Merge branch 'quilt/rr'

Conflicts:
	arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c

7 files changed, 153 insertions, 161 deletions

diff --git a/arch/frv/include/asm/gdb-stub.h b/arch/frv/include/asm/gdb-stub.h
index 24f9738670bd..2da716407ff2 100644
--- a/arch/frv/include/asm/gdb-stub.h
+++ b/arch/frv/include/asm/gdb-stub.h
@@ -90,7 +90,6 @@ extern void gdbstub_do_rx(void);
 extern asmlinkage void __debug_stub_init_break(void);
 extern asmlinkage void __break_hijack_kernel_event(void);
 extern asmlinkage void __break_hijack_kernel_event_breaks_here(void);
-extern asmlinkage void start_kernel(void);
 
 extern asmlinkage void gdbstub_rx_handler(void);
 extern asmlinkage void gdbstub_rx_irq(void);
diff --git a/arch/mn10300/include/asm/gdb-stub.h b/arch/mn10300/include/asm/gdb-stub.h
index e5a6368559af..556cce992548 100644
--- a/arch/mn10300/include/asm/gdb-stub.h
+++ b/arch/mn10300/include/asm/gdb-stub.h
@@ -109,7 +109,6 @@ extern asmlinkage int  gdbstub_intercept(struct pt_regs *, enum exception_code);
 extern asmlinkage void gdbstub_exception(struct pt_regs *, enum exception_code);
 extern asmlinkage void __gdbstub_bug_trap(void);
 extern asmlinkage void __gdbstub_pause(void);
-extern asmlinkage void start_kernel(void);
 
 #ifndef CONFIG_MN10300_CACHE_DISABLED
 extern asmlinkage void gdbstub_purge_cache(void);
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index bbbe4bbb6f34..b866b876446e 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -53,6 +53,12 @@ struct cstate_entry {
 };
 static struct cstate_entry *cpu_cstate_entry;	/* per CPU ptr */
 
+/* Used for the cross-CPU calls */
+struct acpi_processor_cx_cross_cpu {
+	struct acpi_processor_cx *cx;
+	long retval;
+};
+
 static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
 
 #define MWAIT_SUBSTATE_MASK	(0xf)
@@ -67,10 +73,10 @@ static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
 
 #define NATIVE_CSTATE_BEYOND_HALT	(2)
 
-static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
+static void acpi_processor_ffh_cstate_probe_cpu(void *_cxcc)
 {
-	struct acpi_processor_cx *cx = _cx;
-	long retval;
+	struct acpi_processor_cx_cross_cpu *cxcc = _cxcc;
+	struct acpi_processor_cx *cx = cxcc->cx;
 	unsigned int eax, ebx, ecx, edx;
 	unsigned int edx_part;
 	unsigned int cstate_type; /* C-state type and not ACPI C-state type */
@@ -84,16 +90,16 @@ static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
 	edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
 	num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
 
-	retval = 0;
+	cxcc->retval = 0;
 	if (num_cstate_subtype < (cx->address & MWAIT_SUBSTATE_MASK)) {
-		retval = -1;
+		cxcc->retval = -1;
 		goto out;
 	}
 
 	/* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
 	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
 	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
-		retval = -1;
+		cxcc->retval = -1;
 		goto out;
 	}
 
@@ -107,7 +113,7 @@ static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
 			ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
 			cx->address);
 out:
-	return retval;
+	return;
 }
 
 int acpi_processor_ffh_cstate_probe(unsigned int cpu,
@@ -115,6 +121,7 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu,
 {
 	struct cstate_entry *percpu_entry;
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
+	struct acpi_processor_cx_cross_cpu cxcc = { .cx = cx, };
 	long retval;
 
 	if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)
@@ -127,13 +134,18 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu,
 	percpu_entry->states[cx->index].eax = 0;
 	percpu_entry->states[cx->index].ecx = 0;
 
-	/* Make sure we are running on right CPU */
+	/* Run acpi_processor_ffh_cstate_probe_cpu() on the target CPU */
 
