feat(cros_widevine): add ChromeOS widevine SMC handler

The ChromeOS will use the SMC to pass some secrets from firmware to
optee.

Change-Id: Iaf3357d40a7ed22415926acd9d7979df24dd81f1
Signed-off-by: Yi Chou <yich@google.com>

bl31/bl31.mk

@@ -161,6 +161,10 @@ BL31_SOURCES		+=	services/std_svc/drtm/drtm_main.c		\
 				${MBEDTLS_SOURCES}
 endif
 
+ifeq ($(CROS_WIDEVINE_SMC),1)
+BL31_SOURCES		+=	services/oem/chromeos/widevine_smc_handlers.c
+endif
+
 BL31_DEFAULT_LINKER_SCRIPT_SOURCE := bl31/bl31.ld.S
 
 ifneq ($(findstring gcc,$(notdir $(LD))),)

include/services/oem/chromeos/widevine_smc_handlers.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2024, The ChromiumOS Authors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef CROS_WIDEVINE_SMC_HANDLERS_H
+#define CROS_WIDEVINE_SMC_HANDLERS_H
+
+#include <lib/smccc.h>
+
+/*******************************************************************************
+ * Defines for CrOS OEM Service queries
+ ******************************************************************************/
+
+/* 0xC300C050 - 0xC300C05F are CrOS OEM service calls */
+#define CROS_OEM_SMC_ID 0xC050
+#define CROS_OEM_SMC_CALL_ID(func_num)                                         \
+	((SMC_TYPE_FAST << FUNCID_TYPE_SHIFT) |                                \
+	 ((SMC_64) << FUNCID_CC_SHIFT) | (OEN_OEM_START << FUNCID_OEN_SHIFT) | \
+	 (CROS_OEM_SMC_ID) | ((func_num) & FUNCID_NUM_MASK))
+
+enum cros_drm_set {
+	CROS_DRM_SET_TPM_AUTH_PUB = 0U,
+	CROS_DRM_SET_HARDWARE_UNIQUE_KEY = 1U,
+	CROS_DRM_SET_ROOT_OF_TRUST = 2U,
+};
+
+/*******************************************************************************
+ * Defines for runtime services func ids
+ ******************************************************************************/
+
+/* Sets the TPM auth public key. The maximum size is 128 bytes.
+ * |x1| is the length of the data, |x2| is the physical address of the data.
+ */
+#define CROS_OEM_SMC_DRM_SET_TPM_AUTH_PUB_FUNC_ID \
+	CROS_OEM_SMC_CALL_ID(CROS_DRM_SET_TPM_AUTH_PUB)
+
+/* Sets the hardware unique key. The maximum size is 32 bytes.
+ * |x1| is the length of the data, |x2| is the physical address of the data.
+ */
+#define CROS_OEM_SMC_DRM_SET_HARDWARE_UNIQUE_KEY_FUNC_ID \
+	CROS_OEM_SMC_CALL_ID(CROS_DRM_SET_HARDWARE_UNIQUE_KEY)
+
+/* Sets the widevine root of trust. The maximum size is 32 bytes.
+ * |x1| is the length of the data, |x2| is the physical address of the data.
+ */
+#define CROS_OEM_SMC_DRM_SET_ROOT_OF_TRUST_FUNC_ID \
+	CROS_OEM_SMC_CALL_ID(CROS_DRM_SET_ROOT_OF_TRUST)
+
+#define is_cros_oem_smc(_call_id) (((_call_id) & 0xFFF0U) == CROS_OEM_SMC_ID)
+
+struct cros_oem_data {
+	uint8_t *buffer;
+	const uint32_t max_length;
+	uint32_t length;
+};
+
+extern struct cros_oem_data cros_oem_tpm_auth_pk;
+
+extern struct cros_oem_data cros_oem_huk;
+
+extern struct cros_oem_data cros_oem_rot;
+
+#endif /* CROS_WIDEVINE_SMC_HANDLERS_H */

