From: Mario Limonciello <mario.limonciello@xxxxxxx>
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@xxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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))
