On 8/12/10 9:27 PM, Patrick Georgi wrote:
- _bogus = ASSERT((SIZEOF(.bss) + SIZEOF(.data)) == 0, "Do not use
global variables in romstage");
This one looks for the size of .bss and .data (initialized and uninitialized globals) and breaks the build if it finds any. It doesn't tell, which global variables are involved.
- Add .bss and .data to /DISCARD/.
That way, the linker complains about "missing" symbols (as they were discarded), but only if they were used by any surviving code. This means, it's no problem that the global is defined. If you use it later-on, it "mysteriously" breaks. The error message is rather cryptic, too: `variable' referenced in section `.rom.text' of coreboot-builds/kontron_986lcd-m/mainboard/kontron/986lcd-m/crt0.initobj.o: defined in discarded section `.data' of coreboot-builds/kontron_986lcd-m/mainboard/kontron/986lcd-m/crt0.initobj.o collect2: ld returned 1 exit status
I tend to prefer the first option, but it doesn't give _any_ clues which variable is responsible (except for "look for globals"), but at least it does tell the user what the real problem is.
I prefer option one, too, as - it catches all global variables, not just the used ones. We want to be sure that no such code sneaks in even if it's not used. - it provides a clear error message on what is wrong, inszead of the more cryptic one saying that a variable is defined in a discarded section.
There might also be a good opportunity for some naming cleanup: Rename and move ldscript_fallback_cbfs.lb to src/arch/i386/coreboot_rom.ld. Or better call it "romstage.ld" (and adapt coreboot_ram.ld in arch/i386 in the same way)?
I like the latter.
Fixes to both issues are:
Acked-by: Stefan Reinauer stepan@coresystems.de
Stefan