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-rw-r--r--arch/ia64/kernel/acpi.c14
-rw-r--r--arch/ia64/kernel/entry.S14
-rw-r--r--arch/ia64/kernel/iosapic.c6
-rw-r--r--arch/ia64/kernel/irq.c13
-rw-r--r--arch/ia64/kernel/mca.c90
-rw-r--r--arch/ia64/kernel/perfmon.c5
-rw-r--r--arch/ia64/kernel/signal.c101
-rw-r--r--arch/ia64/kernel/smpboot.c114
-rw-r--r--arch/ia64/kernel/time.c9
-rw-r--r--arch/ia64/kernel/topology.c2
10 files changed, 208 insertions, 160 deletions
diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index ecd44bdc839..4722ec51c70 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -284,19 +284,24 @@ acpi_parse_plat_int_src(acpi_table_entry_header * header,
return 0;
}
+#ifdef CONFIG_HOTPLUG_CPU
unsigned int can_cpei_retarget(void)
{
extern int cpe_vector;
+ extern unsigned int force_cpei_retarget;
/*
* Only if CPEI is supported and the override flag
* is present, otherwise return that its re-targettable
* if we are in polling mode.
*/
- if (cpe_vector > 0 && !acpi_cpei_override)
- return 0;
- else
- return 1;
+ if (cpe_vector > 0) {
+ if (acpi_cpei_override || force_cpei_retarget)
+ return 1;
+ else
+ return 0;
+ }
+ return 1;
}
unsigned int is_cpu_cpei_target(unsigned int cpu)
@@ -315,6 +320,7 @@ void set_cpei_target_cpu(unsigned int cpu)
{
acpi_cpei_phys_cpuid = cpu_physical_id(cpu);
}
+#endif
unsigned int get_cpei_target_cpu(void)
{
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index 930fdfca6dd..0e3eda99e54 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1102,9 +1102,6 @@ skip_rbs_switch:
st8 [r2]=r8
st8 [r3]=r10
.work_pending:
- tbit.nz p6,p0=r31,TIF_SIGDELAYED // signal delayed from MCA/INIT/NMI/PMI context?
-(p6) br.cond.sptk.few .sigdelayed
- ;;
tbit.z p6,p0=r31,TIF_NEED_RESCHED // current_thread_info()->need_resched==0?
(p6) br.cond.sptk.few .notify
#ifdef CONFIG_PREEMPT
@@ -1131,17 +1128,6 @@ skip_rbs_switch:
(pLvSys)br.cond.sptk.few .work_pending_syscall_end
br.cond.sptk.many .work_processed_kernel // don't re-check
-// There is a delayed signal that was detected in MCA/INIT/NMI/PMI context where
-// it could not be delivered. Deliver it now. The signal might be for us and
-// may set TIF_SIGPENDING, so redrive ia64_leave_* after processing the delayed
-// signal.
