diff options
Diffstat (limited to 'arch/i386/xen/events.c')
| -rw-r--r-- | arch/i386/xen/events.c | 591 |
1 files changed, 0 insertions, 591 deletions
diff --git a/arch/i386/xen/events.c b/arch/i386/xen/events.c deleted file mode 100644 index da1b173547a1..000000000000 --- a/arch/i386/xen/events.c +++ /dev/null @@ -1,591 +0,0 @@ -/* - * Xen event channels - * - * Xen models interrupts with abstract event channels. Because each - * domain gets 1024 event channels, but NR_IRQ is not that large, we - * must dynamically map irqs<->event channels. The event channels - * interface with the rest of the kernel by defining a xen interrupt - * chip. When an event is recieved, it is mapped to an irq and sent - * through the normal interrupt processing path. - * - * There are four kinds of events which can be mapped to an event - * channel: - * - * 1. Inter-domain notifications. This includes all the virtual - * device events, since they're driven by front-ends in another domain - * (typically dom0). - * 2. VIRQs, typically used for timers. These are per-cpu events. - * 3. IPIs. - * 4. Hardware interrupts. Not supported at present. - * - * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 - */ - -#include <linux/linkage.h> -#include <linux/interrupt.h> -#include <linux/irq.h> -#include <linux/module.h> -#include <linux/string.h> - -#include <asm/ptrace.h> -#include <asm/irq.h> -#include <asm/sync_bitops.h> -#include <asm/xen/hypercall.h> -#include <asm/xen/hypervisor.h> - -#include <xen/events.h> -#include <xen/interface/xen.h> -#include <xen/interface/event_channel.h> - -#include "xen-ops.h" - -/* - * This lock protects updates to the following mapping and reference-count - * arrays. The lock does not need to be acquired to read the mapping tables. - */ -static DEFINE_SPINLOCK(irq_mapping_update_lock); - -/* IRQ <-> VIRQ mapping. */ -static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1}; - -/* IRQ <-> IPI mapping */ -static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -1}; - -/* Packed IRQ information: binding type, sub-type index, and event channel. */ -struct packed_irq -{ - unsigned short evtchn; - unsigned char index; - unsigned char type; -}; - -static struct packed_irq irq_info[NR_IRQS]; - -/* Binding types. */ -enum { - IRQT_UNBOUND, - IRQT_PIRQ, - IRQT_VIRQ, - IRQT_IPI, - IRQT_EVTCHN -}; - -/* Convenient shorthand for packed representation of an unbound IRQ. */ -#define IRQ_UNBOUND mk_irq_info(IRQT_UNBOUND, 0, 0) - -static int evtchn_to_irq[NR_EVENT_CHANNELS] = { - [0 ... NR_EVENT_CHANNELS-1] = -1 -}; -static unsigned long cpu_evtchn_mask[NR_CPUS][NR_EVENT_CHANNELS/BITS_PER_LONG]; -static u8 cpu_evtchn[NR_EVENT_CHANNELS]; - -/* Reference counts for bindings to IRQs. */ -static int irq_bindcount[NR_IRQS]; - -/* Xen will never allocate port zero for any purpose. */ -#define VALID_EVTCHN(chn) ((chn) != 0) - -/* - * Force a proper event-channel callback from Xen after clearing the - * callback mask. We do this in a very simple manner, by making a call - * down into Xen. The pending flag will be checked by Xen on return. - */ -void force_evtchn_callback(void) -{ - (void)HYPERVISOR_xen_version(0, NULL); -} -EXPORT_SYMBOL_GPL(force_evtchn_callback); - -static struct irq_chip xen_dynamic_chip; - -/* Constructor for packed IRQ information. */ -static inline struct packed_irq mk_irq_info(u32 type, u32 index, u32 evtchn) -{ - return (struct packed_irq) { evtchn, index, type }; -} - -/* - * Accessors for packed IRQ information. - */ -static inline unsigned int evtchn_from_irq(int irq) -{ - return irq_info[irq].evtchn; -} - -static inline unsigned