27 files changed, 153 insertions, 106 deletions

diff --git a/arch/powerpc/kernel/btext.c b/arch/powerpc/kernel/btext.c
index 625942ae558..60b3e377b1e 100644
--- a/arch/powerpc/kernel/btext.c
+++ b/arch/powerpc/kernel/btext.c
@@ -99,7 +99,7 @@ void __init btext_prepare_BAT(void)
 
 /* This function can be used to enable the early boot text when doing
  * OF booting or within bootx init. It must be followed by a btext_unmap()
- * call before the logical address becomes unuseable
+ * call before the logical address becomes unusable
  */
 void __init btext_setup_display(int width, int height, int depth, int pitch,
                                 unsigned long address)
diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 3d569e2aff1..3d3d416339d 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -163,7 +163,7 @@ static void crash_kexec_prepare_cpus(int cpu)
 }
 
 /* wait for all the CPUs to hit real mode but timeout if they don't come in */
-#ifdef CONFIG_PPC_STD_MMU_64
+#if defined(CONFIG_PPC_STD_MMU_64) && defined(CONFIG_SMP)
 static void crash_kexec_wait_realmode(int cpu)
 {
         unsigned int msecs;
@@ -188,6 +188,8 @@ static void crash_kexec_wait_realmode(int cpu)
         }
         mb();
 }
+#else
+static inline void crash_kexec_wait_realmode(int cpu) {}
 #endif
 
 /*
@@ -344,9 +346,7 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
         crash_save_cpu(regs, crashing_cpu);
         crash_kexec_prepare_cpus(crashing_cpu);
         cpu_set(crashing_cpu, cpus_in_crash);
-#if defined(CONFIG_PPC_STD_MMU_64) && defined(CONFIG_SMP)
         crash_kexec_wait_realmode(crashing_cpu);
-#endif
 
         machine_kexec_mask_interrupts();
 
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 5c43063d250..9651acc3504 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -379,7 +379,7 @@ interrupt_end_book3e:
         mfspr   r13,SPRN_SPRG_PACA      /* get our PACA */
         b       system_call_common
 
-/* Auxillary Processor Unavailable Interrupt */
+/* Auxiliary Processor Unavailable Interrupt */
         START_EXCEPTION(ap_unavailable);
         NORMAL_EXCEPTION_PROLOG(0xf20, PROLOG_ADDITION_NONE)
         EXCEPTION_COMMON(0xf20, PACA_EXGEN, INTS_KEEP)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index c532cb2c927..aeb739e1876 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -5,7 +5,7 @@
  * handling and other fixed offset specific things.
  *
  * This file is meant to be #included from head_64.S due to
- * position dependant assembly.
+ * position dependent assembly.
  *
  * Most of this originates from head_64.S and thus has the same
  * copyright history.
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 98c4b29a56f..c5c24beb838 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -890,6 +890,15 @@ __secondary_start:
         mtspr   SPRN_SRR1,r4
         SYNC
         RFI
+
+_GLOBAL(start_secondary_resume)
+        /* Reset stack */
+        rlwinm  r1,r1,0,0,(31-THREAD_SHIFT)     /* current_thread_info() */
+        addi    r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
+        li      r3,0
+        std     r3,0(r1)                /* Zero the stack frame pointer */
+        bl      start_secondary
+        b       .
 #endif /* CONFIG_SMP */
 
 #ifdef CONFIG_KVM_BOOK3S_HANDLER
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 9dd21a8c4d5..a91626d87fc 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -766,7 +766,7 @@ DataAccess:
          * miss get to this point to load the TLB.
          *      r10 - TLB_TAG value
          *      r11 - Linux PTE
-         *      r12, r9 - avilable to use
+         *      r12, r9 - available to use
          *      PID - loaded with proper value when we get here
          *      Upon exit, we reload everything and RFI.
          * Actually, it will fit now, but oh well.....a common place
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index cbb3436b592..5e12b741ba5 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -178,7 +178,7 @@ interrupt_base:
         NORMAL_EXCEPTION_PROLOG
         EXC_XFER_EE_LITE(0x0c00, DoSyscall)
 
