150 lines
3.8 KiB
C
150 lines
3.8 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/slab.h>
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#include <linux/uaccess.h>
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#include "tpm.h"
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#include "tpm-dev.h"
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static void user_reader_timeout(struct timer_list *t)
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{
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struct file_priv *priv = from_timer(priv, t, user_read_timer);
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pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
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task_tgid_nr(current));
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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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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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void tpm_common_open(struct file *file, struct tpm_chip *chip,
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struct file_priv *priv)
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{
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priv->chip = chip;
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mutex_init(&priv->buffer_mutex);
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timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
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INIT_WORK(&priv->work, timeout_work);
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file->private_data = priv;
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}
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ssize_t tpm_common_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 = 0;
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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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mutex_lock(&priv->buffer_mutex);
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if (priv->data_pending) {
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ret_size = min_t(ssize_t, size, priv->data_pending);
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rc = copy_to_user(buf, priv->data_buffer, ret_size);
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memset(priv->data_buffer, 0, priv->data_pending);
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if (rc)
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ret_size = -EFAULT;
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priv->data_pending = 0;
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}
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mutex_unlock(&priv->buffer_mutex);
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return ret_size;
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}
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ssize_t tpm_common_write(struct file *file, const char __user *buf,
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size_t size, loff_t *off, struct tpm_space *space)
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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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if (in_size > TPM_BUFSIZE)
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return -E2BIG;
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mutex_lock(&priv->buffer_mutex);
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/* Cannot perform a write until the read has cleared either via
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* tpm_read or a user_read_timer timeout. This also prevents split
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* buffered writes from blocking here.
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*/
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if (priv->data_pending != 0) {
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mutex_unlock(&priv->buffer_mutex);
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return -EBUSY;
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}
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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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if (in_size < 6 ||
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in_size < be32_to_cpu(*((__be32 *) (priv->data_buffer + 2)))) {
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mutex_unlock(&priv->buffer_mutex);
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return -EINVAL;
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}
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/* atomic tpm command send and result receive. We only hold the ops
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* lock during this period so that the tpm can be unregistered even if
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* the char dev is held open.
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*/
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if (tpm_try_get_ops(priv->chip)) {
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mutex_unlock(&priv->buffer_mutex);
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return -EPIPE;
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}
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out_size = tpm_transmit(priv->chip, space, priv->data_buffer,
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sizeof(priv->data_buffer), 0);
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tpm_put_ops(priv->chip);
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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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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 + (120 * 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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void tpm_common_release(struct file *file, struct file_priv *priv)
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{
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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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priv->data_pending = 0;
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}
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