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-rw-r--r--src/vboot/vbnv.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/src/vboot/vbnv.c b/src/vboot/vbnv.c
new file mode 100644
index 0000000000..ce6492855d
--- /dev/null
+++ b/src/vboot/vbnv.c
@@ -0,0 +1,142 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/early_variables.h>
+#include <string.h>
+#include <types.h>
+#include <vboot/vbnv.h>
+#include <vboot/vbnv_layout.h>
+
+static int vbnv_initialized CAR_GLOBAL;
+static uint8_t vbnv[VBOOT_VBNV_BLOCK_SIZE] CAR_GLOBAL;
+
+/* Wrappers for accessing the variables marked as CAR_GLOBAL. */
+static inline int is_vbnv_initialized(void)
+{
+ return car_get_var(vbnv_initialized);
+}
+
+static inline uint8_t *vbnv_data_addr(int index)
+{
+ uint8_t *vbnv_arr = car_get_var_ptr(vbnv);
+
+ return &vbnv_arr[index];
+}
+
+static inline uint8_t vbnv_data(int index)
+{
+ return *vbnv_data_addr(index);
+}
+
+/* Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial. */
+static uint8_t crc8_vbnv(const uint8_t *data, int len)
+{
+ unsigned crc = 0;
+ int i, j;
+
+ for (j = len; j; j--, data++) {
+ crc ^= (*data << 8);
+ for (i = 8; i; i--) {
+ if (crc & 0x8000)
+ crc ^= (0x1070 << 3);
+ crc <<= 1;
+ }
+ }
+
+ return (uint8_t) (crc >> 8);
+}
+
+static void reset_vbnv(uint8_t *vbnv_copy)
+{
+ memset(vbnv_copy, 0, VBOOT_VBNV_BLOCK_SIZE);
+}
+
+/* Read VBNV data into cache. */
+static void vbnv_setup(void)
+{
+ if (!is_vbnv_initialized()) {
+ read_vbnv(vbnv_data_addr(0));
+ car_set_var(vbnv_initialized, 1);
+ }
+}
+
+/* Verify VBNV header and checksum. */
+int verify_vbnv(uint8_t *vbnv_copy)
+{
+ return (HEADER_SIGNATURE == (vbnv_copy[HEADER_OFFSET] & HEADER_MASK)) &&
+ (crc8_vbnv(vbnv_copy, CRC_OFFSET) == vbnv_copy[CRC_OFFSET]);
+}
+
+/*
+ * Read VBNV data from configured storage backend.
+ * If VBNV verification fails, reset the vbnv copy.
+ */
+void read_vbnv(uint8_t *vbnv_copy)
+{
+ if (IS_ENABLED(CONFIG_VBOOT_VBNV_CMOS))
+ read_vbnv_cmos(vbnv_copy);
+ else if (IS_ENABLED(CONFIG_VBOOT_VBNV_EC))
+ read_vbnv_ec(vbnv_copy);
+ else if (IS_ENABLED(CONFIG_VBOOT_VBNV_FLASH))
+ read_vbnv_flash(vbnv_copy);
+
+ /* Check data for consistency */
+ if (!verify_vbnv(vbnv_copy))
+ reset_vbnv(vbnv_copy);
+}
+
+/*
+ * Write VBNV data to configured storage backend.
+ * This assumes that the caller has updated the CRC already.
+ */
+void save_vbnv(const uint8_t *vbnv_copy)
+{
+ if (IS_ENABLED(CONFIG_VBOOT_VBNV_CMOS))
+ save_vbnv_cmos(vbnv_copy);
+ else if (IS_ENABLED(CONFIG_VBOOT_VBNV_EC))
+ save_vbnv_ec(vbnv_copy);
+ else if (IS_ENABLED(CONFIG_VBOOT_VBNV_FLASH))
+ save_vbnv_flash(vbnv_copy);
+
+ /* Clear initialized flag to force cached data to be updated */
+ car_set_var(vbnv_initialized, 0);
+}
+
+/* Save a recovery reason into VBNV. */
+void set_recovery_mode_into_vbnv(int recovery_reason)
+{
+ uint8_t vbnv_copy[VBOOT_VBNV_BLOCK_SIZE];
+
+ read_vbnv(vbnv_copy);
+
+ vbnv_copy[RECOVERY_OFFSET] = recovery_reason;
+ vbnv_copy[CRC_OFFSET] = crc8_vbnv(vbnv_copy, CRC_OFFSET);
+
+ save_vbnv(vbnv_copy);
+}
+
+/* Read the recovery reason from VBNV. */
+int get_recovery_mode_from_vbnv(void)
+{
+ vbnv_setup();
+ return vbnv_data(RECOVERY_OFFSET);
+}
+
+/* Read the BOOT_OPROM_NEEDED flag from VBNV. */
+int vboot_wants_oprom(void)
+{
+ vbnv_setup();
+ return (vbnv_data(BOOT_OFFSET) & BOOT_OPROM_NEEDED) ? 1 : 0;
+}