Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-microblaze.git] / lib / smp_processor_id.c
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 notrace static nokprobe_inline
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         /*
23          * Kernel threads bound to a single CPU can safely use
24          * smp_processor_id():
25          */
26         if (cpumask_equal(current->cpus_ptr, 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         printk("caller is %pS\n", __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 NOKPROBE_SYMBOL(debug_smp_processor_id);
61
62 notrace void __this_cpu_preempt_check(const char *op)
63 {
64         check_preemption_disabled("__this_cpu_", op);
65 }
66 EXPORT_SYMBOL(__this_cpu_preempt_check);
67 NOKPROBE_SYMBOL(__this_cpu_preempt_check);