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 #include "xen-ops.h"
20
21 static efi_char16_t vendor[100] __initdata;
22
23 static efi_system_table_t efi_systab_xen __initdata = {
24 .hdr = {
25 .signature = EFI_SYSTEM_TABLE_SIGNATURE,
26 .revision = 0, /* Initialized later. */
27 .headersize = 0, /* Ignored by Linux Kernel. */
28 .crc32 = 0, /* Ignored by Linux Kernel. */
29 .reserved = 0
30 },
31 .fw_vendor = EFI_INVALID_TABLE_ADDR, /* Initialized later. */
32 .fw_revision = 0, /* Initialized later. */
33 .con_in_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
34 .con_in = NULL, /* Not used under Xen. */
35 .con_out_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
36 .con_out = NULL, /* Not used under Xen. */
37 .stderr_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
38 .stderr = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
39 .runtime = (efi_runtime_services_t *)EFI_INVALID_TABLE_ADDR,
40 /* Not used under Xen. */
41 .boottime = (efi_boot_services_t *)EFI_INVALID_TABLE_ADDR,
42 /* Not used under Xen. */
43 .nr_tables = 0, /* Initialized later. */
44 .tables = EFI_INVALID_TABLE_ADDR /* Initialized later. */
45 };
46
xen_efi_probe(void)47 static efi_system_table_t __init *xen_efi_probe(void)
48 {
49 struct xen_platform_op op = {
50 .cmd = XENPF_firmware_info,
51 .u.firmware_info = {
52 .type = XEN_FW_EFI_INFO,
53 .index = XEN_FW_EFI_CONFIG_TABLE
54 }
55 };
56 union xenpf_efi_info *info = &op.u.firmware_info.u.efi_info;
57
58 if (!xen_initial_domain() || HYPERVISOR_platform_op(&op) < 0)
59 return NULL;
60
61 /* Here we know that Xen runs on EFI platform. */
62 xen_efi_runtime_setup();
63
64 efi_systab_xen.tables = info->cfg.addr;
65 efi_systab_xen.nr_tables = info->cfg.nent;
66
67 op.cmd = XENPF_firmware_info;
68 op.u.firmware_info.type = XEN_FW_EFI_INFO;
69 op.u.firmware_info.index = XEN_FW_EFI_VENDOR;
70 info->vendor.bufsz = sizeof(vendor);
71 set_xen_guest_handle(info->vendor.name, vendor);
72
73 if (HYPERVISOR_platform_op(&op) == 0) {
74 efi_systab_xen.fw_vendor = __pa_symbol(vendor);
75 efi_systab_xen.fw_revision = info->vendor.revision;
76 } else
77 efi_systab_xen.fw_vendor = __pa_symbol(L"UNKNOWN");
78
79 op.cmd = XENPF_firmware_info;
80 op.u.firmware_info.type = XEN_FW_EFI_INFO;
81 op.u.firmware_info.index = XEN_FW_EFI_VERSION;
82
83 if (HYPERVISOR_platform_op(&op) == 0)
84 efi_systab_xen.hdr.revision = info->version;
85
86 op.cmd = XENPF_firmware_info;
87 op.u.firmware_info.type = XEN_FW_EFI_INFO;
88 op.u.firmware_info.index = XEN_FW_EFI_RT_VERSION;
89
90 if (HYPERVISOR_platform_op(&op) == 0)
91 efi.runtime_version = info->version;
92
93 return &efi_systab_xen;
94 }
95
96 /*
97 * Determine whether we're in secure boot mode.
98 */
xen_efi_get_secureboot(void)99 static enum efi_secureboot_mode xen_efi_get_secureboot(void)
100 {
101 static efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
102 enum efi_secureboot_mode mode;
103 efi_status_t status;
104 u8 moksbstate;
105 unsigned long size;
106
107 mode = efi_get_secureboot_mode(efi.get_variable);
108 if (mode == efi_secureboot_mode_unknown) {
109 pr_err("Could not determine UEFI Secure Boot status.\n");
110 return efi_secureboot_mode_unknown;
111 }
112 if (mode != efi_secureboot_mode_enabled)
113 return mode;
114
115 /* See if a user has put the shim into insecure mode. */
116 size = sizeof(moksbstate);
117 status = efi.get_variable(L"MokSBStateRT", &shim_guid,
118 NULL, &size, &moksbstate);
119
120 /* If it fails, we don't care why. Default to secure. */
121 if (status != EFI_SUCCESS)
122 goto secure_boot_enabled;
123
124 if (moksbstate == 1)
125 return efi_secureboot_mode_disabled;
126
127 secure_boot_enabled:
128 pr_info("UEFI Secure Boot is enabled.\n");
129 return efi_secureboot_mode_enabled;
130 }
131
xen_efi_init(struct boot_params * boot_params)132 void __init xen_efi_init(struct boot_params *boot_params)
133 {
134 efi_system_table_t *efi_systab_xen;
135
136 efi_systab_xen = xen_efi_probe();
137
138 if (efi_systab_xen == NULL)
139 return;
140
141 strscpy((char *)&boot_params->efi_info.efi_loader_signature, "Xen",
142 sizeof(boot_params->efi_info.efi_loader_signature));
143 boot_params->efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
144 boot_params->efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
145
146 boot_params->secure_boot = xen_efi_get_secureboot();
147
148 set_bit(EFI_BOOT, &efi.flags);
149 set_bit(EFI_PARAVIRT, &efi.flags);
150 set_bit(EFI_64BIT, &efi.flags);
151 }
152