Change in coreboot[master]: rmodtool: Make memlayout symbols absolute and do not relocate them

[Julius Werner (Code Review)]

Attention is currently required from: Martin Roth, Furquan Shaikh.
Hello build bot (Jenkins), Patrick Georgi, Martin Roth, Furquan Shaikh, Aaron Durbin,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/50629

to look at the new patch set (#3).

Change subject: rmodtool: Make memlayout symbols absolute and do not relocate them
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rmodtool: Make memlayout symbols absolute and do not relocate them

Memlayout is a mechanism to define memory areas outside the normal
program segment constructed by the linker. Therefore, it generally
doesn't make sense to relocate memlayout symbols when the program is
relocated. They tend to refer to things that are always in one specific
spot, independent of where the program is loaded.

This hasn't really hurt us in the past because the use case we have for
rmodules (ramstage on x86) just happens to not really need to refer to
any memlayout-defined areas at the moment. But that use case may come up
in the future so it's still worth fixing.

This patch declares all memlayout-defined symbols as ABSOLUTE() in the
linker, which is then reflected in the symbol table of the generated
ELF. We can then use that distinction to have rmodtool skip them when
generating the relocation table for an rmodule. (Also rearrange rmodtool
a little to make the primary string table more easily accessible to the
rest of the code, so we can refer to symbol names in debug output.)

A similar problem can come up with userspace unit tests, but we cannot
modify the userspace relocation toolchain (and for unfortunate
historical reasons, it tries to relocate even absolute symbols). We'll
just disable PIC and make those binaries fully static to avoid that
issue.

Signed-off-by: Julius Werner 
Change-Id: Ic51d9add3dc463495282b365c1b6d4a9bf11dbf2
---
M src/include/memlayout.h
M tests/Makefile.inc
M util/cbfstool/rmodule.c
M util/cbfstool/rmodule.h
4 files changed, 56 insertions(+), 38 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/29/50629/3