Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
11noinstr static
12unsigned 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 if (current->migration_disabled)
26 goto out;
27
28 /*
29 * It is valid to assume CPU-locality during early bootup:
30 */
31 if (system_state < SYSTEM_SCHEDULING)
32 goto out;
33
34 /*
35 * Avoid recursion:
36 */
37 preempt_disable_notrace();
38
39 instrumentation_begin();
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
49out_enable:
50 instrumentation_end();
51 preempt_enable_no_resched_notrace();
52out:
53 return this_cpu;
54}
55
56noinstr unsigned int debug_smp_processor_id(void)
57{
58 return check_preemption_disabled("smp_processor_id", "");
59}
60EXPORT_SYMBOL(debug_smp_processor_id);
61
62noinstr void __this_cpu_preempt_check(const char *op)
63{
64 check_preemption_disabled("__this_cpu_", op);
65}
66EXPORT_SYMBOL(__this_cpu_preempt_check);