[deliverable/linux.git] / arch / x86 / xen / smp.c

/*
 * Xen SMP support
 *
 * This file implements the Xen versions of smp_ops.  SMP under Xen is
 * very straightforward.  Bringing a CPU up is simply a matter of
 * loading its initial context and setting it running.
 *
 * IPIs are handled through the Xen event mechanism.
 *
 * Because virtual CPUs can be scheduled onto any real CPU, there's no
 * useful topology information for the kernel to make use of.  As a
 * result, all CPUs are treated as if they're single-core and
 * single-threaded.
 *
 * This does not handle HOTPLUG_CPU yet.
 */
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/smp.h>

#include <asm/paravirt.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/cpu.h>

#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>

#include <asm/xen/interface.h>
#include <asm/xen/hypercall.h>

#include <xen/page.h>
#include <xen/events.h>

#include "xen-ops.h"
#include "mmu.h"

static cpumask_t xen_cpu_initialized_map;
static DEFINE_PER_CPU(int, resched_irq) = -1;
static DEFINE_PER_CPU(int, callfunc_irq) = -1;
static DEFINE_PER_CPU(int, debug_irq) = -1;

/*
 * Structure and data for smp_call_function(). This is designed to minimise
 * static memory requirements. It also looks cleaner.
 */
static DEFINE_SPINLOCK(call_lock);

struct call_data_struct {
	void (*func) (void *info);
	void *info;
	atomic_t started;
	atomic_t finished;
	int wait;
};

static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);

static struct call_data_struct *call_data;

/*
 * Reschedule call back. Nothing to do,
 * all the work is done automatically when
 * we return from the interrupt.
 */
static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
{
	return IRQ_HANDLED;
}

static __cpuinit void cpu_bringup_and_idle(void)
{
	int cpu = smp_processor_id();

	cpu_init();
	xen_enable_sysenter();

	preempt_disable();
	per_cpu(cpu_state, cpu) = CPU_ONLINE;

	xen_setup_cpu_clockevents();

	/* We can take interrupts now: we're officially "up". */
	local_irq_enable();

	wmb();			/* make sure everything is out */
	cpu_idle();
}

static int xen_smp_intr_init(unsigned int cpu)
{
	int rc;
	const char *resched_name, *callfunc_name, *debug_name;

	resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
	rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
				    cpu,
				    xen_reschedule_interrupt,
				    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
				    resched_name,
				    NULL);
	if (rc < 0)
		goto fail;
	per_cpu(resched_irq, cpu) = rc;

	callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
				    cpu,
				    xen_call_function_interrupt,
				    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
				    callfunc_name,
				    NULL);
	if (rc < 0)
		goto fail;
	per_cpu(callfunc_irq, cpu) = rc;

	debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
	rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
				     IRQF_DISABLED | IRQF_PERCPU | IRQF_NOBALANCING,
				     debug_name, NULL);
	if (rc < 0)
		goto fail;
	per_cpu(debug_irq, cpu) = rc;

	return 0;

 fail:
	if (per_cpu(resched_irq, cpu) >= 0)
		unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL);
	if (per_cpu(callfunc_irq, cpu) >= 0)
		unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL);
	if (per_cpu(debug_irq, cpu) >= 0)
		unbind_from_irqhandler(per_cpu(debug_irq, cpu), NULL);
	return rc;
}

void __init xen_fill_possible_map(void)
{
	int i, rc;

	for (i = 0; i < NR_CPUS; i++) {
		rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
		if (rc >= 0)
			cpu_set(i, cpu_possible_map);
	}
}

void __init xen_smp_prepare_boot_cpu(void)
{
	int cpu;

	BUG_ON(smp_processor_id() != 0);
	native_smp_prepare_boot_cpu();

