[PATCH v6 5/9] scsi: ufs: UFS crypto API

Satya Tangirala
2019-12-18T14:52:36Z

Introduce functions to manipulate UFS inline encryption hardware
in line with the JEDEC UFSHCI v2.1 specification and to work with the
block keyslot manager.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
drivers/scsi/ufs/Kconfig | 9 +
drivers/scsi/ufs/Makefile | 1 +
drivers/scsi/ufs/ufshcd-crypto.c | 361 +++++++++++++++++++++++++++++++
drivers/scsi/ufs/ufshcd-crypto.h | 86 ++++++++
drivers/scsi/ufs/ufshcd.h | 12 +
5 files changed, 469 insertions(+)
create mode 100644 drivers/scsi/ufs/ufshcd-crypto.c
create mode 100644 drivers/scsi/ufs/ufshcd-crypto.h

diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
index d14c2243e02a..c69f1b49167b 100644
--- a/drivers/scsi/ufs/Kconfig
+++ b/drivers/scsi/ufs/Kconfig
@@ -160,3 +160,12 @@ config SCSI_UFS_BSG

Select this if you need a bsg device node for your UFS controller.
If unsure, say N.
+
+config SCSI_UFS_CRYPTO
+ bool "UFS Crypto Engine Support"
+ depends on SCSI_UFSHCD && BLK_INLINE_ENCRYPTION
+ help
+ Enable Crypto Engine Support in UFS.
+ Enabling this makes it possible for the kernel to use the crypto
+ capabilities of the UFS device (if present) to perform crypto
+ operations on data being transferred to/from the device.
diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
index 94c6c5d7334b..e88cdcde83fd 100644
--- a/drivers/scsi/ufs/Makefile
+++ b/drivers/scsi/ufs/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
obj-$(CONFIG_SCSI_UFS_HISI) += ufs-hisi.o
obj-$(CONFIG_SCSI_UFS_MEDIATEK) += ufs-mediatek.o
obj-$(CONFIG_SCSI_UFS_TI_J721E) += ti-j721e-ufs.o
+ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
diff --git a/drivers/scsi/ufs/ufshcd-crypto.c b/drivers/scsi/ufs/ufshcd-crypto.c
new file mode 100644
index 000000000000..b0aa072d9009
--- /dev/null
+++ b/drivers/scsi/ufs/ufshcd-crypto.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <linux/keyslot-manager.h>
+#include "ufshcd.h"
+#include "ufshcd-crypto.h"
+
+static bool ufshcd_cap_idx_valid(struct ufs_hba *hba, unsigned int cap_idx)
+{
+ return cap_idx < hba->crypto_capabilities.num_crypto_cap;
+}
+
+static u8 get_data_unit_size_mask(unsigned int data_unit_size)
+{
+ if (data_unit_size < 512 || data_unit_size > 65536 ||
+ !is_power_of_2(data_unit_size))
+ return 0;
+
+ return data_unit_size / 512;
+}
+
+static size_t get_keysize_bytes(enum ufs_crypto_key_size size)
+{
+ switch (size) {
+ case UFS_CRYPTO_KEY_SIZE_128:
+ return 16;
+ case UFS_CRYPTO_KEY_SIZE_192:
+ return 24;
+ case UFS_CRYPTO_KEY_SIZE_256:
+ return 32;
+ case UFS_CRYPTO_KEY_SIZE_512:
+ return 64;
+ default:
+ return 0;
+ }
+}
+
+static int ufshcd_crypto_cap_find(struct ufs_hba *hba,
+ enum blk_crypto_mode_num crypto_mode,
+ unsigned int data_unit_size)
+{
+ enum ufs_crypto_alg ufs_alg;
+ u8 data_unit_mask;
+ int cap_idx;
+ enum ufs_crypto_key_size ufs_key_size;
+ union ufs_crypto_cap_entry *ccap_array = hba->crypto_cap_array;
+
+ if (!ufshcd_hba_is_crypto_supported(hba))
+ return -EINVAL;
+
+ switch (crypto_mode) {
+ case BLK_ENCRYPTION_MODE_AES_256_XTS:
+ ufs_alg = UFS_CRYPTO_ALG_AES_XTS;
+ ufs_key_size = UFS_CRYPTO_KEY_SIZE_256;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ data_unit_mask = get_data_unit_size_mask(data_unit_size);
+
+ for (cap_idx = 0; cap_idx < hba->crypto_capabilities.num_crypto_cap;
+ cap_idx++) {
+ if (ccap_array[cap_idx].algorithm_id == ufs_alg &&
+ (ccap_array[cap_idx].sdus_mask & data_unit_mask) &&
+ ccap_array[cap_idx].key_size == ufs_key_size)
+ return cap_idx;
+ }
+
+ return -EINVAL;
+}
+
+/**
+ * ufshcd_crypto_cfg_entry_write_key - Write a key into a crypto_cfg_entry
+ *
+ * Writes the key with the appropriate format - for AES_XTS,
+ * the first half of the key is copied as is, the second half is
+ * copied with an offset halfway into the cfg->crypto_key array.
