel_epb_offline(unsigned int cpu)
 	return 0;
 }
 
-static inline void register_intel_ebp_syscore_ops(void)
-{
-	register_syscore_ops(&intel_epb_syscore_ops);
-}
-#else /* !CONFIG_PM */
-static int intel_epb_online(unsigned int cpu)
-{
-	intel_epb_restore();
-	return 0;
-}
-
-static int intel_epb_offline(unsigned int cpu)
-{
-	return intel_epb_save();
-}
-
-static inline void register_intel_ebp_syscore_ops(void) {}
-#endif
-
 static __init int intel_epb_init(void)
 {
 	int ret;
@@ -226,7 +206,7 @@ static __init int intel_epb_init(void)
 	if (ret < 0)
 		goto err_out_online;
 
-	register_intel_ebp_syscore_ops();
+	register_syscore_ops(&intel_epb_syscore_ops);
 	return 0;
 
 err_out_online:

arch/x86/power/cpu.c

@@ -299,7 +299,17 @@ int hibernate_resume_nonboot_cpu_disable(void)
 	 * address in its instruction pointer may not be possible to resolve
 	 * any more at that point (the page tables used by it previously may
 	 * have been overwritten by hibernate image data).
+	 *
+	 * First, make sure that we wake up all the potentially disabled SMT
+	 * threads which have been initially brought up and then put into
+	 * mwait/cpuidle sleep.
+	 * Those will be put to proper (not interfering with hibernation
+	 * resume) sleep afterwards, and the resumed kernel will decide itself
+	 * what to do with them.
 	 */
+	ret = cpuhp_smt_enable();
+	if (ret)
+		return ret;
 	smp_ops.play_dead = resume_play_dead;
 	ret = disable_nonboot_cpus();
 	smp_ops.play_dead = play_dead;

arch/x86/power/hibernate.c

@@ -11,6 +11,7 @@
 #include <linux/suspend.h>
 #include <linux/scatterlist.h>
 #include <linux/kdebug.h>
+#include <linux/cpu.h>
 
 #include <crypto/hash.h>
 
@@ -245,3 +246,35 @@ out:
 	__flush_tlb_all();
 	return 0;
 }
+
+int arch_resume_nosmt(void)
+{
+	int ret = 0;
+	/*
+	 * We reached this while coming out of hibernation. This means
+	 * that SMT siblings are sleeping in hlt, as mwait is not safe
+	 * against control transition during resume (see comment in
+	 * hibernate_resume_nonboot_cpu_disable()).
+	 *
+	 * If the resumed kernel has SMT disabled, we have to take all the
+	 * SMT siblings out of hlt, and offline them again so that they
+	 * end up in mwait proper.
+	 *
+	 * Called with hotplug disabled.
+	 */
+	cpu_hotplug_enable();
+	if (cpu_smt_control == CPU_SMT_DISABLED ||
+			cpu_smt_control == CPU_SMT_FORCE_DISABLED) {
+		enum cpuhp_smt_control old = cpu_smt_control;
+
+		ret = cpuhp_smt_enable();
+		if (ret)
+			goto out;
+		ret = cpuhp_smt_disable(old);
+		if (ret)
+			goto out;
+	}
+out:
+	cpu_hotplug_disable();
+	return ret;
+}

include/linux/cpu.h

@@ -201,10 +201,14 @@ enum cpuhp_smt_control {
 extern enum cpuhp_smt_control cpu_smt_control;
 extern void cpu_smt_disable(bool force);
 extern void cpu_smt_check_topology(void);
+extern int cpuhp_smt_enable(void);
+extern int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval);
 #else
 # define cpu_smt_control		(CPU_SMT_NOT_IMPLEMENTED)
 static inline void cpu_smt_disable(bool force) { }
 static inline void cpu_smt_check_topology(void) { }
+static inline int cpuhp_smt_enable(void) { return 0; }
+static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; }
 #endif
 
 /*

kernel/cpu.c

@@ -2061,7 +2061,7 @@ static void cpuhp_online_cpu_device(unsigned int cpu)
 	kobject_uevent(&dev->kobj, KOBJ_ONLINE);
 }
 
-static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
+int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
 {
 	int cpu, ret = 0;
 
@@ -2093,7 +2093,7 @@ static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
 	return ret;
 }
 
-static int cpuhp_smt_enable(void)
+int cpuhp_smt_enable(void)
 {
 	int cpu, ret = 0;
 

kernel/power/hibernate.c

@@ -257,6 +257,11 @@ void swsusp_show_speed(ktime_t start, ktime_t stop,
 		(kps % 1000) / 10);
 }
 
+__weak int arch_resume_nosmt(void)
+{
+	return 0;
+}
+
 /**
  * create_image - Create a hibernation image.
  * @platform_mode: Whether or not to use the platform driver.
@@ -324,6 +329,10 @@ static int create_image(int platform_mode)
  Enable_cpus:
 	suspend_enable_secondary_cpus();
 
+	/* Allow architectures to do nosmt-specific post-resume dances */
+	if (!in_suspend)
+		error = arch_resume_nosmt();
+
  Platform_finish:
 	platform_finish(platform_mode);