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         WARN_ON(cpu != 0);
  18
  19         local_irq_save(flags);
  20         func(info);
  21         local_irq_restore(flags);
  22
  23         return 0;
  24 }
  25 EXPORT_SYMBOL(smp_call_function_single);
  26
  27 int smp_call_function_single_async(int cpu, call_single_data_t *csd)
  28 {
  29         unsigned long flags;
  30
  31         local_irq_save(flags);
  32         csd->func(csd->info);
  33         local_irq_restore(flags);
  34         return 0;
  35 }
  36 EXPORT_SYMBOL(smp_call_function_single_async);
  37
  38 void on_each_cpu(smp_call_func_t func, void *info, int wait)
  39 {
  40         unsigned long flags;
  41
  42         local_irq_save(flags);
  43         func(info);
  44         local_irq_restore(flags);
  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_mask(bool (*cond_func)(int cpu, void *info),
  72                            smp_call_func_t func, void *info, bool wait,
  73                            gfp_t gfp_flags, 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(bool (*cond_func)(int cpu, void *info),
  88                       smp_call_func_t func, void *info, bool wait,
  89                       gfp_t gfp_flags)
  90 {
  91         on_each_cpu_cond_mask(cond_func, func, info, wait, gfp_flags, NULL);
  92 }
  93 EXPORT_SYMBOL(on_each_cpu_cond);
  94
  95 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
  96 {
  97         int ret;
  98
  99         if (cpu != 0)
 100                 return -ENXIO;
 101
 102         if (phys)
 103                 hypervisor_pin_vcpu(0);
 104         ret = func(par);
 105         if (phys)
 106                 hypervisor_pin_vcpu(-1);
 107
 108         return ret;
 109 }
 110 EXPORT_SYMBOL_GPL(smp_call_on_cpu);