wolfssl/IDE/GCC-ARM

Example Project for GCC ARM

This example is for Cortex M series, but can be adopted for other architectures.

Design

• All library options are defined in Header/user_settings.h.
• The memory map is located in the linker file in linker.ld.
• Entry point function is reset_handler in armtarget.c.
• The RTC and RNG hardware interface needs implemented for real production applications in armtarget.c

Building

1. Make sure you have gcc-arm-none-eabi installed.
2. Modify the Makefile.common:

• Use correct toolchain path TOOLCHAIN.
• Use correct architecture 'ARCHFLAGS' (default is cortex-m0 / thumb). See GCC ARM Options -mcpu=name.

3. Use make and it will build the static library and wolfCrypt test/benchmark and wolfSSL TLS client targets as .elf and .hex in /Build.

Building for Raspberry Pi

Example Makefile.common changes for Rasperry Pi with Cortex-A53:

1. Change ARCHFLAGS to ARCHFLAGS = -mcpu=cortex-a53 -mthumb -mabi=aapcs to specify Cortex-A53.
2. Comment out SRC_LD, since custom memory map is not applicable.
3. Clear TOOLCHAIN, so it will use default gcc. Set TOOLCHAIN =
4. Comment out LDFLAGS += --specs=nano.specs --specs=nosys.specs to disable newlib-nano.

Note: To comment out a line in a Makefile use place # in front of line.

Example Build

make clean && make

   text	   data	    bss	    dec	    hex   filename
  50076	   2508	     44	  52628	   cd94   ./Build/WolfCryptTest.elf

   text	   data	    bss	    dec	    hex   filename
  39155	   2508	     60	  41723	   a2fb   ./Build/WolfCryptBench.elf

   text	   data	    bss	    dec	    hex	filename
  70368	    464	     36	  70868	  114d4	./Build/WolfSSLClient.elf

Performace Tuning Options

These settings are located in Header/user_settings.h.

• DEBUG_WOLFSSL: Undefine this to disable debug logging.
• NO_ERROR_STRINGS: Disables error strings to save code space.
• NO_INLINE: Disabling inline function saves about 1KB, but is slower.
• WOLFSSL_SMALL_STACK: Enables stack reduction techniques to allocate stack sections over 100 bytes from heap.
• USE_FAST_MATH: Uses stack based math, which is faster than the heap based math.
• ALT_ECC_SIZE: If using fast math and RSA/DH you can define this to reduce your ECC memory consumption.
• FP_MAX_BITS: Is the maximum math size (key size * 2). Used only with USE_FAST_MATH.
• ECC_TIMING_RESISTANT: Enables timing resistance for ECC and uses slightly less memory.
• ECC_SHAMIR: Doubles heap usage, but slightly faster
• RSA_LOW_MEM: Half as much memory but twice as slow. Uses Non-CRT method for private key. AES GCM: GCM_SMALL, GCM_WORD32 or GCM_TABLE: Tunes performance and flash/memory usage.
• CURVED25519_SMALL: Enables small versions of Ed/Curve (FE/GE math).
• USE_SLOW_SHA: Enables smaller/slower version of SHA.
• USE_SLOW_SHA256: About 2k smaller and about 25% slower
• USE_SLOW_SHA512: Over twice as small, but 50% slower
• USE_CERT_BUFFERS_1024 or USE_CERT_BUFFERS_2048: Size of RSA certs / keys to test with.
• BENCH_EMBEDDED: Define this if using the wolfCrypt test/benchmark and using a low memory target.