-        /* Auxillary Processor Unavailable Interrupt */
+        /* Auxiliary Processor Unavailable Interrupt */
         EXCEPTION(0x2020, AuxillaryProcessorUnavailable, unknown_exception, EXC_XFER_EE)
 
         /* Decrementer Interrupt */
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 782f23df7c8..3a319f9c9d3 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -40,7 +40,7 @@
 #include <asm/kvm_book3s_asm.h>
 #include <asm/ptrace.h>
 
-/* The physical memory is layed out such that the secondary processor
+/* The physical memory is laid out such that the secondary processor
  * spin code sits at 0x0000...0x00ff. On server, the vectors follow
  * using the layout described in exceptions-64s.S
  */
@@ -536,6 +536,13 @@ _GLOBAL(pmac_secondary_start)
         add     r13,r13,r4              /* for this processor.          */
         mtspr   SPRN_SPRG_PACA,r13      /* Save vaddr of paca in an SPRG*/
 
+        /* Mark interrupts soft and hard disabled (they might be enabled
+         * in the PACA when doing hotplug)
+         */
+        li      r0,0
+        stb     r0,PACASOFTIRQEN(r13)
+        stb     r0,PACAHARDIRQEN(r13)
+
         /* Create a temp kernel stack for use before relocation is on.  */
         ld      r1,PACAEMERGSP(r13)
         subi    r1,r1,STACK_FRAME_OVERHEAD
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 3e02710d956..5ecf54cfa7d 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -326,7 +326,7 @@ interrupt_base:
         NORMAL_EXCEPTION_PROLOG
         EXC_XFER_EE_LITE(0x0c00, DoSyscall)
 
-        /* Auxillary Processor Unavailable Interrupt */
+        /* Auxiliary Processor Unavailable Interrupt */
         EXCEPTION(0x2900, AuxillaryProcessorUnavailable, unknown_exception, EXC_XFER_EE)
 
         /* Decrementer Interrupt */
diff --git a/arch/powerpc/kernel/idle_power4.S b/arch/powerpc/kernel/idle_power4.S
index 5328709eeed..ba319547860 100644
--- a/arch/powerpc/kernel/idle_power4.S
+++ b/arch/powerpc/kernel/idle_power4.S
@@ -53,24 +53,3 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
         isync
         b       1b
 
-_GLOBAL(power4_cpu_offline_powersave)
-        /* Go to NAP now */
-        mfmsr   r7
-        rldicl  r0,r7,48,1
-        rotldi  r0,r0,16
-        mtmsrd  r0,1                    /* hard-disable interrupts */
-        li      r0,1
-        li      r6,0
-        stb     r0,PACAHARDIRQEN(r13)   /* we'll hard-enable shortly */
-        stb     r6,PACASOFTIRQEN(r13)   /* soft-disable irqs */
-BEGIN_FTR_SECTION
-        DSSALL
-        sync
-END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
-        ori     r7,r7,MSR_EE
-        oris    r7,r7,MSR_POW@h
-        sync
-        isync
-        mtmsrd  r7
-        isync
-        blr
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 63625e0650b..f621b7d2d86 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -246,12 +246,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-void fixup_irqs(const struct cpumask *map)
+void migrate_irqs(void)
 {
         struct irq_desc *desc;
         unsigned int irq;
         static int warned;
         cpumask_var_t mask;
+        const struct cpumask *map = cpu_online_mask;
 
         alloc_cpumask_var(&mask, GFP_KERNEL);
 
diff --git a/arch/powerpc/kernel/l2cr_6xx.S b/arch/powerpc/kernel/l2cr_6xx.S
index 2a2f3c3f6d8..97ec8557f97 100644
--- a/arch/powerpc/kernel/l2cr_6xx.S
+++ b/arch/powerpc/kernel/l2cr_6xx.S
@@ -151,7 +151,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
          /**** Might be a good idea to set L2DO here - to prevent instructions
                from getting into the cache.  But since we invalidate
                the next time we enable the cache it doesn't really matter.
-               Don't do this unless you accomodate all processor variations.
+               Don't do this unless you accommodate all processor variations.
                The bit moved on the 7450.....
           ****/
 
diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 16468362ad5..301db65f05a 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -262,7 +262,7 @@ static void parse_ppp_data(struct seq_file *m)
         seq_printf(m, "system_active_processors=%d\n",
                    ppp_data.active_system_procs);
 