-	retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx);
+	retval = smp_call_function_single(cpu,
+				acpi_processor_ffh_cstate_probe_cpu, &cxcc, 1);
 	if (retval == 0) {
-		/* Use the hint in CST */
-		percpu_entry->states[cx->index].eax = cx->address;
-		percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
+		retval = cxcc.retval;
+		if (retval == 0) {
+			/* Use the hint in CST */
+			percpu_entry->states[cx->index].eax = cx->address;
+			percpu_entry->states[cx->index].ecx =
+					MWAIT_ECX_INTERRUPT_BREAK;
+		}
 	}
 	return retval;
 }
diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
index 4709ead2db52..e9c6f7736b1c 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -510,19 +510,10 @@ static int core_voltage_post_transition(struct powernow_k8_data *data,
 	return 0;
 }
 
-static int check_supported_cpu(unsigned int cpu)
+static long check_supported_cpu(void *unused)
 {
-	cpumask_t oldmask;
 	u32 eax, ebx, ecx, edx;
-	unsigned int rc = 0;
-
-	oldmask = current->cpus_allowed;
-	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-
-	if (smp_processor_id() != cpu) {
-		printk(KERN_ERR PFX "limiting to cpu %u failed\n", cpu);
-		goto out;
-	}
+	unsigned int rc = -ENODEV;
 
 	if (current_cpu_data.x86_vendor != X86_VENDOR_AMD)
 		goto out;
@@ -562,10 +553,9 @@ static int check_supported_cpu(unsigned int cpu)
 			goto out;
 	}
 
-	rc = 1;
+	rc = 0;
 
 out:
-	set_cpus_allowed_ptr(current, &oldmask);
 	return rc;
 }
 
@@ -1121,11 +1111,16 @@ static int transition_frequency_pstate(struct powernow_k8_data *data,
 	return res;
 }
 
-/* Driver entry point to switch to the target frequency */
-static int powernowk8_target(struct cpufreq_policy *pol,
-		unsigned targfreq, unsigned relation)
+struct target_data {
+	struct cpufreq_policy *pol;
+	unsigned targfreq;
+	unsigned relation;
+};
+
+static long powernowk8_target_on_cpu(void *_tdata)
 {
-	cpumask_t oldmask;
+	struct target_data *tdata = _tdata;
+	struct cpufreq_policy *pol = tdata->pol;
 	struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
 	u32 checkfid;
 	u32 checkvid;
@@ -1138,22 +1133,13 @@ static int powernowk8_target(struct cpufreq_policy *pol,
 	checkfid = data->currfid;
 	checkvid = data->currvid;
 
-	/* only run on specific CPU from here on */
-	oldmask = current->cpus_allowed;
-	set_cpus_allowed_ptr(current, &cpumask_of_cpu(pol->cpu));
-
-	if (smp_processor_id() != pol->cpu) {
-		printk(KERN_ERR PFX "limiting to cpu %u failed\n", pol->cpu);
-		goto err_out;
-	}
-
 	if (pending_bit_stuck()) {
 		printk(KERN_ERR PFX "failing targ, change pending bit set\n");
 		goto err_out;
 	}
 
 	dprintk("targ: cpu %d, %d kHz, min %d, max %d, relation %d\n",
-		pol->cpu, targfreq, pol->min, pol->max, relation);
+		pol->cpu, tdata->targfreq, pol->min, pol->max, tdata->relation);
 
 	if (query_current_values_with_pending_wait(data))
 		goto err_out;
@@ -1173,7 +1159,8 @@ static int powernowk8_target(struct cpufreq_policy *pol,
 	}
 
 	if (cpufreq_frequency_table_target(pol, data->powernow_table,
-				targfreq, relation, &newstate))
+					   tdata->targfreq, tdata->relation,
+					   &newstate))
 		goto err_out;
 
 	mutex_lock(&fidvid_mutex);
@@ -1200,10 +1187,19 @@ static int powernowk8_target(struct cpufreq_policy *pol,
 	ret = 0;
 
 err_out:
-	set_cpus_allowed_ptr(current, &oldmask);
 	return ret;
 }
 
+/* Driver entry point to switch to the target frequency */
+static int powernowk8_target(struct cpufreq_policy *pol,
+			     unsigned targfreq, unsigned relation)
+{
+	struct target_data tdata = { .pol = pol,
+				     .targfreq = targfreq,
+				     .relation = relation };
+	return work_on_cpu(pol->cpu, powernowk8_target_on_cpu, &tdata);
+}
+
 /* Driver entry point to verify the policy and range of frequencies */
 static int powernowk8_verify(struct cpufreq_policy *pol)
 {
@@ -1215,19 +1211,42 @@ static int powernowk8_verify(struct cpufreq_policy *pol)
 	return cpufreq_frequency_table_verify(pol, data->powernow_table);
 }
 
