6.4-stable review patch. If anyone has any objections, please let me know.
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From: Jarkko Sakkinen jarkko@kernel.org
commit 8f7f35e5aa6f2182eabcfa3abef4d898a48e9aa8 upstream.
The vendor check introduced by commit 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs") doesn't work properly on a number of Intel fTPMs. On the reported systems the TPM doesn't reply at bootup and returns back the command code. This makes the TPM fail probe on Lenovo Legion Y540 laptop.
Since only Microsoft Pluton is the only known combination of AMD CPU and fTPM from other vendor, disable hwrng otherwise. In order to make sysadmin aware of this, print also info message to the klog.
Cc: stable@vger.kernel.org Fixes: 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs") Reported-by: Todd Brandt todd.e.brandt@intel.com Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217804 Reported-by: Patrick Steinhardt ps@pks.im Reported-by: Raymond Jay Golo rjgolo@gmail.com Reported-by: Ronan Pigott ronan@rjp.ie Reviewed-by: Jerry Snitselaar jsnitsel@redhat.com Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Cc: Thorsten Leemhuis regressions@leemhuis.info Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/tpm/tpm_crb.c | 33 ++++++++------------------------- 1 file changed, 8 insertions(+), 25 deletions(-)
--- a/drivers/char/tpm/tpm_crb.c +++ b/drivers/char/tpm/tpm_crb.c @@ -463,28 +463,6 @@ static bool crb_req_canceled(struct tpm_ return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE; }
-static int crb_check_flags(struct tpm_chip *chip) -{ - u32 val; - int ret; - - ret = crb_request_locality(chip, 0); - if (ret) - return ret; - - ret = tpm2_get_tpm_pt(chip, TPM2_PT_MANUFACTURER, &val, NULL); - if (ret) - goto release; - - if (val == 0x414D4400U /* AMD */) - chip->flags |= TPM_CHIP_FLAG_HWRNG_DISABLED; - -release: - crb_relinquish_locality(chip, 0); - - return ret; -} - static const struct tpm_class_ops tpm_crb = { .flags = TPM_OPS_AUTO_STARTUP, .status = crb_status, @@ -826,9 +804,14 @@ static int crb_acpi_add(struct acpi_devi if (rc) goto out;
- rc = crb_check_flags(chip); - if (rc) - goto out; +#ifdef CONFIG_X86 + /* A quirk for https://www.amd.com/en/support/kb/faq/pa-410 */ + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD && + priv->sm != ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON) { + dev_info(dev, "Disabling hwrng\n"); + chip->flags |= TPM_CHIP_FLAG_HWRNG_DISABLED; + } +#endif /* CONFIG_X86 */
rc = tpm_chip_register(chip);