	/* We've switched to the "real" per-cpu gdt, so make sure the
	   old memory can be recycled */
	make_lowmem_page_readwrite(&per_cpu__gdt_page);

	for_each_possible_cpu(cpu) {
		cpus_clear(per_cpu(cpu_sibling_map, cpu));
		/*
		 * cpu_core_map lives in a per cpu area that is cleared
		 * when the per cpu array is allocated.
		 *
		 * cpus_clear(per_cpu(cpu_core_map, cpu));
		 */
	}

	xen_setup_vcpu_info_placement();
}

void __init xen_smp_prepare_cpus(unsigned int max_cpus)
{
	unsigned cpu;

	for_each_possible_cpu(cpu) {
		cpus_clear(per_cpu(cpu_sibling_map, cpu));
		/*
		 * cpu_core_ map will be zeroed when the per
		 * cpu area is allocated.
		 *
		 * cpus_clear(per_cpu(cpu_core_map, cpu));
		 */
	}

	smp_store_cpu_info(0);
	set_cpu_sibling_map(0);

	if (xen_smp_intr_init(0))
		BUG();

	xen_cpu_initialized_map = cpumask_of_cpu(0);

	/* Restrict the possible_map according to max_cpus. */
	while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
		for (cpu = NR_CPUS - 1; !cpu_possible(cpu); cpu--)
			continue;
		cpu_clear(cpu, cpu_possible_map);
	}

	for_each_possible_cpu (cpu) {
		struct task_struct *idle;

		if (cpu == 0)
			continue;

		idle = fork_idle(cpu);
		if (IS_ERR(idle))
			panic("failed fork for CPU %d", cpu);

		cpu_set(cpu, cpu_present_map);
	}

	//init_xenbus_allowed_cpumask();
}

static __cpuinit int
cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
{
	struct vcpu_guest_context *ctxt;
	struct gdt_page *gdt = &per_cpu(gdt_page, cpu);

	if (cpu_test_and_set(cpu, xen_cpu_initialized_map))
		return 0;

	ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
	if (ctxt == NULL)
		return -ENOMEM;

	ctxt->flags = VGCF_IN_KERNEL;
	ctxt->user_regs.ds = __USER_DS;
	ctxt->user_regs.es = __USER_DS;
	ctxt->user_regs.fs = __KERNEL_PERCPU;
	ctxt->user_regs.gs = 0;
	ctxt->user_regs.ss = __KERNEL_DS;
	ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
	ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */

	memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));

	xen_copy_trap_info(ctxt->trap_ctxt);

	ctxt->ldt_ents = 0;

	BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK);
	make_lowmem_page_readonly(gdt->gdt);

	ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt);
	ctxt->gdt_ents      = ARRAY_SIZE(gdt->gdt);

	ctxt->user_regs.cs = __KERNEL_CS;
	ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);

	ctxt->kernel_ss = __KERNEL_DS;
	ctxt->kernel_sp = idle->thread.sp0;

	ctxt->event_callback_cs     = __KERNEL_CS;
	ctxt->event_callback_eip    = (unsigned long)xen_hypervisor_callback;
	ctxt->failsafe_callback_cs  = __KERNEL_CS;
	ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;

	per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));

	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
		BUG();

	kfree(ctxt);
	return 0;
}

int __cpuinit xen_cpu_up(unsigned int cpu)
{
	struct task_struct *idle = idle_task(cpu);
	int rc;

#if 0
	rc = cpu_up_check(cpu);
	if (rc)
		return rc;
#endif

	init_gdt(cpu);
	per_cpu(current_task, cpu) = idle;
	irq_ctx_init(cpu);
	xen_setup_timer(cpu);

	/* make sure interrupts start blocked */
	per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;

	rc = cpu_initialize_context(cpu, idle);
	if (rc)
		return rc;

	if (num_online_cpus() == 1)
		alternatives_smp_switch(1);

	rc = xen_smp_intr_init(cpu);
	if (rc)
		return rc;

	smp_store_cpu_info(cpu);
	set_cpu_sibling_map(cpu);
	/* This must be done before setting cpu_online_map */
	wmb();

	cpu_set(cpu, cpu_online_map);

	rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
	BUG_ON(rc);

	return 0;
}

void xen_smp_cpus_done(unsigned int max_cpus)
{
}

static void stop_self(void *v)
{
	int cpu = smp_processor_id();

	/* make sure we're not pinning something down */
	load_cr3(swapper_pg_dir);
	/* should set up a minimal gdt */

	HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
	BUG();
}

void xen_smp_send_stop(void)
{
	smp_call_function(stop_self, NULL, 0, 0);
}

void xen_smp_send_reschedule(int cpu)
{
	xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
}


static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector)
{
	unsigned cpu;

	cpus_and(mask, mask, cpu_online_map);

	for_each_cpu_mask(cpu, mask)
		xen_send_IPI_one(cpu, vector);
}

static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
{
	void (*func) (void *info) = call_data->func;
	void *info = call_data->info;
	int wait = call_data->wait;

	/*
	 * Notify initiating CPU that I've grabbed the data and am
	 * about to execute the function
	 */
	mb();
	atomic_inc(&call_data->started);
	/*
	 * At this point the info structure may be out of scope unless wait==1
	 */
	irq_enter();
	(*func)(info);
	__get_cpu_var(irq_stat).irq_call_count++;
	irq_exit();

	if (wait) {
		mb();		/* commit everything before setting finished */
		atomic_inc(&call_data->finished);
	}

	return IRQ_HANDLED;
}

int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
			       void *info, int wait)
{
	struct call_data_struct data;
	int cpus, cpu;
	bool yield;

	/* Holding any lock stops cpus from going down. */
	spin_lock(&call_lock);

	cpu_clear(smp_processor_id(), mask);

	cpus = cpus_weight(mask);
	if (!cpus) {
		spin_unlock(&call_lock);
		return 0;
	}

	/* Can deadlock when called with interrupts disabled */
	WARN_ON(irqs_disabled());

	data.func = func;
	data.info = info;
	atomic_set(&data.started, 0);
	data.wait = wait;
	if (wait)
		atomic_set(&data.finished, 0);

	call_data = &data;
	mb();			/* write everything before IPI */

	/* Send a message to other CPUs and wait for them to respond */
	xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);

	/* Make sure other vcpus get a chance to run if they need to. */
	yield = false;
	for_each_cpu_mask(cpu, mask)
		if (xen_vcpu_stolen(cpu))
			yield = true;

	if (yield)
		HYPERVISOR_sched_op(SCHEDOP_yield, 0);

	/* Wait for response */
	while (atomic_read(&data.started) != cpus ||
	       (wait && atomic_read(&data.finished) != cpus))
		cpu_relax();

	spin_unlock(&call_lock);