+static long __cpuinit powernowk8_cpu_init_on_cpu(void *_data)
+{
+	struct powernow_k8_data *data = _data;
+
+	if (smp_processor_id() != data->cpu) {
+		printk(KERN_ERR PFX "limiting to cpu %u failed\n", data->cpu);
+		return -EIO;
+	}
+
+	if (pending_bit_stuck()) {
+		printk(KERN_ERR PFX "failing init, change pending bit set\n");
+		return -ENODEV;
+	}
+
+	if (query_current_values_with_pending_wait(data))
+		return -ENODEV;
+
+	if (cpu_family == CPU_OPTERON)
+		fidvid_msr_init();
+
+	return 0;
+}
+
 /* per CPU init entry point to the driver */
 static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
 {
 	struct powernow_k8_data *data;
-	cpumask_t oldmask;
 	int rc;
 	static int print_once;
 
 	if (!cpu_online(pol->cpu))
 		return -ENODEV;
 
-	if (!check_supported_cpu(pol->cpu))
-		return -ENODEV;
+	rc = work_on_cpu(pol->cpu, check_supported_cpu, NULL);
+	if (rc != 0)
+		return rc;
 
 	data = kzalloc(sizeof(struct powernow_k8_data), GFP_KERNEL);
 	if (!data) {
@@ -1278,27 +1297,9 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
 		pol->cpuinfo.transition_latency = get_transition_latency(data);
 
 	/* only run on specific CPU from here on */
-	oldmask = current->cpus_allowed;
-	set_cpus_allowed_ptr(current, &cpumask_of_cpu(pol->cpu));
-
-	if (smp_processor_id() != pol->cpu) {
-		printk(KERN_ERR PFX "limiting to cpu %u failed\n", pol->cpu);
-		goto err_out_unmask;
-	}
-
-	if (pending_bit_stuck()) {
-		printk(KERN_ERR PFX "failing init, change pending bit set\n");
-		goto err_out_unmask;
-	}
-
-	if (query_current_values_with_pending_wait(data))
-		goto err_out_unmask;
-
-	if (cpu_family == CPU_OPTERON)
-		fidvid_msr_init();
-
-	/* run on any CPU again */
-	set_cpus_allowed_ptr(current, &oldmask);
+	rc = work_on_cpu(data->cpu, powernowk8_cpu_init_on_cpu, data);
+	if (rc != 0)
+		goto err_out_exit_acpi;
 
 	if (cpu_family == CPU_HW_PSTATE)
 		cpumask_copy(pol->cpus, cpumask_of(pol->cpu));
@@ -1335,8 +1336,7 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
 
 	return 0;
 
-err_out_unmask:
-	set_cpus_allowed_ptr(current, &oldmask);
+err_out_exit_acpi:
 	powernow_k8_cpu_exit_acpi(data);
 
 err_out:
@@ -1361,12 +1361,20 @@ static int __devexit powernowk8_cpu_exit(struct cpufreq_policy *pol)
 	return 0;
 }
 
+static void query_values_on_cpu(void *_err)
+{
+	int *err = _err;
+	struct powernow_k8_data *data = __get_cpu_var(powernow_data);
+
+	*err = query_current_values_with_pending_wait(data);
+}
+
 static unsigned int powernowk8_get(unsigned int cpu)
 {
 	struct powernow_k8_data *data;
-	cpumask_t oldmask = current->cpus_allowed;
 	unsigned int khz = 0;
 	unsigned int first;
+	int err;
 
 	first = cpumask_first(cpu_core_mask(cpu));
 	data = per_cpu(powernow_data, first);
@@ -1374,15 +1382,8 @@ static unsigned int powernowk8_get(unsigned int cpu)
 	if (!data)
 		return -EINVAL;
 
