summaryrefslogtreecommitdiffstats
path: root/arch/x86/xen/efi.c
blob: 1abe455d926a2785eb8049576f9ad345fbff2d8e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
// 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>

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		= EFI_INVALID_TABLE_ADDR, /* 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.
 *
 * Please keep the logic in sync with
 * drivers/firmware/efi/libstub/secureboot.c:efi_get_secureboot().
 */
static enum efi_secureboot_mode xen_efi_get_secureboot(void)
{
	static efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
	static efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
	efi_status_t status;
	u8 moksbstate, secboot, setupmode;
	unsigned long size;

	size = sizeof(secboot);
	status = efi.get_variable(L"SecureBoot", &efi_variable_guid,
				  NULL, &size, &secboot);

	if (status == EFI_NOT_FOUND)
		return efi_secureboot_mode_disabled;

	if (status != EFI_SUCCESS)
		goto out_efi_err;

	size = sizeof(setupmode);
	status = efi.get_variable(L"SetupMode", &efi_variable_guid,
				  NULL, &size, &setupmode);

	if (status != EFI_SUCCESS)
		goto out_efi_err;

	if (secboot == 0 || setupmode == 1)
		return efi_secureboot_mode_disabled;

	/* 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;

 out_efi_err:
	pr_err("Could not determine UEFI Secure Boot status.\n");
	return efi_secureboot_mode_unknown;
}

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;

	strncpy((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);
}