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|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2004 IBM Corporation
* Copyright (C) 2014 Intel Corporation
*
* Authors:
* Leendert van Doorn <leendert@watson.ibm.com>
* Dave Safford <safford@watson.ibm.com>
* Reiner Sailer <sailer@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* Device driver for TCG/TCPA TPM (trusted platform module).
* Specifications at www.trustedcomputinggroup.org
*
* Note, the TPM chip is not interrupt driven (only polling)
* and can have very long timeouts (minutes!). Hence the unusual
* calls to msleep.
*/
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/suspend.h>
#include <linux/freezer.h>
#include <linux/tpm_eventlog.h>
#include "tpm.h"
/*
* Bug workaround - some TPM's don't flush the most
* recently changed pcr on suspend, so force the flush
* with an extend to the selected _unused_ non-volatile pcr.
*/
static u32 tpm_suspend_pcr;
module_param_named(suspend_pcr, tpm_suspend_pcr, uint, 0644);
MODULE_PARM_DESC(suspend_pcr,
"PCR to use for dummy writes to facilitate flush on suspend.");
/**
* tpm_calc_ordinal_duration() - calculate the maximum command duration
* @chip: TPM chip to use.
* @ordinal: TPM command ordinal.
*
* The function returns the maximum amount of time the chip could take
* to return the result for a particular ordinal in jiffies.
*
* Return: A maximal duration time for an ordinal in jiffies.
*/
unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
{
if (chip->flags & TPM_CHIP_FLAG_TPM2)
return tpm2_calc_ordinal_duration(chip, ordinal);
else
return tpm1_calc_ordinal_duration(chip, ordinal);
}
EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz)
{
struct tpm_header *header = buf;
int rc;
ssize_t len = 0;
u32 count, ordinal;
unsigned long stop;
if (bufsiz < TPM_HEADER_SIZE)
return -EINVAL;
if (bufsiz > TPM_BUFSIZE)
bufsiz = TPM_BUFSIZE;
count = be32_to_cpu(header->length);
ordinal = be32_to_cpu(header->ordinal);
if (count == 0)
return -ENODATA;
if (count > bufsiz) {
dev_err(&chip->dev,
"invalid count value %x %zx\n", count, bufsiz);
return -E2BIG;
}
rc = chip->ops->send(chip, buf, count);
if (rc < 0) {
if (rc != -EPIPE)
dev_err(&chip->dev,
"%s: send(): error %d\n", __func__, rc);
return rc;
}
/* A sanity check. send() should just return zero on success e.g.
* not the command length.
*/
if (rc > 0) {
dev_warn(&chip->dev,
"%s: send(): invalid value %d\n", __func__, rc);
rc = 0;
}
if (chip->flags & TPM_CHIP_FLAG_IRQ)
goto out_recv;
stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal);
do {
u8 status = chip->ops->status(chip);
if ((status & chip->ops->req_complete_mask) ==
chip->ops->req_complete_val)
goto out_recv;
if (chip->ops->req_canceled(chip, status)) {
dev_err(&chip->dev, "Operation Canceled\n");
return -ECANCELED;
}
tpm_msleep(TPM_TIMEOUT_POLL);
rmb();
} while (time_before(jiffies, stop));
chip->ops->cancel(chip);
dev_err(&chip->dev, "Operation Timed out\n");
return -ETIME;
out_recv:
len = chip->ops->recv(chip, buf, bufsiz);
if (len < 0) {
rc = len;
dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);
} else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
rc = -EFAULT;
return rc ? rc : len;
}
/**
* tpm_transmit - Internal kernel interface to transmit TPM commands.
* @chip: a TPM chip to use
* @buf: a TPM command buffer
* @bufsiz: length of the TPM command buffer
*
* A wrapper around tpm_try_transmit() that handles TPM2_RC_RETRY returns from
* the TPM and retransmits the command after a delay up to a maximum wait of
* TPM2_DURATION_LONG.
*
* Note that TPM 1.x never returns TPM2_RC_RETRY so the retry logic is TPM 2.0
* only.
