mbedtls: Use `tf_snprintf` instead of `snprintf`
The Trusted Firmware uses a subset of the APIs provided by mbed TLS.
This subset internally uses `snprintf`, but the only format specifier
used is '%d', which is supported by `tf_snprintf`.
This patch makes mbed TLS use `tf_snprintf` instead of `snprintf`,
saving 3 KB in both debug and release builds when TBBR is enabled.
Change-Id: I7f992a21015930d7c0f4660e7a28ceefd60b9597
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/drivers/auth/mbedtls/mbedtls_common.c b/drivers/auth/mbedtls/mbedtls_common.c
index aad49a7..871831e 100644
--- a/drivers/auth/mbedtls/mbedtls_common.c
+++ b/drivers/auth/mbedtls/mbedtls_common.c
@@ -4,10 +4,11 @@
* SPDX-License-Identifier: BSD-3-Clause
*/
-#include <assert.h>
+#include <debug.h>
/* mbed TLS headers */
#include <mbedtls/memory_buffer_alloc.h>
+#include <mbedtls/platform.h>
/*
* mbed TLS heap
@@ -29,6 +30,10 @@
if (!ready) {
/* Initialize the mbed TLS heap */
mbedtls_memory_buffer_alloc_init(heap, MBEDTLS_HEAP_SIZE);
+
+ /* Use reduced version of snprintf to save space. */
+ mbedtls_platform_set_snprintf(tf_snprintf);
+
ready = 1;
}
}
diff --git a/include/drivers/auth/mbedtls/mbedtls_config.h b/include/drivers/auth/mbedtls/mbedtls_config.h
index 7d8d17c..22e7574 100644
--- a/include/drivers/auth/mbedtls/mbedtls_config.h
+++ b/include/drivers/auth/mbedtls/mbedtls_config.h
@@ -19,6 +19,8 @@
#define MBEDTLS_PLATFORM_MEMORY
#define MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
+/* Prevent mbed TLS from using snprintf so that it can use tf_snprintf. */
+#define MBEDTLS_PLATFORM_SNPRINTF_ALT
#define MBEDTLS_PKCS1_V15
#define MBEDTLS_PKCS1_V21