kernel/up.c

   1 /*
   2  * Uniprocessor-only support functions.  The counterpart to kernel/smp.c
   3  */
   4
   5 #include <linux/interrupt.h>
   6 #include <linux/kernel.h>
   7 #include <linux/export.h>
   8 #include <linux/smp.h>
   9 #include <linux/hypervisor.h>
  10
  11 int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
  12                                 int wait)
  13 {
  14         unsigned long flags;
  15
  16         WARN_ON(cpu != 0);
  17
  18         local_irq_save(flags);
  19         func(info);
  20         local_irq_restore(flags);
  21
  22         return 0;
  23 }
  24 EXPORT_SYMBOL(smp_call_function_single);
  25
  26 int smp_call_function_single_async(int cpu, struct call_single_data *csd)
  27 {
  28         unsigned long flags;
  29
  30         local_irq_save(flags);
  31         csd->func(csd->info);
  32         local_irq_restore(flags);
  33         return 0;
  34 }
  35 EXPORT_SYMBOL(smp_call_function_single_async);
  36
  37 int on_each_cpu(smp_call_func_t func, void *info, int wait)
  38 {
  39         unsigned long flags;
  40
  41         local_irq_save(flags);
  42         func(info);
  43         local_irq_restore(flags);
  44         return 0;
  45 }
  46 EXPORT_SYMBOL(on_each_cpu);
  47
  48 /*
  49  * Note we still need to test the mask even for UP
  50  * because we actually can get an empty mask from
  51  * code that on SMP might call us without the local
  52  * CPU in the mask.
  53  */
  54 void on_each_cpu_mask(const struct cpumask *mask,
  55                       smp_call_func_t func, void *info, bool wait)
  56 {
  57         unsigned long flags;
  58
  59         if (cpumask_test_cpu(0, mask)) {
  60                 local_irq_save(flags);
  61                 func(info);
  62                 local_irq_restore(flags);
  63         }
  64 }
  65 EXPORT_SYMBOL(on_each_cpu_mask);
  66
  67 /*
  68  * Preemption is disabled here to make sure the cond_func is called under the
  69  * same condtions in UP and SMP.
  70  */
  71 void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
  72                       smp_call_func_t func, void *info, bool wait,
  73                       gfp_t gfp_flags)
  74 {
  75         unsigned long flags;
  76
  77         preempt_disable();
  78         if (cond_func(0, info)) {
  79                 local_irq_save(flags);
  80                 func(info);
  81                 local_irq_restore(flags);
  82         }
  83         preempt_enable();
  84 }
  85 EXPORT_SYMBOL(on_each_cpu_cond);
  86
  87 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
  88 {
  89         int ret;
  90
  91         if (cpu != 0)
  92                 return -ENXIO;
  93
  94         if (phys)
  95                 hypervisor_pin_vcpu(0);
  96         ret = func(par);
  97         if (phys)
  98                 hypervisor_pin_vcpu(-1);
  99
 100         return ret;
 101 }
 102 EXPORT_SYMBOL_GPL(smp_call_on_cpu);