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 int 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         return 0;
  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(bool (*cond_func)(int cpu, void *info),
  73                            smp_call_func_t func, void *info, bool wait,
  74                            gfp_t gfp_flags, const struct cpumask *mask)
  75 {
  76         unsigned long flags;
  77
  78         preempt_disable();
  79         if (cond_func(0, info)) {
  80                 local_irq_save(flags);
  81                 func(info);
  82                 local_irq_restore(flags);
  83         }
  84         preempt_enable();
  85 }
  86 EXPORT_SYMBOL(on_each_cpu_cond_mask);
  87
  88 void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
  89                       smp_call_func_t func, void *info, bool wait,
  90                       gfp_t gfp_flags)
  91 {
  92         on_each_cpu_cond_mask(cond_func, func, info, wait, gfp_flags, NULL);
  93 }
  94 EXPORT_SYMBOL(on_each_cpu_cond);
  95
  96 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
  97 {
  98         int ret;
  99
 100         if (cpu != 0)
 101                 return -ENXIO;
 102
 103         if (phys)
 104                 hypervisor_pin_vcpu(0);
 105         ret = func(par);
 106         if (phys)
 107                 hypervisor_pin_vcpu(-1);
 108
 109         return ret;
 110 }
 111 EXPORT_SYMBOL_GPL(smp_call_on_cpu);