	return 0;
}
Commit	Line	Data
f87e4cac JF	1	/*
	2	* Xen SMP support
	3	*
	4	* This file implements the Xen versions of smp_ops. SMP under Xen is
	5	* very straightforward. Bringing a CPU up is simply a matter of
	6	* loading its initial context and setting it running.
	7	*
	8	* IPIs are handled through the Xen event mechanism.
	9	*
	10	* Because virtual CPUs can be scheduled onto any real CPU, there's no
	11	* useful topology information for the kernel to make use of. As a
	12	* result, all CPUs are treated as if they're single-core and
	13	* single-threaded.
	14	*
	15	* This does not handle HOTPLUG_CPU yet.
	16	*/
	17	#include <linux/sched.h>
	18	#include <linux/err.h>
	19	#include <linux/smp.h>
	20
	21	#include <asm/paravirt.h>
	22	#include <asm/desc.h>
	23	#include <asm/pgtable.h>
	24	#include <asm/cpu.h>
	25
	26	#include <xen/interface/xen.h>
	27	#include <xen/interface/vcpu.h>
	28
	29	#include <asm/xen/interface.h>
	30	#include <asm/xen/hypercall.h>
	31
	32	#include <xen/page.h>
	33	#include <xen/events.h>
	34
	35	#include "xen-ops.h"
	36	#include "mmu.h"
	37
ecaa6c9d	38	static cpumask_t xen_cpu_initialized_map;
ee523ca1 JF	39	static DEFINE_PER_CPU(int, resched_irq) = -1;
	40	static DEFINE_PER_CPU(int, callfunc_irq) = -1;
	41	static DEFINE_PER_CPU(int, debug_irq) = -1;
f87e4cac JF	42
	43	/*
	44	* Structure and data for smp_call_function(). This is designed to minimise
	45	* static memory requirements. It also looks cleaner.
	46	*/
	47	static DEFINE_SPINLOCK(call_lock);
	48
	49	struct call_data_struct {
	50	void (func) (void info);
	51	void *info;
	52	atomic_t started;
	53	atomic_t finished;
	54	int wait;
	55	};
	56
	57	static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
	58
	59	static struct call_data_struct *call_data;
	60
	61	/*
	62	* Reschedule call back. Nothing to do,
	63	* all the work is done automatically when
	64	* we return from the interrupt.
	65	*/
	66	static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
	67	{
	68	return IRQ_HANDLED;
	69	}
	70
	71	static __cpuinit void cpu_bringup_and_idle(void)
	72	{
	73	int cpu = smp_processor_id();
	74
	75	cpu_init();
e2a81baf	76	xen_enable_sysenter();
f87e4cac JF	77
	78	preempt_disable();
	79	per_cpu(cpu_state, cpu) = CPU_ONLINE;
	80
	81	xen_setup_cpu_clockevents();
	82
	83	/* We can take interrupts now: we're officially "up". */
	84	local_irq_enable();
	85
	86	wmb(); /* make sure everything is out */
	87	cpu_idle();
	88	}
	89
	90	static int xen_smp_intr_init(unsigned int cpu)
	91	{
	92	int rc;
ee523ca1	93	const char resched_name, callfunc_name, *debug_name;
f87e4cac JF	94
	95	resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
	96	rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
	97	cpu,
	98	xen_reschedule_interrupt,
	99	IRQF_DISABLED\|IRQF_PERCPU\|IRQF_NOBALANCING,
	100	resched_name,
	101	NULL);
	102	if (rc < 0)
	103	goto fail;
	104	per_cpu(resched_irq, cpu) = rc;
	105
	106	callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
	107	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
	108	cpu,
	109	xen_call_function_interrupt,
	110	IRQF_DISABLED\|IRQF_PERCPU\|IRQF_NOBALANCING,
	111	callfunc_name,
	112	NULL);
	113	if (rc < 0)
	114	goto fail;
	115	per_cpu(callfunc_irq, cpu) = rc;
	116
ee523ca1 JF	117	debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
	118	rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
	119	IRQF_DISABLED \| IRQF_PERCPU \| IRQF_NOBALANCING,
	120	debug_name, NULL);
	121	if (rc < 0)
	122	goto fail;
	123	per_cpu(debug_irq, cpu) = rc;
	124
f87e4cac JF	125	return 0;
	126
	127	fail:
	128	if (per_cpu(resched_irq, cpu) >= 0)
	129	unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL);
	130	if (per_cpu(callfunc_irq, cpu) >= 0)
	131	unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL);
ee523ca1 JF	132	if (per_cpu(debug_irq, cpu) >= 0)
ee523ca1 JF	133	unbind_from_irqhandler(per_cpu(debug_irq, cpu), NULL);
f87e4cac JF	134	return rc;
