// SPDX-License-Identifier: GPL-2.0 /* * lib/smp_processor_id.c * * DEBUG_PREEMPT variant of smp_processor_id(). */ #include <linux/export.h> #include <linux/sched.h> notrace static unsigned int check_preemption_disabled(const char *what1, const char *what2) { int this_cpu = raw_smp_processor_id(); if (likely(preempt_count())) goto out; if (irqs_disabled()) goto out; /* * Kernel threads bound to a single CPU can safely use * smp_processor_id(): */ if (cpumask_equal(¤t->cpus_allowed, cpumask_of(this_cpu))) goto out; /* * It is valid to assume CPU-locality during early bootup: */ if (system_state < SYSTEM_SCHEDULING) goto out; /* * Avoid recursion: */ preempt_disable_notrace(); if (!printk_ratelimit()) goto out_enable; printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n", what1, what2, preempt_count() - 1, current->comm, current->pid); printk("caller is %pS\n", __builtin_return_address(0)); dump_stack(); out_enable: preempt_enable_no_resched_notrace(); out: return this_cpu; } notrace unsigned int debug_smp_processor_id(void) { return check_preemption_disabled("smp_processor_id", ""); } EXPORT_SYMBOL(debug_smp_processor_id); notrace void __this_cpu_preempt_check(const char *op) { check_preemption_disabled("__this_cpu_", op); } EXPORT_SYMBOL(__this_cpu_preempt_check);