-
-.sigdelayed:
- br.call.sptk.many rp=do_sigdelayed
- cmp.eq p6,p0=r0,r0 // p6 <- 1, always re-check
-(pLvSys)br.cond.sptk.few .work_pending_syscall_end
- br.cond.sptk.many .work_processed_kernel // re-check
-
.work_pending_syscall_end:
adds r2=PT(R8)+16,r12
adds r3=PT(R10)+16,r12
diff --git a/arch/ia64/kernel/iosapic.c b/arch/ia64/kernel/iosapic.c
index 574084f343f..8832c553230 100644
--- a/arch/ia64/kernel/iosapic.c
+++ b/arch/ia64/kernel/iosapic.c
@@ -631,6 +631,7 @@ get_target_cpu (unsigned int gsi, int vector)
{
#ifdef CONFIG_SMP
static int cpu = -1;
+ extern int cpe_vector;
/*
* In case of vector shared by multiple RTEs, all RTEs that
@@ -653,6 +654,11 @@ get_target_cpu (unsigned int gsi, int vector)
if (!cpu_online(smp_processor_id()))
return cpu_physical_id(smp_processor_id());
+#ifdef CONFIG_ACPI
+ if (cpe_vector > 0 && vector == IA64_CPEP_VECTOR)
+ return get_cpei_target_cpu();
+#endif
+
#ifdef CONFIG_NUMA
{
int num_cpus, cpu_index, iosapic_index, numa_cpu, i = 0;
diff --git a/arch/ia64/kernel/irq.c b/arch/ia64/kernel/irq.c
index d33244c3275..5ce908ef9c9 100644
--- a/arch/ia64/kernel/irq.c
+++ b/arch/ia64/kernel/irq.c
@@ -163,8 +163,19 @@ void fixup_irqs(void)
{
unsigned int irq;
extern void ia64_process_pending_intr(void);
+ extern void ia64_disable_timer(void);
+ extern volatile int time_keeper_id;
+
+ ia64_disable_timer();
+
+ /*
+ * Find a new timesync master
+ */
+ if (smp_processor_id() == time_keeper_id) {
+ time_keeper_id = first_cpu(cpu_online_map);
+ printk ("CPU %d is now promoted to time-keeper master\n", time_keeper_id);
+ }
- ia64_set_itv(1<<16);
/*
* Phase 1: Locate irq's bound to this cpu and
* relocate them for cpu removal.
diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index ee7eec9ee57..b57e723f194 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -281,14 +281,10 @@ ia64_mca_log_sal_error_record(int sal_info_type)
ia64_sal_clear_state_info(sal_info_type);
}
-/*
- * platform dependent error handling
- */
-#ifndef PLATFORM_MCA_HANDLERS
-
#ifdef CONFIG_ACPI
int cpe_vector = -1;
+int ia64_cpe_irq = -1;
static irqreturn_t
ia64_mca_cpe_int_handler (int cpe_irq, void *arg, struct pt_regs *ptregs)
@@ -377,8 +373,6 @@ ia64_mca_register_cpev (int cpev)
}
#endif /* CONFIG_ACPI */
-#endif /* PLATFORM_MCA_HANDLERS */
-
/*
* ia64_mca_cmc_vector_setup
*
@@ -630,6 +624,32 @@ copy_reg(const u64 *fr, u64 fnat, u64 *tr, u64 *tnat)
*tnat |= (nat << tslot);
}
+/* Change the comm field on the MCA/INT task to include the pid that
+ * was interrupted, it makes for easier debugging. If that pid was 0
+ * (swapper or nested MCA/INIT) then use the start of the previous comm
+ * field suffixed with its cpu.
+ */
+
+static void
+ia64_mca_modify_comm(const task_t *previous_current)
+{
+ char *p, comm[sizeof(current->comm)];
+ if (previous_current->pid)
+ snprintf(comm, sizeof(comm), "%s %d",
+ current->comm, previous_current->pid);
+ else {
+ int l;
+ if ((p = strchr(previous_current->comm, ' ')))
+ l = p - previous_current->comm;
+ else
+ l = strlen(previous_current->comm);
+ snprintf(comm, sizeof(comm), "%s %*s %d",
+ current->comm, l, previous_current->comm,
+ task_thread_info(previous_current)->cpu);
+ }
+ memcpy(current->comm, comm, sizeof(current->comm));
+}
+
/* On entry to this routine, we are running on the per cpu stack, see
* mca_asm.h. The original stack has not been touched by this event. Some of
* the original stack's registers will be in the RBS on this stack. This stack
@@ -648,7 +668,7 @@ ia64_mca_modify_original_stack(struct pt_regs *regs,
struct ia64_sal_os_state *sos,
const char *type)
{
- char *p, comm[sizeof(current->comm)];
+ char *p;
ia64_va va;
extern char ia64_leave_kernel[]; /* Need asm address, not function descriptor */
const pal_min_state_area_t *ms = sos->pal_min_state;
@@ -721,6 +741,10 @@ ia64_mca_modify_original_stack(struct pt_regs *regs,
/* Verify the previous stack state before we change it */
if (user_mode(regs)) {
msg = "occurred in user space";
+ /* previous_current is guaranteed to be valid when the task was
+ * in user space, so ...
