linux-imx

/*

 * cn_proc.c - process events connector

 *

 * Copyright (C) Matt Helsley, IBM Corp. 2005

 * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>

 * Original copyright notice follows:

 * Copyright (C) 2005 BULL SA.

 *

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */

​

#include <linux/kernel.h>

#include <linux/ktime.h>

#include <linux/init.h>

#include <linux/connector.h>

#include <linux/gfp.h>

#include <linux/ptrace.h>

#include <linux/atomic.h>

#include <linux/pid_namespace.h>

​

#include <linux/cn_proc.h>

​

/*

 * Size of a cn_msg followed by a proc_event structure.  Since the

 * sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we

 * add one 4-byte word to the size here, and then start the actual

 * cn_msg structure 4 bytes into the stack buffer.  The result is that

 * the immediately following proc_event structure is aligned to 8 bytes.

 */

#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4)

​

/* See comment above; we test our assumption about sizeof struct cn_msg here. */

static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)

{

    BUILD_BUG_ON(sizeof(struct cn_msg) != 20);

    return (struct cn_msg *)(buffer + 4);

}

​

static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);

static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };

​

/* proc_event_counts is used as the sequence number of the netlink message */

static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };

​

static inline void send_msg(struct cn_msg *msg)

{

    preempt_disable();

​

    msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;

    ((struct proc_event *)msg->data)->cpu = smp_processor_id();