Many boards start up SPL to run code + data from one common, rather small
SRAM. To implement a sophisticated SPL binary size limit on such boards,
the stack size (as well as malloc size and global data size) must be
subtracted from this SRAM size.
However, to do that properly, the stack size first needs to be known.
This patch adds a new Kconfig option:
- SPL_SYS_REPORT_STACK_F_USAGE: memset(0xaa) the whole area of the stack
very early and check stack usage based on this constant later before the
stack is switched to DRAM
Initializing the stack and checking it is implemented in weak functions,
in case a board does not use the stack as saved in gd->start_addr_sp.
Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>