// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2005 IBM Corporation
 *
 * Authors:
 *      Seiji Munetoh <munetoh@jp.ibm.com>
 *      Stefan Berger <stefanb@us.ibm.com>
 *      Reiner Sailer <sailer@watson.ibm.com>
 *      Kylene Hall <kjhall@us.ibm.com>
 *      Nayna Jain <nayna@linux.vnet.ibm.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * Access to the event log extended by the TCG BIOS of PC platform
 */

#include <linux/device.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/tpm_eventlog.h>

#include "../tpm.h"
#include "common.h"

struct acpi_tcpa {
        struct acpi_table_header hdr;
        u16 platform_class;
        union {
                struct client_hdr {
                        u32 log_max_len __packed;
                        u64 log_start_addr __packed;
                } client;
                struct server_hdr {
                        u16 reserved;
                        u64 log_max_len __packed;
                        u64 log_start_addr __packed;
                } server;
        };
};

/* Check that the given log is indeed a TPM2 log. */
static bool tpm_is_tpm2_log(void *bios_event_log, u64 len)
{
        struct tcg_efi_specid_event_head *efispecid;
        struct tcg_pcr_event *event_header;
        int n;

        if (len < sizeof(*event_header))
                return false;
        len -= sizeof(*event_header);
        event_header = bios_event_log;

        if (len < sizeof(*efispecid))
                return false;
        efispecid = (struct tcg_efi_specid_event_head *)event_header->event;

        n = memcmp(efispecid->signature, TCG_SPECID_SIG,
                   sizeof(TCG_SPECID_SIG));
        return n == 0;
}

static void tpm_bios_log_free(void *data)
{
        kvfree(data);
}

/* read binary bios log */
int tpm_read_log_acpi(struct tpm_chip *chip)
{
        struct acpi_tcpa *buff;
        acpi_status status;
        void __iomem *virt;
        u64 len, start;
        struct tpm_bios_log *log;
        struct acpi_table_tpm2 *tbl;
        struct acpi_tpm2_phy *tpm2_phy;
        int format;
        int ret;

        log = &chip->log;

        /* Unfortuntely ACPI does not associate the event log with a specific
         * TPM, like PPI. Thus all ACPI TPMs will read the same log.
         */
        if (!chip->acpi_dev_handle)
                return -ENODEV;

        if (chip->flags & TPM_CHIP_FLAG_TPM2) {
                status = acpi_get_table("TPM2", 1,
                                        (struct acpi_table_header **)&tbl);
                if (ACPI_FAILURE(status))
                        return -ENODEV;

                if (tbl->header.length <
                                sizeof(*tbl) + sizeof(struct acpi_tpm2_phy)) {
                        acpi_put_table((struct acpi_table_header *)tbl);
                        return -ENODEV;
                }

                tpm2_phy = (void *)tbl + sizeof(*tbl);
                len = tpm2_phy->log_area_minimum_length;

                start = tpm2_phy->log_area_start_address;
                if (!start || !len) {
                        acpi_put_table((struct acpi_table_header *)tbl);
                        return -ENODEV;
                }

                acpi_put_table((struct acpi_table_header *)tbl);
                format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
        } else {
                /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
                status = acpi_get_table(ACPI_SIG_TCPA, 1,
                                        (struct acpi_table_header **)&buff);
                if (ACPI_FAILURE(status))
                        return -ENODEV;

                switch (buff->platform_class) {
                case BIOS_SERVER:
                        len = buff->server.log_max_len;
                        start = buff->server.log_start_addr;
                        break;
                case BIOS_CLIENT:
                default:
                        len = buff->client.log_max_len;
                        start = buff->client.log_start_addr;
                        break;
                }

                acpi_put_table((struct acpi_table_header *)buff);
                format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
        }

        if (!len) {
                dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
                return -EIO;
        }

        /* malloc EventLog space */
        log->bios_event_log = kvmalloc(len, GFP_KERNEL);
        if (!log->bios_event_log)
                return -ENOMEM;

        log->bios_event_log_end = log->bios_event_log + len;

        virt = acpi_os_map_iomem(start, len);
        if (!virt) {
                dev_warn(&chip->dev, "%s: Failed to map ACPI memory\n", __func__);
                /* try EFI log next */
                ret = -ENODEV;
                goto err;
        }

        memcpy_fromio(log->bios_event_log, virt, len);

        acpi_os_unmap_iomem(virt, len);

        if (chip->flags & TPM_CHIP_FLAG_TPM2 &&
            !tpm_is_tpm2_log(log->bios_event_log, len)) {
                /* try EFI log next */
                ret = -ENODEV;
                goto err;
        }

        ret = devm_add_action(&chip->dev, tpm_bios_log_free, log->bios_event_log);
        if (ret) {
                log->bios_event_log = NULL;
                goto err;
        }

        return format;

err:
        tpm_bios_log_free(log->bios_event_log);
        log->bios_event_log = NULL;
        return ret;
}