x86/xen: split off smp_pv.c

obj-$(CONFIG_EVENT_TRACING) += trace.o

obj-$(CONFIG_SMP)		+= smp.o

obj-$(CONFIG_SMP)		+= smp.o smp_pv.o

obj-$(CONFIG_XEN_PVHVM_SMP)  	+= smp_hvm.o

obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o

obj-$(CONFIG_XEN_DEBUG_FS)	+= debugfs.o

/*

 * 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.

 */

#include <linux/sched.h>

#include <linux/err.h>

#include <linux/slab.h>

#include <linux/smp.h>

#include <linux/irq_work.h>

#include <linux/tick.h>

#include <linux/nmi.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 <xen/interface/xenpmu.h>

#include <asm/xen/interface.h>

#include <asm/xen/hypercall.h>

#include <linux/slab.h>

#include <linux/cpumask.h>

#include <linux/percpu.h>

#include <xen/xen.h>

#include <xen/page.h>

#include <xen/events.h>

#include <xen/hvc-console.h>

#include "xen-ops.h"

#include "mmu.h"

#include "smp.h"

#include "pmu.h"

cpumask_var_t xen_cpu_initialized_map;

struct xen_common_irq {

	int irq;

	char *name;

};

static DEFINE_PER_CPU(struct xen_common_irq, xen_resched_irq) = { .irq = -1 };

static DEFINE_PER_CPU(struct xen_common_irq, xen_callfunc_irq) = { .irq = -1 };

static DEFINE_PER_CPU(struct xen_common_irq, xen_callfuncsingle_irq) = { .irq = -1 };

static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = { .irq = -1 };

static DEFINE_PER_CPU(struct xen_common_irq, xen_debug_irq) = { .irq = -1 };

static DEFINE_PER_CPU(struct xen_common_irq, xen_pmu_irq) = { .irq = -1 };

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

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

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

/*

 * Reschedule call back.

	return IRQ_HANDLED;

}

static void cpu_bringup(void)

{

	int cpu;

	cpu_init();

	touch_softlockup_watchdog();

	preempt_disable();

	/* PVH runs in ring 0 and allows us to do native syscalls. Yay! */

	if (!xen_feature(XENFEAT_supervisor_mode_kernel)) {

		xen_enable_sysenter();

		xen_enable_syscall();

	}

	cpu = smp_processor_id();

	smp_store_cpu_info(cpu);

	cpu_data(cpu).x86_max_cores = 1;

	set_cpu_sibling_map(cpu);

	xen_setup_cpu_clockevents();

	notify_cpu_starting(cpu);

	set_cpu_online(cpu, true);

	cpu_set_state_online(cpu);  /* Implies full memory barrier. */

	/* We can take interrupts now: we're officially "up". */

	local_irq_enable();

}

asmlinkage __visible void cpu_bringup_and_idle(void)

{

	cpu_bringup();

	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

}

void xen_smp_intr_free(unsigned int cpu)

{

	if (per_cpu(xen_resched_irq, cpu).irq >= 0) {

	}

}

void xen_smp_intr_free_pv(unsigned int cpu)

{

	if (per_cpu(xen_irq_work, cpu).irq >= 0) {

		unbind_from_irqhandler(per_cpu(xen_irq_work, cpu).irq, NULL);

		per_cpu(xen_irq_work, cpu).irq = -1;

		kfree(per_cpu(xen_irq_work, cpu).name);

		per_cpu(xen_irq_work, cpu).name = NULL;

	}

	if (per_cpu(xen_pmu_irq, cpu).irq >= 0) {

		unbind_from_irqhandler(per_cpu(xen_pmu_irq, cpu).irq, NULL);

		per_cpu(xen_pmu_irq, cpu).irq = -1;

		kfree(per_cpu(xen_pmu_irq, cpu).name);

		per_cpu(xen_pmu_irq, cpu).name = NULL;

	}

}

int xen_smp_intr_init(unsigned int cpu)

{

	int rc;

	return rc;

}

int xen_smp_intr_init_pv(unsigned int cpu)

{

	int rc;

	char *callfunc_name, *pmu_name;

	callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);

	rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,

				    cpu,

				    xen_irq_work_interrupt,

				    IRQF_PERCPU|IRQF_NOBALANCING,

				    callfunc_name,

				    NULL);

	if (rc < 0)

		goto fail;

	per_cpu(xen_irq_work, cpu).irq = rc;

	per_cpu(xen_irq_work, cpu).name = callfunc_name;

	if (is_xen_pmu(cpu)) {

		pmu_name = kasprintf(GFP_KERNEL, "pmu%d", cpu);

		rc = bind_virq_to_irqhandler(VIRQ_XENPMU, cpu,

					     xen_pmu_irq_handler,

					     IRQF_PERCPU|IRQF_NOBALANCING,

					     pmu_name, NULL);

		if (rc < 0)

			goto fail;

		per_cpu(xen_pmu_irq, cpu).irq = rc;

		per_cpu(xen_pmu_irq, cpu).name = pmu_name;

