Commit | Line | Data |
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39c715b7 IM |
1 | /* |
2 | * lib/smp_processor_id.c | |
3 | * | |
4 | * DEBUG_PREEMPT variant of smp_processor_id(). | |
5 | */ | |
6 | #include <linux/module.h> | |
7 | #include <linux/kallsyms.h> | |
4e57b681 | 8 | #include <linux/sched.h> |
39c715b7 IM |
9 | |
10 | unsigned int debug_smp_processor_id(void) | |
11 | { | |
12 | unsigned long preempt_count = preempt_count(); | |
13 | int this_cpu = raw_smp_processor_id(); | |
14 | cpumask_t this_mask; | |
15 | ||
16 | if (likely(preempt_count)) | |
17 | goto out; | |
18 | ||
19 | if (irqs_disabled()) | |
20 | goto out; | |
21 | ||
22 | /* | |
23 | * Kernel threads bound to a single CPU can safely use | |
24 | * smp_processor_id(): | |
25 | */ | |
26 | this_mask = cpumask_of_cpu(this_cpu); | |
27 | ||
28 | if (cpus_equal(current->cpus_allowed, this_mask)) | |
29 | goto out; | |
30 | ||
31 | /* | |
32 | * It is valid to assume CPU-locality during early bootup: | |
33 | */ | |
34 | if (system_state != SYSTEM_RUNNING) | |
35 | goto out; | |
36 | ||
37 | /* | |
38 | * Avoid recursion: | |
39 | */ | |
40 | preempt_disable(); | |
41 | ||
42 | if (!printk_ratelimit()) | |
43 | goto out_enable; | |
44 | ||
45 | printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] code: %s/%d\n", preempt_count(), current->comm, current->pid); | |
46 | print_symbol("caller is %s\n", (long)__builtin_return_address(0)); | |
47 | dump_stack(); | |
48 | ||
49 | out_enable: | |
50 | preempt_enable_no_resched(); | |
51 | out: | |
52 | return this_cpu; | |
53 | } | |
54 | ||
55 | EXPORT_SYMBOL(debug_smp_processor_id); | |
56 |