linux/arch/x86/xen/smp.c

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/*
* 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 cpu_initialized_map;
static DEFINE_PER_CPU(int, resched_irq);
static DEFINE_PER_CPU(int, callfunc_irq);
/*
* 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();
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;
per_cpu(resched_irq, cpu) = per_cpu(callfunc_irq, cpu) = -1;
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;
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);
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 (cpu = 0; cpu < NR_CPUS; 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 (cpu = 0; cpu < NR_CPUS; 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();
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_isset(cpu, cpu_possible_map); 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, 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.esp0 - sizeof(struct pt_regs);
ctxt->kernel_ss = __KERNEL_DS;
ctxt->kernel_sp = idle->thread.esp0;
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);
x86: expand /proc/interrupts to include missing vectors, v2 Add missing IRQs and IRQ descriptions to /proc/interrupts. /proc/interrupts is most useful when it displays every IRQ vector in use by the system, not just those somebody thought would be interesting. This patch inserts the following vector displays to the i386 and x86_64 platforms, as appropriate: rescheduling interrupts TLB flush interrupts function call interrupts thermal event interrupts threshold interrupts spurious interrupts A threshold interrupt occurs when ECC memory correction is occuring at too high a frequency. Thresholds are used by the ECC hardware as occasional ECC failures are part of normal operation, but long sequences of ECC failures usually indicate a memory chip that is about to fail. Thermal event interrupts occur when a temperature threshold has been exceeded for some CPU chip. IIRC, a thermal interrupt is also generated when the temperature drops back to a normal level. A spurious interrupt is an interrupt that was raised then lowered by the device before it could be fully processed by the APIC. Hence the apic sees the interrupt but does not know what device it came from. For this case the APIC hardware will assume a vector of 0xff. Rescheduling, call, and TLB flush interrupts are sent from one CPU to another per the needs of the OS. Typically, their statistics would be used to discover if an interrupt flood of the given type has been occuring. AK: merged v2 and v4 which had some more tweaks AK: replace Local interrupts with Local timer interrupts AK: Fixed description of interrupt types. [ tglx: arch/x86 adaptation ] [ mingo: small cleanup ] Signed-off-by: Joe Korty <joe.korty@ccur.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Tim Hockin <thockin@hockin.org> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-17 16:04:40 +00:00
__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;
}