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authorMasahiro Yamada <masahiroy@kernel.org>2022-05-13 13:39:22 +0200
committerMasahiro Yamada <masahiroy@kernel.org>2022-05-24 09:33:20 +0200
commit7b4537199a4a8480b8c3ba37a2d44765ce76cd9b (patch)
tree0690afa62208ca15fd36069afcbdac85908d0676 /scripts/link-vmlinux.sh
parentmodpost: extract symbol versions from *.cmd files (diff)
downloadlinux-7b4537199a4a8480b8c3ba37a2d44765ce76cd9b.tar.xz
linux-7b4537199a4a8480b8c3ba37a2d44765ce76cd9b.zip
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 $(LD) to update the CRCs in objects, but this step is unneeded too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
Diffstat (limited to 'scripts/link-vmlinux.sh')
-rwxr-xr-xscripts/link-vmlinux.sh10
1 files changed, 9 insertions, 1 deletions
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index eceb3ee7ec06..db34dc3163ae 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -90,7 +90,6 @@ modpost_link()
if is_enabled CONFIG_MODVERSIONS; then
gen_symversions
- lds="${lds} -T .tmp_symversions.lds"
fi
# This might take a while, so indicate that we're doing
@@ -183,6 +182,10 @@ vmlinux_link()
libs="${KBUILD_VMLINUX_LIBS}"
fi
+ if is_enabled CONFIG_MODULES; then
+ objs="${objs} .vmlinux.export.o"
+ fi
+
if [ "${SRCARCH}" = "um" ]; then
wl=-Wl,
ld="${CC}"
@@ -312,6 +315,7 @@ cleanup()
rm -f vmlinux.o
rm -f .vmlinux.d
rm -f .vmlinux.objs
+ rm -f .vmlinux.export.c
}
# Use "make V=1" to debug this script
@@ -363,6 +367,10 @@ info GEN modules.builtin
tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin
+if is_enabled CONFIG_MODULES; then
+ ${MAKE} -f "${srctree}/scripts/Makefile.vmlinux" .vmlinux.export.o
+fi
+
btf_vmlinux_bin_o=""
if is_enabled CONFIG_DEBUG_INFO_BTF; then
btf_vmlinux_bin_o=.btf.vmlinux.bin.o