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![Jason Gunthorpe](/assets/img/avatar_default.png)
This consolidates everything that is only used within tpm-dev.c into tpm-dev.c and out of the publicly visible struct tpm_chip. The per-file allocation lays the ground work for someday fixing the strange forced O_EXCL behaviour of the current code. Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Reviewed-by: Joel Schopp <jschopp@linux.vnet.ibm.com> Reviewed-by: Ashley Lai <adlai@linux.vnet.ibm.com> Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
213 lines
5.2 KiB
C
213 lines
5.2 KiB
C
/*
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* Copyright (C) 2004 IBM Corporation
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* Authors:
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* Leendert van Doorn <leendert@watson.ibm.com>
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* Dave Safford <safford@watson.ibm.com>
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* Reiner Sailer <sailer@watson.ibm.com>
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* Kylene Hall <kjhall@us.ibm.com>
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*
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* Copyright (C) 2013 Obsidian Research Corp
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* Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
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*
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* Device file system interface to the TPM
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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*/
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#include <linux/miscdevice.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include "tpm.h"
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struct file_priv {
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struct tpm_chip *chip;
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/* Data passed to and from the tpm via the read/write calls */
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atomic_t data_pending;
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struct mutex buffer_mutex;
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struct timer_list user_read_timer; /* user needs to claim result */
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struct work_struct work;
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u8 data_buffer[TPM_BUFSIZE];
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};
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static void user_reader_timeout(unsigned long ptr)
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{
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struct file_priv *priv = (struct file_priv *)ptr;
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schedule_work(&priv->work);
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}
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static void timeout_work(struct work_struct *work)
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{
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struct file_priv *priv = container_of(work, struct file_priv, work);
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mutex_lock(&priv->buffer_mutex);
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atomic_set(&priv->data_pending, 0);
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memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
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mutex_unlock(&priv->buffer_mutex);
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}
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static int tpm_open(struct inode *inode, struct file *file)
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{
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struct miscdevice *misc = file->private_data;
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struct tpm_chip *chip = container_of(misc, struct tpm_chip,
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vendor.miscdev);
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struct file_priv *priv;
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/* It's assured that the chip will be opened just once,
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* by the check of is_open variable, which is protected
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* by driver_lock. */
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if (test_and_set_bit(0, &chip->is_open)) {
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dev_dbg(chip->dev, "Another process owns this TPM\n");
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return -EBUSY;
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}
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (priv == NULL) {
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clear_bit(0, &chip->is_open);
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return -ENOMEM;
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}
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priv->chip = chip;
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atomic_set(&priv->data_pending, 0);
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mutex_init(&priv->buffer_mutex);
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setup_timer(&priv->user_read_timer, user_reader_timeout,
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(unsigned long)priv);
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INIT_WORK(&priv->work, timeout_work);
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file->private_data = priv;
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get_device(chip->dev);
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return 0;
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}
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static ssize_t tpm_read(struct file *file, char __user *buf,
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size_t size, loff_t *off)
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{
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struct file_priv *priv = file->private_data;
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ssize_t ret_size;
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int rc;
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del_singleshot_timer_sync(&priv->user_read_timer);
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flush_work(&priv->work);
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ret_size = atomic_read(&priv->data_pending);
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if (ret_size > 0) { /* relay data */
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ssize_t orig_ret_size = ret_size;
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if (size < ret_size)
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ret_size = size;
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mutex_lock(&priv->buffer_mutex);
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rc = copy_to_user(buf, priv->data_buffer, ret_size);
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memset(priv->data_buffer, 0, orig_ret_size);
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if (rc)
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ret_size = -EFAULT;
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mutex_unlock(&priv->buffer_mutex);
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}
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atomic_set(&priv->data_pending, 0);
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return ret_size;
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}
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static ssize_t tpm_write(struct file *file, const char __user *buf,
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size_t size, loff_t *off)
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{
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struct file_priv *priv = file->private_data;
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size_t in_size = size;
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ssize_t out_size;
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/* cannot perform a write until the read has cleared
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either via tpm_read or a user_read_timer timeout.
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This also prevents splitted buffered writes from blocking here.
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*/
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if (atomic_read(&priv->data_pending) != 0)
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return -EBUSY;
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if (in_size > TPM_BUFSIZE)
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return -E2BIG;
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mutex_lock(&priv->buffer_mutex);
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if (copy_from_user
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(priv->data_buffer, (void __user *) buf, in_size)) {
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mutex_unlock(&priv->buffer_mutex);
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return -EFAULT;
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}
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/* atomic tpm command send and result receive */
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out_size = tpm_transmit(priv->chip, priv->data_buffer,
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sizeof(priv->data_buffer));
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if (out_size < 0) {
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mutex_unlock(&priv->buffer_mutex);
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return out_size;
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}
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atomic_set(&priv->data_pending, out_size);
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mutex_unlock(&priv->buffer_mutex);
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/* Set a timeout by which the reader must come claim the result */
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mod_timer(&priv->user_read_timer, jiffies + (60 * HZ));
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return in_size;
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}
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/*
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* Called on file close
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*/
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static int tpm_release(struct inode *inode, struct file *file)
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{
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struct file_priv *priv = file->private_data;
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del_singleshot_timer_sync(&priv->user_read_timer);
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flush_work(&priv->work);
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file->private_data = NULL;
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atomic_set(&priv->data_pending, 0);
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clear_bit(0, &priv->chip->is_open);
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put_device(priv->chip->dev);
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kfree(priv);
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return 0;
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}
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static const struct file_operations tpm_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.open = tpm_open,
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.read = tpm_read,
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.write = tpm_write,
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.release = tpm_release,
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};
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int tpm_dev_add_device(struct tpm_chip *chip)
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{
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int rc;
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chip->vendor.miscdev.fops = &tpm_fops;
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if (chip->dev_num == 0)
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chip->vendor.miscdev.minor = TPM_MINOR;
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else
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chip->vendor.miscdev.minor = MISC_DYNAMIC_MINOR;
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chip->vendor.miscdev.name = chip->devname;
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chip->vendor.miscdev.parent = chip->dev;
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rc = misc_register(&chip->vendor.miscdev);
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if (rc) {
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chip->vendor.miscdev.name = NULL;
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dev_err(chip->dev,
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"unable to misc_register %s, minor %d err=%d\n",
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chip->vendor.miscdev.name,
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chip->vendor.miscdev.minor, rc);
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}
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return rc;
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}
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void tpm_dev_del_device(struct tpm_chip *chip)
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{
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if (chip->vendor.miscdev.name)
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misc_deregister(&chip->vendor.miscdev);
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}
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