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
21static efi_char16_t vendor[100] __initdata;
22
23static 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
47static 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 */
99static 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
132void __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