+ */
+ ia64_mca_modify_comm(previous_current);
goto no_mod;
}
if (r13 != sos->prev_IA64_KR_CURRENT) {
@@ -750,25 +774,7 @@ ia64_mca_modify_original_stack(struct pt_regs *regs,
goto no_mod;
}
- /* Change the comm field on the MCA/INT task to include the pid that
- * was interrupted, it makes for easier debugging. If that pid was 0
- * (swapper or nested MCA/INIT) then use the start of the previous comm
- * field suffixed with its cpu.
- */
- if (previous_current->pid)
- snprintf(comm, sizeof(comm), "%s %d",
- current->comm, previous_current->pid);
- else {
- int l;
- if ((p = strchr(previous_current->comm, ' ')))
- l = p - previous_current->comm;
- else
- l = strlen(previous_current->comm);
- snprintf(comm, sizeof(comm), "%s %*s %d",
- current->comm, l, previous_current->comm,
- task_thread_info(previous_current)->cpu);
- }
- memcpy(current->comm, comm, sizeof(current->comm));
+ ia64_mca_modify_comm(previous_current);
/* Make the original task look blocked. First stack a struct pt_regs,
* describing the state at the time of interrupt. mca_asm.S built a
@@ -908,7 +914,7 @@ no_mod:
static void
ia64_wait_for_slaves(int monarch)
{
- int c, wait = 0;
+ int c, wait = 0, missing = 0;
for_each_online_cpu(c) {
if (c == monarch)
continue;
@@ -919,15 +925,32 @@ ia64_wait_for_slaves(int monarch)
}
}
if (!wait)
- return;
+ goto all_in;
for_each_online_cpu(c) {
if (c == monarch)
continue;
if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) {
udelay(5*1000000); /* wait 5 seconds for slaves (arbitrary) */
+ if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE)
+ missing = 1;
break;
}
}
+ if (!missing)
+ goto all_in;
+ printk(KERN_INFO "OS MCA slave did not rendezvous on cpu");
+ for_each_online_cpu(c) {
+ if (c == monarch)
+ continue;
+ if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE)
+ printk(" %d", c);
+ }
+ printk("\n");
+ return;
+
+all_in:
+ printk(KERN_INFO "All OS MCA slaves have reached rendezvous\n");
+ return;
}
/*
@@ -953,6 +976,10 @@ ia64_mca_handler(struct pt_regs *regs, struct switch_stack *sw,
task_t *previous_current;
oops_in_progress = 1; /* FIXME: make printk NMI/MCA/INIT safe */
+ console_loglevel = 15; /* make sure printks make it to console */
+ printk(KERN_INFO "Entered OS MCA handler. PSP=%lx cpu=%d monarch=%ld\n",
+ sos->proc_state_param, cpu, sos->monarch);
+
previous_current = ia64_mca_modify_original_stack(regs, sw, sos, "MCA");
monarch_cpu = cpu;
if (notify_die(DIE_MCA_MONARCH_ENTER, "MCA", regs, 0, 0, 0)
@@ -1444,11 +1471,13 @@ void __devinit
ia64_mca_cpu_init(void *cpu_data)
{
void *pal_vaddr;
+ static int first_time = 1;
- if (smp_processor_id() == 0) {
+ if (first_time) {
void *mca_data;
int cpu;
+ first_time = 0;
mca_data = alloc_bootmem(sizeof(struct ia64_mca_cpu)
* NR_CPUS + KERNEL_STACK_SIZE);
mca_data = (void *)(((unsigned long)mca_data +
@@ -1704,6 +1733,7 @@ ia64_mca_late_init(void)
desc = irq_descp(irq);
desc->status |= IRQ_PER_CPU;
setup_irq(irq, &mca_cpe_irqaction);
+ ia64_cpe_irq = irq;
}
ia64_mca_register_cpev(cpe_vector);
IA64_MCA_DEBUG("%s: CPEI/P setup and enabled.\n", __FUNCTION__);
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 9c5194b385d..077f21216b6 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -6722,6 +6722,7 @@ __initcall(pfm_init);
void
pfm_init_percpu (void)
{
+ static int first_time=1;
/*
* make sure no measurement is active
* (may inherit programmed PMCs from EFI).
