Heap and Stack Size

To change size of heap in baremetal applications the following option should be specified to the linker: --defsym=__DEFAULT_HEAP_SIZE=${SIZE}, where ${SIZE} is desired heap size, in bytes. It also possible to use size suffixes, like k and m to specify size in kilobytes and megabytes respectively. For stack size respective option is --defsym=__DEFAULT_STACK_SIZE=${STACK_SIZE}. Note that those are linker commands - they are valid only when passed to ld application, if gcc driver is used for linking, then those options should be prefixed with -Wl. For example:

$ arc-elf32-gcc -Wl,--defsym=__DEFAULT_HEAP_SIZE=256m \
  -Wl,--defsym=__DEFAULT_STACK_SIZE=1024m --specs=nosys.specs \
  hello.o -o hello.bin

Those options are valid only when default linker script is used. If custom linker script is used, then effective way to change stack/heap size depends on properties of that linker script - it might be the same, or it might be different.