aboutsummaryrefslogtreecommitdiffstats
path: root/arch/powerpc/platforms/powernv/opal-secvar.c
blob: 14133e120bdd26896dbc514cf94fbf706733c020 (plain) (blame)
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
// SPDX-License-Identifier: GPL-2.0
/*
 * PowerNV code for secure variables
 *
 * Copyright (C) 2019 IBM Corporation
 * Author: Claudio Carvalho
 *         Nayna Jain
 *
 * APIs to access secure variables managed by OPAL.
 */

#define pr_fmt(fmt) "secvar: "fmt

#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/of_platform.h>
#include <asm/opal.h>
#include <asm/secvar.h>
#include <asm/secure_boot.h>

static int opal_status_to_err(int rc)
{
	int err;

	switch (rc) {
	case OPAL_SUCCESS:
		err = 0;
		break;
	case OPAL_UNSUPPORTED:
		err = -ENXIO;
		break;
	case OPAL_PARAMETER:
		err = -EINVAL;
		break;
	case OPAL_RESOURCE:
		err = -ENOSPC;
		break;
	case OPAL_HARDWARE:
		err = -EIO;
		break;
	case OPAL_NO_MEM:
		err = -ENOMEM;
		break;
	case OPAL_EMPTY:
		err = -ENOENT;
		break;
	case OPAL_PARTIAL:
		err = -EFBIG;
		break;
	default:
		err = -EINVAL;
	}

	return err;
}

static int opal_get_variable(const char *key, uint64_t ksize,
			     u8 *data, uint64_t *dsize)
{
	int rc;

	if (!key || !dsize)
		return -EINVAL;

	*dsize = cpu_to_be64(*dsize);

	rc = opal_secvar_get(key, ksize, data, dsize);

	*dsize = be64_to_cpu(*dsize);

	return opal_status_to_err(rc);
}

static int opal_get_next_variable(const char *key, uint64_t *keylen,
				  uint64_t keybufsize)
{
	int rc;

	if (!key || !keylen)
		return -EINVAL;

	*keylen = cpu_to_be64(*keylen);

	rc = opal_secvar_get_next(key, keylen, keybufsize);

	*keylen = be64_to_cpu(*keylen);

	return opal_status_to_err(rc);
}

static int opal_set_variable(const char *key, uint64_t ksize, u8 *data,
			     uint64_t dsize)
{
	int rc;

	if (!key || !data)
		return -EINVAL;

	rc = opal_secvar_enqueue_update(key, ksize, data, dsize);

	return opal_status_to_err(rc);
}

static const struct secvar_operations opal_secvar_ops = {
	.get = opal_get_variable,
	.get_next = opal_get_next_variable,
	.set = opal_set_variable,
};

static int opal_secvar_probe(struct platform_device *pdev)
{
	if (!opal_check_token(OPAL_SECVAR_GET)
			|| !opal_check_token(OPAL_SECVAR_GET_NEXT)
			|| !opal_check_token(OPAL_SECVAR_ENQUEUE_UPDATE)) {
		pr_err("OPAL doesn't support secure variables\n");
		return -ENODEV;
	}

	set_secvar_ops(&opal_secvar_ops);

	return 0;
}

static const struct of_device_id opal_secvar_match[] = {
	{ .compatible = "ibm,secvar-backend",},
	{},
};

static struct platform_driver opal_secvar_driver = {
	.driver = {
		.name = "secvar",
		.of_match_table = opal_secvar_match,
	},
};

static int __init opal_secvar_init(void)
{
	return platform_driver_probe(&opal_secvar_driver, opal_secvar_probe);
}
device_initcall(opal_secvar_init);