kernel/up.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Uniprocessor-only support functions.  The counterpart to kernel/smp.c
   4  */
   5
   6 #include <linux/interrupt.h>
   7 #include <linux/kernel.h>
   8 #include <linux/export.h>
   9 #include <linux/smp.h>
  10 #include <linux/hypervisor.h>
  11
  12 int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
  13                                 int wait)
  14 {
  15         unsigned long flags;
  16
  17         if (cpu != 0)
  18                 return -ENXIO;
  19
  20         local_irq_save(flags);
  21         func(info);
  22         local_irq_restore(flags);
  23
  24         return 0;
  25 }
  26 EXPORT_SYMBOL(smp_call_function_single);
  27
  28 int smp_call_function_single_async(int cpu, call_single_data_t *csd)
  29 {
  30         unsigned long flags;
  31
  32         local_irq_save(flags);
  33         csd->func(csd->info);
  34         local_irq_restore(flags);
  35         return 0;
  36 }
  37 EXPORT_SYMBOL(smp_call_function_single_async);
  38
  39 void on_each_cpu(smp_call_func_t func, void *info, int wait)
  40 {
  41         unsigned long flags;
  42
  43         local_irq_save(flags);
  44         func(info);
  45         local_irq_restore(flags);
  46 }
  47 EXPORT_SYMBOL(on_each_cpu);
  48
  49 /*
  50  * Note we still need to test the mask even for UP
  51  * because we actually can get an empty mask from
  52  * code that on SMP might call us without the local
  53  * CPU in the mask.
  54  */
  55 void on_each_cpu_mask(const struct cpumask *mask,
  56                       smp_call_func_t func, void *info, bool wait)
  57 {
  58         unsigned long flags;
  59
  60         if (cpumask_test_cpu(0, mask)) {
  61                 local_irq_save(flags);
  62                 func(info);
  63                 local_irq_restore(flags);
  64         }
  65 }
  66 EXPORT_SYMBOL(on_each_cpu_mask);
  67
  68 /*
  69  * Preemption is disabled here to make sure the cond_func is called under the
  70  * same condtions in UP and SMP.
  71  */
  72 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
  73                            void *info, bool wait, const struct cpumask *mask)
  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_mask);
  86
  87 void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
  88                       void *info, bool wait)
  89 {
  90         on_each_cpu_cond_mask(cond_func, func, info, wait, NULL);
  91 }
  92 EXPORT_SYMBOL(on_each_cpu_cond);
  93
  94 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
  95 {
  96         int ret;
  97
  98         if (cpu != 0)
  99                 return -ENXIO;
 100
 101         if (phys)
 102                 hypervisor_pin_vcpu(0);
 103         ret = func(par);
 104         if (phys)
 105                 hypervisor_pin_vcpu(-1);
 106
 107         return ret;
 108 }
 109 EXPORT_SYMBOL_GPL(smp_call_on_cpu);