	}

	return 0;

 fail:

	xen_smp_intr_free_pv(cpu);

	return rc;

}

static void __init xen_fill_possible_map(void)

{

	int i, rc;

	if (xen_initial_domain())

		return;

	for (i = 0; i < nr_cpu_ids; i++) {

		rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);

		if (rc >= 0) {

			num_processors++;

			set_cpu_possible(i, true);

		}

	}

}

static void __init xen_filter_cpu_maps(void)

{

	int i, rc;

	unsigned int subtract = 0;

	if (!xen_initial_domain())

		return;

	num_processors = 0;

	disabled_cpus = 0;

	for (i = 0; i < nr_cpu_ids; i++) {

		rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);

		if (rc >= 0) {

			num_processors++;

			set_cpu_possible(i, true);

		} else {

			set_cpu_possible(i, false);

			set_cpu_present(i, false);

			subtract++;

		}

	}

#ifdef CONFIG_HOTPLUG_CPU

	/* This is akin to using 'nr_cpus' on the Linux command line.

	 * Which is OK as when we use 'dom0_max_vcpus=X' we can only

	 * have up to X, while nr_cpu_ids is greater than X. This

	 * normally is not a problem, except when CPU hotplugging

	 * is involved and then there might be more than X CPUs

	 * in the guest - which will not work as there is no

	 * hypercall to expand the max number of VCPUs an already

	 * running guest has. So cap it up to X. */

	if (subtract)

		nr_cpu_ids = nr_cpu_ids - subtract;

#endif

}

static void __init xen_pv_smp_prepare_boot_cpu(void)

{

	BUG_ON(smp_processor_id() != 0);

	native_smp_prepare_boot_cpu();

	if (!xen_feature(XENFEAT_writable_page_tables))

		/* We've switched to the "real" per-cpu gdt, so make

		 * sure the old memory can be recycled. */

		make_lowmem_page_readwrite(xen_initial_gdt);

#ifdef CONFIG_X86_32

	/*

	 * Xen starts us with XEN_FLAT_RING1_DS, but linux code

	 * expects __USER_DS

	 */

	loadsegment(ds, __USER_DS);

	loadsegment(es, __USER_DS);

#endif

	xen_filter_cpu_maps();

	xen_setup_vcpu_info_placement();

	/*

	 * The alternative logic (which patches the unlock/lock) runs before

	 * the smp bootup up code is activated. Hence we need to set this up

	 * the core kernel is being patched. Otherwise we will have only

	 * modules patched but not core code.

	 */

	xen_init_spinlocks();

}

static void __init xen_smp_prepare_cpus(unsigned int max_cpus)

{

	unsigned cpu;

	unsigned int i;

	if (skip_ioapic_setup) {

		char *m = (max_cpus == 0) ?

			"The nosmp parameter is incompatible with Xen; " \

			"use Xen dom0_max_vcpus=1 parameter" :

			"The noapic parameter is incompatible with Xen";

		xen_raw_printk(m);

		panic(m);

	}

	xen_init_lock_cpu(0);

	smp_store_boot_cpu_info();

	cpu_data(0).x86_max_cores = 1;

	for_each_possible_cpu(i) {

		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);

		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);

		zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);

	}

	set_cpu_sibling_map(0);

	xen_pmu_init(0);

	if (xen_smp_intr_init(0))

		BUG();

	if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))

		panic("could not allocate xen_cpu_initialized_map\n");

	cpumask_copy(xen_cpu_initialized_map, cpumask_of(0));

	/* Restrict the possible_map according to max_cpus. */

	while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {

		for (cpu = nr_cpu_ids - 1; !cpu_possible(cpu); cpu--)

			continue;

		set_cpu_possible(cpu, false);

	}

	for_each_possible_cpu(cpu)

		set_cpu_present(cpu, true);

}

static int

cpu_initialize_context(unsigned int cpu, struct task_struct *idle)

{

	struct vcpu_guest_context *ctxt;

	struct desc_struct *gdt;

	unsigned long gdt_mfn;

	/* used to tell cpu_init() that it can proceed with initialization */

	cpumask_set_cpu(cpu, cpu_callout_mask);

	if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))

		return 0;

	ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);

	if (ctxt == NULL)

		return -ENOMEM;

	gdt = get_cpu_gdt_rw(cpu);

#ifdef CONFIG_X86_32

	ctxt->user_regs.fs = __KERNEL_PERCPU;

	ctxt->user_regs.gs = __KERNEL_STACK_CANARY;

#endif

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

	ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;

	ctxt->flags = VGCF_IN_KERNEL;

	ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */

	ctxt->user_regs.ds = __USER_DS;

	ctxt->user_regs.es = __USER_DS;

	ctxt->user_regs.ss = __KERNEL_DS;

	xen_copy_trap_info(ctxt->trap_ctxt);

	ctxt->ldt_ents = 0;

