On Tue Aug 8, 2023 at 7:12 AM EEST, Mario Limonciello wrote:
> The same checks are repeated in 3 places to decide whether to use
> hwrng. Consolidate these into a helper.
>
> Also this fixes a case that one of them was missing a check in the
> cleanup path.
>
> Fixes: 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> drivers/char/tpm/tpm-chip.c | 19 ++++++++++++++-----
> 1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index e904aae9771be..ea6b4013bc38f 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -521,10 +521,20 @@ static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
> return tpm_get_random(chip, data, max);
> }
>
> +static bool tpm_is_hwrng_enabled(struct tpm_chip *chip)
> +{
> + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> + return false;
> + if (tpm_is_firmware_upgrade(chip))
> + return false;
> + if (chip->flags & TPM_CHIP_FLAG_HWRNG_DISABLED)
> + return false;
> + return true;
> +}
> +
> static int tpm_add_hwrng(struct tpm_chip *chip)
> {
> - if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM) || tpm_is_firmware_upgrade(chip) ||
> - chip->flags & TPM_CHIP_FLAG_HWRNG_DISABLED)
> + if (!tpm_is_hwrng_enabled(chip))
> return 0;
>
> snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),
> @@ -629,7 +639,7 @@ int tpm_chip_register(struct tpm_chip *chip)
> return 0;
>
> out_hwrng:
> - if (IS_ENABLED(CONFIG_HW_RANDOM_TPM) && !tpm_is_firmware_upgrade(chip))
> + if (tpm_is_hwrng_enabled(chip))
> hwrng_unregister(&chip->hwrng);
> out_ppi:
> tpm_bios_log_teardown(chip);
> @@ -654,8 +664,7 @@ EXPORT_SYMBOL_GPL(tpm_chip_register);
> void tpm_chip_unregister(struct tpm_chip *chip)
> {
> tpm_del_legacy_sysfs(chip);
> - if (IS_ENABLED(CONFIG_HW_RANDOM_TPM) && !tpm_is_firmware_upgrade(chip) &&
> - !(chip->flags & TPM_CHIP_FLAG_HWRNG_DISABLED))
> + if (tpm_is_hwrng_enabled(chip))
> hwrng_unregister(&chip->hwrng);
> tpm_bios_log_teardown(chip);
> if (chip->flags & TPM_CHIP_FLAG_TPM2 && !tpm_is_firmware_upgrade(chip))
Given my previous queries: should I apply this or revert and apply v3?
BR, Jarkko
