diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 325873385b71..de725ca3be82 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -562,7 +562,8 @@ Description:	Control Symmetric Multi Threading (SMT)
 			 ================ =========================================
 
 			 If control status is "forceoff" or "notsupported" writes
-			 are rejected.
+			 are rejected. Note that enabling SMT on PowerPC skips
+			 offline cores.
 
 What:		/sys/devices/system/cpu/cpuX/power/energy_perf_bias
 Date:		March 2019
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index f4e6f2dd04b7..16bacfe8c7a2 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -145,6 +145,7 @@ static inline int cpu_to_coregroup_id(int cpu)
 
 #ifdef CONFIG_HOTPLUG_SMT
 #include <linux/cpu_smt.h>
+#include <linux/cpumask.h>
 #include <asm/cputhreads.h>
 
 static inline bool topology_is_primary_thread(unsigned int cpu)
@@ -156,6 +157,18 @@ static inline bool topology_smt_thread_allowed(unsigned int cpu)
 {
 	return cpu_thread_in_core(cpu) < cpu_smt_num_threads;
 }
+
+#define topology_is_core_online topology_is_core_online
+static inline bool topology_is_core_online(unsigned int cpu)
+{
+	int i, first_cpu = cpu_first_thread_sibling(cpu);
+
+	for (i = first_cpu; i < first_cpu + threads_per_core; ++i) {
+		if (cpu_online(i))
+			return true;
+	}
+	return false;
+}
 #endif
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 4bd2f87616ba..943430077375 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -959,6 +959,7 @@ void __init setup_arch(char **cmdline_p)
 	mem_topology_setup();
 	/* Set max_mapnr before paging_init() */
 	set_max_mapnr(max_pfn);
+	high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
 
 	/*
 	 * Release secondary cpus out of their spinloops at 0x60 now that
diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index 9b4a675eb8f8..2978fcbe307e 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -73,7 +73,7 @@ void setup_kup(void)
 
 #define CTOR(shift) static void ctor_##shift(void *addr) \
 {							\
-	memset(addr, 0, sizeof(void *) << (shift));	\
+	memset(addr, 0, sizeof(pgd_t) << (shift));	\
 }
 
 CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7);
@@ -117,7 +117,7 @@ EXPORT_SYMBOL_GPL(pgtable_cache);	/* used by kvm_hv module */
 void pgtable_cache_add(unsigned int shift)
 {
 	char *name;
-	unsigned long table_size = sizeof(void *) << shift;
+	unsigned long table_size = sizeof(pgd_t) << shift;
 	unsigned long align = table_size;
 
 	/* When batching pgtable pointers for RCU freeing, we store
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index d325217ab201..da21cb018984 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -290,8 +290,6 @@ void __init mem_init(void)
 	swiotlb_init(ppc_swiotlb_enable, ppc_swiotlb_flags);
 #endif
 
-	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
-
 	kasan_late_init();
 
 	memblock_free_all();
diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
index 7e9074519ad2..4dc8aba33d9b 100644
--- a/drivers/soc/fsl/qbman/qman.c
+++ b/drivers/soc/fsl/qbman/qman.c
@@ -2546,11 +2546,6 @@ release_lock:
 }
 EXPORT_SYMBOL(qman_delete_cgr);
 
-struct cgr_comp {
-	struct qman_cgr *cgr;
-	struct completion completion;
-};
-
 static void qman_delete_cgr_smp_call(void *p)
 {
 	qman_delete_cgr((struct qman_cgr *)p);
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 1209ddaec026..b1fd2a3db91a 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2689,6 +2689,16 @@ int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
 	return ret;
 }
 
+/**
+ * Check if the core a CPU belongs to is online
+ */
+#if !defined(topology_is_core_online)
+static inline bool topology_is_core_online(unsigned int cpu)
+{
+	return true;
+}
+#endif
+
 int cpuhp_smt_enable(void)
 {
 	int cpu, ret = 0;
@@ -2699,7 +2709,7 @@ int cpuhp_smt_enable(void)
 		/* Skip online CPUs and CPUs on offline nodes */
 		if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
 			continue;
-		if (!cpu_smt_thread_allowed(cpu))
+		if (!cpu_smt_thread_allowed(cpu) || !topology_is_core_online(cpu))
 			continue;
 		ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
 		if (ret)