*
* Return:
* * The response length - OK
* * -errno - A system error
*/
ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz)
{
struct tpm_header *header = (struct tpm_header *)buf;
/* space for header and handles */
u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
unsigned int delay_msec = TPM2_DURATION_SHORT;
u32 rc = 0;
ssize_t ret;
const size_t save_size = min(sizeof(save), bufsiz);
/* the command code is where the return code will be */
u32 cc = be32_to_cpu(header->return_code);
/*
* Subtlety here: if we have a space, the handles will be
* transformed, so when we restore the header we also have to
* restore the handles.
*/
memcpy(save, buf, save_size);
for (;;) {
ret = tpm_try_transmit(chip, buf, bufsiz);
if (ret < 0)
break;
rc = be32_to_cpu(header->return_code);
if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
break;
/*
* return immediately if self test returns test
* still running to shorten boot time.
*/
if (rc == TPM2_RC_TESTING && cc == TPM2_CC_SELF_TEST)
break;
if (delay_msec > TPM2_DURATION_LONG) {
if (rc == TPM2_RC_RETRY)
dev_err(&chip->dev, "in retry loop\n");
else
dev_err(&chip->dev,
"self test is still running\n");
break;
}
tpm_msleep(delay_msec);
delay_msec *= 2;
memcpy(buf, save, save_size);
}
return ret;
}
/**
* tpm_transmit_cmd - send a tpm command to the device
* @chip: a TPM chip to use
* @buf: a TPM command buffer
* @min_rsp_body_length: minimum expected length of response body
* @desc: command description used in the error message
*
* Return:
* * 0 - OK
* * -errno - A system error
* * TPM_RC - A TPM error
*/
ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
size_t min_rsp_body_length, const char *desc)
{
const struct tpm_header *header = (struct tpm_header *)buf->data;
int err;
ssize_t len;
len = tpm_transmit(chip, buf->data, PAGE_SIZE);
if (len < 0)
return len;
err = be32_to_cpu(header->return_code);
if (err != 0 && err != TPM_ERR_DISABLED && err != TPM_ERR_DEACTIVATED
&& err != TPM2_RC_TESTING && desc)
dev_err(&chip->dev, "A TPM error (%d) occurred %s\n", err,
desc);
if (err)
return err;
if (len < min_rsp_body_length + TPM_HEADER_SIZE)
return -EFAULT;
return 0;
}
EXPORT_SYMBOL_GPL(tpm_transmit_cmd);
int tpm_get_timeouts(struct tpm_chip *chip)
{
if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
return 0;
if (chip->flags & TPM_CHIP_FLAG_TPM2)
return tpm2_get_timeouts(chip);
else
return tpm1_get_timeouts(chip);
}
EXPORT_SYMBOL_GPL(tpm_get_timeouts);
/**
* tpm_is_tpm2 - do we a have a TPM2 chip?
* @chip: a &struct tpm_chip instance, %NULL for the default chip
*
* Return:
* 1 if we have a TPM2 chip.
* 0 if we don't have a TPM2 chip.
* A negative number for system errors (errno).
*/
int tpm_is_tpm2(struct tpm_chip *chip)
{
int rc;
chip = tpm_find_get_ops(chip);
if (!chip)
return -ENODEV;
rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
tpm_put_ops(chip);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_is_tpm2);
/**
* tpm_pcr_read - read a PCR value from SHA1 bank
* @chip: a &struct tpm_chip instance, %NULL for the default chip
* @pcr_idx: the PCR to be retrieved
* @digest: the PCR bank and buffer current PCR value is written to
*
* Return: same as with tpm_transmit_cmd()
*/
int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest)
{
int rc;
chip = tpm_find_get_ops(chip);
if (!chip)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2)
rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);
else
rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);
tpm_put_ops(chip);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_pcr_read);
/**
* tpm_pcr_extend - extend a PCR value in SHA1 bank.
* @chip: a &struct tpm_chip instance, %NULL for the default chip
* @pcr_idx: the PCR to be retrieved
* @digests: array of tpm_digest structures used to extend PCRs
*
* Note: callers must pass a digest for every allocated PCR bank, in the same
* order of the banks in chip->allocated_banks.