+ * For the other supported crypto algs, the key is just copied.
+ *
+ * @cfg: The crypto config to write to
+ * @key: The key to write
+ * @cap: The crypto capability (which specifies the crypto alg and key size)
+ *
+ * Returns 0 on success, or -EINVAL
+ */
+static int ufshcd_crypto_cfg_entry_write_key(union ufs_crypto_cfg_entry *cfg,
+ const u8 *key,
+ union ufs_crypto_cap_entry cap)
+{
+ size_t key_size_bytes = get_keysize_bytes(cap.key_size);
+
+ if (key_size_bytes == 0)
+ return -EINVAL;
+
+ switch (cap.algorithm_id) {
+ case UFS_CRYPTO_ALG_AES_XTS:
+ key_size_bytes *= 2;
+ if (key_size_bytes > UFS_CRYPTO_KEY_MAX_SIZE)
+ return -EINVAL;
+
+ memcpy(cfg->crypto_key, key, key_size_bytes/2);
+ memcpy(cfg->crypto_key + UFS_CRYPTO_KEY_MAX_SIZE/2,
+ key + key_size_bytes/2, key_size_bytes/2);
+ return 0;
+ case UFS_CRYPTO_ALG_BITLOCKER_AES_CBC:
+ /* fall through */
+ case UFS_CRYPTO_ALG_AES_ECB:
+ /* fall through */
+ case UFS_CRYPTO_ALG_ESSIV_AES_CBC:
+ memcpy(cfg->crypto_key, key, key_size_bytes);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static void ufshcd_program_key(struct ufs_hba *hba,
+ const union ufs_crypto_cfg_entry *cfg,
+ int slot)
+{
+ int i;
+ u32 slot_offset = hba->crypto_cfg_register + slot * sizeof(*cfg);
+
+ pm_runtime_get_sync(hba->dev);
+ ufshcd_hold(hba, false);
+ /* Clear the dword 16 */
+ ufshcd_writel(hba, 0, slot_offset + 16 * sizeof(cfg->reg_val[0]));
+ /* Ensure that CFGE is cleared before programming the key */
+ wmb();
+ for (i = 0; i < 16; i++) {
+ ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[i]),
+ slot_offset + i * sizeof(cfg->reg_val[0]));
+ /* Spec says each dword in key must be written sequentially */
+ wmb();
+ }
+ /* Write dword 17 */
+ ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[17]),
+ slot_offset + 17 * sizeof(cfg->reg_val[0]));
+ /* Dword 16 must be written last */
+ wmb();
+ /* Write dword 16 */
+ ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[16]),
+ slot_offset + 16 * sizeof(cfg->reg_val[0]));
+ wmb();
+ ufshcd_release(hba);
+ pm_runtime_put_sync(hba->dev);
+}
+
+static void ufshcd_clear_keyslot(struct ufs_hba *hba, int slot)
+{
+ union ufs_crypto_cfg_entry cfg = { 0 };
+
+ ufshcd_program_key(hba, &cfg, slot);
+}
+
+/* Clear all keyslots at driver init time */
+static void ufshcd_clear_all_keyslots(struct ufs_hba *hba)
+{
+ int slot;
+
+ for (slot = 0; slot < ufshcd_num_keyslots(hba); slot++)