-        /* pool related entries are apropriate for shared configs */
+        /* pool related entries are appropriate for shared configs */
         if (lppaca_of(0).shared_proc) {
                 unsigned long pool_idle_time, pool_procs;
 
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index f4adf89d761..10f0aadee95 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -203,7 +203,7 @@ void __init free_unused_pacas(void)
 {
         int new_size;
 
-        new_size = PAGE_ALIGN(sizeof(struct paca_struct) * num_possible_cpus());
+        new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 
         if (new_size >= paca_size)
                 return;
diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c
index 97e0ae41494..c4063b7f49a 100644
--- a/arch/powerpc/kernel/perf_event.c
+++ b/arch/powerpc/kernel/perf_event.c
@@ -759,7 +759,7 @@ static int power_pmu_add(struct perf_event *event, int ef_flags)
 
         /*
          * If group events scheduling transaction was started,
-         * skip the schedulability test here, it will be peformed
+         * skip the schedulability test here, it will be performed
          * at commit time(->commit_txn) as a whole
          */
         if (cpuhw->group_flag & PERF_EVENT_TXN)
diff --git a/arch/powerpc/kernel/ppc_save_regs.S b/arch/powerpc/kernel/ppc_save_regs.S
index e83ba3f078e..1b1787d5289 100644
--- a/arch/powerpc/kernel/ppc_save_regs.S
+++ b/arch/powerpc/kernel/ppc_save_regs.S
@@ -15,7 +15,7 @@
 
 /*
  * Grab the register values as they are now.
- * This won't do a particularily good job because we really
+ * This won't do a particularly good job because we really
  * want our caller's caller's registers, and our caller has
  * already executed its prologue.
  * ToDo: We could reach back into the caller's save area to do
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 05b7139d6a2..e74fa12afc8 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -683,7 +683,7 @@ void __init early_init_devtree(void *params)
 #endif
 
 #ifdef CONFIG_PHYP_DUMP
-        /* scan tree to see if dump occured during last boot */
+        /* scan tree to see if dump occurred during last boot */
         of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 #endif
 
@@ -739,7 +739,7 @@ void __init early_init_devtree(void *params)
 
         DBG("Scanning CPUs ...\n");
 
-        /* Retreive CPU related informations from the flat tree
+        /* Retrieve CPU related informations from the flat tree
          * (altivec support, boot CPU ID, ...)
          */
         of_scan_flat_dt(early_init_dt_scan_cpus, NULL);
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 895b082f1e4..55613e33e26 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -463,7 +463,7 @@ static int vr_set(struct task_struct *target, const struct user_regset *regset,
 #ifdef CONFIG_VSX
 /*
  * Currently to set and and get all the vsx state, you need to call
- * the fp and VMX calls aswell.  This only get/sets the lower 32
+ * the fp and VMX calls as well.  This only get/sets the lower 32
  * 128bit VSX registers.
  */
 
diff --git a/arch/powerpc/kernel/rtasd.c b/arch/powerpc/kernel/rtasd.c
index 7980ec0e1e1..67f6c3b5135 100644
--- a/arch/powerpc/kernel/rtasd.c
+++ b/arch/powerpc/kernel/rtasd.c
@@ -465,7 +465,7 @@ static void start_event_scan(void)
         pr_debug("rtasd: will sleep for %d milliseconds\n",
                  (30000 / rtas_event_scan_rate));
 
