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// 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, u64 ksize, u8 *data, u64 *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, u64 *keylen, u64 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, u64 ksize, u8 *data, u64 dsize)
{
int rc;
if (!key || !data)
return -EINVAL;
rc = opal_secvar_enqueue_update(key, ksize, data, dsize);
return opal_status_to_err(rc);
}
static ssize_t opal_secvar_format(char *buf, size_t bufsize)
{
ssize_t rc = 0;
struct device_node *node;
const char *format;
node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
if (!of_device_is_available(node)) {
rc = -ENODEV;
goto out;
}
rc = of_property_read_string(node, "format", &format);
if (rc)
goto out;
rc = snprintf(buf, bufsize, "%s", format);
out:
of_node_put(node);
return rc;
}
static int opal_secvar_max_size(u64 *max_size)
{
int rc;
struct device_node *node;
node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
if (!node)
return -ENODEV;
if (!of_device_is_available(node)) {
rc = -ENODEV;
goto out;
}
rc = of_property_read_u64(node, "max-var-size", max_size);
out:
of_node_put(node);
return rc;
}
static const struct secvar_operations opal_secvar_ops = {
.get = opal_get_variable,
.get_next = opal_get_next_variable,
.set = opal_set_variable,
.format = opal_secvar_format,
.max_size = opal_secvar_max_size,
};
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;
}
return set_secvar_ops(&opal_secvar_ops);
}
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);
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