174 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright 2021 Google LLC4 *5 * sysfs support for blk-crypto. This file contains the code which exports the6 * crypto capabilities of devices via /sys/block/$disk/queue/crypto/.7 */8 9#include <linux/blk-crypto-profile.h>10 11#include "blk-crypto-internal.h"12 13struct blk_crypto_kobj {14 struct kobject kobj;15 struct blk_crypto_profile *profile;16};17 18struct blk_crypto_attr {19 struct attribute attr;20 ssize_t (*show)(struct blk_crypto_profile *profile,21 struct blk_crypto_attr *attr, char *page);22};23 24static struct blk_crypto_profile *kobj_to_crypto_profile(struct kobject *kobj)25{26 return container_of(kobj, struct blk_crypto_kobj, kobj)->profile;27}28 29static struct blk_crypto_attr *attr_to_crypto_attr(struct attribute *attr)30{31 return container_of(attr, struct blk_crypto_attr, attr);32}33 34static ssize_t max_dun_bits_show(struct blk_crypto_profile *profile,35 struct blk_crypto_attr *attr, char *page)36{37 return sysfs_emit(page, "%u\n", 8 * profile->max_dun_bytes_supported);38}39 40static ssize_t num_keyslots_show(struct blk_crypto_profile *profile,41 struct blk_crypto_attr *attr, char *page)42{43 return sysfs_emit(page, "%u\n", profile->num_slots);44}45 46#define BLK_CRYPTO_RO_ATTR(_name) \47 static struct blk_crypto_attr _name##_attr = __ATTR_RO(_name)48 49BLK_CRYPTO_RO_ATTR(max_dun_bits);50BLK_CRYPTO_RO_ATTR(num_keyslots);51 52static struct attribute *blk_crypto_attrs[] = {53 &max_dun_bits_attr.attr,54 &num_keyslots_attr.attr,55 NULL,56};57 58static const struct attribute_group blk_crypto_attr_group = {59 .attrs = blk_crypto_attrs,60};61 62/*63 * The encryption mode attributes. To avoid hard-coding the list of encryption64 * modes, these are initialized at boot time by blk_crypto_sysfs_init().65 */66static struct blk_crypto_attr __blk_crypto_mode_attrs[BLK_ENCRYPTION_MODE_MAX];67static struct attribute *blk_crypto_mode_attrs[BLK_ENCRYPTION_MODE_MAX + 1];68 69static umode_t blk_crypto_mode_is_visible(struct kobject *kobj,70 struct attribute *attr, int n)71{72 struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj);73 struct blk_crypto_attr *a = attr_to_crypto_attr(attr);74 int mode_num = a - __blk_crypto_mode_attrs;75 76 if (profile->modes_supported[mode_num])77 return 0444;78 return 0;79}80 81static ssize_t blk_crypto_mode_show(struct blk_crypto_profile *profile,82 struct blk_crypto_attr *attr, char *page)83{84 int mode_num = attr - __blk_crypto_mode_attrs;85 86 return sysfs_emit(page, "0x%x\n", profile->modes_supported[mode_num]);87}88 89static const struct attribute_group blk_crypto_modes_attr_group = {90 .name = "modes",91 .attrs = blk_crypto_mode_attrs,92 .is_visible = blk_crypto_mode_is_visible,93};94 95static const struct attribute_group *blk_crypto_attr_groups[] = {96 &blk_crypto_attr_group,97 &blk_crypto_modes_attr_group,98 NULL,99};100 101static ssize_t blk_crypto_attr_show(struct kobject *kobj,102 struct attribute *attr, char *page)103{104 struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj);105 struct blk_crypto_attr *a = attr_to_crypto_attr(attr);106 107 return a->show(profile, a, page);108}109 110static const struct sysfs_ops blk_crypto_attr_ops = {111 .show = blk_crypto_attr_show,112};113 114static void blk_crypto_release(struct kobject *kobj)115{116 kfree(container_of(kobj, struct blk_crypto_kobj, kobj));117}118 119static const struct kobj_type blk_crypto_ktype = {120 .default_groups = blk_crypto_attr_groups,121 .sysfs_ops = &blk_crypto_attr_ops,122 .release = blk_crypto_release,123};124 125/*126 * If the request_queue has a blk_crypto_profile, create the "crypto"127 * subdirectory in sysfs (/sys/block/$disk/queue/crypto/).128 */129int blk_crypto_sysfs_register(struct gendisk *disk)130{131 struct request_queue *q = disk->queue;132 struct blk_crypto_kobj *obj;133 int err;134 135 if (!q->crypto_profile)136 return 0;137 138 obj = kzalloc(sizeof(*obj), GFP_KERNEL);139 if (!obj)140 return -ENOMEM;141 obj->profile = q->crypto_profile;142 143 err = kobject_init_and_add(&obj->kobj, &blk_crypto_ktype,144 &disk->queue_kobj, "crypto");145 if (err) {146 kobject_put(&obj->kobj);147 return err;148 }149 q->crypto_kobject = &obj->kobj;150 return 0;151}152 153void blk_crypto_sysfs_unregister(struct gendisk *disk)154{155 kobject_put(disk->queue->crypto_kobject);156}157 158static int __init blk_crypto_sysfs_init(void)159{160 int i;161 162 BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0);163 for (i = 1; i < BLK_ENCRYPTION_MODE_MAX; i++) {164 struct blk_crypto_attr *attr = &__blk_crypto_mode_attrs[i];165 166 attr->attr.name = blk_crypto_modes[i].name;167 attr->attr.mode = 0444;168 attr->show = blk_crypto_mode_show;169 blk_crypto_mode_attrs[i - 1] = &attr->attr;170 }171 return 0;172}173subsys_initcall(blk_crypto_sysfs_init);174