Merge tag 'tpmdd-v6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd

Pull more tpm updates from Jarkko Sakkinen:
 "Two more bug fixes for tpm_crb, categorically disabling rng for AMD
  CPU's in the tpm_crb driver, discarding the earlier probing approach"

* tag 'tpmdd-v6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
  tpm: Enable hwrng only for Pluton on AMD CPUs
  tpm_crb: Fix an error handling path in crb_acpi_add()

1 files changed, 11 insertions, 27 deletions

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 9eb1a185901235..ea085b14ab7c9f 100644
--- 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_chip *chip, u8 status)
 	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,
@@ -797,12 +775,13 @@ static int crb_acpi_add(struct acpi_device *device)
 				FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
 				buf->header.length,
 				ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON);
-			return -EINVAL;
+			rc = -EINVAL;
+			goto out;
 		}
 		crb_pluton = ACPI_ADD_PTR(struct tpm2_crb_pluton, buf, sizeof(*buf));
 		rc = crb_map_pluton(dev, priv, buf, crb_pluton);
 		if (rc)
-			return rc;
+			goto out;
 	}
 
 	priv->sm = sm;
@@ -826,9 +805,14 @@ static int crb_acpi_add(struct acpi_device *device)
 	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);