diff mbox series

[v17,2/6] tpm: tpm_tis: Rewrite "tpm_tis_req_canceled()"

Message ID 20211024164855.250362-3-amirmizi6@gmail.com (mailing list archive)
State New, archived
Headers show
Series Add tpm i2c ptp driver | expand

Commit Message

Amir Mizinski Oct. 24, 2021, 4:48 p.m. UTC 
From: Amir Mizinski <amirmizi6@gmail.com>

tpm_tis_req_canceled() function is used to check if the caller requested
to abort the current operation. It was found that in some cases
tpm_tis_req_canceled() wrongly returned true.
Since a cancel request sets the TPM_STS.commandReady field to TRUE, the
tpm_tis_req_canceled() function should check only the TPM_STS.commandReady
field value.
The case for TPM_VID_WINBOND is wrong and was therefore removed.

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

Fixes: 1f866057291f ("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 Oct. 25, 2021, 11:43 p.m. UTC | #1 
On Sun, 2021-10-24 at 19:48 +0300, amirmizi6@gmail.com wrote:
> From: Amir Mizinski <amirmizi6@gmail.com>
> 
> tpm_tis_req_canceled() function is used to check if the caller requested
> to abort the current operation. It was found that in some cases
> tpm_tis_req_canceled() wrongly returned true.
> Since a cancel request sets the TPM_STS.commandReady field to TRUE, the
> tpm_tis_req_canceled() function should check only the TPM_STS.commandReady
> field value.
> The case for TPM_VID_WINBOND is wrong and was therefore removed.
> 
> Also, the default comparison is wrong. Only cmdReady bit needs to be
> compared instead of the full lower status register byte.
> 
> Fixes: 1f866057291f ("tpm: Fix cancellation of TPM commands (polling mode)")
> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>

Also here, I'm not sure about the fixes tag (same reasoning
as for 1/6).

/Jarkko
diff mbox series

Patch

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 98de2fd..e1c4a5a 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -661,13 +661,11 @@  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);
 	}
 }