From 7bef731f0b709f3b9858bf6210fab79c0b675c23 Mon Sep 17 00:00:00 2001
From: Gilles Peskine <Gilles.Peskine@arm.com>
Date: Wed, 10 Dec 2025 18:16:03 +0100
Subject: [PATCH] Create a TF-PSA-Crypto make helper for Mbed TLS

Currently, Mbed TLS can be built with make, and we rely on this in many
`all.sh` components. Mbed TLS knows how to build TF-PSA-Crypto, but this
changes from time to time, and it's hard to do the necessary changes in both
repositories at the same time.

Create a file that Mbed TLS can consume to find out some information needed
to build TF-PSA-Crypto, such as the locations of various files.

Create this file in Mbed TLS. Once we have finished moving code to it, the
file will move to TF-PSA-Crypto.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
---
 library/Makefile           |  2 ++
 scripts/common.make        |  2 ++
 scripts/crypto-common.make | 25 +++++++++++++++++++++++++
 3 files changed, 29 insertions(+)
 create mode 100644 scripts/crypto-common.make

diff --git a/library/Makefile b/library/Makefile
index 807e3f1adb..8195e2423a 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -14,6 +14,8 @@ This is a fatal error
 endif
 include $(MBEDTLS_PATH)/framework/exported.make
 
+include $(MBEDTLS_PATH)/scripts/crypto-common.make
+
 TF_PSA_CRYPTO_CORE_PATH = $(MBEDTLS_PATH)/tf-psa-crypto/core
 TF_PSA_CRYPTO_DRIVERS_BUILTIN_SRC_PATH = $(MBEDTLS_PATH)/tf-psa-crypto/drivers/builtin/src
 
diff --git a/scripts/common.make b/scripts/common.make
index 5350d87efc..9be3b2db53 100644
--- a/scripts/common.make
+++ b/scripts/common.make
@@ -16,6 +16,8 @@ This is a fatal error
 endif
 include $(MBEDTLS_PATH)/framework/exported.make
 
+include $(MBEDTLS_PATH)/scripts/crypto-common.make
+
 CFLAGS	?= -O2
 WARNING_CFLAGS ?= -Wall -Wextra -Wformat=2 -Wno-format-nonliteral
 WARNING_CXXFLAGS ?= -Wall -Wextra -Wformat=2 -Wno-format-nonliteral -std=c++11 -pedantic
diff --git a/scripts/crypto-common.make b/scripts/crypto-common.make
new file mode 100644
index 0000000000..5a79bc482b
--- /dev/null
+++ b/scripts/crypto-common.make
@@ -0,0 +1,25 @@
+# Helper code for the make build system in Mbed TLS: define some variables
+# providing information such as file paths.
+# This file is only meant to exist for a short transition period.
+# It may change or be removed without notice.
+# Do not use it if you are not Mbed TLS!
+
+# Assume that this makefile is located in a first-level subdirectory of the
+# Mbed TLS root, and is accessed directly (not via VPATH or such).
+# If this is not the case, TF_PSA_CRYPTO_PATH or MBEDTLS_PATH must be defined
+# before including this file.
+ifneq ($(origin TF_PSA_CRYPTO_PATH), undefined)
+  # TF_PSA_CRYPTO_PATH was defined before including this file, good.
+else ifneq ($(origin MBEDTLS_PATH), undefined)
+  TF_PSA_CRYPTO_PATH := $(MBEDTLS_PATH)/tf-psa-crypto
+else
+  # $(dir $(lastword $(MAKEFILE_LIST))) is the path to this file, possibly
+  # a relative path, with a trailing slash. Strip off another directory
+  # from that.
+  TF_PSA_CRYPTO_PATH := $(patsubst %/,%,$(dir $(patsubst %/,%,$(dir $(lastword $(MAKEFILE_LIST))))))/tf-psa-crypto
+endif
+
+ifeq (,$(wildcard $(TF_PSA_CRYPTO_PATH)/core/psa_crypto.c))
+  $(error $$(TF_PSA_CRYPTO_PATH)/core/psa_crypto.c not found)
+endif
+