Re: [PATCH v5] tpm_tis: Add missing tpm_request/relinquish_locality() calls

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Feb 12, 2021 at 12:06:00PM +0100, Lukasz Majczak wrote:
> There are missing calls to tpm_request_locality() before the calls to
> the tpm_get_timeouts() and tpm_tis_probe_irq_single() - both functions
> internally send commands to the tpm using tpm_tis_send_data()
> which in turn, at the very beginning, calls the tpm_tis_status().
> This one tries to read TPM_STS register, what fails and propagates
> this error upward. The read fails due to lack of acquired locality,
> as it is described in
> TCG PC Client Platform TPM Profile (PTP) Specification,
> paragraph 6.1 FIFO Interface Locality Usage per Register,
> Table 39 Register Behavior Based on Locality Setting for FIFO
> - a read attempt to TPM_STS_x Registers returns 0xFF in case of lack
> of locality. The described situation manifests itself with
> the following warning trace:
> 
> [    4.324298] TPM returned invalid status
> [    4.324806] WARNING: CPU: 2 PID: 1 at drivers/char/tpm/tpm_tis_core.c:275 tpm_tis_status+0x86/0x8f
> 
> Tested on Samsung Chromebook Pro (Caroline), TPM 1.2 (SLB 9670)
> Fixes: a3fbfae82b4c ("tpm: take TPM chip power gating out of tpm_transmit()")
> 
> Signed-off-by: Lukasz Majczak <lma@semihalf.com>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>