-	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-	if (smp_processor_id() != cpu) {
-		printk(KERN_ERR PFX
-			"limiting to CPU %d failed in powernowk8_get\n", cpu);
-		set_cpus_allowed_ptr(current, &oldmask);
-		return 0;
-	}
-
-	if (query_current_values_with_pending_wait(data))
+	smp_call_function_single(first, query_values_on_cpu, &err, true);
+	if (err)
 		goto out;
 
 	if (cpu_family == CPU_HW_PSTATE)
@@ -1393,7 +1394,6 @@ static unsigned int powernowk8_get(unsigned int cpu)
 
 
 out:
-	set_cpus_allowed_ptr(current, &oldmask);
 	return khz;
 }
 
@@ -1419,7 +1419,7 @@ static int __cpuinit powernowk8_init(void)
 	unsigned int i, supported_cpus = 0;
 
 	for_each_online_cpu(i) {
-		if (check_supported_cpu(i))
+		if (work_on_cpu(i, check_supported_cpu, NULL) == 0)
 			supported_cpus++;
 	}
 
diff --git a/arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c b/arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c
index c9f1fdc02830..c9727f62a820 100644
--- a/arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c
+++ b/arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c
@@ -323,14 +323,8 @@ static unsigned int get_cur_freq(unsigned int cpu)
 {
 	unsigned l, h;
 	unsigned clock_freq;
-	cpumask_t saved_mask;
 
-	saved_mask = current->cpus_allowed;
-	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-	if (smp_processor_id() != cpu)
-		return 0;
-
-	rdmsr(MSR_IA32_PERF_STATUS, l, h);
+	rdmsr_on_cpu(cpu, MSR_IA32_PERF_STATUS, &l, &h);
 	clock_freq = extract_clock(l, cpu, 0);
 
 	if (unlikely(clock_freq == 0)) {
@@ -340,11 +334,9 @@ static unsigned int get_cur_freq(unsigned int cpu)
 		 * P-state transition (like TM2). Get the last freq set 
 		 * in PERF_CTL.
 		 */
-		rdmsr(MSR_IA32_PERF_CTL, l, h);
+		rdmsr_on_cpu(cpu, MSR_IA32_PERF_CTL, &l, &h);
 		clock_freq = extract_clock(l, cpu, 1);
 	}
-
-	set_cpus_allowed_ptr(current, &saved_mask);
 	return clock_freq;
 }
 
@@ -467,15 +459,10 @@ static int centrino_target (struct cpufreq_policy *policy,
 	struct cpufreq_freqs	freqs;
 	int			retval = 0;
 	unsigned int		j, k, first_cpu, tmp;
-	cpumask_var_t saved_mask, covered_cpus;
+	cpumask_var_t covered_cpus;
 
-	if (unlikely(!alloc_cpumask_var(&saved_mask, GFP_KERNEL)))
-		return -ENOMEM;
-	if (unlikely(!alloc_cpumask_var(&covered_cpus, GFP_KERNEL))) {
-		free_cpumask_var(saved_mask);
+	if (unlikely(!alloc_cpumask_var(&covered_cpus, GFP_KERNEL)))
 		return -ENOMEM;
-	}
-	cpumask_copy(saved_mask, &current->cpus_allowed);
 
 	if (unlikely(per_cpu(centrino_model, cpu) == NULL)) {
 		retval = -ENODEV;
@@ -493,7 +480,7 @@ static int centrino_target (struct cpufreq_policy *policy,
 
 	first_cpu = 1;
 	for_each_cpu(j, policy->cpus) {
-		const struct cpumask *mask;
+		int good_cpu;
 
 		/* cpufreq holds the hotplug lock, so we are safe here */
 		if (!cpu_online(j))
@@ -504,32 +491,30 @@ static int centrino_target (struct cpufreq_policy *policy,
 		 * Make sure we are running on CPU that wants to change freq
 		 */
 		if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
-			mask = policy->cpus;
+			good_cpu = cpumask_any_and(policy->cpus,
+						   cpu_online_mask);
 		else
-			mask = cpumask_of(j);
+			good_cpu = j;
 
