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 11 noinstr static 12 unsigned 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 51 out_enable: 52 instrumentation_end(); 53 preempt_enable_no_resched_notrace(); 54 out: 55 return this_cpu; 56 } 57 58 noinstr unsigned int debug_smp_processor_id(void) 59 { 60 return check_preemption_disabled("smp_processor_id", ""); 61 } 62 EXPORT_SYMBOL(debug_smp_processor_id); 63 64 noinstr void __this_cpu_preempt_check(const char *op) 65 { 66 check_preemption_disabled("__this_cpu_", op); 67 } 68 EXPORT_SYMBOL(__this_cpu_preempt_check); 69