| 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/kallsyms.h> |
| 9 | #include <linux/sched.h> |
| 10 | |
| 11 | notrace static unsigned int check_preemption_disabled(const char *what1, |
| 12 | 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(¤t->cpus_allowed, 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 | print_symbol("caller is %s\n", (long)__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 | |
| 61 | notrace void __this_cpu_preempt_check(const char *op) |
| 62 | { |
| 63 | check_preemption_disabled("__this_cpu_", op); |
| 64 | } |
| 65 | EXPORT_SYMBOL(__this_cpu_preempt_check); |