int index_from_irq(int irq) -{ - return irq_info[irq].index; -} - -static inline unsigned int type_from_irq(int irq) -{ - return irq_info[irq].type; -} - -static inline unsigned long active_evtchns(unsigned int cpu, - struct shared_info *sh, - unsigned int idx) -{ - return (sh->evtchn_pending[idx] & - cpu_evtchn_mask[cpu][idx] & - ~sh->evtchn_mask[idx]); -} - -static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu) -{ - int irq = evtchn_to_irq[chn]; - - BUG_ON(irq == -1); -#ifdef CONFIG_SMP - irq_desc[irq].affinity = cpumask_of_cpu(cpu); -#endif - - __clear_bit(chn, cpu_evtchn_mask[cpu_evtchn[chn]]); - __set_bit(chn, cpu_evtchn_mask[cpu]); - - cpu_evtchn[chn] = cpu; -} - -static void init_evtchn_cpu_bindings(void) -{ -#ifdef CONFIG_SMP - int i; - /* By default all event channels notify CPU#0. */ - for (i = 0; i < NR_IRQS; i++) - irq_desc[i].affinity = cpumask_of_cpu(0); -#endif - - memset(cpu_evtchn, 0, sizeof(cpu_evtchn)); - memset(cpu_evtchn_mask[0], ~0, sizeof(cpu_evtchn_mask[0])); -} - -static inline unsigned int cpu_from_evtchn(unsigned int evtchn) -{ - return cpu_evtchn[evtchn]; -} - -static inline void clear_evtchn(int port) -{ - struct shared_info *s = HYPERVISOR_shared_info; - sync_clear_bit(port, &s->evtchn_pending[0]); -} - -static inline void set_evtchn(int port) -{ - struct shared_info *s = HYPERVISOR_shared_info; - sync_set_bit(port, &s->evtchn_pending[0]); -} - - -/** - * notify_remote_via_irq - send event to remote end of event channel via irq - * @irq: irq of event channel to send event to - * - * Unlike notify_remote_via_evtchn(), this is safe to use across - * save/restore. Notifications on a broken connection are silently - * dropped. - */ -void notify_remote_via_irq(int irq) -{ - int evtchn = evtchn_from_irq(irq); - - if (VALID_EVTCHN(evtchn)) - notify_remote_via_evtchn(evtchn); -} -EXPORT_SYMBOL_GPL(notify_remote_via_irq); - -static void mask_evtchn(int port) -{ - struct shared_info *s = HYPERVISOR_shared_info; - sync_set_bit(port, &s->evtchn_mask[0]); -} - -static void unmask_evtchn(int port) -{ - struct shared_info *s = HYPERVISOR_shared_info; - unsigned int cpu = get_cpu(); - - BUG_ON(!irqs_disabled()); - - /* Slow path (hypercall) if this is a non-local port. */ - if (unlikely(cpu != cpu_from_evtchn(port))) { - struct evtchn_unmask unmask = { .port = port }; - (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask); - } else { - struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu); - - sync_clear_bit(port, &s->evtchn_mask[0]); - - /* - * The following is basically the equivalent of - * 'hw_resend_irq'. Just like a real IO-APIC we 'lose - * the interrupt edge' if the channel is masked. - */ - if (sync_test_bit(port, &s->evtchn_pending[0]) && - !sync_test_and_set_bit(port / BITS_PER_LONG, - &vcpu_info->evtchn_pending_sel)) - vcpu_info->evtchn_upcall_pending = 1; - } - - put_cpu(); -} - -static int find_unbound_irq(void) -{ - int irq; - - /* Only allocate from dynirq range */ - for (irq = 0; irq < NR_IRQS; irq++) - if (irq_bindcount[irq] == 0) - break; - - if (irq == NR_IRQS) - panic("No available IRQ to bind to: increase NR_IRQS!