@@ -1252,6 +1252,71 @@ int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
}
EXPORT_SYMBOL_GPL(qcom_scm_ice_set_key);
+/**
+ * qcom_scm_derive_sw_secret() - Derive software secret from wrapped key
+ * @wkey: the hardware wrapped key inaccessible to software
+ * @wkey_size: size of the wrapped key
+ * @sw_secret: the secret to be derived which is exactly the secret size
+ * @sw_secret_size: size of the sw_secret
+ *
+ * Derive a software secret from a hardware wrapped key for software crypto
+ * operations.
+ * For wrapped keys, the key needs to be unwrapped, in order to derive a
+ * software secret, which can be done in the hardware from a secure execution
+ * environment.
+ *
+ * For more information on sw secret, please refer to "Hardware-wrapped keys"
+ * section of Documentation/block/inline-encryption.rst.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int qcom_scm_derive_sw_secret(const u8 *wkey, size_t wkey_size,
+ u8 *sw_secret, size_t sw_secret_size)
+{
+ struct qcom_scm_desc desc = {
+ .svc = QCOM_SCM_SVC_ES,
+ .cmd = QCOM_SCM_ES_DERIVE_SW_SECRET,
+ .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RW,
+ QCOM_SCM_VAL, QCOM_SCM_RW,
+ QCOM_SCM_VAL),
+ .args[1] = wkey_size,
+ .args[3] = sw_secret_size,
+ .owner = ARM_SMCCC_OWNER_SIP,
+ };
+
+ int ret;
+
+ void *wkey_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ wkey_size,
+ GFP_KERNEL);
+ if (!wkey_buf)
+ return -ENOMEM;
+
+ void *secret_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ sw_secret_size,
+ GFP_KERNEL);
+ if (!secret_buf) {
+ ret = -ENOMEM;
+ goto out_free_wrapped;
+ }
+
+ memcpy(wkey_buf, wkey, wkey_size);
+ desc.args[0] = qcom_tzmem_to_phys(wkey_buf);
+ desc.args[2] = qcom_tzmem_to_phys(secret_buf);
+
+ ret = qcom_scm_call(__scm->dev, &desc, NULL);
+ if (!ret)
+ memcpy(sw_secret, secret_buf, sw_secret_size);
+
+ memzero_explicit(secret_buf, sw_secret_size);
+
+out_free_wrapped:
+ memzero_explicit(wkey_buf, wkey_size);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_scm_derive_sw_secret);
+
/**
* qcom_scm_hdcp_available() - Check if secure environment supports HDCP.
*
@@ -127,6 +127,7 @@ struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void);
#define QCOM_SCM_SVC_ES 0x10 /* Enterprise Security */
#define QCOM_SCM_ES_INVALIDATE_ICE_KEY 0x03
#define QCOM_SCM_ES_CONFIG_SET_ICE_KEY 0x04
+#define QCOM_SCM_ES_DERIVE_SW_SECRET 0x07
#define QCOM_SCM_SVC_HDCP 0x11
#define QCOM_SCM_HDCP_INVOKE 0x01
@@ -103,6 +103,8 @@ bool qcom_scm_ice_available(void);
int qcom_scm_ice_invalidate_key(u32 index);
int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
enum qcom_scm_ice_cipher cipher, u32 data_unit_size);
+int qcom_scm_derive_sw_secret(const u8 *wkey, size_t wkey_size,
+ u8 *sw_secret, size_t sw_secret_size);
bool qcom_scm_hdcp_available(void);
int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp);