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