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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * lib/smp_processor_id.c | |
4 | * | |
5 | * DEBUG_PREEMPT variant of smp_processor_id(). | |
6 | */ | |
7 | #include <linux/export.h> | |
8 | #include <linux/kallsyms.h> | |
9 | #include <linux/sched.h> | |
10 | ||
11 | notrace static unsigned int check_preemption_disabled(const char *what1, | |
12 | const char *what2) | |
13 | { | |
14 | int this_cpu = raw_smp_processor_id(); | |
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 | if (cpumask_equal(¤t->cpus_allowed, cpumask_of(this_cpu))) | |
27 | goto out; | |
28 | ||
29 | /* | |
30 | * It is valid to assume CPU-locality during early bootup: | |
31 | */ | |
32 | if (system_state < SYSTEM_SCHEDULING) | |
33 | goto out; | |
34 | ||
35 | /* | |
36 | * Avoid recursion: | |
37 | */ | |
38 | preempt_disable_notrace(); | |
39 | ||
40 | if (!printk_ratelimit()) | |
41 | goto out_enable; | |
42 | ||
43 | printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n", | |
44 | what1, what2, preempt_count() - 1, current->comm, current->pid); | |
45 | ||
46 | print_symbol("caller is %s\n", (long)__builtin_return_address(0)); | |
47 | dump_stack(); | |
48 | ||
49 | out_enable: | |
50 | preempt_enable_no_resched_notrace(); | |
51 | out: | |
52 | return this_cpu; | |
53 | } | |
54 | ||
55 | notrace unsigned int debug_smp_processor_id(void) | |
56 | { | |
57 | return check_preemption_disabled("smp_processor_id", ""); | |
58 | } | |
59 | EXPORT_SYMBOL(debug_smp_processor_id); | |
60 | ||
61 | notrace void __this_cpu_preempt_check(const char *op) | |
62 | { | |
63 | check_preemption_disabled("__this_cpu_", op); | |
64 | } | |
65 | EXPORT_SYMBOL(__this_cpu_preempt_check); |