*
* Return: same as with tpm_transmit_cmd()
*/
int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digests)
{
int rc;
int i;
chip = tpm_find_get_ops(chip);
if (!chip)
return -ENODEV;
for (i = 0; i < chip->nr_allocated_banks; i++) {
if (digests[i].alg_id != chip->allocated_banks[i].alg_id) {
rc = -EINVAL;
goto out;
}
}
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
rc = tpm2_pcr_extend(chip, pcr_idx, digests);
goto out;
}
rc = tpm1_pcr_extend(chip, pcr_idx, digests[0].digest,
"attempting extend a PCR value");
out:
tpm_put_ops(chip);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_pcr_extend);
int tpm_auto_startup(struct tpm_chip *chip)
{
int rc;
if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP))
return 0;
if (chip->flags & TPM_CHIP_FLAG_TPM2)
rc = tpm2_auto_startup(chip);
else
rc = tpm1_auto_startup(chip);
return rc;
}
/*
* We are about to suspend. Save the TPM state
* so that it can be restored.
*/
int tpm_pm_suspend(struct device *dev)
{
struct tpm_chip *chip = dev_get_drvdata(dev);
int rc = 0;
if (!chip)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
goto suspended;
if ((chip->flags & TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED) &&
!pm_suspend_via_firmware())
goto suspended;
rc = tpm_try_get_ops(chip);
if (!rc) {
if (chip->flags & TPM_CHIP_FLAG_TPM2)
tpm2_shutdown(chip, TPM2_SU_STATE);
else
rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
tpm_put_ops(chip);
}
suspended:
chip->flags |= TPM_CHIP_FLAG_SUSPENDED;
if (rc)
dev_err(dev, "Ignoring error %d while suspending\n", rc);
return 0;
}
EXPORT_SYMBOL_GPL(tpm_pm_suspend);
/*
* Resume from a power safe. The BIOS already restored
* the TPM state.
*/
int tpm_pm_resume(struct device *dev)
{
struct tpm_chip *chip = dev_get_drvdata(dev);
if (chip == NULL)
return -ENODEV;
chip->flags &= ~TPM_CHIP_FLAG_SUSPENDED;
/*
* Guarantee that SUSPENDED is written last, so that hwrng does not
* activate before the chip has been fully resumed.
*/
wmb();
return 0;
}
EXPORT_SYMBOL_GPL(tpm_pm_resume);
/**
* tpm_get_random() - get random bytes from the TPM's RNG
* @chip: a &struct tpm_chip instance, %NULL for the default chip
* @out: destination buffer for the random bytes
* @max: the max number of bytes to write to @out
*
* Return: number of random bytes read or a negative error value.
*/
int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
{
int rc;
if (!out || max > TPM_MAX_RNG_DATA)
return -EINVAL;
chip = tpm_find_get_ops(chip);
if (!chip)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2)
rc = tpm2_get_random(chip, out, max);
else
rc = tpm1_get_random(chip, out, max);
tpm_put_ops(chip);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_get_random);
static int __init tpm_init(void)
{
int rc;
rc = class_register(&tpm_class);
if (rc) {
pr_err("couldn't create tpm class\n");
return rc;
}
rc = class_register(&tpmrm_class);
if (rc) {
pr_err("couldn't create tpmrm class\n");
goto out_destroy_tpm_class;
}
rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm");
if (rc < 0) {
pr_err("tpm: failed to allocate char dev region\n");
goto out_destroy_tpmrm_class;
}
rc = tpm_dev_common_init();
if (rc) {
pr_err("tpm: failed to allocate char dev region\n");
goto out_unreg_chrdev;
}
return 0;
out_unreg_chrdev:
unregister_chrdev_region(tpm_devt, 2 * TPM_NUM_DEVICES);
out_destroy_tpmrm_class:
class_unregister(&tpmrm_class);
out_destroy_tpm_class:
class_unregister(&tpm_class);
return rc;
}
static void __exit tpm_exit(void)
{
idr_destroy(&dev_nums_idr);
class_unregister(&tpm_class);
class_unregister(&tpmrm_class);
unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);
tpm_dev_common_exit();
}
subsys_initcall(tpm_init);
module_exit(tpm_exit);
MODULE_AUTHOR("Leendert van Doorn <leendert@watson.ibm.com>");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");
|