diff --git a/rules.mk b/rules.mk
new file mode 100644
index 0000000..5f4960b
--- /dev/null
+++ b/rules.mk
@@ -0,0 +1,70 @@
+# Copyright (C) 2015 The Android Open Source Project.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+# This file is not used in the Android build process! It's used only by Trusty.
+
+
+LOCAL_DIR := $(GET_LOCAL_DIR)
+LOCAL_PATH := $(GET_LOCAL_DIR)
+
+MODULE := $(LOCAL_DIR)
+
+TARGET_ARCH := $(ARCH)
+TARGET_2ND_ARCH := $(ARCH)
+
+# Reset local variables
+LOCAL_CFLAGS :=
+LOCAL_C_INCLUDES :=
+LOCAL_SRC_FILES_$(TARGET_ARCH) :=
+LOCAL_SRC_FILES_$(TARGET_2ND_ARCH) :=
+LOCAL_CFLAGS_$(TARGET_ARCH) :=
+LOCAL_CFLAGS_$(TARGET_2ND_ARCH) :=
+LOCAL_ADDITIONAL_DEPENDENCIES :=
+
+# get target_c_flags, target_c_includes, target_src_files
+MODULE_SRCDEPS += $(LOCAL_DIR)/crypto-sources.mk
+include $(LOCAL_DIR)/crypto-sources.mk
+
+# Some files in BoringSSL use OS functions that aren't supported by Trusty. The
+# easiest way to deal with them is not to include them. As long as no path to
+# the functions defined in these files exists, the linker will be happy. If
+# such a path is created, it'll be a link-time error and something more complex
+# may need to be considered.
+LOCAL_SRC_FILES := $(filter-out android_compat_hacks.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/bio/connect.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/bio/fd.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/bio/file.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/bio/socket.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/bio/socket_helper.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/directory_posix.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/rand/urandom.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/time_support.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/x509/by_dir.c,$(LOCAL_SRC_FILES))
+LOCAL_SRC_FILES := $(filter-out src/crypto/x509v3/v3_utl.c,$(LOCAL_SRC_FILES))
+
+# BoringSSL detects Trusty based on this define and does things like switch to
+# no-op threading functions.
+MODULE_CFLAGS += -DTRUSTY
+
+MODULE_SRCS += $(addprefix $(LOCAL_DIR)/,$(LOCAL_SRC_FILES))
+MODULE_SRCS += $(addprefix $(LOCAL_DIR)/,$(LOCAL_SRC_FILES_$(ARCH)))
+LOCAL_C_INCLUDES := src/crypto src/include
+
+GLOBAL_INCLUDES += $(addprefix $(LOCAL_DIR)/,$(LOCAL_C_INCLUDES))
+
+MODULE_DEPS := \
+	lib/openssl-stubs \
+	lib/libc-trusty
+
+include make/module.mk