[RFC PATCH 1/5] firmware: qcom_scm: Add support for programming inline crypto keys

Eric Biggers
2020-01-10T06:18:29Z

Add support for the Inline Crypto Engine (ICE) key programming interface
that's needed for the ufs-qcom driver to use inline encryption on
Snapdragon SoCs. This interface consists of two SMC calls: one to
program a key into a keyslot, and one to invalidate a keyslot.

Although the UFS specification defines a standard way to do this, on
these SoCs the Linux kernel isn't permitted to access the needed crypto
configuration registers directly; these SMC calls must be used instead.

For now I only wired up the 64-bit versions of these calls, as it's all
I'm able to test right now.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
drivers/firmware/qcom_scm-32.c | 14 ++++++
drivers/firmware/qcom_scm-64.c | 31 ++++++++++++++
drivers/firmware/qcom_scm.c | 78 ++++++++++++++++++++++++++++++++++
drivers/firmware/qcom_scm.h | 9 ++++
include/linux/qcom_scm.h | 17 ++++++++
5 files changed, 149 insertions(+)

diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
index 48e2ef794ea3c..95f2b59223fb8 100644
--- a/drivers/firmware/qcom_scm-32.c
+++ b/drivers/firmware/qcom_scm-32.c
@@ -583,6 +583,20 @@ int __qcom_scm_pas_mss_reset(struct device *dev, bool reset)
return ret ? : le32_to_cpu(out);
}

+int __qcom_scm_ice_set_key(struct device *dev, u32 index, dma_addr_t key_phys,
+ int key_size, enum qcom_scm_ice_cipher_mode mode,
+ int data_unit_size)
+{
+ /* Untested on 32-bit, so disabled for now. */
+ return -ENODEV;
+}
+
+int __qcom_scm_ice_invalidate_key(struct device *dev, u32 index)
+{
+ /* Untested on 32-bit, so disabled for now. */
+ return -ENODEV;
+}
+
int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
{
return qcom_scm_call_atomic2(QCOM_SCM_SVC_BOOT, QCOM_SCM_SET_DLOAD_MODE,
diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c
index 3c5850350974d..41d67667556f1 100644
--- a/drivers/firmware/qcom_scm-64.c
+++ b/drivers/firmware/qcom_scm-64.c
@@ -420,6 +420,37 @@ int __qcom_scm_pas_mss_reset(struct device *dev, bool reset)
return ret ? : res.a1;
}

+int __qcom_scm_ice_set_key(struct device *dev, u32 index, dma_addr_t key_phys,
+ int key_size, enum qcom_scm_ice_cipher_mode mode,
+ int data_unit_size)
+{
+ struct qcom_scm_desc desc = {0};
+ struct arm_smccc_res res;
+
+ desc.args[0] = index;
+ desc.args[1] = key_phys;
+ desc.args[2] = key_size;
+ desc.args[3] = mode;
+ desc.args[4] = data_unit_size;
+ desc.arginfo = QCOM_SCM_ARGS(5, QCOM_SCM_VAL, QCOM_SCM_RW, QCOM_SCM_VAL,
+ QCOM_SCM_VAL, QCOM_SCM_VAL);
+
+ return qcom_scm_call(dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_CONFIG_SET_ICE_KEY, &desc, &res);
+}
+
+int __qcom_scm_ice_invalidate_key(struct device *dev, u32 index)
+{
+ struct qcom_scm_desc desc = {0};
+ struct arm_smccc_res res;
+
+ desc.args[0] = index;
+ desc.arginfo = QCOM_SCM_ARGS(1);
+
+ return qcom_scm_call(dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_INVALIDATE_ICE_KEY, &desc, &res);
+}
+
int __qcom_scm_set_remote_state(struct device *dev, u32 state, u32 id)
{
struct qcom_scm_desc desc = {0};
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 1ba0df4b97aba..a37d3f69448a8 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -12,6 +12,7 @@
#include <linux/dma-direct.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
+#include <linux/slab.h>
#include <linux/types.h>
#include <linux/qcom_scm.h>
#include <linux/of.h>
@@ -344,6 +345,83 @@ int qcom_scm_pas_shutdown(u32 peripheral)
}
EXPORT_SYMBOL(qcom_scm_pas_shutdown);

