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