@@ -6734,8 +6735,10 @@ pfm_init_percpu (void)
*/
pfm_unfreeze_pmu();
- if (smp_processor_id() == 0)
+ if (first_time) {
register_percpu_irq(IA64_PERFMON_VECTOR, &perfmon_irqaction);
+ first_time=0;
+ }
ia64_setreg(_IA64_REG_CR_PMV, IA64_PERFMON_VECTOR);
ia64_srlz_d();
diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index 463f6bb44d0..1d7903ee212 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -588,104 +588,3 @@ ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
}
return 0;
}
-
-/* Set a delayed signal that was detected in MCA/INIT/NMI/PMI context where it
- * could not be delivered. It is important that the target process is not
- * allowed to do any more work in user space. Possible cases for the target
- * process:
- *
- * - It is sleeping and will wake up soon. Store the data in the current task,
- * the signal will be sent when the current task returns from the next
- * interrupt.
- *
- * - It is running in user context. Store the data in the current task, the
- * signal will be sent when the current task returns from the next interrupt.
- *
- * - It is running in kernel context on this or another cpu and will return to
- * user context. Store the data in the target task, the signal will be sent
- * to itself when the target task returns to user space.
- *
- * - It is running in kernel context on this cpu and will sleep before
- * returning to user context. Because this is also the current task, the
- * signal will not get delivered and the task could sleep indefinitely.
- * Store the data in the idle task for this cpu, the signal will be sent
- * after the idle task processes its next interrupt.
- *
- * To cover all cases, store the data in the target task, the current task and
- * the idle task on this cpu. Whatever happens, the signal will be delivered
- * to the target task before it can do any useful user space work. Multiple
- * deliveries have no unwanted side effects.
- *
- * Note: This code is executed in MCA/INIT/NMI/PMI context, with interrupts
- * disabled. It must not take any locks nor use kernel structures or services
- * that require locks.
- */
-
-/* To ensure that we get the right pid, check its start time. To avoid extra
- * include files in thread_info.h, convert the task start_time to unsigned long,
- * giving us a cycle time of > 580 years.
- */
-static inline unsigned long
-start_time_ul(const struct task_struct *t)
-{
- return t->start_time.tv_sec * NSEC_PER_SEC + t->start_time.tv_nsec;
-}
-
-void
-set_sigdelayed(pid_t pid, int signo, int code, void __user *addr)
-{
- struct task_struct *t;
- unsigned long start_time = 0;
- int i;
-
- for (i = 1; i <= 3; ++i) {
- switch (i) {
- case 1:
- t = find_task_by_pid(pid);
- if (t)
- start_time = start_time_ul(t);
- break;
- case 2:
- t = current;
- break;
- default:
- t = idle_task(smp_processor_id());
- break;
- }
-
- if (!t)
- return;
- task_thread_info(t)->sigdelayed.signo = signo;
- task_thread_info(t)->sigdelayed.code = code;
- task_thread_info(t)->sigdelayed.addr = addr;
- task_thread_info(t)->sigdelayed.start_time = start_time;
- task_thread_info(t)->sigdelayed.pid = pid;
- wmb();
- set_tsk_thread_flag(t, TIF_SIGDELAYED);
- }
-}
-
-/* Called from entry.S when it detects TIF_SIGDELAYED, a delayed signal that
- * was detected in MCA/INIT/NMI/PMI context where it could not be delivered.
