===============================================================================
				Patch 1
===============================================================================

diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 16d7e33..2a31b52 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -68,6 +68,7 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
 		ppc_save_regs(newregs);
 }
 
+extern bool kexec_cpu_wake(void);
 extern void kexec_smp_wait(void);	/* get and clear naca physid, wait for
 					  master to copy new code to 0 */
 extern int crashing_cpu;
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index f92b0b5..39f721d 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -255,6 +255,16 @@ struct machdep_calls {
 	void (*machine_shutdown)(void);
 
 #ifdef CONFIG_KEXEC
+#if (defined CONFIG_PPC64) && (defined CONFIG_PPC_BOOK3S)
+
+	/*
+	 * The pseries and powernv book3s platforms have a special requirement
+	 * that soft-offline CPUs have to be woken up before kexec, to avoid
+	 * CPUs getting stuck. This callback prepares the system for the
+	 * impending wakeup of the offline CPUs.
+	 */
+	void (*kexec_wake_prepare)(void);
+#endif
 	void (*kexec_cpu_down)(int crash_shutdown, int secondary);
 
 	/* Called to do what every setup is needed on image and the
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 879b3aa..2ef6c58 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -182,6 +182,14 @@ static void kexec_smp_down(void *arg)
 	/* NOTREACHED */
 }
 
+bool kexec_cpu_wake(void)
+{
+	kexec_smp_down(NULL);
+
+	/* NOTREACHED */
+	return true;
+}
+
 static void kexec_prepare_cpus_wait(int wait_state)
 {
 	int my_cpu, i, notified=-1;
@@ -202,7 +210,7 @@ static void kexec_prepare_cpus_wait(int wait_state)
 	 * these possible-but-not-online-but-should-be CPUs and chaperone them
 	 * into kexec_smp_wait().
 	 */
-	for_each_online_cpu(i) {
+	for_each_present_cpu(i) {
 		if (i == my_cpu)
 			continue;
 
@@ -228,6 +236,8 @@ static void kexec_prepare_cpus_wait(int wait_state)
  * threads as offline -- and again, these CPUs will be stuck.
  *
  * So, we online all CPUs that should be running, including secondary threads.
+ *
+ * TODO: Update this comment
  */
 static void wake_offline_cpus(void)
 {
@@ -237,7 +247,8 @@ static void wake_offline_cpus(void)
 		if (!cpu_online(cpu)) {
 			printk(KERN_INFO "kexec: Waking offline cpu %d.\n",
 			       cpu);
-			WARN_ON(cpu_up(cpu));
+			/* This should work even though the cpu is offline */
+			smp_send_reschedule(cpu);
 		}
 	}
 }



===============================================================================
				Patch 2
===============================================================================

diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h
index 75501bf..910081c 100644
--- a/arch/powerpc/platforms/powernv/powernv.h
+++ b/arch/powerpc/platforms/powernv/powernv.h
@@ -27,4 +27,8 @@ extern void pnv_lpc_init(void);
 
 bool cpu_core_split_required(void);
 
+#ifdef CONFIG_KEXEC
+extern void pnv_kexec_wake_prepare(void);
+#endif
+
 #endif /* _POWERNV_H */
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 8c16a5f..8dbccb7 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -331,6 +331,7 @@ define_machine(powernv) {
 	.calibrate_decr		= generic_calibrate_decr,
 	.dma_set_mask		= pnv_dma_set_mask,
 #ifdef CONFIG_KEXEC
+	.kexec_wake_prepare	= pnv_kexec_wake_prepare,
 	.kexec_cpu_down		= pnv_kexec_cpu_down,
 #endif
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index 0062a43..0b017b0 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -32,6 +32,7 @@
 #include <asm/opal.h>
 #include <asm/runlatch.h>
 #include <asm/code-patching.h>
+#include <asm/kexec.h>
 
 #include "powernv.h"
 
@@ -140,6 +141,15 @@ static int pnv_smp_cpu_disable(void)
 	return 0;
 }
 
+#ifdef CONFIG_KEXEC
+static bool kexec_wake_offline_cpus;
+
+void pnv_kexec_wake_prepare(void)
+{
+	kexec_wake_offline_cpus = true;
+}
+#endif
+
 static void pnv_smp_cpu_kill_self(void)
 {
 	unsigned int cpu;
@@ -170,6 +180,11 @@ static void pnv_smp_cpu_kill_self(void)
 		if (cpu_core_split_required())
 			continue;
 