-		set_cpus_allowed_ptr(current, mask);
-		preempt_disable();
-		if (unlikely(!cpu_isset(smp_processor_id(), *mask))) {
+		if (good_cpu >= nr_cpu_ids) {
 			dprintk("couldn't limit to CPUs in this domain\n");
 			retval = -EAGAIN;
 			if (first_cpu) {
 				/* We haven't started the transition yet. */
-				goto migrate_end;
+				goto out;
 			}
-			preempt_enable();
 			break;
 		}
 
 		msr = per_cpu(centrino_model, cpu)->op_points[newstate].index;
 
 		if (first_cpu) {
-			rdmsr(MSR_IA32_PERF_CTL, oldmsr, h);
+			rdmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, &oldmsr, &h);
 			if (msr == (oldmsr & 0xffff)) {
 				dprintk("no change needed - msr was and needs "
 					"to be %x\n", oldmsr);
 				retval = 0;
-				goto migrate_end;
+				goto out;
 			}
 
 			freqs.old = extract_clock(oldmsr, cpu, 0);
@@ -553,14 +538,11 @@ static int centrino_target (struct cpufreq_policy *policy,
 			oldmsr |= msr;
 		}
 
-		wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);
-		if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
-			preempt_enable();
+		wrmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, oldmsr, h);
+		if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 			break;
-		}
 
-		cpu_set(j, *covered_cpus);
-		preempt_enable();
+		cpumask_set_cpu(j, covered_cpus);
 	}
 
 	for_each_cpu(k, policy->cpus) {
@@ -578,10 +560,8 @@ static int centrino_target (struct cpufreq_policy *policy,
 		 * Best effort undo..
 		 */
 
-		for_each_cpu_mask_nr(j, *covered_cpus) {
-			set_cpus_allowed_ptr(current, &cpumask_of_cpu(j));
-			wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);
-		}
+		for_each_cpu(j, covered_cpus)
+			wrmsr_on_cpu(j, MSR_IA32_PERF_CTL, oldmsr, h);
 
 		tmp = freqs.new;
 		freqs.new = freqs.old;
@@ -593,15 +573,9 @@ static int centrino_target (struct cpufreq_policy *policy,
 			cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 		}
 	}
-	set_cpus_allowed_ptr(current, saved_mask);
 	retval = 0;
-	goto out;
 
-migrate_end:
-	preempt_enable();
-	set_cpus_allowed_ptr(current, saved_mask);
 out:
-	free_cpumask_var(saved_mask);
 	free_cpumask_var(covered_cpus);
 	return retval;
 }
diff --git a/arch/x86/kernel/cpu/cpufreq/speedstep-ich.c b/arch/x86/kernel/cpu/cpufreq/speedstep-ich.c
index 016c1a4fa3fc..ed9c539ba646 100644
--- a/arch/x86/kernel/cpu/cpufreq/speedstep-ich.c
+++ b/arch/x86/kernel/cpu/cpufreq/speedstep-ich.c
@@ -89,7 +89,8 @@ static int speedstep_find_register(void)
  * speedstep_set_state - set the SpeedStep state
  * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
  *
- *   Tries to change the SpeedStep state.
+ *   Tries to change the SpeedStep state.  Can be called from
+ *   smp_call_function_single.
  */
 static void speedstep_set_state(unsigned int state)
 {
@@ -143,6 +144,11 @@ static void speedstep_set_state(unsigned int state)
 	return;
 }
 
+/* Wrapper for smp_call_function_single. */
+static void _speedstep_set_state(void *_state)
+{
+	speedstep_set_state(*(unsigned int *)_state);
+}
 
 /**
  * speedstep_activate - activate SpeedStep control in the chipset
@@ -226,22 +232,28 @@ static unsigned int speedstep_detect_chipset(void)
 	return 0;
 }
 
-static unsigned int _speedstep_get(const struct cpumask *cpus)
-{
+struct get_freq_data {
 	unsigned int speed;
-	cpumask_t cpus_allowed;
-
-	cpus_allowed = current->cpus_allowed;
-	set_cpus_allowed_ptr(current, cpus);
-	speed = speedstep_get_frequency(speedstep_processor);
-	set_cpus_allowed_ptr(current, &cpus_allowed);
-	dprintk("detected %u kHz as current frequency\n", speed);
-	return speed;
+	unsigned int processor;
+};
+
+static void get_freq_data(void *_data)
+{
+	struct get_freq_data *data = _data;
+
+	data->speed = speedstep_get_frequency(data->processor);
 }
 
 static unsigned int speedstep_get(unsigned int cpu)
 {
-	return _speedstep_get(cpumask_of(cpu));
+	struct get_freq_data data = { .processor = cpu };
+
+	/* You're supposed to ensure CPU is online. */
+	if (smp_call_function_single(cpu, get_freq_data, &data, 1) != 0)
+		BUG();
+
+	dprintk("detected %u kHz as current frequency\n", data.speed);
+	return data.speed;
 }
 
