Change in coreboot[master]: security/tpm: Fix TPM 1.2 state machine issues

[Philipp Deppenwiese (Code Review)]

Philipp Deppenwiese has uploaded this change for review. ( https://review.coreboot.org/28085

Change subject: security/tpm: Fix TPM 1.2 state machine issues
......................................................................

security/tpm: Fix TPM 1.2 state machine issues

* Add hard_reset mechanism and result checks
  for the ramstage TPM driver.
* Move enabling TPM before activating otherwise
  it isn't successful.

More information can be found via the TCG
specification.

Tested=Elgon

Change-Id: Ided110e0c1889b302e29acac6d8d2341f97eb10b
Signed-off-by: Philipp Deppenwiese 
---
M src/drivers/tpm/tpm.c
M src/security/tpm/tspi/tspi.c
2 files changed, 24 insertions(+), 19 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/85/28085/1

diff --git a/src/drivers/tpm/tpm.c b/src/drivers/tpm/tpm.c
index e4a81c3..e7c1165 100644
--- a/src/drivers/tpm/tpm.c
+++ b/src/drivers/tpm/tpm.c
@@ -17,6 +17,7 @@
 #include <stddef.h>
 #include <bootstate.h>
 #include <security/tpm/tspi.h>
+#include <reset.h>

#if IS_ENABLED(CONFIG_ARCH_X86)
 #include <arch/acpi.h>
@@ -24,12 +25,15 @@

static void init_tpm_dev(void *unused)
 {
+	uint32_t result;
 #if IS_ENABLED(CONFIG_ARCH_X86)
    int s3resume = acpi_is_wakeup_s3();
-	tpm_setup(s3resume);
+	result = tpm_setup(s3resume);
 #else
-	tpm_setup(false);
+	result = tpm_setup(false);
 #endif
+	if (result == TPM_E_MUST_REBOOT)
+		do_hard_reset();
 }

BOOT_STATE_INIT_ENTRY(BS_DEV_INIT, BS_ON_ENTRY, init_tpm_dev, NULL);
diff --git a/src/security/tpm/tspi/tspi.c b/src/security/tpm/tspi/tspi.c
index 950e930..f3093e7 100644
--- a/src/security/tpm/tspi/tspi.c
+++ b/src/security/tpm/tspi/tspi.c
@@ -25,17 +25,31 @@
 #if IS_ENABLED(CONFIG_TPM1)
 static uint32_t tpm1_invoke_state_machine(void)
 {
-	uint8_t disable;
+	uint8_t disabled;
    uint8_t deactivated;
    uint32_t result = TPM_SUCCESS;

/* Check that the TPM is enabled and activated. */
-	result = tlcl_get_flags(&disable, &deactivated, NULL);
+	result = tlcl_get_flags(&disabled, &deactivated, NULL);
    if (result != TPM_SUCCESS) {
    	printk(BIOS_ERR, "TPM: Can't read capabilities.\n");
    	return result;
    }

+	if (disabled) {
+		printk(BIOS_INFO, "TPM: disabled (%d)."
+		       "Enabling...\n", disabled);
+
+		result = tlcl_set_enable();
+		if (result != TPM_SUCCESS) {
+			printk(BIOS_ERR, "TPM: Can't set enabled state.\n");
+			return result;
+		}
+
+		printk(BIOS_INFO, "TPM: Must reboot to re-enable\n");
+		result = TPM_E_MUST_REBOOT;
+	}
+
    if (!!deactivated != IS_ENABLED(CONFIG_TPM_DEACTIVATE)) {
    	printk(BIOS_INFO,
    	       "TPM: Unexpected TPM deactivated state. Toggling...\n");
@@ -50,19 +64,6 @@
    	result = TPM_E_MUST_REBOOT;
    }

-	if (disable && !deactivated) {
-		printk(BIOS_INFO, "TPM: disabled (%d). Enabling...\n", disable);
-
-		result = tlcl_set_enable();
-		if (result != TPM_SUCCESS) {
-			printk(BIOS_ERR, "TPM: Can't set enabled state.\n");
-			return result;
-		}
-
-		printk(BIOS_INFO, "TPM: Must reboot to re-enable\n");
-		result = TPM_E_MUST_REBOOT;
-	}
-
    return result;
 }
 #endif
@@ -122,8 +123,8 @@
    	result = tlcl_physical_presence_cmd_enable();
    	if (result != TPM_SUCCESS) {
    		printk(
-			    BIOS_ERR,
-			    "TPM: Can't enable physical presence command.\n");
+				BIOS_ERR,
+				"TPM: Can't enable physical presence command.\n");
    		goto out;
    	}