139 lines
3.3 KiB
C
139 lines
3.3 KiB
C
// 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;
|
|
}
|