1 files changed, 531 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
new file mode 100644
index 000000000..0f941cb32
--- /dev/null
+++ b/drivers/char/tpm/tpm-interface.c
@@ -0,0 +1,531 @@
+// 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);
+
+/**
+ * tpm_send - send a TPM command
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
+ * @cmd:	a TPM command buffer
+ * @buflen:	the length of the TPM command buffer
+ *
+ * Return: same as with tpm_transmit_cmd()
+ */
+int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
+{
+	struct tpm_buf buf;
+	int rc;
+
+	chip = tpm_find_get_ops(chip);
+	if (!chip)
+		return -ENODEV;
+
+	buf.data = cmd;
+	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to a send a command");
+
+	tpm_put_ops(chip);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(tpm_send);
+
+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;
+
+	tpm_class = class_create(THIS_MODULE, "tpm");
+	if (IS_ERR(tpm_class)) {
+		pr_err("couldn't create tpm class\n");
+		return PTR_ERR(tpm_class);
+	}
+
+	tpmrm_class = class_create(THIS_MODULE, "tpmrm");
+	if (IS_ERR(tpmrm_class)) {
+		pr_err("couldn't create tpmrm class\n");
+		rc = PTR_ERR(tpmrm_class);
+		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_destroy(tpmrm_class);
+out_destroy_tpm_class:
+	class_destroy(tpm_class);
+
+	return rc;
+}
+
+static void __exit tpm_exit(void)
+{
+	idr_destroy(&dev_nums_idr);
+	class_destroy(tpm_class);
+	class_destroy(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");