 /**
@@ -257,16 +269,16 @@ static int speedstep_target(struct cpufreq_policy *policy,
 			     unsigned int target_freq,
 			     unsigned int relation)
 {
-	unsigned int newstate = 0;
+	unsigned int newstate = 0, policy_cpu;
 	struct cpufreq_freqs freqs;
-	cpumask_t cpus_allowed;
 	int i;
 
 	if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
 				target_freq, relation, &newstate))
 		return -EINVAL;
 
-	freqs.old = _speedstep_get(policy->cpus);
+	policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
+	freqs.old = speedstep_get(policy_cpu);
 	freqs.new = speedstep_freqs[newstate].frequency;
 	freqs.cpu = policy->cpu;
 
@@ -276,20 +288,13 @@ static int speedstep_target(struct cpufreq_policy *policy,
 	if (freqs.old == freqs.new)
 		return 0;
 
-	cpus_allowed = current->cpus_allowed;
-
 	for_each_cpu(i, policy->cpus) {
 		freqs.cpu = i;
 		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 	}
 
-	/* switch to physical CPU where state is to be changed */
-	set_cpus_allowed_ptr(current, policy->cpus);
-
-	speedstep_set_state(newstate);
-
-	/* allow to be run on all CPUs */
-	set_cpus_allowed_ptr(current, &cpus_allowed);
+	smp_call_function_single(policy_cpu, _speedstep_set_state, &newstate,
+				 true);
 
 	for_each_cpu(i, policy->cpus) {
 		freqs.cpu = i;
@@ -312,33 +317,35 @@ static int speedstep_verify(struct cpufreq_policy *policy)
 	return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
 }
 
+static long get_freqs_on_cpu(void *_policy)
+{
+	struct cpufreq_policy *policy = _policy;
+
+	return speedstep_get_freqs(speedstep_processor,
+				   &speedstep_freqs[SPEEDSTEP_LOW].frequency,
+				   &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
+				   &policy->cpuinfo.transition_latency,
+				   &speedstep_set_state);
+}
 
 static int speedstep_cpu_init(struct cpufreq_policy *policy)
 {
-	int result = 0;
-	unsigned int speed;
-	cpumask_t cpus_allowed;
+	int result;
+	unsigned int policy_cpu, speed;
 
 	/* only run on CPU to be set, or on its sibling */
 #ifdef CONFIG_SMP
 	cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
 #endif
-
-	cpus_allowed = current->cpus_allowed;
-	set_cpus_allowed_ptr(current, policy->cpus);
+	policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
 
 	/* detect low and high frequency and transition latency */
-	result = speedstep_get_freqs(speedstep_processor,
-				     &speedstep_freqs[SPEEDSTEP_LOW].frequency,
-				     &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
-				     &policy->cpuinfo.transition_latency,
-				     &speedstep_set_state);
-	set_cpus_allowed_ptr(current, &cpus_allowed);
+	result = work_on_cpu(policy_cpu, get_freqs_on_cpu, policy);
 	if (result)
 		return result;
 
 	/* get current speed setting */
-	speed = _speedstep_get(policy->cpus);
+	speed = speedstep_get(policy_cpu);
 	if (!speed)
 		return -EIO;
 
diff --git a/arch/x86/kernel/cpu/cpufreq/speedstep-lib.c b/arch/x86/kernel/cpu/cpufreq/speedstep-lib.c
index 2e3c6862657b..f4c290b8482f 100644
--- a/arch/x86/kernel/cpu/cpufreq/speedstep-lib.c
+++ b/arch/x86/kernel/cpu/cpufreq/speedstep-lib.c
@@ -226,6 +226,7 @@ static unsigned int pentium4_get_frequency(void)
 }
 
 
+/* Warning: may get called from smp_call_function_single. */
 unsigned int speedstep_get_frequency(unsigned int processor)
 {
 	switch (processor) {