// 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;
}