| /* |
| * 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/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" |
| |
| cpumask_var_t xen_cpu_initialized_map; |
| |
| static DEFINE_PER_CPU(int, xen_resched_irq); |
| static DEFINE_PER_CPU(int, xen_callfunc_irq); |
| static DEFINE_PER_CPU(int, xen_callfuncsingle_irq); |
| static DEFINE_PER_CPU(int, xen_debug_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); |
| |
| /* |
| * 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) |
| { |
| inc_irq_stat(irq_resched_count); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static __cpuinit void cpu_bringup(void) |
| { |
| int cpu = smp_processor_id(); |
| |
| cpu_init(); |
| touch_softlockup_watchdog(); |
| preempt_disable(); |
| |
| 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(); |
| |
| set_cpu_online(cpu, true); |
| percpu_write(cpu_state, CPU_ONLINE); |
| wmb(); |
| |
| /* We can take interrupts now: we're officially "up". */ |
| local_irq_enable(); |
| |
| wmb(); /* make sure everything is out */ |
| } |
| |
| static __cpuinit void cpu_bringup_and_idle(void) |
| { |
| cpu_bringup(); |
| 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(xen_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(xen_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(xen_debug_irq, cpu) = rc; |
| |
| callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu); |
| rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR, |
| cpu, |
| xen_call_function_single_interrupt, |
| IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, |
| callfunc_name, |
| NULL); |
| if (rc < 0) |
| goto fail; |
| per_cpu(xen_callfuncsingle_irq, cpu) = rc; |
| |
| return 0; |
| |
| fail: |
| if (per_cpu(xen_resched_irq, cpu) >= 0) |
| unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL); |
| if (per_cpu(xen_callfunc_irq, cpu) >= 0) |
| unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL); |
| if (per_cpu(xen_debug_irq, cpu) >= 0) |
| unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL); |
| if (per_cpu(xen_callfuncsingle_irq, cpu) >= 0) |
| unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), |
| NULL); |
| |
| return rc; |
| } |
| |
| static void __init xen_fill_possible_map(void) |
| { |
| int i, rc; |
| |
| 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_smp_prepare_boot_cpu(void) |
| { |
| 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(xen_initial_gdt); |
| |
| xen_setup_vcpu_info_placement(); |
| } |
| |
| static void __init xen_smp_prepare_cpus(unsigned int max_cpus) |
| { |
| unsigned cpu; |
| |
| xen_init_lock_cpu(0); |
| |
| smp_store_cpu_info(0); |
| cpu_data(0).x86_max_cores = 1; |
| set_cpu_sibling_map(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) { |
| struct task_struct *idle; |
| |
| if (cpu == 0) |
| continue; |
| |
| idle = fork_idle(cpu); |
| if (IS_ERR(idle)) |
| panic("failed fork for CPU %d", cpu); |
| |
| set_cpu_present(cpu, true); |
| } |
| } |
| |
| static __cpuinit int |
| cpu_initialize_context(unsigned int cpu, struct task_struct *idle) |
| { |
| struct vcpu_guest_context *ctxt; |
| struct desc_struct *gdt; |
| unsigned long gdt_mfn; |
| |
| 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_table(cpu); |
| |
| ctxt->flags = VGCF_IN_KERNEL; |
| ctxt->user_regs.ds = __USER_DS; |
| ctxt->user_regs.es = __USER_DS; |
| ctxt->user_regs.ss = __KERNEL_DS; |
| #ifdef CONFIG_X86_32 |
| ctxt->user_regs.fs = __KERNEL_PERCPU; |
| ctxt->user_regs.gs = __KERNEL_STACK_CANARY; |
| #else |
| ctxt->gs_base_kernel = per_cpu_offset(cpu); |
| #endif |
| 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 & ~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->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; |
| |
| #ifdef CONFIG_X86_32 |
| ctxt->event_callback_cs = __KERNEL_CS; |
| ctxt->failsafe_callback_cs = __KERNEL_CS; |
