diff mbox series

[v7,3/7] tpm: tpm_tis: Rewrite "tpm_tis_req_canceled()"

Message ID 20200427124931.115697-4-amirmizi6@gmail.com (mailing list archive)
State New, archived
Headers show
Series Add tpm i2c ptp driver | expand

Commit Message

Amir Mizinski April 27, 2020, 12:49 p.m. UTC 
From: Amir Mizinski <amirmizi6@gmail.com>

Using this function while reading/writing data resulted in an aborted
operation.
After investigating the issue according to the TCG TPM Profile (PTP)
Specifications, I found that "request to cancel" should occur only if
TPM_STS.commandReady bit is lit.
Note that i couldn't find a case where the present condition
(in the linux kernel) is valid, so I'm removing the case for
"TPM_VID_WINBOND" since we have no need for it.

Also, the default comparison is wrong. Only cmdReady bit needs to be
compared instead of the full lower status register byte.

Fixes: 1f86605 (tpm: Fix cancellation of TPM commands (polling mode))
Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Comments

Jarkko Sakkinen April 29, 2020, 5:37 a.m. UTC | #1 
On Mon, Apr 27, 2020 at 03:49:27PM +0300, amirmizi6@gmail.com wrote:
> From: Amir Mizinski <amirmizi6@gmail.com>
> 
> Using this function while reading/writing data resulted in an aborted
> operation.
> After investigating the issue according to the TCG TPM Profile (PTP)
> Specifications, I found that "request to cancel" should occur only if
> TPM_STS.commandReady bit is lit.
> Note that i couldn't find a case where the present condition
> (in the linux kernel) is valid, so I'm removing the case for
> "TPM_VID_WINBOND" since we have no need for it.
> 
> Also, the default comparison is wrong. Only cmdReady bit needs to be
> compared instead of the full lower status register byte.
> 
> Fixes: 1f86605 (tpm: Fix cancellation of TPM commands (polling mode))

Needs to have exactly 12 hex digits of the hash.

/Jarkko
Amir Mizinski April 30, 2020, 10:29 a.m. UTC | #2 
On 2020-04-29 05:37, Jarkko Sakkinen wrote:
> On Mon, Apr 27, 2020 at 03:49:27PM +0300, amirmizi6@gmail.com wrote:
>> From: Amir Mizinski <amirmizi6@gmail.com>
>>
>> Using this function while reading/writing data resulted in an aborted
>> operation.
>> After investigating the issue according to the TCG TPM Profile (PTP)
>> Specifications, I found that "request to cancel" should occur only if
>> TPM_STS.commandReady bit is lit.
>> Note that i couldn't find a case where the present condition
>> (in the linux kernel) is valid, so I'm removing the case for
>> "TPM_VID_WINBOND" since we have no need for it.
>>
>> Also, the default comparison is wrong. Only cmdReady bit needs to be
>> compared instead of the full lower status register byte.
>>
>> Fixes: 1f86605 (tpm: Fix cancellation of TPM commands (polling mode))
>
> Needs to have exactly 12 hex digits of the hash.
>

Ok, i'll fix this for version 8. Thank you.

> /Jarkko
diff mbox series

Patch

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 5dd5604..682f950 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -715,13 +715,11 @@  static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status)
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 
 	switch (priv->manufacturer_id) {
-	case TPM_VID_WINBOND:
-		return ((status == TPM_STS_VALID) ||
-			(status == (TPM_STS_VALID | TPM_STS_COMMAND_READY)));
 	case TPM_VID_STM:
 		return (status == (TPM_STS_VALID | TPM_STS_COMMAND_READY));
 	default:
-		return (status == TPM_STS_COMMAND_READY);
+		return ((status & TPM_STS_COMMAND_READY) ==
+			TPM_STS_COMMAND_READY);
 	}
 }