tree 1627e6abc9001f0b519ed65daa86be46d52c4117
parent 34e00accf612bc5448ae709245c2b408edf39f46
author Ard Biesheuvel <ard.biesheuvel@linaro.org> 1486115645 +0000
committer Linus Torvalds <torvalds@linux-foundation.org> 1486139305 -0800

kbuild: modversions: add infrastructure for emitting relative CRCs

This add the kbuild infrastructure that will allow architectures to emit
vmlinux symbol CRCs as 32-bit offsets to another location in the kernel
where the actual value is stored. This works around problems with CRCs
being mistaken for relocatable symbols on kernels that self relocate at
runtime (i.e., powerpc with CONFIG_RELOCATABLE=y)

For the kbuild side of things, this comes down to the following:

 - introducing a Kconfig symbol MODULE_REL_CRCS

 - adding a -R switch to genksyms to instruct it to emit the CRC symbols
   as references into the .rodata section

 - making modpost distinguish such references from absolute CRC symbols
   by the section index (SHN_ABS)

 - making kallsyms disregard non-absolute symbols with a __crc_ prefix

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>