linux/scripts/mod
Masahiro Yamada 7b4537199a kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS
include/{linux,asm-generic}/export.h defines a weak symbol, __crc_*
as a placeholder.

Genksyms writes the version CRCs into the linker script, which will be
used for filling the __crc_* symbols. The linker script format depends
on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset
to the reference of CRC.

It is time to get rid of this complexity.

Now that modpost parses text files (.*.cmd) to collect all the CRCs,
it can generate C code that will be linked to the vmlinux or modules.

Generate a new C file, .vmlinux.export.c, which contains the CRCs of
symbols exported by vmlinux. It is compiled and linked to vmlinux in
scripts/link-vmlinux.sh.

Put the CRCs of symbols exported by modules into the existing *.mod.c
files. No additional build step is needed for modules. As before,
*.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal.

No linker magic is used here. The new C implementation works in the
same way, whether CONFIG_RELOCATABLE is enabled or not.
CONFIG_MODULE_REL_CRCS is no longer needed.

Previously, Kbuild invoked additional $(LD) to update the CRCs in
objects, but this step is unneeded too.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-05-24 16:33:20 +09:00
..
.gitignore .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
devicetable-offsets.c HID: intel-ish-hid: add support for MODULE_DEVICE_TABLE() 2021-11-09 11:41:46 +01:00
empty.c
file2alias.c HID: intel-ish-hid: add support for MODULE_DEVICE_TABLE() 2021-11-09 11:41:46 +01:00
list.h modpost: import include/linux/list.h 2022-05-08 03:17:00 +09:00
Makefile scripts/mod: disable LTO for empty.c 2021-01-14 08:21:09 -08:00
mk_elfconfig.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
modpost.c kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS 2022-05-24 16:33:20 +09:00
modpost.h modpost: remove left-over cross_compile declaration 2022-05-11 21:46:39 +09:00
sumversion.c modpost: use bool type where appropriate 2022-05-08 03:17:00 +09:00