arch/i386/mach-xen/irqflags.c

   1 #include <linux/module.h>
   2 #include <linux/smp.h>
   3 #include <asm/irqflags.h>
   4 #include <asm/hypervisor.h>
   5
   6 /* interrupt control.. */
   7
   8 /*
   9  * The use of 'barrier' in the following reflects their use as local-lock
  10  * operations. Reentrancy must be prevented (e.g., __cli()) /before/ following
  11  * critical operations are executed. All critical operations must complete
  12  * /before/ reentrancy is permitted (e.g., __sti()). Alpha architecture also
  13  * includes these barriers, for example.
  14  */
  15
  16 unsigned long __raw_local_save_flags(void)
  17 {
  18         struct vcpu_info *_vcpu;
  19         unsigned long flags;
  20
  21         preempt_disable();
  22         _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
  23         flags = _vcpu->evtchn_upcall_mask;
  24         preempt_enable();
  25
  26         return flags;
  27 }
  28 EXPORT_SYMBOL(__raw_local_save_flags);
  29
  30 void raw_local_irq_restore(unsigned long flags)
  31 {
  32         struct vcpu_info *_vcpu;
  33
  34         preempt_disable();
  35         _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
  36         if ((_vcpu->evtchn_upcall_mask = flags) == 0) {
  37                 barrier(); /* unmask then check (avoid races) */
  38                 if (unlikely(_vcpu->evtchn_upcall_pending))
  39                         force_evtchn_callback();
  40                 preempt_enable();
  41         } else
  42                 preempt_enable_no_resched();
  43
  44 }
  45 EXPORT_SYMBOL(raw_local_irq_restore);
  46
  47 void raw_local_irq_disable(void)
  48 {
  49         struct vcpu_info *_vcpu;
  50
  51         preempt_disable();
  52         _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
  53         _vcpu->evtchn_upcall_mask = 1;
  54         preempt_enable_no_resched();
  55 }
  56 EXPORT_SYMBOL(raw_local_irq_disable);
  57
  58 void raw_local_irq_enable(void)
  59 {
  60         struct vcpu_info *_vcpu;
  61
  62         preempt_disable();
  63         _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
  64         _vcpu->evtchn_upcall_mask = 0;
  65         barrier(); /* unmask then check (avoid races) */
  66         if (unlikely(_vcpu->evtchn_upcall_pending))
  67                 force_evtchn_callback();
  68         preempt_enable();
  69 }
  70 EXPORT_SYMBOL(raw_local_irq_enable);
  71
  72 /* Cannot use preempt_enable() here as we would recurse in preempt_sched(). */
  73 int raw_irqs_disabled(void)
  74 {
  75         struct vcpu_info *_vcpu;
  76         int disabled;
  77
  78         preempt_disable();
  79         _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
  80         disabled = (_vcpu->evtchn_upcall_mask != 0);
  81         preempt_enable_no_resched();
  82         return disabled;
  83 }
  84 EXPORT_SYMBOL(raw_irqs_disabled);
  85
  86 unsigned long __raw_local_irq_save(void)
  87 {
  88         struct vcpu_info *_vcpu;
  89         unsigned long flags;
  90
  91         preempt_disable();
  92         _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
  93         flags = _vcpu->evtchn_upcall_mask;
  94         _vcpu->evtchn_upcall_mask = 1;
  95         preempt_enable_no_resched();
  96
  97         return flags;
  98 }
  99 EXPORT_SYMBOL(__raw_local_irq_save);