Support shared Mbed TLS heap for FVP
This patch introduces the shared Mbed TLS heap optimisation for Arm
platforms. The objective is the Mbed TLS heap to be shared between BL1
and BL2 so as to not allocate the heap memory twice. To achieve that,
the patch introduces all the necessary helpers for implementing this
optimisation. It also applies it for FVP.
Change-Id: I6d85eaa1361517b7490956b2ac50f5fa0d0bb008
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>
diff --git a/plat/arm/common/arm_dyn_cfg.c b/plat/arm/common/arm_dyn_cfg.c
index b9c73f0..f2570a8 100644
--- a/plat/arm/common/arm_dyn_cfg.c
+++ b/plat/arm/common/arm_dyn_cfg.c
@@ -8,6 +8,9 @@
#include <assert.h>
#include <debug.h>
#include <desc_image_load.h>
+#if TRUSTED_BOARD_BOOT
+#include <mbedtls_config.h>
+#endif
#include <plat_arm.h>
#include <platform.h>
#include <platform_def.h>
@@ -16,9 +19,94 @@
#if LOAD_IMAGE_V2
-/* Variable to store the address to TB_FW_CONFIG passed from BL1 */
+/* Variable to store the address of TB_FW_CONFIG file */
static void *tb_fw_cfg_dtb;
+
+#if TRUSTED_BOARD_BOOT
+
+static void *mbedtls_heap_addr;
+static size_t mbedtls_heap_size;
+
+/*
+ * This function is the implementation of the shared Mbed TLS heap between
+ * BL1 and BL2 for Arm platforms. The shared heap address is passed from BL1
+ * to BL2 with a pointer. This pointer resides inside the TB_FW_CONFIG file
+ * which is a DTB.
+ *
+ * This function is placed inside an #if directive for the below reasons:
+ * - To allocate space for the Mbed TLS heap --only if-- Trusted Board Boot
+ * is enabled.
+ * - This implementation requires the DTB to be present so that BL1 has a
+ * mechanism to pass the pointer to BL2. If LOAD_IMAGE_V2=0 then
+ * TB_FW_CONFIG is not present, which means that this implementation
+ * cannot be applied.
+ */
+int arm_get_mbedtls_heap(void **heap_addr, size_t *heap_size)
+{
+ assert(heap_addr != NULL);
+ assert(heap_size != NULL);
+
+#if defined(IMAGE_BL1) || BL2_AT_EL3
+
+ /* If in BL1 or BL2_AT_EL3 define a heap */
+ static unsigned char heap[TF_MBEDTLS_HEAP_SIZE];
+
+ *heap_addr = heap;
+ *heap_size = sizeof(heap);
+ mbedtls_heap_addr = heap;
+ mbedtls_heap_size = sizeof(heap);
+
+#elif defined(IMAGE_BL2)
+
+ int err;
+
+ /* If in BL2, retrieve the already allocated heap's info from DTB */
+ err = arm_get_dtb_mbedtls_heap_info(tb_fw_cfg_dtb, heap_addr,
+ heap_size);
+ if (err < 0) {
+ ERROR("BL2: unable to retrieve shared Mbed TLS heap "
+ "information from DTB\n");
+ panic();
+ }
+#endif
+
+ return 0;
+}
+
+/*
+ * Puts the shared Mbed TLS heap information to the DTB.
+ * Executed only from BL1.
+ */
+void arm_bl1_set_mbedtls_heap(void)
+{
+ int err;
+
+ /*
+ * If tb_fw_cfg_dtb==NULL then DTB is not present for the current
+ * platform. As such, we don't attempt to write to the DTB at all.
+ *
+ * If mbedtls_heap_addr==NULL, then it means we are using the default
+ * heap implementation. As such, BL2 will have its own heap for sure
+ * and hence there is no need to pass any information to the DTB.
+ *
+ * In the latter case, if we still wanted to write in the DTB the heap
+ * information, we would need to call plat_get_mbedtls_heap to retrieve
+ * the default heap's address and size.
+ */
+ if ((tb_fw_cfg_dtb != NULL) && (mbedtls_heap_addr != NULL)) {
+ err = arm_set_dtb_mbedtls_heap_info(tb_fw_cfg_dtb,
+ mbedtls_heap_addr, mbedtls_heap_size);
+ if (err < 0) {
+ ERROR("BL1: unable to write shared Mbed TLS heap "
+ "information to DTB\n");
+ panic();
+ }
+ }
+}
+
+#endif /* TRUSTED_BOARD_BOOT */
+
/*
* Helper function to load TB_FW_CONFIG and populate the load information to
* arg0 of BL2 entrypoint info.
@@ -45,7 +133,9 @@
return;
}
+ /* At this point we know that a DTB is indeed available */
config_base = arm_tb_fw_info.image_info.image_base;
+ tb_fw_cfg_dtb = (void *)config_base;
/* The BL2 ep_info arg0 is modified to point to TB_FW_CONFIG */
image_desc = bl1_plat_get_image_desc(BL2_IMAGE_ID);