On Mon, Nov 14, 2022 at 8:44 PM Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx> wrote:
From: Jiri Slaby <jslaby@xxxxxxx>
Until the link-vmlinux.sh split (cf. the commit below), the linker was
run with jobserver set in MAKEFLAGS. After the split, the command in
Makefile.vmlinux_o is not prefixed by "+" anymore, so this information
is lost.
Restore it as linkers working in parallel (namely gcc LTO) make a use of
it. Actually, they complain, if jobserver is not set:
lto-wrapper: warning: jobserver is not available: '--jobserver-auth=' is not present in 'MAKEFLAGS'
Fixes: 5d45950dfbb1 (kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o)
This Fixes is wrong since GCC LTO is not in upstream code.