arch/powerpc/platforms/powernv/opal-secvar.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * PowerNV code for secure variables
   4  *
   5  * Copyright (C) 2019 IBM Corporation
   6  * Author: Claudio Carvalho
   7  *         Nayna Jain
   8  *
   9  * APIs to access secure variables managed by OPAL.
  10  */
  11
  12 #define pr_fmt(fmt) "secvar: "fmt
  13
  14 #include <linux/types.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/of_platform.h>
  17 #include <asm/opal.h>
  18 #include <asm/secvar.h>
  19 #include <asm/secure_boot.h>
  20
  21 static int opal_status_to_err(int rc)
  22 {
  23         int err;
  24
  25         switch (rc) {
  26         case OPAL_SUCCESS:
  27                 err = 0;
  28                 break;
  29         case OPAL_UNSUPPORTED:
  30                 err = -ENXIO;
  31                 break;
  32         case OPAL_PARAMETER:
  33                 err = -EINVAL;
  34                 break;
  35         case OPAL_RESOURCE:
  36                 err = -ENOSPC;
  37                 break;
  38         case OPAL_HARDWARE:
  39                 err = -EIO;
  40                 break;
  41         case OPAL_NO_MEM:
  42                 err = -ENOMEM;
  43                 break;
  44         case OPAL_EMPTY:
  45                 err = -ENOENT;
  46                 break;
  47         case OPAL_PARTIAL:
  48                 err = -EFBIG;
  49                 break;
  50         default:
  51                 err = -EINVAL;
  52         }
  53
  54         return err;
  55 }
  56
  57 static int opal_get_variable(const char *key, uint64_t ksize,
  58                              u8 *data, uint64_t *dsize)
  59 {
  60         int rc;
  61
  62         if (!key || !dsize)
  63                 return -EINVAL;
  64
  65         *dsize = cpu_to_be64(*dsize);
  66
  67         rc = opal_secvar_get(key, ksize, data, dsize);
  68
  69         *dsize = be64_to_cpu(*dsize);
  70
  71         return opal_status_to_err(rc);
  72 }
  73
  74 static int opal_get_next_variable(const char *key, uint64_t *keylen,
  75                                   uint64_t keybufsize)
  76 {
  77         int rc;
  78
  79         if (!key || !keylen)
  80                 return -EINVAL;
  81
  82         *keylen = cpu_to_be64(*keylen);
  83
  84         rc = opal_secvar_get_next(key, keylen, keybufsize);
  85
  86         *keylen = be64_to_cpu(*keylen);
  87
  88         return opal_status_to_err(rc);
  89 }
  90
  91 static int opal_set_variable(const char *key, uint64_t ksize, u8 *data,
  92                              uint64_t dsize)
  93 {
  94         int rc;
  95
  96         if (!key || !data)
  97                 return -EINVAL;
  98
  99         rc = opal_secvar_enqueue_update(key, ksize, data, dsize);
 100
 101         return opal_status_to_err(rc);
 102 }
 103
 104 static const struct secvar_operations opal_secvar_ops = {
 105         .get = opal_get_variable,
 106         .get_next = opal_get_next_variable,
 107         .set = opal_set_variable,
 108 };
 109
 110 static int opal_secvar_probe(struct platform_device *pdev)
 111 {
 112         if (!opal_check_token(OPAL_SECVAR_GET)
 113                         || !opal_check_token(OPAL_SECVAR_GET_NEXT)
 114                         || !opal_check_token(OPAL_SECVAR_ENQUEUE_UPDATE)) {
 115                 pr_err("OPAL doesn't support secure variables\n");
 116                 return -ENODEV;
 117         }
 118
 119         set_secvar_ops(&opal_secvar_ops);
 120
 121         return 0;
 122 }
 123
 124 static const struct of_device_id opal_secvar_match[] = {
 125         { .compatible = "ibm,secvar-backend",},
 126         {},
 127 };
 128
 129 static struct platform_driver opal_secvar_driver = {
 130         .driver = {
 131                 .name = "secvar",
 132                 .of_match_table = opal_secvar_match,
 133         },
 134 };
 135
 136 static int __init opal_secvar_init(void)
 137 {
 138         return platform_driver_probe(&opal_secvar_driver, opal_secvar_probe);
 139 }
 140 device_initcall(opal_secvar_init);