+/**
+ * qcom_scm_ice_available() - Is the ICE key programming interface available?
+ *
+ * Return: true iff the SCM calls wrapped by qcom_scm_ice_set_key() and
+ * qcom_scm_ice_invalidate_key() are available.
+ */
+bool qcom_scm_ice_available(void)
+{
+ if (IS_ENABLED(CONFIG_ARM)) /* Not implemented/tested on 32-bit yet. */
+ return false;
+ return __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_CONFIG_SET_ICE_KEY) &&
+ __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_INVALIDATE_ICE_KEY);
+}
+EXPORT_SYMBOL(qcom_scm_ice_available);
+
+/**
+ * qcom_scm_ice_set_key() - Set an inline encryption key
+ * @index: the keyslot into which to set the key
+ * @key: the key to program
+ * @key_size: the size of the key in bytes
+ * @mode: the encryption algorithm the key is for
+ * @data_unit_size: the encryption data unit size, i.e. the size of each
+ * individual plaintext and ciphertext. Given in 512-byte
+ * units, e.g. 1 = 512 bytes, 8 = 4096 bytes, etc.
+ *
+ * Program a key into a keyslot of Qualcomm ICE (Inline Cryptographic Engine),
+ * where it can then be used to encrypt/decrypt UFS I/O requests inline.
+ *
+ * The UFSHCI standard defines a standard way to do this, but it doesn't work on
+ * these SoCs; only these SCM calls do...
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int qcom_scm_ice_set_key(u32 index, const u8 *key, int key_size,
+ enum qcom_scm_ice_cipher_mode mode, int data_unit_size)
+{
+ u8 *keybuf;
+ dma_addr_t key_phys;
+ int err;
+
+ keybuf = kmemdup(key, key_size, GFP_KERNEL);
+ if (!keybuf)
+ return -ENOMEM;
+
+ key_phys = dma_map_single(__scm->dev, keybuf, key_size, DMA_TO_DEVICE);
+ if (dma_mapping_error(__scm->dev, key_phys)) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ err = __qcom_scm_ice_set_key(__scm->dev, index, key_phys, key_size,
+ mode, data_unit_size);
+
+ dma_unmap_single(__scm->dev, key_phys, key_size, DMA_TO_DEVICE);
+out:
+ kzfree(keybuf);
+ return err;
+}
+EXPORT_SYMBOL(qcom_scm_ice_set_key);
+
+/**
+ * qcom_scm_ice_invalidate_key() - Invalidate an inline encryption key
+ * @index: the keyslot to invalidate
+ *
+ * The UFSHCI standard defines a standard way to do this, but it doesn't work on
+ * these SoCs; only these SCM calls do...
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int qcom_scm_ice_invalidate_key(u32 index)
+{
+ return __qcom_scm_ice_invalidate_key(__scm->dev, index);
+}
+EXPORT_SYMBOL(qcom_scm_ice_invalidate_key);
+
static int qcom_scm_pas_reset_assert(struct reset_controller_dev *rcdev,
unsigned long idx)
{
diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
index 81dcf5f1138e7..28bfec9c11f86 100644
--- a/drivers/firmware/qcom_scm.h
+++ b/drivers/firmware/qcom_scm.h
@@ -67,6 +67,15 @@ extern int __qcom_scm_pas_auth_and_reset(struct device *dev, u32 peripheral);
extern int __qcom_scm_pas_shutdown(struct device *dev, u32 peripheral);
extern int __qcom_scm_pas_mss_reset(struct device *dev, bool reset);

+#define QCOM_SCM_SVC_ES 0x10 /* Enterprise Security */
+#define QCOM_SCM_ES_CONFIG_SET_ICE_KEY 0x04
+#define QCOM_SCM_ES_INVALIDATE_ICE_KEY 0x03
+extern int __qcom_scm_ice_set_key(struct device *dev, u32 index,
+ dma_addr_t key_phys, int key_size,
+ enum qcom_scm_ice_cipher_mode mode,
+ int data_unit_size);
+extern int __qcom_scm_ice_invalidate_key(struct device *dev, u32 index);
+
/* common error codes */
#define QCOM_SCM_V2_EBUSY -12
#define QCOM_SCM_ENOMEM -5
diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
index d05ddac9a57e8..0f56801ac6e14 100644
--- a/include/linux/qcom_scm.h
+++ b/include/linux/qcom_scm.h
@@ -44,6 +44,13 @@ enum qcom_scm_sec_dev_id {
QCOM_SCM_ICE_DEV_ID = 20,
};

+enum qcom_scm_ice_cipher_mode {
+ QCOM_SCM_ICE_CIPHER_MODE_XTS_128 = 0,
+ QCOM_SCM_ICE_CIPHER_MODE_CBC_128 = 1,
+ QCOM_SCM_ICE_CIPHER_MODE_XTS_256 = 3,
+ QCOM_SCM_ICE_CIPHER_MODE_CBC_256 = 4,
+};
+
#define QCOM_SCM_VMID_HLOS 0x3
#define QCOM_SCM_VMID_MSS_MSA 0xF
#define QCOM_SCM_VMID_WLAN 0x18
@@ -73,6 +80,11 @@ extern int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr,
phys_addr_t size);
extern int qcom_scm_pas_auth_and_reset(u32 peripheral);
extern int qcom_scm_pas_shutdown(u32 peripheral);
+extern bool qcom_scm_ice_available(void);
+extern int qcom_scm_ice_set_key(u32 index, const u8 *key, int key_size,
+ enum qcom_scm_ice_cipher_mode mode,
+ int data_unit_size);
+extern int qcom_scm_ice_invalidate_key(u32 index);
extern int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
unsigned int *src,
const struct qcom_scm_vmperm *newvm,
@@ -113,6 +125,11 @@ static inline int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr,
static inline int
qcom_scm_pas_auth_and_reset(u32 peripheral) { return -ENODEV; }
static inline int qcom_scm_pas_shutdown(u32 peripheral) { return -ENODEV; }
+static inline bool qcom_scm_ice_available(void) { return false; }
+static inline int qcom_scm_ice_set_key(u32 index, const u8 *key, int key_size,
+ enum qcom_scm_ice_cipher_mode mode,
+ int data_unit_size) { return -ENODEV; }
+static inline int qcom_scm_ice_invalidate_key(u32 index) { return -ENODEV; }
static inline int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
unsigned int *src,
const struct qcom_scm_vmperm *newvm,
--
2.24.1