\n"); - - return irq; -} - -int bind_evtchn_to_irq(unsigned int evtchn) -{ - int irq; - - spin_lock(&irq_mapping_update_lock); - - irq = evtchn_to_irq[evtchn]; - - if (irq == -1) { - irq = find_unbound_irq(); - - dynamic_irq_init(irq); - set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, - handle_level_irq, "event"); - - evtchn_to_irq[evtchn] = irq; - irq_info[irq] = mk_irq_info(IRQT_EVTCHN, 0, evtchn); - } - - irq_bindcount[irq]++; - - spin_unlock(&irq_mapping_update_lock); - - return irq; -} -EXPORT_SYMBOL_GPL(bind_evtchn_to_irq); - -static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu) -{ - struct evtchn_bind_ipi bind_ipi; - int evtchn, irq; - - spin_lock(&irq_mapping_update_lock); - - irq = per_cpu(ipi_to_irq, cpu)[ipi]; - if (irq == -1) { - irq = find_unbound_irq(); - if (irq < 0) - goto out; - - dynamic_irq_init(irq); - set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, - handle_level_irq, "ipi"); - - bind_ipi.vcpu = cpu; - if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi, - &bind_ipi) != 0) - BUG(); - evtchn = bind_ipi.port; - - evtchn_to_irq[evtchn] = irq; - irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn); - - per_cpu(ipi_to_irq, cpu)[ipi] = irq; - - bind_evtchn_to_cpu(evtchn, cpu); - } - - irq_bindcount[irq]++; - - out: - spin_unlock(&irq_mapping_update_lock); - return irq; -} - - -static int bind_virq_to_irq(unsigned int virq, unsigned int cpu) -{ - struct evtchn_bind_virq bind_virq; - int evtchn, irq; - - spin_lock(&irq_mapping_update_lock); - - irq = per_cpu(virq_to_irq, cpu)[virq]; - - if (irq == -1) { - bind_virq.virq = virq; - bind_virq.vcpu = cpu; - if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq, - &bind_virq) != 0) - BUG(); - evtchn = bind_virq.port; - - irq = find_unbound_irq(); - - dynamic_irq_init(irq); - set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, - handle_level_irq, "virq"); - - evtchn_to_irq[evtchn] = irq; - irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn); - - per_cpu(virq_to_irq, cpu)[virq] = irq; - - bind_evtchn_to_cpu(evtchn, cpu); - } - - irq_bindcount[irq]++; - - spin_unlock(&irq_mapping_update_lock); - - return irq; -} - -static void unbind_from_irq(unsigned int irq) -{ - struct evtchn_close close; - int evtchn = evtchn_from_irq(irq); - - spin_lock(&irq_mapping_update_lock); - - if (VALID_EVTCHN(evtchn) && (--irq_bindcount[irq] == 0)) { - close.port = evtchn; - if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0) - BUG(); - - switch (type_from_irq(irq)) { - case IRQT_VIRQ: - per_cpu(virq_to_irq, cpu_from_evtchn(evtchn)) - [index_from_irq(irq)] = -1; - break; - default: - break; - } - - /* Closed ports are implicitly re-bound to VCPU0. */ - bind_evtchn_to_cpu(evtchn, 0); - - evtchn_to_irq[evtchn] = -1; - irq_info[irq] = IRQ_UNBOUND; - - dynamic_irq_init(irq); - } - - spin_unlock(&irq_mapping_update_lock); -} - -int bind_evtchn_to_irqhandler(unsigned int evtchn, - irqreturn_t (*handler)(int, void *), - unsigned long irqflags, - const char *devname, void *dev_id) -{ - unsigned int irq; - int retval; - - irq = bind_evtchn_to_irq(evtchn); - retval = request_irq(irq, handler, irqflags, devname, dev_id); - if (retval != 0) { - unbind_from_irq(irq); - return retval; - } - - return irq; -} -EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler); - -int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu, - irqreturn_t (*handler)(int, void *), - unsigned long irqflags, const char *devname, void *dev_id) -{ - unsigned int irq; - int retval; - - irq = bind_virq_to_irq(virq, cpu); - retval = request_irq(irq, handler, irqflags, devname, dev_id); - if (retval != 0) { - unbind_from_irq(irq); - return retval; - } - - return irq; -} -EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler); - -int bind_ipi_to_irqhandler(enum ipi_vector ipi, - unsigned int cpu, - irq_handler_t handler, - unsigned long irqflags, - const char *devname, - void *dev_id) -{ - int irq, retval; - - irq = bind_ipi_to_irq(ipi, cpu); - if (irq < 0) - return irq; - - retval = request_irq(irq, handler, irqflags, devname, dev_id); - if (retval != 0) { - unbind_from_irq(irq); - return retval; - } - - return irq; -} - -void unbind_from_irqhandler(unsigned int irq, void *dev_id) -{ - free_irq(irq, dev_id); - unbind_from_irq(irq); -} -EXPORT_SYMBOL_GPL(unbind_from_irqhandler); - -void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector) -{ - int irq = per_cpu(ipi_to_irq, cpu)[vector]; - BUG_ON(irq < 0); - notify_remote_via_irq(irq); -} - - -/* - * Search the CPUs pending events bitmasks. For each one found, map - * the event number to an irq, and feed it into do_IRQ() for - * handling. - * - * Xen uses a two-level bitmap to speed searching. The first level is - * a bitset of words which contain pending event bits. The second - * level is a bitset of pending events themselves. - */ -fastcall void xen_evtchn_do_upcall(struct pt_regs *regs) -{ - int cpu = get_cpu(); - struct shared_info *s = HYPERVISOR_shared_info; - struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu); - unsigned long pending_words; - - vcpu_info->evtchn_upcall_pending = 0; - - /* NB. No need for a barrier here -- XCHG is a barrier on x86. */ - pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0); - while (pending_words != 0) { - unsigned long pending_bits; - int word_idx = __ffs(pending_words); - pending_words &= ~(1UL << word_idx); - - while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) { - int bit_idx = __ffs(pending_bits); - int port = (word_idx * BITS_PER_LONG) + bit_idx; - int irq = evtchn_to_irq[port]; - - if (irq != -1) { - regs->orig_eax = ~irq; - do_IRQ(regs); - } - } - } - - put_cpu(); -} - -/* Rebind an evtchn so that it gets delivered to a specific cpu */ -static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu) -{ - struct evtchn_bind_vcpu bind_vcpu; - int evtchn = evtchn_from_irq(irq); - - if (!VALID_EVTCHN(evtchn)) - return; - - /* Send future instances of this interrupt to other vcpu. */ - bind_vcpu.port = evtchn; - bind_vcpu.vcpu = tcpu; - - /* - * If this fails, it usually just indicates that we're dealing with a - * virq or IPI channel, which don't actually need to be rebound. Ignore - * it, but don't do the xenlinux-level rebind in that case. - */ - if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0) - bind_evtchn_to_cpu(evtchn, tcpu); -} - - -static void set_affinity_irq(unsigned irq, cpumask_t dest) -{ - unsigned tcpu = first_cpu(dest); - rebind_irq_to_cpu(irq, tcpu); -} - -static void enable_dynirq(unsigned int irq) -{ - int evtchn = evtchn_from_irq(irq); - - if (VALID_EVTCHN(evtchn)) - unmask_evtchn(evtchn); -} - -static void disable_dynirq(unsigned int irq) -{ - int evtchn = evtchn_from_irq(irq); - - if (VALID_EVTCHN(evtchn)) - mask_evtchn(evtchn); -} - -static void ack_dynirq(unsigned int irq) -{ - int evtchn = evtchn_from_irq(irq); - - move_native_irq(irq); - - if (VALID_EVTCHN(evtchn)) - clear_evtchn(evtchn); -} - -static int retrigger_dynirq(unsigned int irq) -{ - int evtchn = evtchn_from_irq(irq); - int ret = 0; - - if (VALID_EVTCHN(evtchn)) { - set_evtchn(evtchn); - ret = 1; - } - - return ret; -} - -static struct irq_chip xen_dynamic_chip __read_mostly = { - .name = "xen-dyn", - .mask = disable_dynirq, - .unmask = enable_dynirq, - .ack = ack_dynirq, - .set_affinity = set_affinity_irq, - .retrigger = retrigger_dynirq, -}; - -void __init xen_init_IRQ(void) -{ - int i; - - init_evtchn_cpu_bindings(); - - /* No event channels are 'live' right now. */ - for (i = 0; i < NR_EVENT_CHANNELS; i++) - mask_evtchn(i); - - /* Dynamic IRQ space is currently unbound. Zero the refcnts. */ - for (i = 0; i < NR_IRQS; i++) - irq_bindcount[i] = 0; - - irq_ctx_init(smp_processor_id()); -} |