+ ufshcd_clear_keyslot(hba, slot);
+}
+
+static int ufshcd_crypto_keyslot_program(struct keyslot_manager *ksm,
+ const struct blk_crypto_key *key,
+ unsigned int slot)
+{
+ struct ufs_hba *hba = keyslot_manager_private(ksm);
+ int err = 0;
+ u8 data_unit_mask;
+ union ufs_crypto_cfg_entry cfg;
+ int cap_idx;
+
+ cap_idx = ufshcd_crypto_cap_find(hba, key->crypto_mode,
+ key->data_unit_size);
+
+ if (!ufshcd_is_crypto_enabled(hba) ||
+ !ufshcd_keyslot_valid(hba, slot) ||
+ !ufshcd_cap_idx_valid(hba, cap_idx))
+ return -EINVAL;
+
+ data_unit_mask = get_data_unit_size_mask(key->data_unit_size);
+
+ if (!(data_unit_mask & hba->crypto_cap_array[cap_idx].sdus_mask))
+ return -EINVAL;
+
+ memset(&cfg, 0, sizeof(cfg));
+ cfg.data_unit_size = data_unit_mask;
+ cfg.crypto_cap_idx = cap_idx;
+ cfg.config_enable |= UFS_CRYPTO_CONFIGURATION_ENABLE;
+
+ err = ufshcd_crypto_cfg_entry_write_key(&cfg, key->raw,
+ hba->crypto_cap_array[cap_idx]);
+ if (err)
+ return err;
+
+ ufshcd_program_key(hba, &cfg, slot);
+
+ memzero_explicit(&cfg, sizeof(cfg));
+ return 0;
+}
+
+static int ufshcd_crypto_keyslot_evict(struct keyslot_manager *ksm,
+ const struct blk_crypto_key *key,
+ unsigned int slot)
+{
+ struct ufs_hba *hba = keyslot_manager_private(ksm);
+
+ if (!ufshcd_is_crypto_enabled(hba) ||
+ !ufshcd_keyslot_valid(hba, slot))
+ return -EINVAL;
+
+ /*
+ * Clear the crypto cfg on the device. Clearing CFGE
+ * might not be sufficient, so just clear the entire cfg.
+ */
+ ufshcd_clear_keyslot(hba, slot);
+
+ return 0;
+}
+
+/* Functions implementing UFSHCI v2.1 specification behaviour */
+void ufshcd_crypto_enable(struct ufs_hba *hba)
+{
+ if (!ufshcd_hba_is_crypto_supported(hba))
+ return;
+
+ hba->caps |= UFSHCD_CAP_CRYPTO;
+
+ /* Reset might clear all keys, so reprogram all the keys. */
+ keyslot_manager_reprogram_all_keys(hba->ksm);
+}
+EXPORT_SYMBOL_GPL(ufshcd_crypto_enable);
+
+void ufshcd_crypto_disable(struct ufs_hba *hba)
+{
+ hba->caps &= ~UFSHCD_CAP_CRYPTO;
+}
+EXPORT_SYMBOL_GPL(ufshcd_crypto_disable);
+
+static const struct keyslot_mgmt_ll_ops ufshcd_ksm_ops = {
+ .keyslot_program = ufshcd_crypto_keyslot_program,
+ .keyslot_evict = ufshcd_crypto_keyslot_evict,
+};
+
+enum blk_crypto_mode_num ufshcd_blk_crypto_mode_num_for_alg_dusize(
+ enum ufs_crypto_alg ufs_crypto_alg,
+ enum ufs_crypto_key_size key_size)
+{
+ /*
+ * This is currently the only mode that UFS and blk-crypto both support.