services/oem/chromeos/widevine_smc_handlers.c

@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2024, The ChromiumOS Authors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <common/debug.h>
+#include <common/runtime_svc.h>
+#include <lib/psci/psci.h>
+#include <lib/xlat_tables/xlat_tables_v2.h>
+#include <services/oem/chromeos/widevine_smc_handlers.h>
+#include <tools_share/uuid.h>
+
+#define CROS_OEM_TPM_AUTH_PK_MAX_LEN 128
+#define CROS_OEM_HUK_LEN 32
+#define CROS_OEM_ROT_LEN 32
+
+static uint8_t cros_oem_tpm_auth_pk_buffer[CROS_OEM_TPM_AUTH_PK_MAX_LEN];
+static uint8_t cros_oem_huk_buffer[CROS_OEM_HUK_LEN];
+static uint8_t cros_oem_rot_len_buffer[CROS_OEM_ROT_LEN];
+
+struct cros_oem_data cros_oem_tpm_auth_pk = {
+	.buffer = cros_oem_tpm_auth_pk_buffer,
+	.max_length = sizeof(cros_oem_tpm_auth_pk_buffer),
+};
+
+struct cros_oem_data cros_oem_huk = {
+	.buffer = cros_oem_huk_buffer,
+	.max_length = sizeof(cros_oem_huk_buffer),
+};
+
+struct cros_oem_data cros_oem_rot = {
+	.buffer = cros_oem_rot_len_buffer,
+	.max_length = sizeof(cros_oem_rot_len_buffer),
+};
+
+static uintptr_t cros_write_data(struct cros_oem_data *data,
+				 u_register_t length, u_register_t address,
+				 void *handle)
+{
+	uintptr_t aligned_address;
+	uintptr_t aligned_size;
+	int32_t rc;
+
+	if (data->length) {
+		SMC_RET1(handle, PSCI_E_ALREADY_ON);
+	}
+
+	if (length > data->max_length) {
+		SMC_RET1(handle, PSCI_E_INVALID_PARAMS);
+	}
+
+	aligned_address = page_align(address, DOWN);
+	aligned_size = page_align(length + (address - aligned_address), UP);
+
+	/*
+	 * We do not validate the passed in address because we are trusting the
+	 * non-secure world at this point still.
+	 */
+	rc = mmap_add_dynamic_region(aligned_address, aligned_address,
+				     aligned_size, MT_MEMORY | MT_RO | MT_NS);
+	if (rc != 0) {
+		SMC_RET1(handle, PSCI_E_INVALID_ADDRESS);
+	}
+
+	memcpy(data->buffer, (void *)address, length);
+	data->length = length;
+
+	mmap_remove_dynamic_region(aligned_address, aligned_size);
+	SMC_RET1(handle, SMC_OK);
+}
+
+/* Handler for servicing specific SMC calls. */
+static uintptr_t cros_oem_svc_smc_handler(uint32_t smc_fid, u_register_t x1,
+					  u_register_t x2, u_register_t x3,
+					  u_register_t x4, void *cookie,
+					  void *handle, u_register_t flags)
+{
+	switch (smc_fid) {
+	case CROS_OEM_SMC_DRM_SET_TPM_AUTH_PUB_FUNC_ID:
+		return cros_write_data(&cros_oem_tpm_auth_pk, x1, x2, handle);
+	case CROS_OEM_SMC_DRM_SET_HARDWARE_UNIQUE_KEY_FUNC_ID:
+		return cros_write_data(&cros_oem_huk, x1, x2, handle);
+	case CROS_OEM_SMC_DRM_SET_ROOT_OF_TRUST_FUNC_ID:
+		return cros_write_data(&cros_oem_rot, x1, x2, handle);
+	default:
+		WARN("Unimplemented OEM Call: 0x%x\n", smc_fid);
+		SMC_RET1(handle, SMC_UNK);
+	}
+}
+
+/* Register OEM Service Calls as runtime service */
+DECLARE_RT_SVC(cros_oem_svc_smc_handler, OEN_OEM_START, OEN_OEM_END,
+	       SMC_TYPE_FAST, NULL, cros_oem_svc_smc_handler);

