From: Mario Limonciello mario.limonciello@amd.com
commit cacc6e22932f373a91d7be55a9b992dc77f4c59b upstream.
The same checks are repeated in three 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@amd.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/tpm/tpm-chip.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
--- 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 * 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 *c 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))