1/*
 2 * lib/smp_processor_id.c
 3 *
 4 * DEBUG_PREEMPT variant of smp_processor_id().
 5 */
 6#include <linux/export.h>
 7#include <linux/kallsyms.h>
 8#include <linux/sched.h>
 9
10notrace unsigned int debug_smp_processor_id(void)
 
11{
12	unsigned long preempt_count = preempt_count();
13	int this_cpu = raw_smp_processor_id();
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	if (cpumask_equal(tsk_cpus_allowed(current), cpumask_of(this_cpu)))
26		goto out;
27
 
 
 
 
 
28	/*
29	 * It is valid to assume CPU-locality during early bootup:
30	 */
31	if (system_state != SYSTEM_RUNNING)
32		goto out;
33
34	/*
35	 * Avoid recursion:
36	 */
37	preempt_disable_notrace();
38
 
39	if (!printk_ratelimit())
40		goto out_enable;
41
42	printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
43			"code: %s/%d\n",
44			preempt_count() - 1, current->comm, current->pid);
45	print_symbol("caller is %s\n", (long)__builtin_return_address(0));
46	dump_stack();
47
48out_enable:
 
49	preempt_enable_no_resched_notrace();
50out:
51	return this_cpu;
52}
53
 
 
 
 
54EXPORT_SYMBOL(debug_smp_processor_id);
55

 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#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
51out_enable:
52	instrumentation_end();
53	preempt_enable_no_resched_notrace();
54out:
55	return this_cpu;
56}
57
58noinstr unsigned int debug_smp_processor_id(void)
59{
60	return check_preemption_disabled("smp_processor_id", "");
61}
62EXPORT_SYMBOL(debug_smp_processor_id);
63
64noinstr void __this_cpu_preempt_check(const char *op)
65{
66	check_preemption_disabled("__this_cpu_", op);
67}
68EXPORT_SYMBOL(__this_cpu_preempt_check);