kbuild: reuse mksysmap output for kallsyms

scripts/mksysmap internally runs ${NM} (dropping some symbols).

When CONFIG_KALLSYMS=y, mksysmap creates .tmp_System.map, but it is
almost the same as the output from the ${NM} invocation in kallsyms().
It is true scripts/mksysmap drops some symbols, but scripts/kallsyms.c
ignores more anyway.

Keep the mksysmap output as *.syms, and reuse it for kallsyms and
'cmp -s'. It saves one ${NM} invocation.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 23ac13fd9d89a861352f4c6818cb75bb027e9427..6492c0862657541f41fb1d0952a9a3b21b244b2b 100755 (executable)
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -157,7 +157,7 @@ kallsyms()
        fi
 
        info KSYMS ${2}
-       ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2}
+       cat ${1} | scripts/kallsyms ${kallsymopt} > ${2}
 }
 
 # Perform one step in kallsyms generation, including temporary linking of
@@ -170,7 +170,8 @@ kallsyms_step()
        kallsyms_S=${kallsyms_vmlinux}.S
 
        vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
-       kallsyms ${kallsyms_vmlinux} ${kallsyms_S}
+       mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms
+       kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S}
 
        info AS ${kallsyms_S}
        ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
@@ -182,6 +183,7 @@ kallsyms_step()
 # See mksymap for additional details
 mksysmap()
 {
+       info NM ${2}
        ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
 }
 
@@ -283,7 +285,6 @@ if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then
        ${RESOLVE_BTFIDS} vmlinux
 fi
 
-info SYSMAP System.map
 mksysmap vmlinux System.map
 
 if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
@@ -296,9 +297,7 @@ fi
 
 # step a (see comment above)
 if is_enabled CONFIG_KALLSYMS; then
-       mksysmap ${kallsyms_vmlinux} .tmp_System.map
-
-       if ! cmp -s System.map .tmp_System.map; then
+       if ! cmp -s System.map ${kallsyms_vmlinux}.syms; then
                echo >&2 Inconsistent kallsyms data
                echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
                exit 1