From 98fd78437c56efeebe2e38c944f5af0a1a59fe8a Mon Sep 17 00:00:00 2001 From: Angus Gratton Date: Fri, 28 Jul 2023 12:16:05 +1000 Subject: [PATCH] esp32: Allow malloc() to allocate from SPIRAM. Also shrinks the "prefer internal" threshold to 8KB, any allocation larger than this will try PSRAM first. Change the mbedTLS config to use regular malloc() as well, instead of internal only. The default is set to internal-only due to to potential physical security issue of readout via PSRAM on the original ESP32. However, as MicroPython runs from plaintext flash and all other context is in the MP heap of PSRAM then it's hard to see how worsens physical security for MP. This work was funded through GitHub Sponsors. Signed-off-by: Angus Gratton --- ports/esp32/boards/sdkconfig.base | 9 +++++++++ ports/esp32/boards/sdkconfig.spiram | 6 +++++- ports/esp32/boards/sdkconfig.spiram_sx | 6 +++++- 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/ports/esp32/boards/sdkconfig.base b/ports/esp32/boards/sdkconfig.base index bf6c3f45c5..b98d5d0678 100644 --- a/ports/esp32/boards/sdkconfig.base +++ b/ports/esp32/boards/sdkconfig.base @@ -49,6 +49,15 @@ CONFIG_LWIP_PPP_CHAP_SUPPORT=y # Use 4kiB output buffer instead of default 16kiB CONFIG_MBEDTLS_ASYMMETRIC_CONTENT_LEN=y +# Allow mbedTLS to allocate from PSRAM or internal memory +# +# (The ESP-IDF default is internal-only, partly for physical security to prevent +# possible information leakage from unencrypted PSRAM contents on the original +# ESP32 - no PSRAM encryption on that chip. MicroPython doesn't support flash +# encryption and is already storing the Python heap in PSRAM so this isn't a +# significant factor in overall physical security.) +CONFIG_MBEDTLS_DEFAULT_MEM_ALLOC=y + # ULP coprocessor support # Only on: ESP32, ESP32S2, ESP32S3 CONFIG_ULP_COPROC_ENABLED=y diff --git a/ports/esp32/boards/sdkconfig.spiram b/ports/esp32/boards/sdkconfig.spiram index 74d35f7b4a..4dfc63624b 100644 --- a/ports/esp32/boards/sdkconfig.spiram +++ b/ports/esp32/boards/sdkconfig.spiram @@ -3,7 +3,11 @@ CONFIG_SPIRAM=y CONFIG_SPIRAM_CACHE_WORKAROUND=y CONFIG_SPIRAM_IGNORE_NOTFOUND=y -CONFIG_SPIRAM_USE_CAPS_ALLOC=y +CONFIG_SPIRAM_USE_MALLOC=y + +# This is the threshold for preferring small allocations from internal memory +# first, before failing over to PSRAM. +CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=8192 # SPIRAM increases the size of the firmware and overflows iram0_0_seg, due # to PSRAM bug workarounds. Apply some options to reduce the firmware size. diff --git a/ports/esp32/boards/sdkconfig.spiram_sx b/ports/esp32/boards/sdkconfig.spiram_sx index 329a507337..efe53ada41 100644 --- a/ports/esp32/boards/sdkconfig.spiram_sx +++ b/ports/esp32/boards/sdkconfig.spiram_sx @@ -7,4 +7,8 @@ CONFIG_SPIRAM_SPEED_80M=y CONFIG_SPIRAM=y CONFIG_SPIRAM_BOOT_INIT=y CONFIG_SPIRAM_IGNORE_NOTFOUND=y -CONFIG_SPIRAM_USE_CAPS_ALLOC=y +CONFIG_SPIRAM_USE_MALLOC=y + +# This is the threshold for preferring small allocations from internal memory +# first, before failing over to PSRAM. +CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=8192