kernel/power/em_netlink.c

// SPDX-License-Identifier: GPL-2.0
/*
 *
 * Generic netlink for energy model.
 *
 * Copyright (c) 2025 Valve Corporation.
 * Author: Changwoo Min <changwoo@igalia.com>
 */

#define pr_fmt(fmt) "energy_model: " fmt

#include <linux/energy_model.h>
#include <net/sock.h>
#include <net/genetlink.h>
#include <uapi/linux/energy_model.h>

#include "em_netlink.h"
#include "em_netlink_autogen.h"

#define EM_A_PD_CPUS_LEN		256

/*************************** Command encoding ********************************/
static int __em_nl_get_pd_size(struct em_perf_domain *pd, void *data)
{
	char cpus_buf[EM_A_PD_CPUS_LEN];
	int *tot_msg_sz = data;
	int msg_sz, cpus_sz;

	cpus_sz = snprintf(cpus_buf, sizeof(cpus_buf), "%*pb",
			   cpumask_pr_args(to_cpumask(pd->cpus)));

	msg_sz = nla_total_size(0) +			/* EM_A_PDS_PD */
		 nla_total_size(sizeof(u32)) +		/* EM_A_PD_PD_ID */
		 nla_total_size_64bit(sizeof(u64)) +	/* EM_A_PD_FLAGS */
		 nla_total_size(cpus_sz);		/* EM_A_PD_CPUS */

	*tot_msg_sz += nlmsg_total_size(genlmsg_msg_size(msg_sz));
	return 0;
}

static int __em_nl_get_pd(struct em_perf_domain *pd, void *data)
{
	char cpus_buf[EM_A_PD_CPUS_LEN];
	struct sk_buff *msg = data;
	struct nlattr *entry;

	entry = nla_nest_start(msg, EM_A_PDS_PD);
	if (!entry)
		goto out_cancel_nest;

	if (nla_put_u32(msg, EM_A_PD_PD_ID, pd->id))
		goto out_cancel_nest;

	if (nla_put_u64_64bit(msg, EM_A_PD_FLAGS, pd->flags, EM_A_PD_PAD))
		goto out_cancel_nest;

	snprintf(cpus_buf, sizeof(cpus_buf), "%*pb",
		 cpumask_pr_args(to_cpumask(pd->cpus)));
	if (nla_put_string(msg, EM_A_PD_CPUS, cpus_buf))
		goto out_cancel_nest;

	nla_nest_end(msg, entry);

	return 0;

out_cancel_nest:
	nla_nest_cancel(msg, entry);

	return -EMSGSIZE;
}

int em_nl_get_pds_doit(struct sk_buff *skb, struct genl_info *info)
{
	struct sk_buff *msg;
	void *hdr;
	int cmd = info->genlhdr->cmd;
	int ret = -EMSGSIZE, msg_sz = 0;

	for_each_em_perf_domain(__em_nl_get_pd_size, &msg_sz);

	msg = genlmsg_new(msg_sz, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	hdr = genlmsg_put_reply(msg, info, &em_nl_family, 0, cmd);
	if (!hdr)
		goto out_free_msg;

	ret = for_each_em_perf_domain(__em_nl_get_pd, msg);
	if (ret)
		goto out_cancel_msg;

	genlmsg_end(msg, hdr);

	return genlmsg_reply(msg, info);

out_cancel_msg:
	genlmsg_cancel(msg, hdr);
out_free_msg:
	nlmsg_free(msg);

	return ret;
}

static struct em_perf_domain *__em_nl_get_pd_table_id(struct nlattr **attrs)
{
	struct em_perf_domain *pd;
	int id;

	if (!attrs[EM_A_PD_TABLE_PD_ID])
		return NULL;

	id = nla_get_u32(attrs[EM_A_PD_TABLE_PD_ID]);
	pd = em_perf_domain_get_by_id(id);
	return pd;
}

static int __em_nl_get_pd_table_size(const struct em_perf_domain *pd)
{
	int id_sz, ps_sz;

	id_sz = nla_total_size(sizeof(u32));		/* EM_A_PD_TABLE_PD_ID */
	ps_sz = nla_total_size(0) +			/* EM_A_PD_TABLE_PS */
		nla_total_size_64bit(sizeof(u64)) +	/* EM_A_PS_PERFORMANCE */
		nla_total_size_64bit(sizeof(u64)) +	/* EM_A_PS_FREQUENCY */
		nla_total_size_64bit(sizeof(u64)) +	/* EM_A_PS_POWER */
		nla_total_size_64bit(sizeof(u64)) +	/* EM_A_PS_COST */
		nla_total_size_64bit(sizeof(u64));	/* EM_A_PS_FLAGS */
	ps_sz *= pd->nr_perf_states;

	return nlmsg_total_size(genlmsg_msg_size(id_sz + ps_sz));
}

static int __em_nl_get_pd_table(struct sk_buff *msg, const struct em_perf_domain *pd)
{
	struct em_perf_state *table, *ps;
	struct nlattr *entry;
	int i;

	if (nla_put_u32(msg, EM_A_PD_TABLE_PD_ID, pd->id))
		goto out_err;

