blob: 1afec32de6f21c001447b6545b440aff6308bdd2
| 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 | |
| 10 | notrace static unsigned int check_preemption_disabled(const char *what1, |
| 11 | const char *what2) |
| 12 | { |
| 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 %s%s() in preemptible [%08x] code: %s/%d\n", |
| 43 | what1, what2, preempt_count() - 1, current->comm, current->pid); |
| 44 | |
| 45 | print_symbol("caller is %s\n", (long)__builtin_return_address(0)); |
| 46 | dump_stack(); |
| 47 | |
| 48 | out_enable: |
| 49 | preempt_enable_no_resched_notrace(); |
| 50 | out: |
| 51 | return this_cpu; |
| 52 | } |
| 53 | |
| 54 | notrace unsigned int debug_smp_processor_id(void) |
| 55 | { |
| 56 | return check_preemption_disabled("smp_processor_id", ""); |
| 57 | } |
| 58 | EXPORT_SYMBOL(debug_smp_processor_id); |
| 59 | |
| 60 | notrace void __this_cpu_preempt_check(const char *op) |
| 61 | { |
| 62 | check_preemption_disabled("__this_cpu_", op); |
| 63 | } |
| 64 | EXPORT_SYMBOL(__this_cpu_preempt_check); |
| 65 |