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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/kprobes.h> | |
9 | #include <linux/sched.h> | |
10 | ||
11 | noinstr static | |
12 | unsigned int check_preemption_disabled(const char *what1, 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 | if (is_percpu_thread()) | |
23 | goto out; | |
24 | ||
25 | #ifdef CONFIG_SMP | |
26 | if (current->migration_disabled) | |
27 | goto out; | |
28 | #endif | |
29 | ||
30 | /* | |
31 | * It is valid to assume CPU-locality during early bootup: | |
32 | */ | |
33 | if (system_state < SYSTEM_SCHEDULING) | |
34 | goto out; | |
35 | ||
36 | /* | |
37 | * Avoid recursion: | |
38 | */ | |
39 | preempt_disable_notrace(); | |
40 | ||
41 | instrumentation_begin(); | |
42 | if (!printk_ratelimit()) | |
43 | goto out_enable; | |
44 | ||
45 | printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n", | |
46 | what1, what2, preempt_count() - 1, current->comm, current->pid); | |
47 | ||
48 | printk("caller is %pS\n", __builtin_return_address(0)); | |
49 | dump_stack(); | |
50 | instrumentation_end(); | |
51 | ||
52 | out_enable: | |
53 | preempt_enable_no_resched_notrace(); | |
54 | out: | |
55 | return this_cpu; | |
56 | } | |
57 | ||
58 | noinstr unsigned int debug_smp_processor_id(void) | |
59 | { | |
60 | return check_preemption_disabled("smp_processor_id", ""); | |
61 | } | |
62 | EXPORT_SYMBOL(debug_smp_processor_id); | |
63 | ||
64 | noinstr void __this_cpu_preempt_check(const char *op) | |
65 | { | |
66 | check_preemption_disabled("__this_cpu_", op); | |
67 | } | |
68 | EXPORT_SYMBOL(__this_cpu_preempt_check); |