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Commit 554b841d authored by Mario Limonciello's avatar Mario Limonciello Committed by Jarkko Sakkinen
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tpm: Disable RNG for all AMD fTPMs



The TPM RNG functionality is not necessary for entropy when the CPU
already supports the RDRAND instruction. The TPM RNG functionality
was previously disabled on a subset of AMD fTPM series, but reports
continue to show problems on some systems causing stutter root caused
to TPM RNG functionality.

Expand disabling TPM RNG use for all AMD fTPMs whether they have versions
that claim to have fixed or not. To accomplish this, move the detection
into part of the TPM CRB registration and add a flag indicating that
the TPM should opt-out of registration to hwrng.

Cc: stable@vger.kernel.org # 6.1.y+
Fixes: b006c439 ("hwrng: core - start hwrng kthread also for untrusted sources")
Fixes: f1324bbc ("tpm: disable hwrng for fTPM on some AMD designs")
Reported-by: default avatar <daniil.stas@posteo.net>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217719


Reported-by: default avatar <bitlord0xff@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217212


Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent 0de030b3
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