1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2014 Oracle Co., Daniel Kiper 4 */ 5 6 #include <linux/bitops.h> 7 #include <linux/efi.h> 8 #include <linux/init.h> 9 #include <linux/string.h> 10 11 #include <xen/xen.h> 12 #include <xen/xen-ops.h> 13 #include <xen/interface/platform.h> 14 15 #include <asm/page.h> 16 #include <asm/setup.h> 17 #include <asm/xen/hypercall.h> 18 19 static efi_char16_t vendor[100] __initdata; 20 21 static efi_system_table_t efi_systab_xen __initdata = { 22 .hdr = { 23 .signature = EFI_SYSTEM_TABLE_SIGNATURE, 24 .revision = 0, /* Initialized later. */ 25 .headersize = 0, /* Ignored by Linux Kernel. */ 26 .crc32 = 0, /* Ignored by Linux Kernel. */ 27 .reserved = 0 28 }, 29 .fw_vendor = EFI_INVALID_TABLE_ADDR, /* Initialized later. */ 30 .fw_revision = 0, /* Initialized later. */ 31 .con_in_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ 32 .con_in = NULL, /* Not used under Xen. */ 33 .con_out_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ 34 .con_out = NULL, /* Not used under Xen. */ 35 .stderr_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ 36 .stderr = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ 37 .runtime = (efi_runtime_services_t *)EFI_INVALID_TABLE_ADDR, 38 /* Not used under Xen. */ 39 .boottime = (efi_boot_services_t *)EFI_INVALID_TABLE_ADDR, 40 /* Not used under Xen. */ 41 .nr_tables = 0, /* Initialized later. */ 42 .tables = EFI_INVALID_TABLE_ADDR /* Initialized later. */ 43 }; 44 45 static efi_system_table_t __init *xen_efi_probe(void) 46 { 47 struct xen_platform_op op = { 48 .cmd = XENPF_firmware_info, 49 .u.firmware_info = { 50 .type = XEN_FW_EFI_INFO, 51 .index = XEN_FW_EFI_CONFIG_TABLE 52 } 53 }; 54 union xenpf_efi_info *info = &op.u.firmware_info.u.efi_info; 55 56 if (!xen_initial_domain() || HYPERVISOR_platform_op(&op) < 0) 57 return NULL; 58 59 /* Here we know that Xen runs on EFI platform. */ 60 xen_efi_runtime_setup(); 61 62 efi_systab_xen.tables = info->cfg.addr; 63 efi_systab_xen.nr_tables = info->cfg.nent; 64 65 op.cmd = XENPF_firmware_info; 66 op.u.firmware_info.type = XEN_FW_EFI_INFO; 67 op.u.firmware_info.index = XEN_FW_EFI_VENDOR; 68 info->vendor.bufsz = sizeof(vendor); 69 set_xen_guest_handle(info->vendor.name, vendor); 70 71 if (HYPERVISOR_platform_op(&op) == 0) { 72 efi_systab_xen.fw_vendor = __pa_symbol(vendor); 73 efi_systab_xen.fw_revision = info->vendor.revision; 74 } else 75 efi_systab_xen.fw_vendor = __pa_symbol(L"UNKNOWN"); 76 77 op.cmd = XENPF_firmware_info; 78 op.u.firmware_info.type = XEN_FW_EFI_INFO; 79 op.u.firmware_info.index = XEN_FW_EFI_VERSION; 80 81 if (HYPERVISOR_platform_op(&op) == 0) 82 efi_systab_xen.hdr.revision = info->version; 83 84 op.cmd = XENPF_firmware_info; 85 op.u.firmware_info.type = XEN_FW_EFI_INFO; 86 op.u.firmware_info.index = XEN_FW_EFI_RT_VERSION; 87 88 if (HYPERVISOR_platform_op(&op) == 0) 89 efi.runtime_version = info->version; 90 91 return &efi_systab_xen; 92 } 93 94 /* 95 * Determine whether we're in secure boot mode. 96 */ 97 static enum efi_secureboot_mode xen_efi_get_secureboot(void) 98 { 99 static efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID; 100 enum efi_secureboot_mode mode; 101 efi_status_t status; 102 u8 moksbstate; 103 unsigned long size; 104 105 mode = efi_get_secureboot_mode(efi.get_variable); 106 if (mode == efi_secureboot_mode_unknown) { 107 pr_err("Could not determine UEFI Secure Boot status.\n"); 108 return efi_secureboot_mode_unknown; 109 } 110 if (mode != efi_secureboot_mode_enabled) 111 return mode; 112 113 /* See if a user has put the shim into insecure mode. */ 114 size = sizeof(moksbstate); 115 status = efi.get_variable(L"MokSBStateRT", &shim_guid, 116 NULL, &size, &moksbstate); 117 118 /* If it fails, we don't care why. Default to secure. */ 119 if (status != EFI_SUCCESS) 120 goto secure_boot_enabled; 121 122 if (moksbstate == 1) 123 return efi_secureboot_mode_disabled; 124 125 secure_boot_enabled: 126 pr_info("UEFI Secure Boot is enabled.\n"); 127 return efi_secureboot_mode_enabled; 128 } 129 130 void __init xen_efi_init(struct boot_params *boot_params) 131 { 132 efi_system_table_t *efi_systab_xen; 133 134 efi_systab_xen = xen_efi_probe(); 135 136 if (efi_systab_xen == NULL) 137 return; 138 139 strncpy((char *)&boot_params->efi_info.efi_loader_signature, "Xen", 140 sizeof(boot_params->efi_info.efi_loader_signature)); 141 boot_params->efi_info.efi_systab = (__u32)__pa(efi_systab_xen); 142 boot_params->efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32); 143 144 boot_params->secure_boot = xen_efi_get_secureboot(); 145 146 set_bit(EFI_BOOT, &efi.flags); 147 set_bit(EFI_PARAVIRT, &efi.flags); 148 set_bit(EFI_64BIT, &efi.flags); 149 } 150