+ */
+ if (ufs_crypto_alg == UFS_CRYPTO_ALG_AES_XTS &&
+ key_size == UFS_CRYPTO_KEY_SIZE_256)
+ return BLK_ENCRYPTION_MODE_AES_256_XTS;
+
+ return BLK_ENCRYPTION_MODE_INVALID;
+}
+
+/**
+ * ufshcd_hba_init_crypto - Read crypto capabilities, init crypto fields in hba
+ * @hba: Per adapter instance
+ *
+ * Return: 0 if crypto was initialized or is not supported, else a -errno value.
+ */
+int ufshcd_hba_init_crypto(struct ufs_hba *hba)
+{
+ int cap_idx = 0;
+ int err = 0;
+ unsigned int crypto_modes_supported[BLK_ENCRYPTION_MODE_MAX];
+ enum blk_crypto_mode_num blk_mode_num;
+
+ /* Default to disabling crypto */
+ hba->caps &= ~UFSHCD_CAP_CRYPTO;
+
+ /* Return 0 if crypto support isn't present */
+ if (!(hba->capabilities & MASK_CRYPTO_SUPPORT))
+ goto out;
+
+ /*
+ * Crypto Capabilities should never be 0, because the
+ * config_array_ptr > 04h. So we use a 0 value to indicate that
+ * crypto init failed, and can't be enabled.
+ */
+ hba->crypto_capabilities.reg_val =
+ cpu_to_le32(ufshcd_readl(hba, REG_UFS_CCAP));
+ hba->crypto_cfg_register =
+ (u32)hba->crypto_capabilities.config_array_ptr * 0x100;
+ hba->crypto_cap_array =
+ devm_kcalloc(hba->dev,
+ hba->crypto_capabilities.num_crypto_cap,
+ sizeof(hba->crypto_cap_array[0]),
+ GFP_KERNEL);
+ if (!hba->crypto_cap_array) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ memset(crypto_modes_supported, 0, sizeof(crypto_modes_supported));
+ /*
+ * Store all the capabilities now so that we don't need to repeatedly
+ * access the device each time we want to know its capabilities
+ */
+ for (cap_idx = 0; cap_idx < hba->crypto_capabilities.num_crypto_cap;
+ cap_idx++) {
+ hba->crypto_cap_array[cap_idx].reg_val =
+ cpu_to_le32(ufshcd_readl(hba,
+ REG_UFS_CRYPTOCAP +
+ cap_idx * sizeof(__le32)));
+ blk_mode_num = ufshcd_blk_crypto_mode_num_for_alg_dusize(
+ hba->crypto_cap_array[cap_idx].algorithm_id,
+ hba->crypto_cap_array[cap_idx].key_size);
+ if (blk_mode_num == BLK_ENCRYPTION_MODE_INVALID)
+ continue;
+ crypto_modes_supported[blk_mode_num] |=
+ hba->crypto_cap_array[cap_idx].sdus_mask * 512;
+ }
+
+ ufshcd_clear_all_keyslots(hba);
+
+ hba->ksm = keyslot_manager_create(ufshcd_num_keyslots(hba),
+ &ufshcd_ksm_ops,
+ crypto_modes_supported, hba);
+
+ if (!hba->ksm) {
+ err = -ENOMEM;
+ goto out_free_caps;
+ }
+
+ return 0;
+
+out_free_caps:
+ devm_kfree(hba->dev, hba->crypto_cap_array);
+out:
+ /* Indicate that init failed by setting crypto_capabilities to 0 */
+ hba->crypto_capabilities.reg_val = 0;
+ return err;
+}
+EXPORT_SYMBOL_GPL(ufshcd_hba_init_crypto);
+
+void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
+ struct request_queue *q)
+{
+ if (!ufshcd_hba_is_crypto_supported(hba) || !q)
+ return;
+
+ q->ksm = hba->ksm;
+}
+EXPORT_SYMBOL_GPL(ufshcd_crypto_setup_rq_keyslot_manager);
+
+void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
+ struct request_queue *q)
+{
+ keyslot_manager_destroy(hba->ksm);
+}
+EXPORT_SYMBOL_GPL(ufshcd_crypto_destroy_rq_keyslot_manager);
+
diff --git a/drivers/scsi/ufs/ufshcd-crypto.h b/drivers/scsi/ufs/ufshcd-crypto.h
new file mode 100644
index 000000000000..61996c6520e9
--- /dev/null
+++ b/drivers/scsi/ufs/ufshcd-crypto.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef _UFSHCD_CRYPTO_H
+#define _UFSHCD_CRYPTO_H
+
+#ifdef CONFIG_SCSI_UFS_CRYPTO
+#include <linux/keyslot-manager.h>
+#include "ufshcd.h"
+#include "ufshci.h"
+
+static inline int ufshcd_num_keyslots(struct ufs_hba *hba)
+{
+ return hba->crypto_capabilities.config_count + 1;
+}
+
+static inline bool ufshcd_keyslot_valid(struct ufs_hba *hba, unsigned int slot)
+{
+ /*
+ * The actual number of configurations supported is (CFGC+1), so slot
+ * numbers range from 0 to config_count inclusive.