-        /* Retreive errors from nvram if any */
+        /* Retrieve errors from nvram if any */
         retreive_nvram_error_log();
 
         schedule_delayed_work_on(cpumask_first(cpu_online_mask),
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 9d4882a4664..21f30cb6807 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -509,6 +509,9 @@ void __init smp_setup_cpu_maps(void)
          */
         cpu_init_thread_core_maps(nthreads);
 
+        /* Now that possible cpus are set, set nr_cpu_ids for later use */
+        nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
+
         free_unused_pacas();
 }
 #endif /* CONFIG_SMP */
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 98136050917..cbdbb14be4b 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -57,6 +57,25 @@
 #define DBG(fmt...)
 #endif
 
+
+/* Store all idle threads, this can be reused instead of creating
+* a new thread. Also avoids complicated thread destroy functionality
+* for idle threads.
+*/
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
+ * removed after init for !CONFIG_HOTPLUG_CPU.
+ */
+static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
+#define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
+#define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
+#else
+static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
+#define get_idle_for_cpu(x)      (idle_thread_array[(x)])
+#define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
+#endif
+
 struct thread_info *secondary_ti;
 
 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
@@ -238,23 +257,6 @@ static void __devinit smp_store_cpu_info(int id)
         per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
 }
 
-static void __init smp_create_idle(unsigned int cpu)
-{
-        struct task_struct *p;
-
-        /* create a process for the processor */
-        p = fork_idle(cpu);
-        if (IS_ERR(p))
-                panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
-#ifdef CONFIG_PPC64
-        paca[cpu].__current = p;
-        paca[cpu].kstack = (unsigned long) task_thread_info(p)
-                + THREAD_SIZE - STACK_FRAME_OVERHEAD;
-#endif
-        current_set[cpu] = task_thread_info(p);
-        task_thread_info(p)->cpu = cpu;
-}
-
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
         unsigned int cpu;
@@ -288,10 +290,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
                         max_cpus = NR_CPUS;
         else
                 max_cpus = 1;
-
-        for_each_possible_cpu(cpu)
-                if (cpu != boot_cpuid)
-                        smp_create_idle(cpu);
 }
 
 void __devinit smp_prepare_boot_cpu(void)
@@ -305,7 +303,7 @@ void __devinit smp_prepare_boot_cpu(void)
 
 #ifdef CONFIG_HOTPLUG_CPU
 /* State of each CPU during hotplug phases */
-DEFINE_PER_CPU(int, cpu_state) = { 0 };
+static DEFINE_PER_CPU(int, cpu_state) = { 0 };
 
 int generic_cpu_disable(void)
 {
@@ -317,30 +315,8 @@ int generic_cpu_disable(void)
         set_cpu_online(cpu, false);
 #ifdef CONFIG_PPC64
         vdso_data->processorCount--;
-        fixup_irqs(cpu_online_mask);
-#endif
-        return 0;
-}
-
-int generic_cpu_enable(unsigned int cpu)
-{
-        /* Do the normal bootup if we haven't
-         * already bootstrapped. */
-        if (system_state != SYSTEM_RUNNING)
-                return -ENOSYS;
-
-        /* get the target out of it's holding state */
-        per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
-        smp_wmb();
-
-        while (!cpu_online(cpu))
-                cpu_relax();
-
-#ifdef CONFIG_PPC64
-        fixup_irqs(cpu_online_mask);
-        /* counter the irq disable in fixup_irqs */
-        local_irq_enable();
 #endif
+        migrate_irqs();
         return 0;
 }
 
@@ -362,37 +338,89 @@ void generic_mach_cpu_die(void)
         unsigned int cpu;
 
         local_irq_disable();
+        idle_task_exit();
         cpu = smp_processor_id();
         printk(KERN_DEBUG "CPU%d offline\n", cpu);
         __get_cpu_var(cpu_state) = CPU_DEAD;
         smp_wmb();
         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
                 cpu_relax();
-        set_cpu_online(cpu, true);
-        local_irq_enable();
+}
+
+void generic_set_cpu_dead(unsigned int cpu)
+{
+        per_cpu(cpu_state, cpu) = CPU_DEAD;
 }
 #endif
 
