[mirror_ubuntu-hirsute-kernel.git] / lib / smp_processor_id.c

// 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;

	/*
	 * Kernel threads bound to a single CPU can safely use
	 * smp_processor_id():
	 */
	if (current->nr_cpus_allowed == 1)
		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();
	instrumentation_end();

out_enable:
	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);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
39c715b7 IM	2	/*
	3	* lib/smp_processor_id.c
	4	*
	5	* DEBUG_PREEMPT variant of smp_processor_id().
	6	*/
8bc3bcc9	7	#include <linux/export.h>
984640ce	8	#include <linux/kprobes.h>
4e57b681	9	#include <linux/sched.h>
39c715b7	10
126f21f0	11	noinstr static
984640ce	12	unsigned int check_preemption_disabled(const char what1, const char what2)
39c715b7	13	{
39c715b7	14	int this_cpu = raw_smp_processor_id();
39c715b7	15
4a2b4b22	16	if (likely(preempt_count()))
39c715b7 IM	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	*/
e950cca3	26	if (current->nr_cpus_allowed == 1)
39c715b7 IM	27	goto out;
	28
	29	/*
	30	* It is valid to assume CPU-locality during early bootup:
	31	*/
1c3c5eab	32	if (system_state < SYSTEM_SCHEDULING)
39c715b7 IM	33	goto out;
	34
	35	/*
	36	* Avoid recursion:
	37	*/
5568b139	38	preempt_disable_notrace();
39c715b7	39
126f21f0	40	instrumentation_begin();
39c715b7 IM	41	if (!printk_ratelimit())
	42	goto out_enable;
	43
188a8140 CL	44	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",
	45	what1, what2, preempt_count() - 1, current->comm, current->pid);
	46
d202d47b	47	printk("caller is %pS\n", __builtin_return_address(0));
39c715b7	48	dump_stack();
126f21f0	49	instrumentation_end();
39c715b7 IM	50
39c715b7 IM	51	out_enable:
5568b139	52	preempt_enable_no_resched_notrace();
39c715b7 IM	53	out:
	54	return this_cpu;
	55	}
	56
126f21f0	57	noinstr unsigned int debug_smp_processor_id(void)
188a8140 CL	58	{
	59	return check_preemption_disabled("smp_processor_id", "");
	60	}
39c715b7 IM	61	EXPORT_SYMBOL(debug_smp_processor_id);
39c715b7 IM	62
126f21f0	63	noinstr void __this_cpu_preempt_check(const char *op)
188a8140 CL	64	{
	65	check_preemption_disabled("__this_cpu_", op);
	66	}
	67	EXPORT_SYMBOL(__this_cpu_preempt_check);