Quelle  smp_processor_id.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * lib/smp_processor_id.c
 *
 * DEBUG_PREEMPT variant of smp_processor_id().
 */
#include <linux/export.h>
#include <linux/kprobes.h>
#include <linux/sched.h>

noinstr static
unsigned int check_preemption_disabled(const char *what1, const char *what2)
{
 int this_cpu = raw_smp_processor_id();

 if (likely(preempt_count()))
  goto out;

 if (irqs_disabled())
  goto out;

 if (is_percpu_thread())
  goto out;

 if (current->migration_disabled)
  goto out;

 /*
 * It is valid to assume CPU-locality during early bootup:
 */
 if (system_state < SYSTEM_SCHEDULING)
  goto out;

 /*
 * Avoid recursion:
 */
 preempt_disable_notrace();

 instrumentation_begin();
 if (!printk_ratelimit())
  goto out_enable;

 printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",
  what1, what2, preempt_count() - 1, current->comm, current->pid);

 printk("caller is %pS\n", __builtin_return_address(0));
 dump_stack();

out_enable:
 instrumentation_end();
 preempt_enable_no_resched_notrace();
out:
 return this_cpu;
}

noinstr unsigned int debug_smp_processor_id(void)
{
 return check_preemption_disabled("smp_processor_id", "");
}
EXPORT_SYMBOL(debug_smp_processor_id);

noinstr void __this_cpu_preempt_check(const char *op)
{
 check_preemption_disabled("__this_cpu_", op);
}
EXPORT_SYMBOL(__this_cpu_preempt_check);