	135	}
	136
	137	void __init xen_fill_possible_map(void)
	138	{
	139	int i, rc;
	140
	141	for (i = 0; i < NR_CPUS; i++) {
	142	rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
	143	if (rc >= 0)
	144	cpu_set(i, cpu_possible_map);
	145	}
	146	}
	147
	148	void __init xen_smp_prepare_boot_cpu(void)
	149	{
	150	int cpu;
	151
	152	BUG_ON(smp_processor_id() != 0);
	153	native_smp_prepare_boot_cpu();
	154
f87e4cac JF	155	/* We've switched to the "real" per-cpu gdt, so make sure the
	156	old memory can be recycled */
	157	make_lowmem_page_readwrite(&per_cpu__gdt_page);
	158
7bf0c23e	159	for_each_possible_cpu(cpu) {
d5a7430d	160	cpus_clear(per_cpu(cpu_sibling_map, cpu));
08357611 MT	161	/*
	162	* cpu_core_map lives in a per cpu area that is cleared
	163	* when the per cpu array is allocated.
	164	*
	165	* cpus_clear(per_cpu(cpu_core_map, cpu));
	166	*/
f87e4cac	167	}
60223a32 JF	168
60223a32 JF	169	xen_setup_vcpu_info_placement();
f87e4cac JF	170	}
	171
	172	void __init xen_smp_prepare_cpus(unsigned int max_cpus)
	173	{
	174	unsigned cpu;
	175
7bf0c23e	176	for_each_possible_cpu(cpu) {
d5a7430d	177	cpus_clear(per_cpu(cpu_sibling_map, cpu));
08357611 MT	178	/*
	179	* cpu_core_ map will be zeroed when the per
	180	* cpu area is allocated.
	181	*
	182	* cpus_clear(per_cpu(cpu_core_map, cpu));
	183	*/
f87e4cac JF	184	}
	185
	186	smp_store_cpu_info(0);
	187	set_cpu_sibling_map(0);
	188
	189	if (xen_smp_intr_init(0))
	190	BUG();
	191
ecaa6c9d	192	xen_cpu_initialized_map = cpumask_of_cpu(0);
f87e4cac JF	193
	194	/* Restrict the possible_map according to max_cpus. */
	195	while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
7c04e64a	196	for (cpu = NR_CPUS - 1; !cpu_possible(cpu); cpu--)
f87e4cac JF	197	continue;
	198	cpu_clear(cpu, cpu_possible_map);
	199	}
	200
	201	for_each_possible_cpu (cpu) {
	202	struct task_struct *idle;
	203
	204	if (cpu == 0)
	205	continue;
	206
	207	idle = fork_idle(cpu);
	208	if (IS_ERR(idle))
	209	panic("failed fork for CPU %d", cpu);
	210
	211	cpu_set(cpu, cpu_present_map);
	212	}
	213
	214	//init_xenbus_allowed_cpumask();
	215	}
	216
	217	static __cpuinit int
	218	cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
	219	{
	220	struct vcpu_guest_context *ctxt;
	221	struct gdt_page *gdt = &per_cpu(gdt_page, cpu);
	222
ecaa6c9d	223	if (cpu_test_and_set(cpu, xen_cpu_initialized_map))
f87e4cac JF	224	return 0;
	225
	226	ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
	227	if (ctxt == NULL)
	228	return -ENOMEM;
	229
	230	ctxt->flags = VGCF_IN_KERNEL;
	231	ctxt->user_regs.ds = __USER_DS;
	232	ctxt->user_regs.es = __USER_DS;
	233	ctxt->user_regs.fs = __KERNEL_PERCPU;
	234	ctxt->user_regs.gs = 0;
	235	ctxt->user_regs.ss = __KERNEL_DS;
	236	ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
	237	ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
	238
	239	memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
	240
	241	xen_copy_trap_info(ctxt->trap_ctxt);
	242
	243	ctxt->ldt_ents = 0;
	244
	245	BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK);
	246	make_lowmem_page_readonly(gdt->gdt);
	247
	248	ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt);
	249	ctxt->gdt_ents = ARRAY_SIZE(gdt->gdt);
	250
	251	ctxt->user_regs.cs = __KERNEL_CS;
faca6227	252	ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
f87e4cac JF	253
f87e4cac JF	254	ctxt->kernel_ss = __KERNEL_DS;
faca6227	255	ctxt->kernel_sp = idle->thread.sp0;
f87e4cac JF	256
	257	ctxt->event_callback_cs = __KERNEL_CS;
	258	ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback;
	259	ctxt->failsafe_callback_cs = __KERNEL_CS;
	260	ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
	261
	262	per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
	263	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
	264
	265	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
	266	BUG();
	267
	268	kfree(ctxt);
	269	return 0;
	270	}
	271
