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Ingo Molnar39c715b2005-06-21 17:14:34 -07001/*
2 * lib/smp_processor_id.c
3 *
4 * DEBUG_PREEMPT variant of smp_processor_id().
5 */
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -05006#include <linux/export.h>
Ingo Molnar39c715b2005-06-21 17:14:34 -07007#include <linux/kallsyms.h>
Tim Schmielau4e57b682005-10-30 15:03:48 -08008#include <linux/sched.h>
Ingo Molnar39c715b2005-06-21 17:14:34 -07009
Christoph Lameter188a8142014-04-07 15:39:44 -070010notrace static unsigned int check_preemption_disabled(const char *what1,
11 const char *what2)
Ingo Molnar39c715b2005-06-21 17:14:34 -070012{
Ingo Molnar39c715b2005-06-21 17:14:34 -070013 int this_cpu = raw_smp_processor_id();
Ingo Molnar39c715b2005-06-21 17:14:34 -070014
Peter Zijlstra4a2b4b22013-08-14 14:55:24 +020015 if (likely(preempt_count()))
Ingo Molnar39c715b2005-06-21 17:14:34 -070016 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 */
Ingo Molnar0c98d342017-02-05 15:38:10 +010025 if (cpumask_equal(&current->cpus_allowed, cpumask_of(this_cpu)))
Ingo Molnar39c715b2005-06-21 17:14:34 -070026 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 */
Steven Rostedt5568b132008-05-12 21:20:44 +020037 preempt_disable_notrace();
Ingo Molnar39c715b2005-06-21 17:14:34 -070038
39 if (!printk_ratelimit())
40 goto out_enable;
41
Christoph Lameter188a8142014-04-07 15:39:44 -070042 printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",
43 what1, what2, preempt_count() - 1, current->comm, current->pid);
44
Ingo Molnar39c715b2005-06-21 17:14:34 -070045 print_symbol("caller is %s\n", (long)__builtin_return_address(0));
46 dump_stack();
47
48out_enable:
Steven Rostedt5568b132008-05-12 21:20:44 +020049 preempt_enable_no_resched_notrace();
Ingo Molnar39c715b2005-06-21 17:14:34 -070050out:
51 return this_cpu;
52}
53
Christoph Lameter188a8142014-04-07 15:39:44 -070054notrace unsigned int debug_smp_processor_id(void)
55{
56 return check_preemption_disabled("smp_processor_id", "");
57}
Ingo Molnar39c715b2005-06-21 17:14:34 -070058EXPORT_SYMBOL(debug_smp_processor_id);
59
Christoph Lameter188a8142014-04-07 15:39:44 -070060notrace void __this_cpu_preempt_check(const char *op)
61{
62 check_preemption_disabled("__this_cpu_", op);
63}
64EXPORT_SYMBOL(__this_cpu_preempt_check);