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
|
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Copyright(c) 2015, 2016 Intel Corporation.
*/
#include <linux/string.h>
#include <linux/string_helpers.h>
#include "efivar.h"
/* GUID for HFI1 variables in EFI */
#define HFI1_EFIVAR_GUID EFI_GUID(0xc50a953e, 0xa8b2, 0x42a6, \
0xbf, 0x89, 0xd3, 0x33, 0xa6, 0xe9, 0xe6, 0xd4)
/* largest EFI data size we expect */
#define EFI_DATA_SIZE 4096
/*
* Read the named EFI variable. Return the size of the actual data in *size
* and a kmalloc'ed buffer in *return_data. The caller must free the
* data. It is guaranteed that *return_data will be NULL and *size = 0
* if this routine fails.
*
* Return 0 on success, -errno on failure.
*/
static int read_efi_var(const char *name, unsigned long *size,
void **return_data)
{
efi_status_t status;
efi_char16_t *uni_name;
efi_guid_t guid;
unsigned long temp_size;
void *temp_buffer;
void *data;
int i;
int ret;
/* set failure return values */
*size = 0;
*return_data = NULL;
if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
return -EOPNOTSUPP;
uni_name = kcalloc(strlen(name) + 1, sizeof(efi_char16_t), GFP_KERNEL);
temp_buffer = kzalloc(EFI_DATA_SIZE, GFP_KERNEL);
if (!uni_name || !temp_buffer) {
ret = -ENOMEM;
goto fail;
}
/* input: the size of the buffer */
temp_size = EFI_DATA_SIZE;
/* convert ASCII to unicode - it is a 1:1 mapping */
for (i = 0; name[i]; i++)
uni_name[i] = name[i];
/* need a variable for our GUID */
guid = HFI1_EFIVAR_GUID;
/* call into EFI runtime services */
status = efi.get_variable(
uni_name,
&guid,
NULL,
&temp_size,
temp_buffer);
/*
* It would be nice to call efi_status_to_err() here, but that
* is in the EFIVAR_FS code and may not be compiled in.
* However, even that is insufficient since it does not cover
* EFI_BUFFER_TOO_SMALL which could be an important return.
* For now, just split out success or not found.
*/
ret = status == EFI_SUCCESS ? 0 :
status == EFI_NOT_FOUND ? -ENOENT :
-EINVAL;
if (ret)
goto fail;
/*
* We have successfully read the EFI variable into our
* temporary buffer. Now allocate a correctly sized
* buffer.
*/
data = kmemdup(temp_buffer, temp_size, GFP_KERNEL);
if (!data) {
ret = -ENOMEM;
goto fail;
}
*size = temp_size;
*return_data = data;
fail:
kfree(uni_name);
kfree(temp_buffer);
return ret;
}
/*
* Read an HFI1 EFI variable of the form:
* <PCIe address>-<kind>
* Return an kalloc'ed array and size of the data.
*
* Returns 0 on success, -errno on failure.
*/
int read_hfi1_efi_var(struct hfi1_devdata *dd, const char *kind,
unsigned long *size, void **return_data)
{
char prefix_name[64];
char name[128];
int result;
/* create a common prefix */
snprintf(prefix_name, sizeof(prefix_name), "%04x:%02x:%02x.%x",
pci_domain_nr(dd->pcidev->bus),
dd->pcidev->bus->number,
PCI_SLOT(dd->pcidev->devfn),
PCI_FUNC(dd->pcidev->devfn));
snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
result = read_efi_var(name, size, return_data);
/*
* If reading the lowercase EFI variable fail, read the uppercase
* variable.
*/
if (result) {
string_upper(prefix_name, prefix_name);
snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
result = read_efi_var(name, size, return_data);
}
return result;
}
|
