1 files changed, 125 insertions, 0 deletions
diff --git a/drivers/char/tpm/eventlog/efi.c b/drivers/char/tpm/eventlog/efi.c
new file mode 100644
index 0000000000..4e9d7c2bf3
--- /dev/null
+++ b/drivers/char/tpm/eventlog/efi.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017 Google
+ *
+ * Authors:
+ *      Thiebaud Weksteen <tweek@google.com>
+ */
+
+#include <linux/device.h>
+#include <linux/efi.h>
+#include <linux/tpm_eventlog.h>
+
+#include "../tpm.h"
+#include "common.h"
+
+/* read binary bios log from EFI configuration table */
+int tpm_read_log_efi(struct tpm_chip *chip)
+{
+
+	struct efi_tcg2_final_events_table *final_tbl = NULL;
+	int final_events_log_size = efi_tpm_final_log_size;
+	struct linux_efi_tpm_eventlog *log_tbl;
+	struct tpm_bios_log *log;
+	u32 log_size;
+	u8 tpm_log_version;
+	void *tmp;
+	int ret;
+
+	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
+		return -ENODEV;
+
+	if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
+		return -ENODEV;
+
+	log = &chip->log;
+
+	log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl), MEMREMAP_WB);
+	if (!log_tbl) {
+		pr_err("Could not map UEFI TPM log table !\n");
+		return -ENOMEM;
+	}
+
+	log_size = log_tbl->size;
+	memunmap(log_tbl);
+
+	if (!log_size) {
+		pr_warn("UEFI TPM log area empty\n");
+		return -EIO;
+	}
+
+	log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl) + log_size,
+			   MEMREMAP_WB);
+	if (!log_tbl) {
+		pr_err("Could not map UEFI TPM log table payload!\n");
+		return -ENOMEM;
+	}
+
+	/* malloc EventLog space */
+	log->bios_event_log = devm_kmemdup(&chip->dev, log_tbl->log, log_size, GFP_KERNEL);
+	if (!log->bios_event_log) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	log->bios_event_log_end = log->bios_event_log + log_size;
+	tpm_log_version = log_tbl->version;
+
+	ret = tpm_log_version;
+
+	if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
+	    final_events_log_size == 0 ||
+	    tpm_log_version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
+		goto out;
+
+	final_tbl = memremap(efi.tpm_final_log,
+			     sizeof(*final_tbl) + final_events_log_size,
+			     MEMREMAP_WB);
+	if (!final_tbl) {
+		pr_err("Could not map UEFI TPM final log\n");
+		devm_kfree(&chip->dev, log->bios_event_log);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * The 'final events log' size excludes the 'final events preboot log'
+	 * at its beginning.
+	 */
+	final_events_log_size -= log_tbl->final_events_preboot_size;
+
+	/*
+	 * Allocate memory for the 'combined log' where we will append the
+	 * 'final events log' to.
+	 */
+	tmp = devm_krealloc(&chip->dev, log->bios_event_log,
+			    log_size + final_events_log_size,
+			    GFP_KERNEL);
+	if (!tmp) {
+		devm_kfree(&chip->dev, log->bios_event_log);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	log->bios_event_log = tmp;
+
+	/*
+	 * Append any of the 'final events log' that didn't also end up in the
+	 * 'main log'. Events can be logged in both if events are generated
+	 * between GetEventLog() and ExitBootServices().
+	 */
+	memcpy((void *)log->bios_event_log + log_size,
+	       final_tbl->events + log_tbl->final_events_preboot_size,
+	       final_events_log_size);
+	/*
+	 * The size of the 'combined log' is the size of the 'main log' plus
+	 * the size of the 'final events log'.
+	 */
+	log->bios_event_log_end = log->bios_event_log +
+		log_size + final_events_log_size;
+
+out:
+	memunmap(final_tbl);
+	memunmap(log_tbl);
+	return ret;
+}