bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 06:44:00 -04:00
Code Issues Packages Projects Releases Wiki Activity

kbuild: remove PROVIDE() for kallsyms symbols

Browse Source 
This reimplements commit 951bcae6c5 ("kallsyms: Avoid weak references
for kallsyms symbols") because I am not a big fan of PROVIDE().

As an alternative solution, this commit prepends one more kallsyms step.

    KSYMS   .tmp_vmlinux.kallsyms0.S          # added
    AS      .tmp_vmlinux.kallsyms0.o          # added
    LD      .tmp_vmlinux.btf
    BTF     .btf.vmlinux.bin.o
    LD      .tmp_vmlinux.kallsyms1
    NM      .tmp_vmlinux.kallsyms1.syms
    KSYMS   .tmp_vmlinux.kallsyms1.S
    AS      .tmp_vmlinux.kallsyms1.o
    LD      .tmp_vmlinux.kallsyms2
    NM      .tmp_vmlinux.kallsyms2.syms
    KSYMS   .tmp_vmlinux.kallsyms2.S
    AS      .tmp_vmlinux.kallsyms2.o
    LD      vmlinux

Step 0 takes /dev/null as input, and generates .tmp_vmlinux.kallsyms0.o,
which has a valid kallsyms format with the empty symbol list, and can be
linked to vmlinux. Since it is really small, the added compile-time cost
is negligible.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
This commit is contained in:
Masahiro Yamada
2024-06-10 20:25:17 +09:00
parent ddf4132983
commit c442db3f49
4 changed files with 7 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
scripts/link-vmlinux.sh
View File

@@ -227,6 +227,10 @@ btf_vmlinux_bin_o=
kallsymso=
strip_debug=
if is_enabled CONFIG_KALLSYMS; then
kallsyms /dev/null .tmp_vmlinux.kallsyms0
fi
if is_enabled CONFIG_DEBUG_INFO_BTF; then
if ! gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then
echo >&2 "Failed to generate BTF for vmlinux"
@@ -239,9 +243,10 @@ if is_enabled CONFIG_KALLSYMS; then
# kallsyms support
# Generate section listing all symbols and add it into vmlinux
# It's a three step process:
# It's a four step process:
# 0) Generate a dummy __kallsyms with empty symbol list.
# 1) Link .tmp_vmlinux.kallsyms1 so it has all symbols and sections,
# but __kallsyms is empty.
# with a dummy __kallsyms.
# Running kallsyms on that gives us .tmp_kallsyms1.o with
# the right size
# 2) Link .tmp_vmlinux.kallsyms2 so it now has a __kallsyms section of