services/spd/opteed/opteed.mk

@@ -33,3 +33,11 @@ $(eval $(call add_define,PLAT_XLAT_TABLES_DYNAMIC))
 $(eval $(call add_define,OPTEE_ALLOW_SMC_LOAD))
 include lib/libfdt/libfdt.mk
 endif
+
+CROS_WIDEVINE_SMC		:=	0
+ifeq ($(CROS_WIDEVINE_SMC),1)
+ifeq ($(OPTEE_ALLOW_SMC_LOAD),0)
+$(error When CROS_WIDEVINE_SMC=1, OPTEE_ALLOW_SMC_LOAD must also be 1)
+endif
+$(eval $(call add_define,CROS_WIDEVINE_SMC))
+endif

services/spd/opteed/opteed_main.c

@@ -33,6 +33,7 @@
 #include <libfdt.h>
 #endif  /* OPTEE_ALLOW_SMC_LOAD */
 #include <plat/common/platform.h>
+#include <services/oem/chromeos/widevine_smc_handlers.h>
 #include <tools_share/uuid.h>
 
 #include "opteed_private.h"
@@ -61,7 +62,7 @@ DEFINE_SVC_UUID2(optee_image_load_uuid,
 	0xb1eafba3, 0x5d31, 0x4612, 0xb9, 0x06,
 	0xc4, 0xc7, 0xa4, 0xbe, 0x3c, 0xc0);
 
-#define OPTEED_FDT_SIZE 256
+#define OPTEED_FDT_SIZE 1024
 static uint8_t fdt_buf[OPTEED_FDT_SIZE] __aligned(CACHE_WRITEBACK_GRANULE);
 
 #else
@@ -299,6 +300,62 @@ static int add_coreboot_node(void *fdt)
 }
 #endif /* COREBOOT */
 
+#if CROS_WIDEVINE_SMC
+/*
+ * Adds a options/widevine node with the widevine table information to a device
+ * tree. Returns zero on success or if there is no widevine table information;
+ * failure code otherwise.
+ */
+static int add_options_widevine_node(void *fdt)
+{
+	int ret;
+
+	ret = fdt_begin_node(fdt, "options");
+	if (ret)
+		return ret;
+
+	ret = fdt_begin_node(fdt, "op-tee");
+	if (ret)
+		return ret;
+
+	ret = fdt_begin_node(fdt, "widevine");
+	if (ret)
+		return ret;
+
+	if (cros_oem_tpm_auth_pk.length) {
+		ret = fdt_property(fdt, "tcg,tpm-auth-public-key",
+				   cros_oem_tpm_auth_pk.buffer,
+				   cros_oem_tpm_auth_pk.length);
+		if (ret)
+			return ret;
+	}
+
+	if (cros_oem_huk.length) {
+		ret = fdt_property(fdt, "op-tee,hardware-unique-key",
+				   cros_oem_huk.buffer, cros_oem_huk.length);
+		if (ret)
+			return ret;
+	}
+
+	if (cros_oem_rot.length) {
+		ret = fdt_property(fdt, "google,widevine-root-of-trust-ecc-p256",
+				   cros_oem_rot.buffer, cros_oem_rot.length);
+		if (ret)
+			return ret;
+	}
+
+	ret = fdt_end_node(fdt);
+	if (ret)
+		return ret;
+
+	ret = fdt_end_node(fdt);
+	if (ret)
+		return ret;
+
+	return fdt_end_node(fdt);
+}
+#endif /* CROS_WIDEVINE_SMC */
+
 /*
  * Creates a device tree for passing into OP-TEE. Currently is populated with
  * the coreboot table address.
@@ -326,6 +383,12 @@ static int create_opteed_dt(void)
 		return ret;
 #endif /* COREBOOT */
 
+#if CROS_WIDEVINE_SMC
+	ret = add_options_widevine_node(fdt_buf);
+	if (ret)
+		return ret;
+#endif /* CROS_WIDEVINE_SMC */
+
 	ret = fdt_end_node(fdt_buf);
 	if (ret)
 		return ret;