Merge branch 'drm-next-3.13' of git://people.freedesktop.org/~agd5f/linux into drm...
[platform/adaptation/renesas_rcar/renesas_kernel.git] / lib / smp_processor_id.c
1 /*
2  * lib/smp_processor_id.c
3  *
4  * DEBUG_PREEMPT variant of smp_processor_id().
5  */
6 #include <linux/export.h>
7 #include <linux/kallsyms.h>
8 #include <linux/sched.h>
9
10 notrace unsigned int debug_smp_processor_id(void)
11 {
12         int this_cpu = raw_smp_processor_id();
13
14         if (likely(preempt_count()))
15                 goto out;
16
17         if (irqs_disabled())
18                 goto out;
19
20         /*
21          * Kernel threads bound to a single CPU can safely use
22          * smp_processor_id():
23          */
24         if (cpumask_equal(tsk_cpus_allowed(current), cpumask_of(this_cpu)))
25                 goto out;
26
27         /*
28          * It is valid to assume CPU-locality during early bootup:
29          */
30         if (system_state != SYSTEM_RUNNING)
31                 goto out;
32
33         /*
34          * Avoid recursion:
35          */
36         preempt_disable_notrace();
37
38         if (!printk_ratelimit())
39                 goto out_enable;
40
41         printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
42                         "code: %s/%d\n",
43                         preempt_count() - 1, current->comm, current->pid);
44         print_symbol("caller is %s\n", (long)__builtin_return_address(0));
45         dump_stack();
46
47 out_enable:
48         preempt_enable_no_resched_notrace();
49 out:
50         return this_cpu;
51 }
52
53 EXPORT_SYMBOL(debug_smp_processor_id);
54