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Certain ECs which cannot load both the RO and RW images into memory simultaneously have a little firmware (LFW) loader that is loaded into the beginning of the program memory. This loader is responsible for loading the RO/RW images, however once we begin executing code from main(), the loader has already completed it's purpose. We can reuse this space by allocating portions of the .bss section here. This currently saves us 3k for mec1322. This section is .bss.slow. To use this feature simply define the following config option in board.h. #define CONFIG_REPLACE_LOADER_WITH_BSS_SLOW In some cases, such as the mec1322, this region of RAM is optimized for code and not data. Therefore, ideally infrequently used data should go into this region. BUG=chrome-os-partner:46056 BUG=chrome-os-partner:46063 BRANCH=None TEST=Flash GLaDOS; sysjump rw; Verify that we are in rw; sysjump ro; Verify we are back in ro. TEST=Build GLaDOS, check output memory map for LDR_REGION and .bss.slow section. TEST=make -j buildall tests Change-Id: I5b95cacc211278cf780a857b5a2ecfc1a0a28c45 Signed-off-by: Aseda Aboagye <aaboagye@google.com> Reviewed-on: https://chromium-review.googlesource.com/305254 Commit-Ready: Aseda Aboagye <aaboagye@chromium.org> Tested-by: Aseda Aboagye <aaboagye@chromium.org> Reviewed-by: Andrey Petrov <andrey.petrov@intel.com> Reviewed-by: Shawn N <shawnn@chromium.org>