	272	int __cpuinit xen_cpu_up(unsigned int cpu)
	273	{
	274	struct task_struct *idle = idle_task(cpu);
	275	int rc;
	276
	277	#if 0
	278	rc = cpu_up_check(cpu);
	279	if (rc)
	280	return rc;
	281	#endif
	282
	283	init_gdt(cpu);
	284	per_cpu(current_task, cpu) = idle;
f87e4cac JF	285	irq_ctx_init(cpu);
	286	xen_setup_timer(cpu);
	287
	288	/* make sure interrupts start blocked */
	289	per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
	290
	291	rc = cpu_initialize_context(cpu, idle);
	292	if (rc)
	293	return rc;
	294
	295	if (num_online_cpus() == 1)
	296	alternatives_smp_switch(1);
	297
	298	rc = xen_smp_intr_init(cpu);
	299	if (rc)
	300	return rc;
	301
	302	smp_store_cpu_info(cpu);
	303	set_cpu_sibling_map(cpu);
	304	/* This must be done before setting cpu_online_map */
	305	wmb();
	306
	307	cpu_set(cpu, cpu_online_map);
	308
	309	rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
	310	BUG_ON(rc);
	311
	312	return 0;
	313	}
	314
	315	void xen_smp_cpus_done(unsigned int max_cpus)
	316	{
	317	}
	318
	319	static void stop_self(void *v)
	320	{
	321	int cpu = smp_processor_id();
	322
	323	/* make sure we're not pinning something down */
	324	load_cr3(swapper_pg_dir);
	325	/* should set up a minimal gdt */
	326
	327	HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
	328	BUG();
	329	}
	330
	331	void xen_smp_send_stop(void)
	332	{
fefa629a	333	smp_call_function(stop_self, NULL, 0, 0);
f87e4cac JF	334	}
	335
	336	void xen_smp_send_reschedule(int cpu)
	337	{
	338	xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
	339	}
	340
	341
	342	static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector)
	343	{
	344	unsigned cpu;
	345
	346	cpus_and(mask, mask, cpu_online_map);
	347
	348	for_each_cpu_mask(cpu, mask)
	349	xen_send_IPI_one(cpu, vector);
	350	}
	351
	352	static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
	353	{
	354	void (func) (void info) = call_data->func;
	355	void *info = call_data->info;
	356	int wait = call_data->wait;
	357
	358	/*
	359	* Notify initiating CPU that I've grabbed the data and am
	360	* about to execute the function
	361	*/
	362	mb();
	363	atomic_inc(&call_data->started);
	364	/*
	365	* At this point the info structure may be out of scope unless wait==1
	366	*/
	367	irq_enter();
	368	(*func)(info);
38e760a1	369	__get_cpu_var(irq_stat).irq_call_count++;
f87e4cac JF	370	irq_exit();
	371
	372	if (wait) {
	373	mb(); /* commit everything before setting finished */
	374	atomic_inc(&call_data->finished);
	375	}
	376
	377	return IRQ_HANDLED;
	378	}
	379
	380	int xen_smp_call_function_mask(cpumask_t mask, void (func)(void ),
	381	void *info, int wait)
	382	{
	383	struct call_data_struct data;
f0d73394 JF	384	int cpus, cpu;
f0d73394 JF	385	bool yield;
f87e4cac JF	386
	387	/* Holding any lock stops cpus from going down. */
	388	spin_lock(&call_lock);
	389
	390	cpu_clear(smp_processor_id(), mask);
	391
	392	cpus = cpus_weight(mask);
	393	if (!cpus) {
	394	spin_unlock(&call_lock);
	395	return 0;
	396	}
	397
	398	/* Can deadlock when called with interrupts disabled */
	399	WARN_ON(irqs_disabled());
	400
	401	data.func = func;
	402	data.info = info;
	403	atomic_set(&data.started, 0);
	404	data.wait = wait;
	405	if (wait)
	406	atomic_set(&data.finished, 0);
	407
	408	call_data = &data;
	409	mb(); /* write everything before IPI */
	410
	411	/* Send a message to other CPUs and wait for them to respond */
	412	xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
	413
f0d73394 JF	414	/* Make sure other vcpus get a chance to run if they need to. */
	415	yield = false;
	416	for_each_cpu_mask(cpu, mask)
	417	if (xen_vcpu_stolen(cpu))
	418	yield = true;
	419
	420	if (yield)
	421	HYPERVISOR_sched_op(SCHEDOP_yield, 0);
f87e4cac JF	422
	423	/* Wait for response */
	424	while (atomic_read(&data.started) != cpus \|\|
	425	(wait && atomic_read(&data.finished) != cpus))
	426	cpu_relax();
	427
	428	spin_unlock(&call_lock);
	429
	430	return 0;
	431	}