-static int __devinit cpu_enable(unsigned int cpu)
+struct create_idle {
+        struct work_struct work;
+        struct task_struct *idle;
+        struct completion done;
+        int cpu;
+};
+
+static void __cpuinit do_fork_idle(struct work_struct *work)
 {
-        if (smp_ops && smp_ops->cpu_enable)
-                return smp_ops->cpu_enable(cpu);
+        struct create_idle *c_idle =
+                container_of(work, struct create_idle, work);
+
+        c_idle->idle = fork_idle(c_idle->cpu);
+        complete(&c_idle->done);
+}
+
+static int __cpuinit create_idle(unsigned int cpu)
+{
+        struct thread_info *ti;
+        struct create_idle c_idle = {
+                .cpu    = cpu,
+                .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
+        };
+        INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
+
+        c_idle.idle = get_idle_for_cpu(cpu);
+
+        /* We can't use kernel_thread since we must avoid to
+         * reschedule the child. We use a workqueue because
+         * we want to fork from a kernel thread, not whatever
+         * userspace process happens to be trying to online us.
+         */
+        if (!c_idle.idle) {
+                schedule_work(&c_idle.work);
+                wait_for_completion(&c_idle.done);
+        } else
+                init_idle(c_idle.idle, cpu);
+        if (IS_ERR(c_idle.idle)) {              
+                pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
+                return PTR_ERR(c_idle.idle);
+        }
+        ti = task_thread_info(c_idle.idle);
+
+#ifdef CONFIG_PPC64
+        paca[cpu].__current = c_idle.idle;
+        paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
+#endif
+        ti->cpu = cpu;
+        current_set[cpu] = ti;
 
-        return -ENOSYS;
+        return 0;
 }
 
 int __cpuinit __cpu_up(unsigned int cpu)
 {
-        int c;
+        int rc, c;
 
         secondary_ti = current_set[cpu];
-        if (!cpu_enable(cpu))
-                return 0;
 
         if (smp_ops == NULL ||
             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
                 return -EINVAL;
 
+        /* Make sure we have an idle thread */
+        rc = create_idle(cpu);
+        if (rc)
+                return rc;
+
         /* Make sure callin-map entry is 0 (can be leftover a CPU
          * hotplug
          */
@@ -502,7 +530,7 @@ static struct device_node *cpu_to_l2cache(int cpu)
 }
 
 /* Activate a secondary processor. */
-int __devinit start_secondary(void *unused)
+void __devinit start_secondary(void *unused)
 {
         unsigned int cpu = smp_processor_id();
         struct device_node *l2_cache;
@@ -523,6 +551,10 @@ int __devinit start_secondary(void *unused)
 
         secondary_cpu_time_init();
 
+#ifdef CONFIG_PPC64
+        if (system_state == SYSTEM_RUNNING)
+                vdso_data->processorCount++;
+#endif
         ipi_call_lock();
         notify_cpu_starting(cpu);
         set_cpu_online(cpu, true);
@@ -558,7 +590,8 @@ int __devinit start_secondary(void *unused)
         local_irq_enable();
 
         cpu_idle();
-        return 0;
+
+        BUG();
 }
 
 int setup_profiling_timer(unsigned int multiplier)
@@ -585,7 +618,11 @@ void __init smp_cpus_done(unsigned int max_cpus)
 
         free_cpumask_var(old_mask);
 
+        if (smp_ops && smp_ops->bringup_done)
+                smp_ops->bringup_done();
+
         dump_numa_cpu_topology();
+
 }
 
 int arch_sd_sibling_asym_packing(void)
@@ -660,5 +697,9 @@ void cpu_die(void)
 {
         if (ppc_md.cpu_die)
                 ppc_md.cpu_die();
+
+        /* If we return, we re-enter start_secondary */
+        start_secondary_resume();
 }
+
 #endif
diff --git a/arch/powerpc/kernel/swsusp_32.S b/arch/powerpc/kernel/swsusp_32.S
index b0754e23743..ba4dee3d233 100644
--- a/arch/powerpc/kernel/swsusp_32.S
+++ b/arch/powerpc/kernel/swsusp_32.S
@@ -143,7 +143,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
 