- */
-
-void
-do_sigdelayed(void)
-{
- struct siginfo siginfo;
- pid_t pid;
- struct task_struct *t;
-
- clear_thread_flag(TIF_SIGDELAYED);
- memset(&siginfo, 0, sizeof(siginfo));
- siginfo.si_signo = current_thread_info()->sigdelayed.signo;
- siginfo.si_code = current_thread_info()->sigdelayed.code;
- siginfo.si_addr = current_thread_info()->sigdelayed.addr;
- pid = current_thread_info()->sigdelayed.pid;
- t = find_task_by_pid(pid);
- if (!t)
- return;
- if (current_thread_info()->sigdelayed.start_time != start_time_ul(t))
- return;
- force_sig_info(siginfo.si_signo, &siginfo, t);
-}
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index b681ef34a86..c4b633b36da 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -70,6 +70,12 @@
#endif
#ifdef CONFIG_HOTPLUG_CPU
+#ifdef CONFIG_PERMIT_BSP_REMOVE
+#define bsp_remove_ok 1
+#else
+#define bsp_remove_ok 0
+#endif
+
/*
* Store all idle threads, this can be reused instead of creating
* a new thread. Also avoids complicated thread destroy functionality
@@ -104,7 +110,7 @@ struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
/*
* ITC synchronization related stuff:
*/
-#define MASTER 0
+#define MASTER (0)
#define SLAVE (SMP_CACHE_BYTES/8)
#define NUM_ROUNDS 64 /* magic value */
@@ -151,6 +157,27 @@ char __initdata no_int_routing;
unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
+#ifdef CONFIG_FORCE_CPEI_RETARGET
+#define CPEI_OVERRIDE_DEFAULT (1)
+#else
+#define CPEI_OVERRIDE_DEFAULT (0)
+#endif
+
+unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
+
+static int __init
+cmdl_force_cpei(char *str)
+{
+ int value=0;
+
+ get_option (&str, &value);
+ force_cpei_retarget = value;
+
+ return 1;
+}
+
+__setup("force_cpei=", cmdl_force_cpei);
+
static int __init
nointroute (char *str)
{
@@ -161,6 +188,27 @@ nointroute (char *str)
__setup("nointroute", nointroute);
+static void fix_b0_for_bsp(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+ int cpuid;
+ static int fix_bsp_b0 = 1;
+
+ cpuid = smp_processor_id();
+
+ /*
+ * Cache the b0 value on the first AP that comes up
+ */
+ if (!(fix_bsp_b0 && cpuid))
+ return;
+
+ sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
+ printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
+
+ fix_bsp_b0 = 0;
+#endif
+}
+
void
sync_master (void *arg)
{
@@ -327,8 +375,9 @@ smp_setup_percpu_timer (void)
static void __devinit
smp_callin (void)
{
- int cpuid, phys_id;
+ int cpuid, phys_id, itc_master;
extern void ia64_init_itm(void);
+ extern volatile int time_keeper_id;
#ifdef CONFIG_PERFMON
extern void pfm_init_percpu(void);
@@ -336,6 +385,7 @@ smp_callin (void)
cpuid = smp_processor_id();
phys_id = hard_smp_processor_id();
+ itc_master = time_keeper_id;
if (cpu_online(cpuid)) {
printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
@@ -343,6 +393,8 @@ smp_callin (void)
BUG();
}
+ fix_b0_for_bsp();
+
lock_ipi_calllock();
cpu_set(cpuid, cpu_online_map);
unlock_ipi_calllock();
@@ -365,8 +417,8 @@ smp_callin (void)
* calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
* local_bh_enable(), which bugs out if irqs are not enabled...
