cr50: preserve ordely nv spaces over TPM resetstabilize-quickfix-14526.91.B-cr50_stabstabilize-14528.B-cr50_stabstabilize-14526.89.B-cr50_stabstabilize-14526.84.B-cr50_stabstabilize-14526.73.B-cr50_stabstabilize-14526.67.B-cr50_stabstabilize-14526.57.B-cr50_stabrelease-R100-14526.B-cr50_stab

This CL in case of unorderly TPM reset that doesn't also reset GSC
preserves RAM-backed values of orderly nv indices.

BUG=b:201101365
TEST=1) create an orderly counter
     2) increment it
     3) trigger EC reset
     4) verify that the counter value was preserved

Cq-Depend: chromium:3417937
Change-Id: I799183ad06584055d025c2acf5f83ff2ded32d39
Signed-off-by: Andrey Pronin <apronin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3418122
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Commit-Queue: Mary Ruthven <mruthven@chromium.org>

3 files changed, 42 insertions, 4 deletions

diff --git a/board/cr50/tpm_nvmem_ops.c b/board/cr50/tpm_nvmem_ops.c
index ba295c7f4f..76f740c0ee 100644
--- a/board/cr50/tpm_nvmem_ops.c
+++ b/board/cr50/tpm_nvmem_ops.c
@@ -108,3 +108,15 @@ size_t read_tpm_nvmem_size(uint16_t obj_index)
 
 	return size;
 }
+
+BUILD_ASSERT(TPM_ORDERLY_STATE_SIZE >= RAM_INDEX_SPACE);
+
+void tpm_orderly_state_capture(char copy[TPM_ORDERLY_STATE_SIZE])
+{
+	NvStateCapture(copy);
+}
+
+void tpm_orderly_state_restore(const char copy[TPM_ORDERLY_STATE_SIZE])
+{
+	NvStateRestore(copy);
+}
diff --git a/board/cr50/tpm_nvmem_ops.h b/board/cr50/tpm_nvmem_ops.h
index ef1c5a07fc..da8036b16f 100644
--- a/board/cr50/tpm_nvmem_ops.h
+++ b/board/cr50/tpm_nvmem_ops.h
@@ -7,6 +7,8 @@
 #ifndef __EC_BOARD_CR50_TPM_NVMEM_OPS_H
 #define __EC_BOARD_CR50_TPM_NVMEM_OPS_H
 
+#define TPM_ORDERLY_STATE_SIZE 512
+
 enum tpm_read_rv {
 	TPM_READ_SUCCESS,
 	TPM_READ_NOT_FOUND,
@@ -46,4 +48,8 @@ enum tpm_write_rv write_tpm_nvmem_hidden(uint16_t object_index,
 /* return size of hidden nvmem object, 0 if not found */
 size_t read_tpm_nvmem_size(uint16_t obj_index);
 
+void tpm_orderly_state_capture(char copy[TPM_ORDERLY_STATE_SIZE]);
+
+void tpm_orderly_state_restore(const char copy[TPM_ORDERLY_STATE_SIZE]);
+
 #endif  /* ! __EC_BOARD_CR50_TPM_NVMEM_OPS_H */
diff --git a/common/tpm_registers.c b/common/tpm_registers.c
index d0ae42e904..429e895283 100644
--- a/common/tpm_registers.c
+++ b/common/tpm_registers.c
@@ -21,6 +21,7 @@
 #include "system_chip.h"
 #include "task.h"
 #include "tpm_manufacture.h"
+#include "tpm_nvmem_ops.h"
 #include "tpm_registers.h"
 #include "util.h"
 #include "watchdog.h"
@@ -850,8 +851,21 @@ void tpm_reinstate_nvmem_commits(void)
 	task_set_event(TASK_ID_TPM, TPM_EVENT_COMMIT, 0);
 }
 
-static void tpm_reset_now(int wipe_first)
+/*
+ * Reset TPM stack state.
+ * Called at boot, when AP resets (TPM_RESET_EVENT) and when a TPM data wipe
+ * is requested.
+ *
+ * Parameters:
+ *     wipe_first - wipe TPM nvmem as a part of reset.
+ *     can_preserve_orderly - preserve orderly nvmem spaces over a possibly
+ *         unorderly shutdown (unless wipe_first is requested). This is a GSC
+ *         specific modification to TPM behavior.
+ */
+static void tpm_reset_now(int wipe_first, int can_preserve_orderly)
 {
+	char orderly_state_copy[TPM_ORDERLY_STATE_SIZE];
+
 	if_stop();
 
 	/* This is more related to TPM task activity than TPM transactions */
@@ -874,6 +888,9 @@ static void tpm_reset_now(int wipe_first)
 	 */
 	nvmem_enable_commits();
 
+	if (can_preserve_orderly && !wipe_first)
+		tpm_orderly_state_capture(orderly_state_copy);
+
 	/*
 	 * Clear the TPM library's zero-init data.  Note that the linker script
 	 * includes this file's .bss in the same section, so it will be cleared
@@ -889,6 +906,9 @@ static void tpm_reset_now(int wipe_first)
 	/* Re-initialize our registers */
 	tpm_init();
 
+	if (can_preserve_orderly && !wipe_first)
+		tpm_orderly_state_restore(orderly_state_copy);
+
 	if (waiting_for_reset != TASK_ID_INVALID) {
 		/* Wake the waiting task, if any */
 		task_set_event(waiting_for_reset, TPM_EVENT_RESET, 0);
@@ -908,7 +928,7 @@ static void tpm_reset_now(int wipe_first)
 
 int tpm_sync_reset(int wipe_first)
 {
-	tpm_reset_now(wipe_first);
+	tpm_reset_now(wipe_first, 1);
 
 	return wipe_result;
 }
@@ -957,7 +977,7 @@ void tpm_task(void *u)
 				__func__, __LINE__, evt);
 	}
 
-	tpm_reset_now(0);
+	tpm_reset_now(0, 0);
 	while (1) {
 		uint8_t *response = NULL;
 		unsigned response_size;
@@ -971,7 +991,7 @@ void tpm_task(void *u)
 			evt = task_wait_event(-1);
 
 		if (evt & TPM_EVENT_RESET) {
-			tpm_reset_now(wipe_requested);
+			tpm_reset_now(wipe_requested, 1);
 			if (evt & TPM_EVENT_ALT_EXTENSION) {
 				/*
 				 * Need to tell the waiting task that