         /* Disable MSR:DR to make sure we don't take a TLB or
          * hash miss during the copy, as our hash table will
-         * for a while be unuseable. For .text, we assume we are
+         * for a while be unusable. For .text, we assume we are
          * covered by a BAT. This works only for non-G5 at this
          * point. G5 will need a better approach, possibly using
          * a small temporary hash table filled with large mappings,
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index aa9269600ca..375480c56eb 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -577,14 +577,21 @@ void timer_interrupt(struct pt_regs * regs)
         struct clock_event_device *evt = &decrementer->event;
         u64 now;
 
+        /* Ensure a positive value is written to the decrementer, or else
+         * some CPUs will continue to take decrementer exceptions.
+         */
+        set_dec(DECREMENTER_MAX);
+
+        /* Some implementations of hotplug will get timer interrupts while
+         * offline, just ignore these
+         */
+        if (!cpu_online(smp_processor_id()))
+                return;
+
         trace_timer_interrupt_entry(regs);
 
         __get_cpu_var(irq_stat).timer_irqs++;
 
-        /* Ensure a positive value is written to the decrementer, or else
-         * some CPUs will continuue to take decrementer exceptions */
-        set_dec(DECREMENTER_MAX);
-
 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
         if (atomic_read(&ppc_n_lost_interrupts) != 0)
                 do_IRQ(regs);
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index bd74fac169b..5ddb801bc15 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -959,7 +959,7 @@ void __kprobes program_check_exception(struct pt_regs *regs)
          * ESR_DST (!?) or 0.  In the process of chasing this with the
          * hardware people - not sure if it can happen on any illegal
          * instruction or only on FP instructions, whether there is a
-         * pattern to occurences etc. -dgibson 31/Mar/2003 */
+         * pattern to occurrences etc. -dgibson 31/Mar/2003 */
         switch (do_mathemu(regs)) {
         case 0:
                 emulate_single_step(regs);
diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
index b4b167b3364..baa33a7517b 100644
--- a/arch/powerpc/kernel/udbg_16550.c
+++ b/arch/powerpc/kernel/udbg_16550.c
@@ -1,5 +1,5 @@
 /*
- * udbg for NS16550 compatable serial ports
+ * udbg for NS16550 compatible serial ports
  *
  * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp
  *
diff --git a/arch/powerpc/kernel/vdso32/sigtramp.S b/arch/powerpc/kernel/vdso32/sigtramp.S
index 68d49dd71dc..cf0c9c9c24f 100644
--- a/arch/powerpc/kernel/vdso32/sigtramp.S
+++ b/arch/powerpc/kernel/vdso32/sigtramp.S
@@ -19,7 +19,7 @@
 
 /* The nop here is a hack.  The dwarf2 unwind routines subtract 1 from
    the return address to get an address in the middle of the presumed
-   call instruction.  Since we don't have a call here, we artifically
+   call instruction.  Since we don't have a call here, we artificially
    extend the range covered by the unwind info by adding a nop before
    the real start.  */
         nop
diff --git a/arch/powerpc/kernel/vdso64/sigtramp.S b/arch/powerpc/kernel/vdso64/sigtramp.S
index 59eb59bb408..45ea281e9a2 100644
--- a/arch/powerpc/kernel/vdso64/sigtramp.S
+++ b/arch/powerpc/kernel/vdso64/sigtramp.S
@@ -20,7 +20,7 @@
 
 /* The nop here is a hack.  The dwarf2 unwind routines subtract 1 from
    the return address to get an address in the middle of the presumed
-   call instruction.  Since we don't have a call here, we artifically
+   call instruction.  Since we don't have a call here, we artificially
    extend the range covered by the unwind info by padding before the
    real start.  */
         nop