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58 lines
1.2 KiB
C
58 lines
1.2 KiB
C
/*
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* lib/smp_processor_id.c
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*
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* DEBUG_PREEMPT variant of smp_processor_id().
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*/
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/sched.h>
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notrace unsigned int debug_smp_processor_id(void)
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{
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unsigned long preempt_count = preempt_count();
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int this_cpu = raw_smp_processor_id();
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cpumask_of_cpu_ptr_declare(this_mask);
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if (likely(preempt_count))
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goto out;
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if (irqs_disabled())
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goto out;
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/*
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* Kernel threads bound to a single CPU can safely use
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* smp_processor_id():
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*/
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cpumask_of_cpu_ptr_next(this_mask, this_cpu);
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if (cpus_equal(current->cpus_allowed, *this_mask))
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goto out;
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/*
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* It is valid to assume CPU-locality during early bootup:
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*/
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if (system_state != SYSTEM_RUNNING)
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goto out;
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/*
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* Avoid recursion:
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*/
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preempt_disable_notrace();
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if (!printk_ratelimit())
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goto out_enable;
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printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
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"code: %s/%d\n",
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preempt_count() - 1, current->comm, current->pid);
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print_symbol("caller is %s\n", (long)__builtin_return_address(0));
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dump_stack();
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out_enable:
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preempt_enable_no_resched_notrace();
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out:
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return this_cpu;
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}
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EXPORT_SYMBOL(debug_smp_processor_id);
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