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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Mon, 16 May 2022 14:14:41 -0700
Message-ID: <CAKwvOd=SkLwa-0i873oUDt9hRQxA=8dbc26v4Di_rysnE=pJpg@mail.gmail.com>
Subject: Re: [PATCH v3 0/4] pass -march= only to compiler
To:     Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ardb@kernel.org>
Cc:     Russell King <rmk+kernel@armlinux.org.uk>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev
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+ Ard (I messed up my command line invocation of git send-email, sorry
for more noise)
https://lore.kernel.org/llvm/20220516210954.1660716-1-ndesaulniers@google.com/

On Mon, May 16, 2022 at 2:10 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> When both -march= and -Wa,-march= are specified for assembler or
> assembler-with-cpp sources, GCC and Clang will prefer the -Wa,-march=
> value but Clang will warn that -march= is unused.
>
> warning: argument unused during compilation: '-march=armv6k'
> [-Wunused-command-line-argument]
>
> This is the top group of warnings we observe when using clang to
> assemble the kernel via `ARCH=arm make LLVM=1`.
>
> Arnd sent a v2 of my previous patch
> https://lore.kernel.org/linux-arm-kernel/20210928154143.2106903-14-arnd@kernel.org/
> I added yet a few more instances I found since then.
>
> Fixing this will allow us to enable
> -Werror=unused-command-line-argument for clang builds.
>
> Nick Desaulniers (4):
>   ARM: remove lazy evaluation in Makefile
>   ARM: use .arch directives instead of assembler command line flags
>   ARM: only use -mtp=cp15 for the compiler
>   ARM: pass -march= only to compiler
>
>  arch/arm/Makefile                   | 76 ++++++++++++++++-------------
>  arch/arm/boot/compressed/Makefile   |  1 -
>  arch/arm/common/Makefile            |  2 -
>  arch/arm/common/mcpm_head.S         |  2 +
>  arch/arm/common/vlock.S             |  2 +
>  arch/arm/kernel/Makefile            |  2 -
>  arch/arm/kernel/hyp-stub.S          |  2 +
>  arch/arm/kernel/swp_emulate.c       |  1 +
>  arch/arm/lib/Makefile               |  4 --
>  arch/arm/lib/delay-loop.S           |  4 ++
>  arch/arm/mach-at91/Makefile         |  3 --
>  arch/arm/mach-at91/pm_suspend.S     |  4 ++
>  arch/arm/mach-imx/Makefile          |  3 --
>  arch/arm/mach-imx/headsmp.S         |  2 +
>  arch/arm/mach-imx/resume-imx6.S     |  2 +
>  arch/arm/mach-imx/suspend-imx6.S    |  2 +
>  arch/arm/mach-mvebu/Makefile        |  3 --
>  arch/arm/mach-mvebu/coherency_ll.S  |  1 +
>  arch/arm/mach-mvebu/pmsu.c          |  1 +
>  arch/arm/mach-npcm/Makefile         |  2 -
>  arch/arm/mach-npcm/headsmp.S        |  2 +
>  arch/arm/mach-tegra/Makefile        |  2 -
>  arch/arm/mach-tegra/reset-handler.S |  2 +
>  arch/arm/mach-tegra/sleep-tegra20.S |  2 +
>  arch/arm/mach-tegra/sleep-tegra30.S |  2 +
>  arch/arm/mm/Makefile                | 15 ------
>  arch/arm/mm/abort-ev6.S             |  1 +
>  arch/arm/mm/abort-ev7.S             |  1 +
>  arch/arm/mm/cache-v6.S              |  2 +
>  arch/arm/mm/cache-v7.S              |  2 +
>  arch/arm/mm/cache-v7m.S             |  2 +
>  arch/arm/mm/copypage-feroceon.c     |  1 +
>  arch/arm/mm/proc-v6.S               |  2 +
>  arch/arm/mm/proc-v7-2level.S        |  2 +
>  arch/arm/mm/proc-v7.S               |  2 +
>  arch/arm/mm/tlb-v6.S                |  2 +
>  arch/arm/mm/tlb-v7.S                |  2 +
>  drivers/memory/Makefile             |  2 -
>  drivers/memory/ti-emif-sram-pm.S    |  1 +
>  drivers/soc/bcm/brcmstb/pm/Makefile |  1 -
>  drivers/soc/bcm/brcmstb/pm/s2-arm.S |  1 +
>  41 files changed, 94 insertions(+), 74 deletions(-)
>
>
> base-commit: 0ac824f379fba2c2b17b75fd5ada69cd68c66348
> --
> 2.36.0.550.gb090851708-goog
>


-- 
Thanks,
~Nick Desaulniers