	rcu_read_lock();
	table = em_perf_state_from_pd((struct em_perf_domain *)pd);

	for (i = 0; i < pd->nr_perf_states; i++) {
		ps = &table[i];

		entry = nla_nest_start(msg, EM_A_PD_TABLE_PS);
		if (!entry)
			goto out_unlock_ps;

		if (nla_put_u64_64bit(msg, EM_A_PS_PERFORMANCE,
				      ps->performance, EM_A_PS_PAD))
			goto out_cancel_ps_nest;
		if (nla_put_u64_64bit(msg, EM_A_PS_FREQUENCY,
				      ps->frequency, EM_A_PS_PAD))
			goto out_cancel_ps_nest;
		if (nla_put_u64_64bit(msg, EM_A_PS_POWER,
				      ps->power, EM_A_PS_PAD))
			goto out_cancel_ps_nest;
		if (nla_put_u64_64bit(msg, EM_A_PS_COST,
				      ps->cost, EM_A_PS_PAD))
			goto out_cancel_ps_nest;
		if (nla_put_u64_64bit(msg, EM_A_PS_FLAGS,
				      ps->flags, EM_A_PS_PAD))
			goto out_cancel_ps_nest;

		nla_nest_end(msg, entry);
	}
	rcu_read_unlock();
	return 0;

out_cancel_ps_nest:
	nla_nest_cancel(msg, entry);
out_unlock_ps:
	rcu_read_unlock();
out_err:
	return -EMSGSIZE;
}

int em_nl_get_pd_table_doit(struct sk_buff *skb, struct genl_info *info)
{
	int cmd = info->genlhdr->cmd;
	int msg_sz, ret = -EMSGSIZE;
	struct em_perf_domain *pd;
	struct sk_buff *msg;
	void *hdr;

	pd = __em_nl_get_pd_table_id(info->attrs);
	if (!pd)
		return -EINVAL;

	msg_sz = __em_nl_get_pd_table_size(pd);

	msg = genlmsg_new(msg_sz, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	hdr = genlmsg_put_reply(msg, info, &em_nl_family, 0, cmd);
	if (!hdr)
		goto out_free_msg;

	ret = __em_nl_get_pd_table(msg, pd);
	if (ret)
		goto out_free_msg;

	genlmsg_end(msg, hdr);
	return genlmsg_reply(msg, info);

out_free_msg:
	nlmsg_free(msg);
	return ret;
}


/**************************** Event encoding *********************************/
static void __em_notify_pd_table(const struct em_perf_domain *pd, int ntf_type)
{
	struct sk_buff *msg;
	int msg_sz, ret = -EMSGSIZE;
	void *hdr;

	if (!genl_has_listeners(&em_nl_family, &init_net, EM_NLGRP_EVENT))
		return;

	msg_sz = __em_nl_get_pd_table_size(pd);

	msg = genlmsg_new(msg_sz, GFP_KERNEL);
	if (!msg)
		return;

	hdr = genlmsg_put(msg, 0, 0, &em_nl_family, 0, ntf_type);
	if (!hdr)
		goto out_free_msg;

	ret = __em_nl_get_pd_table(msg, pd);
	if (ret)
		goto out_free_msg;

	genlmsg_end(msg, hdr);

	genlmsg_multicast(&em_nl_family, msg, 0, EM_NLGRP_EVENT, GFP_KERNEL);

	return;

out_free_msg:
	nlmsg_free(msg);
	return;
}

void em_notify_pd_created(const struct em_perf_domain *pd)
{
	__em_notify_pd_table(pd, EM_CMD_PD_CREATED);
}

void em_notify_pd_updated(const struct em_perf_domain *pd)
{
	__em_notify_pd_table(pd, EM_CMD_PD_UPDATED);
}

static int __em_notify_pd_deleted_size(const struct em_perf_domain *pd)
{
	int id_sz = nla_total_size(sizeof(u32)); /* EM_A_PD_TABLE_PD_ID */

	return nlmsg_total_size(genlmsg_msg_size(id_sz));
}

void em_notify_pd_deleted(const struct em_perf_domain *pd)
{
	struct sk_buff *msg;
	void *hdr;
	int msg_sz;

	if (!genl_has_listeners(&em_nl_family, &init_net, EM_NLGRP_EVENT))
		return;

	msg_sz = __em_notify_pd_deleted_size(pd);

	msg = genlmsg_new(msg_sz, GFP_KERNEL);
	if (!msg)
		return;

	hdr = genlmsg_put(msg, 0, 0, &em_nl_family, 0, EM_CMD_PD_DELETED);
	if (!hdr)
		goto out_free_msg;

	if (nla_put_u32(msg, EM_A_PD_TABLE_PD_ID, pd->id)) {
		goto out_free_msg;
	}

	genlmsg_end(msg, hdr);

	genlmsg_multicast(&em_nl_family, msg, 0, EM_NLGRP_EVENT, GFP_KERNEL);

	return;

out_free_msg:
	nlmsg_free(msg);
	return;
}

/**************************** Initialization *********************************/
static int __init em_netlink_init(void)
{
	return genl_register_family(&em_nl_family);
}
postcore_initcall(em_netlink_init);