Eric Lee / smarc-fsl-linux-kernel

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lib/smp_processor_id.c 1.38 KB
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81f7e3824   Eric Lee   Initial Release, ... 
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  // SPDX-License-Identifier: GPL-2.0
  /*
   * lib/smp_processor_id.c
   *
   * DEBUG_PREEMPT variant of smp_processor_id().
   */
  #include <linux/export.h>
  #include <linux/kallsyms.h>
  #include <linux/sched.h>
  
  notrace 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;
  
  	/*
  	 * Kernel threads bound to a single CPU can safely use
  	 * smp_processor_id():
  	 */
  	if (cpumask_equal(&current->cpus_allowed, cpumask_of(this_cpu)))
  		goto out;
  
  	/*
  	 * It is valid to assume CPU-locality during early bootup:
  	 */
  	if (system_state < SYSTEM_SCHEDULING)
  		goto out;
  
  	/*
  	 * Avoid recursion:
  	 */
  	preempt_disable_notrace();
  
  	if (!printk_ratelimit())
  		goto out_enable;
  
  	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d
  ",
  		what1, what2, preempt_count() - 1, current->comm, current->pid);
  
  	print_symbol("caller is %s
  ", (long)__builtin_return_address(0));
  	dump_stack();
  
  out_enable:
  	preempt_enable_no_resched_notrace();
  out:
  	return this_cpu;
  }
  
  notrace unsigned int debug_smp_processor_id(void)
  {
  	return check_preemption_disabled("smp_processor_id", "");
  }
  EXPORT_SYMBOL(debug_smp_processor_id);
  
  notrace void __this_cpu_preempt_check(const char *op)
  {
  	check_preemption_disabled("__this_cpu_", op);
  }
  EXPORT_SYMBOL(__this_cpu_preempt_check);