Thread (42 messages) 42 messages, 4 authors, 2019-02-08

Re: [PATCH v11 00/16] Remove nested TPM operations

From: Jarkko Sakkinen <hidden>
Date: 2019-02-08 11:50:37
Also in: linux-integrity, lkml

On Thu, Feb 07, 2019 at 09:14:54PM -0500, Stefan Berger wrote:
quoted hunk ↗ jump to hunk
+EXPORT_SYMBOL_GPL(tpm_chip_start);

 /**
  * tpm_chip_stop() - power off the TPM
@@ -131,7 +132,7 @@ void tpm_chip_stop(struct tpm_chip *chip)
     if (chip->ops->clk_enable)
         chip->ops->clk_enable(chip, false);
 }
-
+EXPORT_SYMBOL_GPL(tpm_chip_stop);
These are already fixed.
quoted hunk ↗ jump to hunk
 /**
  * tpm_try_get_ops() - Get a ref to the tpm_chip
@@ -474,8 +475,11 @@ static void tpm_del_char_device(struct tpm_chip *chip)
     /* Make the driver uncallable. */
     down_write(&chip->ops_sem);
-    if (chip->flags & TPM_CHIP_FLAG_TPM2)
+    if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+        tpm_chip_start(chip, 0);
         tpm2_shutdown(chip, TPM2_SU_CLEAR);
+        tpm_chip_stop(chip, 0);
+    }
Thanks!

Needs to be also done in tpm_pm_suspend() but there it is also better to
take locks because in-kernel subsystem might be using TPM even user
space has been freezed (e.g. hibernate possibly in future).

mutex_lock(&chip->tpm_mutex);
if (!tpm_chip_start(chip, 0)) {
	tpm2_shutdown(chip, TPM2_SU_CLEAR);
	tpm_chip_stop(chip, 0);
}
mutex_unlock(&chip->tpm_mutex);

Fixed now.
quoted hunk ↗ jump to hunk
     chip->ops = NULL;
     up_write(&chip->ops_sem);
 }
diff --git a/drivers/char/tpm/tpm-interface.c
b/drivers/char/tpm/tpm-interface.c
index 02e8cffd1163..fcd845ad8c3c 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -124,6 +124,8 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
void *buf, size_t bufsiz)
         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;
+    else
+        rc = 0;
Why is this needed?

/Jarkko
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