diff mbox series

[02/46] kbuild: pass jobserver to cmd_ld_vmlinux.o

Message ID	20221114114344.18650-3-jirislaby@kernel.org
State	New
Headers	Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; From: "Jiri Slaby (SUSE)" <jirislaby@kernel.org> To: linux-kernel@vger.kernel.org Cc: Jiri Slaby <jslaby@suse.cz>, Sedat Dilek <sedat.dilek@gmail.com>, Masahiro Yamada <masahiroy@kernel.org>, Michal Marek <michal.lkml@markovi.net>, Nick Desaulniers <ndesaulniers@google.com>, Martin Liska <mliska@suse.cz> Subject: [PATCH 02/46] kbuild: pass jobserver to cmd_ld_vmlinux.o Date: Mon, 14 Nov 2022 12:43:00 +0100 Message-Id: <20221114114344.18650-3-jirislaby@kernel.org> In-Reply-To: <20221114114344.18650-1-jirislaby@kernel.org> References: <20221114114344.18650-1-jirislaby@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	gcc-LTO support for the kernel \| [00/46] gcc-LTO support for the kernel [01/46] x86/boot: robustify calling startup_{32,64}() from the decompressor code [02/46] kbuild: pass jobserver to cmd_ld_vmlinux.o [03/46] kbuild: lto: preserve MAKEFLAGS for module linking [04/46] compiler.h: introduce __visible_on_lto [05/46] compiler.h: introduce __global_on_lto [06/46] Compiler Attributes, lto: introduce __noreorder [07/46] tracepoint, lto: Mark static call functions as __visible [08/46] static_call, lto: Mark static keys as __visible [09/46] static_call, lto: Mark static_call_return0() as __visible [10/46] static_call, lto: Mark func_a() as __visible_on_lto [11/46] x86/alternative, lto: Mark int3_() as global and __visible [12/46] x86/paravirt, lto: Mark native_steal_clock() as __visible_on_lto [13/46] x86/preempt, lto: Mark preempt_schedule_thunk() as __visible [14/46] x86/sev, lto: Mark cpuid_table_copy as __visible_on_lto [15/46] x86/xen, lto: Mark xen_vcpu_stolen() as __visible [16/46] x86, lto: Mark gdt_page and native_sched_clock() as __visible [17/46] amd, lto: Mark amd pmu and pstate functions as __visible_on_lto [18/46] entry, lto: Mark raw_irqentry_exit_cond_resched() as __visible [19/46] export, lto: Mark __kstrtab* in EXPORT_SYMBOL() as global and __visible [20/46] softirq, lto: Mark irq_enter/exit_rcu() as __visible [21/46] btf, lto: pass scope as strings [22/46] btf, lto: Make all BTF IDs global on LTO [23/46] init.h, lto: mark initcalls as __noreorder [24/46] bpf, lto: mark interpreter jump table as __noreorder [25/46] sched, lto: mark sched classes as __noreorder [26/46] x86/apic, lto: Mark apic_driver*() as __noreorder [27/46] linkage, lto: use C version for SYSCALL_ALIAS() / cond_syscall() [28/46] scripts, lto: re-add gcc-ld [29/46] scripts, lto: use CONFIG_LTO for many LTO specific actions [30/46] Kbuild, lto: Add Link Time Optimization support [31/46] x86/purgatory, lto: Disable gcc LTO for purgatory [32/46] x86/realmode, lto: Disable gcc LTO for real mode code [33/46] x86/vdso, lto: Disable gcc LTO for the vdso [34/46] scripts, lto: disable gcc LTO for some mod sources [35/46] Kbuild, lto: disable gcc LTO for bounds+asm-offsets [36/46] lib/string, lto: disable gcc LTO for string.o [37/46] Compiler attributes, lto: disable __flatten with LTO [38/46] Kbuild, lto: don't include weak source file symbols in System.map [39/46] x86, lto: Disable relative init pointers with gcc LTO [40/46] x86/livepatch, lto: Disable live patching with gcc LTO [41/46] x86/lib, lto: Mark 32bit mem{cpy,move,set} as __used [42/46] mm/kasan, lto: Mark kasan mem{cpy,move,set} as __used [43/46] scripts, lto: check C symbols for modversions [44/46] scripts/bloat-o-meter, lto: handle gcc LTO [45/46] kasan, lto: remove extra BUILD_BUG() in memory_is_poisoned [46/46] x86, lto: Finally enable gcc LTO for x86

Commit Message

Jiri Slaby Nov. 14, 2022, 11:43 a.m. UTC

  From: Jiri Slaby <jslaby@suse.cz>

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)
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Martin Liska <mliska@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 scripts/Makefile.vmlinux_o | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Masahiro Yamada Nov. 14, 2022, 5:57 p.m. UTC | #1

On Mon, Nov 14, 2022 at 8:44 PM Jiri Slaby (SUSE) <jirislaby@kernel.org> wrote:
>
> From: Jiri Slaby <jslaby@suse.cz>
>
> 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.






> Cc: Sedat Dilek <sedat.dilek@gmail.com>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Michal Marek <michal.lkml@markovi.net>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Martin Liska <mliska@suse.cz>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> ---
>  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 0edfdb40364b..1c86895cfcf8 100644
> --- a/scripts/Makefile.vmlinux_o
> +++ b/scripts/Makefile.vmlinux_o
> @@ -58,7 +58,7 @@ define rule_ld_vmlinux.o
>  endef
>
>  vmlinux.o: $(initcalls-lds) vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
> -       $(call if_changed_rule,ld_vmlinux.o)
> +       +$(call if_changed_rule,ld_vmlinux.o)
>
>  targets += vmlinux.o
>
> --
> 2.38.1
>

Jiri Slaby Nov. 15, 2022, 6:36 a.m. UTC | #2

On 14. 11. 22, 18:57, Masahiro Yamada wrote:
> On Mon, Nov 14, 2022 at 8:44 PM Jiri Slaby (SUSE) <jirislaby@kernel.org> wrote:
>>
>> From: Jiri Slaby <jslaby@suse.cz>
>>
>> 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.

Yup, this is a left-over. Now dropped from both.

thanks,

diff mbox series

Patch

diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 0edfdb40364b..1c86895cfcf8 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -58,7 +58,7 @@  define rule_ld_vmlinux.o
 endef
 
 vmlinux.o: $(initcalls-lds) vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
-	$(call if_changed_rule,ld_vmlinux.o)
+	+$(call if_changed_rule,ld_vmlinux.o)
 
 targets += vmlinux.o