This is a note to let you know that I've just added the patch titled

tpm: only attempt to disable the LPC CLKRUN if is already enabled

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: tpm-only-attempt-to-disable-the-lpc-clkrun-if-is-already-enabled.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 6c9f0ce0dffe64da2204f38b0fd90f3ae2a8903c Mon Sep 17 00:00:00 2001

From: Javier Martinez Canillas javierm@redhat.com Date: Mon, 25 Dec 2017 03:22:51 +0100 Subject: tpm: only attempt to disable the LPC CLKRUN if is already enabled

From: Javier Martinez Canillas javierm@redhat.com

commit 6c9f0ce0dffe64da2204f38b0fd90f3ae2a8903c upstream.

Commit 5e572cab92f0 ("tpm: Enable CLKRUN protocol for Braswell systems") added logic in the TPM TIS driver to disable the Low Pin Count CLKRUN signal during TPM transactions.

Unfortunately this breaks other devices that are attached to the LPC bus like for example PS/2 mouse and keyboards.

One flaw with the logic is that it assumes that the CLKRUN is always enabled, and so it unconditionally enables it after a TPM transaction.

But it could be that the CLKRUN# signal was already disabled in the LPC bus and so after the driver probes, CLKRUN_EN will remain enabled which may break other devices that are attached to the LPC bus but don't have support for the CLKRUN protocol.

Fixes: 5e572cab92f0 ("tpm: Enable CLKRUN protocol for Braswell systems") Signed-off-by: Javier Martinez Canillas javierm@redhat.com Tested-by: James Ettle james@ettle.org.uk Tested-by: Jeffery Miller jmiller@neverware.com Reviewed-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Tested-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/char/tpm/tpm_tis_core.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -694,7 +694,8 @@ static void tpm_tis_clkrun_enable(struct struct tpm_tis_data *data = dev_get_drvdata(&chip->dev); u32 clkrun_val;

- if (!IS_ENABLED(CONFIG_X86) || !is_bsw()) + if (!IS_ENABLED(CONFIG_X86) || !is_bsw() || + !data->ilb_base_addr) return;

if (value) { @@ -751,6 +752,7 @@ int tpm_tis_core_init(struct device *dev acpi_handle acpi_dev_handle) { u32 vendor, intfcaps, intmask; + u32 clkrun_val; u8 rid; int rc, probe; struct tpm_chip *chip; @@ -776,6 +778,13 @@ int tpm_tis_core_init(struct device *dev ILB_REMAP_SIZE); if (!priv->ilb_base_addr) return -ENOMEM; + + clkrun_val = ioread32(priv->ilb_base_addr + LPC_CNTRL_OFFSET); + /* Check if CLKRUN# is already not enabled in the LPC bus */ + if (!(clkrun_val & LPC_CLKRUN_EN)) { + iounmap(priv->ilb_base_addr); + priv->ilb_base_addr = NULL; + } }

if (chip->ops->clk_enable != NULL)

Patches currently in stable-queue which might be from javierm@redhat.com are

queue-4.15/tpm-delete-the-tpm_tis_clk_enable-flag.patch queue-4.15/tpm-only-attempt-to-disable-the-lpc-clkrun-if-is-already-enabled.patch