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authorMasahiro Yamada <masahiroy@kernel.org>2024-05-20 14:42:09 +0200
committerMasahiro Yamada <masahiroy@kernel.org>2024-05-29 09:40:03 +0200
commit04b8cb0945b4bf679c71dc2351e0d3c25481e3c6 (patch)
tree67b4240922e264d508ea96c843c68305a3a58174 /scripts/link-vmlinux.sh
parentkbuild: scripts/gdb: Replace missed $(srctree)/$(src) w/ $(src) (diff)
downloadlinux-04b8cb0945b4bf679c71dc2351e0d3c25481e3c6.tar.xz
linux-04b8cb0945b4bf679c71dc2351e0d3c25481e3c6.zip
kbuild: avoid unneeded kallsyms step 3
Since commit 951bcae6c5a0 ("kallsyms: Avoid weak references for kallsyms symbols"), the kallsyms step 3 always occurs. You can compare the build logs. [Before 951bcae6c5a0] $ git checkout 951bcae6c5a0^ $ make defconfig all [ snip ] LD .tmp_vmlinux.kallsyms1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.S LD .tmp_vmlinux.kallsyms2 NM .tmp_vmlinux.kallsyms2.syms KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.S LD vmlinux [After 951bcae6c5a0] $ git checkout 951bcae6c5a0 $ make defconfig all [ snip ] LD .tmp_vmlinux.kallsyms1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.S LD .tmp_vmlinux.kallsyms2 NM .tmp_vmlinux.kallsyms2.syms KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.S LD .tmp_vmlinux.kallsyms3 # should not happen NM .tmp_vmlinux.kallsyms3.syms # should not happen KSYMS .tmp_vmlinux.kallsyms3.S # should not happen AS .tmp_vmlinux.kallsyms3.S # should not happen LD vmlinux The resulting vmlinux is correct, but it always requires an additional linking step. The symbols produced by kallsyms are excluded from kallsyms itself because they were previously missing in step 1. With those symbols excluded, the symbol lists matched between step 1 and step 2, eliminating the need for step 3. Now, this has a negative effect. Since 951bcae6c5a0, the PROVIDE() directives provide the fallback definitions, which are not trimmed from the sysbol list in step 1 because ${kallsymso_prev} is empty at this point. In step 2, ${kallsymso_prev} is set, and the kallsyms_* symbols are trimmed from the symbol list. Due to the table size difference between step 1 and step 2 (the former is larger due to the presence of kallsyms_*), step 3 is triggered. Now that the kallsyms_* symbols are always linked, let's stop omitting them from kallsyms. This avoids unnecessary step 3. Fixes: 951bcae6c5a0 ("kallsyms: Avoid weak references for kallsyms symbols") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/link-vmlinux.sh')
-rwxr-xr-xscripts/link-vmlinux.sh6
1 files changed, 3 insertions, 3 deletions
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 7862a8101747..b0d39a927fbc 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -179,7 +179,7 @@ kallsyms_step()
kallsyms_S=${kallsyms_vmlinux}.S
vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
- mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms ${kallsymso_prev}
+ mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms
kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S}
info AS ${kallsyms_S}
@@ -193,7 +193,7 @@ kallsyms_step()
mksysmap()
{
info NM ${2}
- ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} ${3}
+ ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
}
sorttable()
@@ -282,7 +282,7 @@ if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then
${RESOLVE_BTFIDS} vmlinux
fi
-mksysmap vmlinux System.map ${kallsymso}
+mksysmap vmlinux System.map
if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
info SORTTAB vmlinux