diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 04b60af027ae..ea0dbf2bbeef 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -49,6 +49,9 @@ extern unsigned int debug_smp_processor_id(void); /* from linux/smp.h */
 #define get_lppaca()	(get_paca()->lppaca_ptr)
 #define get_slb_shadow()	(get_paca()->slb_shadow_ptr)
 
+/* Maximum number of threads per core. */
+#define	MAX_SMT		8
+
 struct task_struct;
 
 /*
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index fac963e10d39..553cd22b2ccc 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -30,6 +30,7 @@
 #include <asm/percpu.h>
 
 extern int boot_cpuid;
+extern int boot_hw_cpuid;
 extern int spinning_secondaries;
 
 extern void cpu_die(void);
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 2ff2b8a19f71..9c689ee4b6a3 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -207,6 +207,7 @@ void __init allocate_pacas(void)
 {
 	u64 limit;
 	int cpu;
+	unsigned int nr_cpus;
 
 	limit = ppc64_rma_size;
 
@@ -219,20 +220,32 @@ void __init allocate_pacas(void)
 	limit = min(0x10000000ULL, limit);
 #endif
 
-	paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
+	/*
+	 * Always align up the nr_cpu_ids to SMT threads and allocate
+	 * the paca. This will help us to prepare for a situation where
+	 * boot cpu id > nr_cpus_id. We will use the last nthreads
+	 * slots (nthreads == threads per core) to accommodate a core
+	 * that contains boot cpu thread.
+	 *
+	 * Do not change nr_cpu_ids value here. Let us do that in
+	 * early_init_dt_scan_cpus() where we know exact value
+	 * of threads per core.
+	 */
+	nr_cpus = _ALIGN_UP(nr_cpu_ids, MAX_SMT);
+	paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpus);
 
 	paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 	memset(paca, 0, paca_size);
 
 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas at %p\n",
-		paca_size, nr_cpu_ids, paca);
+		paca_size, nr_cpus, paca);
 
-	allocate_lppacas(nr_cpu_ids, limit);
+	allocate_lppacas(nr_cpus, limit);
 
-	allocate_slb_shadows(nr_cpu_ids, limit);
+	allocate_slb_shadows(nr_cpus, limit);
 
 	/* Can't use for_each_*_cpu, as they aren't functional yet */
-	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
+	for (cpu = 0; cpu < nr_cpus; cpu++)
 		initialise_paca(&paca[cpu], cpu);
 }
 
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index f83056297441..93837093c5cb 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -302,6 +302,29 @@ static void __init check_cpu_feature_properties(unsigned long node)
 	}
 }
 
+/*
+ * Adjust the logical id of a boot cpu to fall under nr_cpu_ids. Map it to
+ * last core slot in the allocated paca array.
+ *
+ * e.g. on SMT=8 system, kernel booted with nr_cpus=1 and boot cpu = 33,
+ * align nr_cpu_ids to MAX_SMT value 8. Allocate paca array to hold up-to
+ * MAX_SMT=8 cpus. Since boot cpu 33 is greater than nr_cpus (8), adjust
+ * its logical id so that new id becomes less than nr_cpu_ids. Make sure
+ * that boot cpu's new logical id is aligned to its thread id and falls
+ * under last nthreads slots available in paca array. In this case the
+ * boot cpu 33 is adjusted to new boot cpu id 1.
+ *
+ */
+static inline void adjust_boot_cpuid(int nthreads, int phys_id)
+{
+	boot_hw_cpuid = phys_id;
+	if (boot_cpuid >= nr_cpu_ids) {
+		boot_cpuid = (boot_cpuid % nthreads) + (nr_cpu_ids - nthreads);
+		pr_info("Adjusted logical boot cpu id: logical %d physical %d\n",
+			boot_cpuid, phys_id);
+	}
+}
+
 static int __init early_init_dt_scan_cpus(unsigned long node,
 					  const char *uname, int depth,
 					  void *data)
@@ -325,6 +348,18 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 
 	nthreads = len / sizeof(int);
 
+#ifdef CONFIG_SMP
+	/*
+	 * Now that we know threads per core lets align nr_cpu_ids to
+	 * correct SMT value.
+	 */
+	if (nr_cpu_ids % nthreads) {
+		nr_cpu_ids = _ALIGN_UP(nr_cpu_ids, nthreads);
+		pr_info("Aligned nr_cpus to SMT=%d, nr_cpu_ids = %d\n",
+				 nthreads, nr_cpu_ids);
+	}
+#endif
+
 	/*
 	 * Now see if any of these threads match our boot cpu.
 	 * NOTE: This must match the parsing done in smp_setup_cpu_maps.
@@ -363,7 +398,9 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 	DBG("boot cpu: logical %d physical %d\n", found,
 	    be32_to_cpu(intserv[found_thread]));
 	boot_cpuid = found;
-	set_hard_smp_processor_id(found, be32_to_cpu(intserv[found_thread]));
+	adjust_boot_cpuid(nthreads, be32_to_cpu(intserv[found_thread]));
+	set_hard_smp_processor_id(boot_cpuid,
+					be32_to_cpu(intserv[found_thread]));
 
 	/*
 	 * PAPR defines "logical" PVR values for cpus that
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 2e3bc16d02b2..46b1e0972a20 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -85,6 +85,7 @@ struct machdep_calls *machine_id;
 EXPORT_SYMBOL(machine_id);
 
 int boot_cpuid = -1;
+int boot_hw_cpuid = -1;
 EXPORT_SYMBOL_GPL(boot_cpuid);
 
 /*
@@ -473,6 +474,7 @@ void __init smp_setup_cpu_maps(void)
 	struct device_node *dn = NULL;
 	int cpu = 0;
 	int nthreads = 1;
+	bool boot_cpu_added = false;
 
 	DBG("smp_setup_cpu_maps()\n");
 
@@ -499,6 +501,24 @@ void __init smp_setup_cpu_maps(void)
 		}
 
 		nthreads = len / sizeof(int);
+		/*
+		 * If boot cpu hasn't been added to paca and there are only
+		 * last nthreads slots available in paca array then wait
+		 * for boot cpu to show up.
+		 */
+		if (!boot_cpu_added && (cpu + nthreads) >= nr_cpu_ids) {
+			int found = 0;
+
+			DBG("Holding last nthreads paca slots for boot cpu\n");
+			for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
+				if (boot_hw_cpuid == be32_to_cpu(intserv[j])) {
+					found = 1;
+					break;
+				}
+			}
+			if (!found)
+				continue;
+		}
 
 		for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
 			bool avail;
@@ -514,6 +534,11 @@ void __init smp_setup_cpu_maps(void)
 			set_cpu_present(cpu, avail);
 			set_hard_smp_processor_id(cpu, be32_to_cpu(intserv[j]));
 			set_cpu_possible(cpu, true);
+			if (boot_hw_cpuid == be32_to_cpu(intserv[j])) {
+				DBG("Boot cpu %d (hard id %d) added to paca\n",
+				    cpu, be32_to_cpu(intserv[j]));
+				boot_cpu_added = true;
+			}
 			cpu++;
 		}
 	}