+ */
+ return slot < ufshcd_num_keyslots(hba);
+}
+
+static inline bool ufshcd_hba_is_crypto_supported(struct ufs_hba *hba)
+{
+ return hba->crypto_capabilities.reg_val != 0;
+}
+
+static inline bool ufshcd_is_crypto_enabled(struct ufs_hba *hba)
+{
+ return hba->caps & UFSHCD_CAP_CRYPTO;
+}
+
+/* Functions implementing UFSHCI v2.1 specification behaviour */
+void ufshcd_crypto_enable(struct ufs_hba *hba);
+
+void ufshcd_crypto_disable(struct ufs_hba *hba);
+
+int ufshcd_hba_init_crypto(struct ufs_hba *hba);
+
+void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
+ struct request_queue *q);
+
+void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
+ struct request_queue *q);
+
+#else /* CONFIG_SCSI_UFS_CRYPTO */
+
+static inline bool ufshcd_keyslot_valid(struct ufs_hba *hba,
+ unsigned int slot)
+{
+ return false;
+}
+
+static inline bool ufshcd_hba_is_crypto_supported(struct ufs_hba *hba)
+{
+ return false;
+}
+
+static inline bool ufshcd_is_crypto_enabled(struct ufs_hba *hba)
+{
+ return false;
+}
+
+static inline void ufshcd_crypto_enable(struct ufs_hba *hba) { }
+
+static inline void ufshcd_crypto_disable(struct ufs_hba *hba) { }
+
+static inline int ufshcd_hba_init_crypto(struct ufs_hba *hba)
+{
+ return 0;
+}
+
+static inline void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
+ struct request_queue *q) { }
+
+static inline void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
+ struct request_queue *q) { }
+
+#endif /* CONFIG_SCSI_UFS_CRYPTO */
+
+#endif /* _UFSHCD_CRYPTO_H */
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index dbb581244bdb..6c8e2d04e9f8 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -525,6 +525,10 @@ struct ufs_stats {
* @is_urgent_bkops_lvl_checked: keeps track if the urgent bkops level for
* device is known or not.
* @scsi_block_reqs_cnt: reference counting for scsi block requests
+ * @crypto_capabilities: Content of crypto capabilities register (0x100)
+ * @crypto_cap_array: Array of crypto capabilities
+ * @crypto_cfg_register: Start of the crypto cfg array
+ * @ksm: the keyslot manager tied to this hba
*/
struct ufs_hba {
void __iomem *mmio_base;
@@ -741,6 +745,14 @@ struct ufs_hba {

struct device bsg_dev;
struct request_queue *bsg_queue;
+
+#ifdef CONFIG_SCSI_UFS_CRYPTO
+ /* crypto */
+ union ufs_crypto_capabilities crypto_capabilities;
+ union ufs_crypto_cap_entry *crypto_cap_array;
+ u32 crypto_cfg_register;
+ struct keyslot_manager *ksm;
+#endif /* CONFIG_SCSI_UFS_CRYPTO */
};

/* Returns true if clocks can be gated. Otherwise false */
--
2.24.1.735.g03f4e72817-goog