linux-brain/kernel/up.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Uniprocessor-only support functions.  The counterpart to kernel/smp.c
 */

#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/smp.h>
#include <linux/hypervisor.h>

int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
				int wait)
{
	unsigned long flags;

	WARN_ON(cpu != 0);

	local_irq_save(flags);
	func(info);
	local_irq_restore(flags);

	return 0;
}
EXPORT_SYMBOL(smp_call_function_single);

int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
{
	unsigned long flags;

	local_irq_save(flags);
	csd->func(csd->info);
	local_irq_restore(flags);
	return 0;
}
EXPORT_SYMBOL(smp_call_function_single_async);

void on_each_cpu(smp_call_func_t func, void *info, int wait)
{
	unsigned long flags;

	local_irq_save(flags);
	func(info);
	local_irq_restore(flags);
}
EXPORT_SYMBOL(on_each_cpu);

/*
 * Note we still need to test the mask even for UP
 * because we actually can get an empty mask from
 * code that on SMP might call us without the local
 * CPU in the mask.
 */
void on_each_cpu_mask(const struct cpumask *mask,
		      smp_call_func_t func, void *info, bool wait)
{
	unsigned long flags;

	if (cpumask_test_cpu(0, mask)) {
		local_irq_save(flags);
		func(info);
		local_irq_restore(flags);
	}
}
EXPORT_SYMBOL(on_each_cpu_mask);

/*
 * Preemption is disabled here to make sure the cond_func is called under the
 * same condtions in UP and SMP.
 */
void on_each_cpu_cond_mask(bool (*cond_func)(int cpu, void *info),
			   smp_call_func_t func, void *info, bool wait,
			   gfp_t gfp_flags, const struct cpumask *mask)
{
	unsigned long flags;

	preempt_disable();
	if (cond_func(0, info)) {
		local_irq_save(flags);
		func(info);
		local_irq_restore(flags);
	}
	preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);

void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
		      smp_call_func_t func, void *info, bool wait,
		      gfp_t gfp_flags)
{
	on_each_cpu_cond_mask(cond_func, func, info, wait, gfp_flags, NULL);
}
EXPORT_SYMBOL(on_each_cpu_cond);

int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
{
	int ret;

	if (cpu != 0)
		return -ENXIO;

	if (phys)
		hypervisor_pin_vcpu(0);
	ret = func(par);
	if (phys)
		hypervisor_pin_vcpu(-1);

	return ret;
}
EXPORT_SYMBOL_GPL(smp_call_on_cpu);