tlcl: automatically detect if platform hierarchy is disabled

Instead of passing a special flag when 'tpmc' starts, auto-detect
if platform hierarchy is disabled in TlclLibInit(). See discussion
in https://chromium-review.googlesource.com/#/c/362520/.

BRANCH=none
BUG=chrome-os-partner:55210
BUG=chrome-os-partner:55250
TEST=boot on kevin, verify that 'tpmc read 0x1008 0xd' works

Change-Id: Id94e7faadf835f7ea58a944e914163d6849e85c1
Reviewed-on: https://chromium-review.googlesource.com/362771
Commit-Ready: Andrey Pronin <apronin@chromium.org>
Tested-by: Andrey Pronin <apronin@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

4 files changed, 38 insertions, 20 deletions

diff --git a/firmware/include/tlcl.h b/firmware/include/tlcl.h
index 31347eba..53731200 100644
--- a/firmware/include/tlcl.h
+++ b/firmware/include/tlcl.h
@@ -28,12 +28,6 @@ uint32_t TlclLibInit(void);
  */
 uint32_t TlclLibClose(void);
 
-/**
- * Indicate that we access tlcl with user privileges from OS userland
- * as opposed to from firmware. May affect required NVRAM read authorization.
- */
-void TlclLibAccessAsUser(void);
-
 /* Low-level operations */
 
 /**
diff --git a/firmware/lib/tpm2_lite/tlcl.c b/firmware/lib/tpm2_lite/tlcl.c
index 9d7e1dfb..a03125d3 100644
--- a/firmware/lib/tpm2_lite/tlcl.c
+++ b/firmware/lib/tpm2_lite/tlcl.c
@@ -10,6 +10,7 @@
 #include "rollback_index.h"
 #include "tpm2_marshaling.h"
 #include "utility.h"
+#include "tlcl.h"
 
 static struct tpm2_response *tpm_process_command(TPM_CC command,
 						 void *command_body)
@@ -42,19 +43,40 @@ static struct tpm2_response *tpm_process_command(TPM_CC command,
 	return response;
 }
 
-uint32_t TlclLibInit(void)
+static uint32_t tlcl_read_ph_disabled(void)
 {
-	return VbExTpmInit();
+	uint32_t rv;
+	TPM_STCLEAR_FLAGS flags;
+
+	rv = TlclGetSTClearFlags(&flags);
+	if (rv != TPM_SUCCESS)
+		return rv;
+
+	tpm_set_ph_disabled(!flags.phEnable);
+
+	return TPM_SUCCESS;
 }
 
-uint32_t TlclLibClose(void)
+uint32_t TlclLibInit(void)
 {
-	return VbExTpmClose();
+	uint32_t rv;
+
+	rv = VbExTpmInit();
+	if (rv != TPM_SUCCESS)
+		return rv;
+
+	rv = tlcl_read_ph_disabled();
+	if (rv != TPM_SUCCESS) {
+		TlclLibClose();
+		return rv;
+	}
+
+	return TPM_SUCCESS;
 }
 
-void TlclLibAccessAsUser(void)
+uint32_t TlclLibClose(void)
 {
-	tpm_set_ph_disabled(1);
+	return VbExTpmClose();
 }
 
 uint32_t TlclSendReceive(const uint8_t *request, uint8_t *response,
@@ -100,7 +122,7 @@ uint32_t TlclContinueSelfTest(void)
 	return TPM_SUCCESS;
 }
 
-int32_t TlclDefineSpace(uint32_t index, uint32_t perm, uint32_t size)
+uint32_t TlclDefineSpace(uint32_t index, uint32_t perm, uint32_t size)
 {
 	VBDEBUG(("%s called, NOT YET IMPLEMENTED\n", __func__));
 	return TPM_SUCCESS;
@@ -250,6 +272,7 @@ static uint32_t tlcl_disable_platform_hierarchy(void)
 	if (!response || response->hdr.tpm_code)
 		return TPM_E_INTERNAL_INCONSISTENCY;
 
+	tpm_set_ph_disabled(1);
 	return TPM_SUCCESS;
 }
 
@@ -334,7 +357,7 @@ uint32_t TlclWrite(uint32_t index, const void *data, uint32_t length)
 	return TPM_SUCCESS;
 }
 
-int32_t TlclPCRRead(uint32_t index, void *data, uint32_t length)
+uint32_t TlclPCRRead(uint32_t index, void *data, uint32_t length)
 {
 	VBDEBUG(("%s called, NOT YET IMPLEMENTED\n", __func__));
 	return TPM_SUCCESS;
diff --git a/firmware/lib/tpm_lite/tlcl.c b/firmware/lib/tpm_lite/tlcl.c
index 181b516a..bf2d27f9 100644
--- a/firmware/lib/tpm_lite/tlcl.c
+++ b/firmware/lib/tpm_lite/tlcl.c
@@ -152,10 +152,6 @@ uint32_t TlclLibClose(void) {
   return VbExTpmClose();
 }
 
-void TlclLibAccessAsUser(void) {
-  /* no-op for TPM1.2 */
-}
-
 uint32_t TlclStartup(void) {
   VBDEBUG(("TPM: Startup\n"));
   return Send(tpm_startup_cmd.buffer);
diff --git a/utility/tpmc.c b/utility/tpmc.c
index f621661e..beb739f9 100644
--- a/utility/tpmc.c
+++ b/utility/tpmc.c
@@ -491,6 +491,8 @@ static int n_commands = sizeof(command_table) / sizeof(command_table[0]);
 
 int main(int argc, char* argv[]) {
   char *progname;
+  uint32_t result;
+
   progname = strrchr(argv[0], '/');
   if (progname)
     progname++;
@@ -515,8 +517,11 @@ int main(int argc, char* argv[]) {
       return 0;
     }
 
-    TlclLibInit();
-    TlclLibAccessAsUser();
+    result = TlclLibInit();
+    if (result) {
+      fprintf(stderr, "initialization failed with code %d\n", result);
+      return result > OTHER_ERROR ? OTHER_ERROR : result;
+    }
 
     for (c = command_table; c < command_table + n_commands; c++) {
       if (strcmp(cmd, c->name) == 0 || strcmp(cmd, c->abbr) == 0) {