*/
- Dprintk("Going to syncup ITC with BP.\n");
- ia64_sync_itc(0);
+ Dprintk("Going to syncup ITC with ITC Master.\n");
+ ia64_sync_itc(itc_master);
}
/*
@@ -635,6 +687,47 @@ remove_siblinginfo(int cpu)
}
extern void fixup_irqs(void);
+
+int migrate_platform_irqs(unsigned int cpu)
+{
+ int new_cpei_cpu;
+ irq_desc_t *desc = NULL;
+ cpumask_t mask;
+ int retval = 0;
+
+ /*
+ * dont permit CPEI target to removed.
+ */
+ if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
+ printk ("CPU (%d) is CPEI Target\n", cpu);
+ if (can_cpei_retarget()) {
+ /*
+ * Now re-target the CPEI to a different processor
+ */
+ new_cpei_cpu = any_online_cpu(cpu_online_map);
+ mask = cpumask_of_cpu(new_cpei_cpu);
+ set_cpei_target_cpu(new_cpei_cpu);
+ desc = irq_descp(ia64_cpe_irq);
+ /*
+ * Switch for now, immediatly, we need to do fake intr
+ * as other interrupts, but need to study CPEI behaviour with
+ * polling before making changes.
+ */
+ if (desc) {
+ desc->handler->disable(ia64_cpe_irq);
+ desc->handler->set_affinity(ia64_cpe_irq, mask);
+ desc->handler->enable(ia64_cpe_irq);
+ printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
+ }
+ }
+ if (!desc) {
+ printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
+ retval = -EBUSY;
+ }
+ }
+ return retval;
+}
+
/* must be called with cpucontrol mutex held */
int __cpu_disable(void)
{
@@ -643,8 +736,17 @@ int __cpu_disable(void)
/*
* dont permit boot processor for now
*/
- if (cpu == 0)
- return -EBUSY;
+ if (cpu == 0 && !bsp_remove_ok) {
+ printk ("Your platform does not support removal of BSP\n");
+ return (-EBUSY);
+ }
+
+ cpu_clear(cpu, cpu_online_map);
+
+ if (migrate_platform_irqs(cpu)) {
+ cpu_set(cpu, cpu_online_map);
+ return (-EBUSY);
+ }
remove_siblinginfo(cpu);
cpu_clear(cpu, cpu_online_map);
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 307d01e15b2..ac167436e93 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -32,7 +32,7 @@
extern unsigned long wall_jiffies;
-#define TIME_KEEPER_ID 0 /* smp_processor_id() of time-keeper */
+volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
#ifdef CONFIG_IA64_DEBUG_IRQ
@@ -71,7 +71,7 @@ timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
new_itm += local_cpu_data->itm_delta;
- if (smp_processor_id() == TIME_KEEPER_ID) {
+ if (smp_processor_id() == time_keeper_id) {
/*
* Here we are in the timer irq handler. We have irqs locally
* disabled, but we don't know if the timer_bh is running on
@@ -236,6 +236,11 @@ static struct irqaction timer_irqaction = {
.name = "timer"
};
+void __devinit ia64_disable_timer(void)
+{
+ ia64_set_itv(1 << 16);
+}
+
void __init
time_init (void)
{
diff --git a/arch/ia64/kernel/topology.c b/arch/ia64/kernel/topology.c
index 6e5eea19fa6..3b6fd798c4d 100644
--- a/arch/ia64/kernel/topology.c
+++ b/arch/ia64/kernel/topology.c
@@ -36,7 +36,7 @@ int arch_register_cpu(int num)
parent = &sysfs_nodes[cpu_to_node(num)];
#endif /* CONFIG_NUMA */
-#ifdef CONFIG_ACPI
+#if defined (CONFIG_ACPI) && defined (CONFIG_HOTPLUG_CPU)
/*
* If CPEI cannot be re-targetted, and this is
* CPEI target, then dont create the control file