| #endif |
| ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback; |
| 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; |
| } |
| |
| static int __cpuinit xen_cpu_up(unsigned int cpu) |
| { |
| struct task_struct *idle = idle_task(cpu); |
| int rc; |
| |
| per_cpu(current_task, cpu) = idle; |
| #ifdef CONFIG_X86_32 |
| irq_ctx_init(cpu); |
| #else |
| clear_tsk_thread_flag(idle, TIF_FORK); |
| per_cpu(kernel_stack, cpu) = |
| (unsigned long)task_stack_page(idle) - |
| KERNEL_STACK_OFFSET + THREAD_SIZE; |
| #endif |
| xen_setup_runstate_info(cpu); |
| xen_setup_timer(cpu); |
| xen_init_lock_cpu(cpu); |
| |
| per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; |
| |
| /* 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; |
| |
| rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL); |
| BUG_ON(rc); |
| |
| while(per_cpu(cpu_state, cpu) != CPU_ONLINE) { |
| HYPERVISOR_sched_op(SCHEDOP_yield, NULL); |
| barrier(); |
| } |
| |
| 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_cpu_die(unsigned int cpu) |
| { |
| while (HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL)) { |
| current->state = TASK_UNINTERRUPTIBLE; |
| schedule_timeout(HZ/10); |
| } |
| unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL); |
| unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL); |
| unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL); |
| unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL); |
| xen_uninit_lock_cpu(cpu); |
| xen_teardown_timer(cpu); |
| |
| if (num_online_cpus() == 1) |
| alternatives_smp_switch(0); |
| } |
| |
| static void __cpuinit xen_play_dead(void) /* used only with CPU_HOTPLUG */ |
| { |
| play_dead_common(); |
| HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL); |
| cpu_bringup(); |
| } |
| |
| #else /* !CONFIG_HOTPLUG_CPU */ |
| static int xen_cpu_disable(void) |
| { |
| return -ENOSYS; |
| } |
| |
| static void xen_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 */ |
| |
| HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL); |
| BUG(); |
| } |
| |
| static void xen_smp_send_stop(void) |
| { |
| smp_call_function(stop_self, NULL, 0); |
| } |
| |
| static void xen_smp_send_reschedule(int cpu) |
| { |
| xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR); |
| } |
| |
| static void xen_send_IPI_mask(const struct cpumask *mask, |
| enum ipi_vector vector) |
| { |
| unsigned cpu; |
| |
| for_each_cpu_and(cpu, mask, cpu_online_mask) |
| xen_send_IPI_one(cpu, vector); |
| } |
| |
| static void xen_smp_send_call_function_ipi(const struct cpumask *mask) |
| { |
| int cpu; |
| |
| xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR); |
| |
| /* Make sure other vcpus get a chance to run if they need to. */ |
| for_each_cpu(cpu, mask) { |
| if (xen_vcpu_stolen(cpu)) { |
| HYPERVISOR_sched_op(SCHEDOP_yield, NULL); |
| break; |
| } |
| } |
| } |
| |
| static void xen_smp_send_call_function_single_ipi(int cpu) |
| { |
| xen_send_IPI_mask(cpumask_of(cpu), |
| XEN_CALL_FUNCTION_SINGLE_VECTOR); |
| } |
| |
| static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id) |
| { |
| irq_enter(); |
| generic_smp_call_function_interrupt(); |
| inc_irq_stat(irq_call_count); |
| irq_exit(); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id) |
| { |
| irq_enter(); |
| generic_smp_call_function_single_interrupt(); |
| inc_irq_stat(irq_call_count); |
| irq_exit(); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static const struct smp_ops xen_smp_ops __initdata = { |
| .smp_prepare_boot_cpu = xen_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_cpu_die, |
| .cpu_disable = xen_cpu_disable, |
| .play_dead = xen_play_dead, |
| |
| .smp_send_stop = xen_smp_send_stop, |
| .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(); |
| xen_init_spinlocks(); |
| } |