// SPDX-License-Identifier: GPL-2.0
/*
 * lib/smp_processor_id.c
 *
 * DEBUG_PREEMPT variant of smp_processor_id().
 */
#include <linux/export.h>
#include <linux/kprobes.h>
#include <linux/sched.h>

noinstr 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;

        if (is_percpu_thread())
                goto out;

        if (current->migration_disabled)
                goto out;

        /*
         * It is valid to assume CPU-locality during early bootup:
         */
        if (system_state < SYSTEM_SCHEDULING)
                goto out;

        /*
         * Avoid recursion:
         */
        preempt_disable_notrace();

        instrumentation_begin();
        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:
        instrumentation_end();
        preempt_enable_no_resched_notrace();
out:
        return this_cpu;
}

noinstr unsigned int debug_smp_processor_id(void)
{
        return check_preemption_disabled("smp_processor_id", "");
}
EXPORT_SYMBOL(debug_smp_processor_id);

noinstr void __this_cpu_preempt_check(const char *op)
{
        check_preemption_disabled("__this_cpu_", op);
}
EXPORT_SYMBOL(__this_cpu_preempt_check);