Re: [PATCH v2 1/2] kbuild: pass jobserver to cmd_ld_vmlinux.o

From: Jiri Slaby
Date: Tue Sep 20 2022 - 02:16:36 EST


On 19. 07. 22, 11:15, Masahiro Yamada wrote:
On Tue, Jul 19, 2022 at 5:41 PM Jiri Slaby <jslaby@xxxxxxx> wrote:

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 (esp. the LTO ones) make a use
of it. In this case, it is gcc producing this warning otherwise:
lto-wrapper: warning: jobserver is not available: ‘--jobserver-auth=’ is not present in ‘MAKEFLAGS’

Cc: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Michal Marek <michal.lkml@xxxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: Signed-off-by: Martin Liska <mliska@xxxxxxx>
Fixes: 5d45950dfbb1 (kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o)
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---

Notes:
[v2] only commit message updated


Did you read my previous email?

https://lore.kernel.org/linux-kbuild/CAK7LNAS46hrVh3FNiHHL8_Hqp85VgWnsHyjQ4t-TFH_H344NOg@xxxxxxxxxxxxxx/

Huh, I neither received this email nor the linked one to my inbox. @suse.cz somehow filters mails from you :/. Let me figure out (and use kernel.org account for now). (And get back to your comments too.)

scripts/Makefile.vmlinux_o | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 84019814f33f..886db0659d9c 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -65,7 +65,7 @@ define rule_ld_vmlinux.o
endef

vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
- $(call if_changed_rule,ld_vmlinux.o)
+ +$(call if_changed_rule,ld_vmlinux.o)

targets += vmlinux.o

--
2.37.1




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