	BUG_ON((unsigned long)gdt & ~PAGE_MASK);

	gdt_mfn = arbitrary_virt_to_mfn(gdt);

	make_lowmem_page_readonly(gdt);

	make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));

	ctxt->gdt_frames[0] = gdt_mfn;

	ctxt->gdt_ents      = GDT_ENTRIES;

	ctxt->kernel_ss = __KERNEL_DS;

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

#ifdef CONFIG_X86_32

	ctxt->event_callback_cs     = __KERNEL_CS;

	ctxt->failsafe_callback_cs  = __KERNEL_CS;

#else

	ctxt->gs_base_kernel = per_cpu_offset(cpu);

#endif

	ctxt->event_callback_eip    =

		(unsigned long)xen_hypervisor_callback;

	ctxt->failsafe_callback_eip =

		(unsigned long)xen_failsafe_callback;

	ctxt->user_regs.cs = __KERNEL_CS;

	per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);

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

	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));

	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, xen_vcpu_nr(cpu), ctxt))

		BUG();

	kfree(ctxt);

	return 0;

}

static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)

{

	int rc;

	common_cpu_up(cpu, idle);

	xen_setup_runstate_info(cpu);

	/*

	 * PV VCPUs are always successfully taken down (see 'while' loop

	 * in xen_cpu_die()), so -EBUSY is an error.

	 */

	rc = cpu_check_up_prepare(cpu);

	if (rc)

		return rc;

	/* make sure interrupts start blocked */

	per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;

	rc = cpu_initialize_context(cpu, idle);

	if (rc)

		return rc;

	xen_pmu_init(cpu);

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

	BUG_ON(rc);

	while (cpu_report_state(cpu) != CPU_ONLINE)

		HYPERVISOR_sched_op(SCHEDOP_yield, NULL);

	return 0;

}

static void xen_smp_cpus_done(unsigned int max_cpus)

{

}

#ifdef CONFIG_HOTPLUG_CPU

static int xen_cpu_disable(void)

{

	unsigned int cpu = smp_processor_id();

	if (cpu == 0)

		return -EBUSY;

	cpu_disable_common();

	load_cr3(swapper_pg_dir);

	return 0;

}

static void xen_pv_cpu_die(unsigned int cpu)

{

	while (HYPERVISOR_vcpu_op(VCPUOP_is_up,

				  xen_vcpu_nr(cpu), NULL)) {

		__set_current_state(TASK_UNINTERRUPTIBLE);

		schedule_timeout(HZ/10);

	}

	if (common_cpu_die(cpu) == 0) {

		xen_smp_intr_free(cpu);

		xen_uninit_lock_cpu(cpu);

		xen_teardown_timer(cpu);

		xen_pmu_finish(cpu);

	}

}

static void xen_play_dead(void) /* used only with HOTPLUG_CPU */

{

	play_dead_common();

	HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(smp_processor_id()), NULL);

	cpu_bringup();

	/*

	 * commit 4b0c0f294 (tick: Cleanup NOHZ per cpu data on cpu down)

	 * clears certain data that the cpu_idle loop (which called us

	 * and that we return from) expects. The only way to get that

	 * data back is to call:

	 */

	tick_nohz_idle_enter();

	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

}

#else /* !CONFIG_HOTPLUG_CPU */

static int xen_cpu_disable(void)

{

	return -ENOSYS;

}

static void xen_pv_cpu_die(unsigned int cpu)

{

	BUG();

}

static void xen_play_dead(void)

{

	BUG();

}

#endif

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 */

	set_cpu_online(cpu, false);

	HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL);

	BUG();

}

static void xen_stop_other_cpus(int wait)

{

	smp_call_function(stop_self, NULL, wait);

}

void xen_smp_send_reschedule(int cpu)

{

	xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);

	return IRQ_HANDLED;

}

static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)

{

	irq_enter();

	irq_work_run();

	inc_irq_stat(apic_irq_work_irqs);

	irq_exit();

	return IRQ_HANDLED;

}

static const struct smp_ops xen_smp_ops __initconst = {

	.smp_prepare_boot_cpu = xen_pv_smp_prepare_boot_cpu,

	.smp_prepare_cpus = xen_smp_prepare_cpus,

	.smp_cpus_done = xen_smp_cpus_done,

	.cpu_up = xen_cpu_up,

	.cpu_die = xen_pv_cpu_die,

	.cpu_disable = xen_cpu_disable,

	.play_dead = xen_play_dead,

	.stop_other_cpus = xen_stop_other_cpus,

	.smp_send_reschedule = xen_smp_send_reschedule,

	.send_call_func_ipi = xen_smp_send_call_function_ipi,

	.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,

};

void __init xen_smp_init(void)

{

	smp_ops = xen_smp_ops;

	xen_fill_possible_map();

}

void xen_smp_send_reschedule(int cpu);

void xen_smp_send_call_function_ipi(const struct cpumask *mask);

void xen_smp_send_call_function_single_ipi(int cpu);

struct xen_common_irq {

	int irq;

	char *name;

};

#else /* CONFIG_SMP */

static inline int xen_smp_intr_init(unsigned int cpu)