+#ifdef CONFIG_KEXEC
+		if (kexec_wake_offline_cpus)
+			kexec_cpu_wake(); /* This function won't return! */
+#endif
+
 		if (!generic_check_cpu_restart(cpu))
 			DBG("CPU%d Unexpected exit while offline !\n", cpu);
 	}




===============================================================================
				Patch 3
===============================================================================

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 20d6297..d026028 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -31,6 +31,7 @@
 #include <asm/vdso_datapage.h>
 #include <asm/xics.h>
 #include <asm/plpar_wrappers.h>
+#include <asm/kexec.h>
 
 #include "offline_states.h"
 
@@ -143,6 +144,13 @@ static void pseries_mach_cpu_die(void)
 			get_lppaca()->donate_dedicated_cpu = 0;
 		get_lppaca()->idle = 0;
 
+#if CONFIG_KEXEC
+		if (get_preferred_offline_state(cpu) == CPU_STATE_KEXEC_WAKE) {
+			/* This function won't return! */
+			kexec_cpu_wake();
+		}
+#endif
+
 		if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
 			unregister_slb_shadow(hwcpu);
 
diff --git a/arch/powerpc/platforms/pseries/kexec.c b/arch/powerpc/platforms/pseries/kexec.c
index 13fa95b3..fc135e6 100644
--- a/arch/powerpc/platforms/pseries/kexec.c
+++ b/arch/powerpc/platforms/pseries/kexec.c
@@ -20,6 +20,17 @@
 #include <asm/plpar_wrappers.h>
 
 #include "pseries.h"
+#include "offline_states.h"
+
+void pseries_kexec_wake_prepare(void)
+{
+	unsigned int cpu;
+
+	for_each_present_cpu(cpu) {
+		if (!cpu_online(cpu))
+			set_preferred_offline_state(cpu, CPU_STATE_KEXEC_WAKE);
+	}
+}
 
 static void pseries_kexec_cpu_down(int crash_shutdown, int secondary)
 {
diff --git a/arch/powerpc/platforms/pseries/offline_states.h b/arch/powerpc/platforms/pseries/offline_states.h
index 08672d9..32fe5e8 100644
--- a/arch/powerpc/platforms/pseries/offline_states.h
+++ b/arch/powerpc/platforms/pseries/offline_states.h
@@ -5,6 +5,9 @@
 enum cpu_state_vals {
 	CPU_STATE_OFFLINE,
 	CPU_STATE_INACTIVE,
+#ifdef CONFIG_KEXEC
+	CPU_STATE_KEXEC_WAKE,
+#endif
 	CPU_STATE_ONLINE,
 	CPU_MAX_OFFLINE_STATES
 };
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 361add6..35ecb99 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -38,6 +38,8 @@ static inline void smp_init_pseries_xics(void) { };
 #endif
 
 #ifdef CONFIG_KEXEC
+extern void pseries_kexec_wake_prepare(void);
+
 extern void setup_kexec_cpu_down_xics(void);
 extern void setup_kexec_cpu_down_mpic(void);
 #else
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index adc21a0..c1a0722 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -808,6 +808,7 @@ define_machine(pseries) {
 	.system_reset_exception = pSeries_system_reset_exception,
 	.machine_check_exception = pSeries_machine_check_exception,
 #ifdef CONFIG_KEXEC
+	.kexec_wake_prepare	= pseries_kexec_wake_prepare,
 	.machine_kexec          = pSeries_machine_kexec,
 #endif
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE



===============================================================================
				Patch 4
===============================================================================

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 28c5706..55a6350 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1684,13 +1684,6 @@ int kernel_kexec(void)
 		kernel_restart_prepare(NULL);
 		migrate_to_reboot_cpu();
 
-		/*
-		 * migrate_to_reboot_cpu() disables CPU hotplug assuming that
-		 * no further code needs to use CPU hotplug (which is true in
-		 * the reboot case). However, the kexec path depends on using
-		 * CPU hotplug again; so re-enable it here.
-		 */
-		cpu_hotplug_enable();
 		printk(KERN_EMERG "Starting new kernel\n");
 		machine_shutdown();
 	}
