// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2014 Oracle Co., Daniel Kiper
 */

#include <linux/bitops.h>
#include <linux/efi.h>
#include <linux/init.h>
#include <linux/string.h>

#include <xen/xen.h>
#include <xen/xen-ops.h>
#include <xen/interface/platform.h>

#include <asm/page.h>
#include <asm/setup.h>
#include <asm/xen/hypercall.h>

#include "xen-ops.h"

static efi_char16_t vendor[100] __initdata;

static efi_system_table_t efi_systab_xen __initdata = {
        .hdr = {
                .signature      = EFI_SYSTEM_TABLE_SIGNATURE,
                .revision       = 0, /* Initialized later. */
                .headersize     = 0, /* Ignored by Linux Kernel. */
                .crc32          = 0, /* Ignored by Linux Kernel. */
                .reserved       = 0
        },
        .fw_vendor      = EFI_INVALID_TABLE_ADDR, /* Initialized later. */
        .fw_revision    = 0,                      /* Initialized later. */
        .con_in_handle  = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
        .con_in         = NULL,                   /* Not used under Xen. */
        .con_out_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
        .con_out        = NULL,                   /* Not used under Xen. */
        .stderr_handle  = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
        .stderr         = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
        .runtime        = (efi_runtime_services_t *)EFI_INVALID_TABLE_ADDR,
                                                  /* Not used under Xen. */
        .boottime       = (efi_boot_services_t *)EFI_INVALID_TABLE_ADDR,
                                                  /* Not used under Xen. */
        .nr_tables      = 0,                      /* Initialized later. */
        .tables         = EFI_INVALID_TABLE_ADDR  /* Initialized later. */
};

static efi_system_table_t __init *xen_efi_probe(void)
{
        struct xen_platform_op op = {
                .cmd = XENPF_firmware_info,
                .u.firmware_info = {
                        .type = XEN_FW_EFI_INFO,
                        .index = XEN_FW_EFI_CONFIG_TABLE
                }
        };
        union xenpf_efi_info *info = &op.u.firmware_info.u.efi_info;

        if (!xen_initial_domain() || HYPERVISOR_platform_op(&op) < 0)
                return NULL;

        /* Here we know that Xen runs on EFI platform. */
        xen_efi_runtime_setup();

        efi_systab_xen.tables = info->cfg.addr;
        efi_systab_xen.nr_tables = info->cfg.nent;

        op.cmd = XENPF_firmware_info;
        op.u.firmware_info.type = XEN_FW_EFI_INFO;
        op.u.firmware_info.index = XEN_FW_EFI_VENDOR;
        info->vendor.bufsz = sizeof(vendor);
        set_xen_guest_handle(info->vendor.name, vendor);

        if (HYPERVISOR_platform_op(&op) == 0) {
                efi_systab_xen.fw_vendor = __pa_symbol(vendor);
                efi_systab_xen.fw_revision = info->vendor.revision;
        } else
                efi_systab_xen.fw_vendor = __pa_symbol(L"UNKNOWN");

        op.cmd = XENPF_firmware_info;
        op.u.firmware_info.type = XEN_FW_EFI_INFO;
        op.u.firmware_info.index = XEN_FW_EFI_VERSION;

        if (HYPERVISOR_platform_op(&op) == 0)
                efi_systab_xen.hdr.revision = info->version;

        op.cmd = XENPF_firmware_info;
        op.u.firmware_info.type = XEN_FW_EFI_INFO;
        op.u.firmware_info.index = XEN_FW_EFI_RT_VERSION;

        if (HYPERVISOR_platform_op(&op) == 0)
                efi.runtime_version = info->version;

        return &efi_systab_xen;
}

/*
 * Determine whether we're in secure boot mode.
 */
static enum efi_secureboot_mode xen_efi_get_secureboot(void)
{
        static efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
        enum efi_secureboot_mode mode;
        efi_status_t status;
        u8 moksbstate;
        unsigned long size;

        mode = efi_get_secureboot_mode(efi.get_variable);
        if (mode == efi_secureboot_mode_unknown) {
                pr_err("Could not determine UEFI Secure Boot status.\n");
                return efi_secureboot_mode_unknown;
        }
        if (mode != efi_secureboot_mode_enabled)
                return mode;

        /* See if a user has put the shim into insecure mode. */
        size = sizeof(moksbstate);
        status = efi.get_variable(L"MokSBStateRT", &shim_guid,
                                  NULL, &size, &moksbstate);

        /* If it fails, we don't care why. Default to secure. */
        if (status != EFI_SUCCESS)
                goto secure_boot_enabled;

        if (moksbstate == 1)
                return efi_secureboot_mode_disabled;

 secure_boot_enabled:
        pr_info("UEFI Secure Boot is enabled.\n");
        return efi_secureboot_mode_enabled;
}

void __init xen_efi_init(struct boot_params *boot_params)
{
        efi_system_table_t *efi_systab_xen;

        efi_systab_xen = xen_efi_probe();

        if (efi_systab_xen == NULL)
                return;

        strscpy((char *)&boot_params->efi_info.efi_loader_signature, "Xen",
                        sizeof(boot_params->efi_info.efi_loader_signature));
        boot_params->efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
        boot_params->efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);

        boot_params->secure_boot = xen_efi_get_secureboot();

        set_bit(EFI_BOOT, &efi.flags);
        set_bit(EFI_PARAVIRT, &efi.flags);
        set_bit(EFI_64BIT, &efi.flags);
}