Re: [PATCH v3 3/4] ARM: only use -mtp=cp15 for the compiler

From: Nick Desaulniers <ndesaulniers@google.com>
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
Subject: Re: [PATCH v3 3/4] ARM: only use -mtp=cp15 for the compiler
Date: Mon, 16 May 2022 14:15:58 -0700	[thread overview]
Message-ID: <CAKwvOd=x9Fcedp8TaHtReLtjc0MARRH8Wo7aCCLfyG-rV02okA@mail.gmail.com> (raw)
In-Reply-To: <20220516210954.1660716-4-ndesaulniers@google.com>

+ 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:
>
> Avoids an error from the assembler for CONFIG_THUMB2 kernels:
>
> clang-15: error: hardware TLS register is not supported for the thumbv4t
> sub-architecture
>
> This flag only makes sense to pass to the compiler, not the assembler.
>
> Perhaps CFLAGS_ABI can be renamed to CPPFLAGS_ABI to reflect that they
> will be passed to both the compiler and assembler for sources that
> require pre-processing.
>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
>  arch/arm/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index 99a7ed7e9f09..1029c2503aef 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -108,7 +108,7 @@ CFLAGS_ABI  += -meabi gnu
>  endif
>
>  ifeq ($(CONFIG_CURRENT_POINTER_IN_TPIDRURO),y)
> -CFLAGS_ABI     += -mtp=cp15
> +KBUILD_CFLAGS  += -mtp=cp15
>  endif
>
>  # Accept old syntax despite ".syntax unified"
> --
> 2.36.0.550.gb090851708-goog
>


-- 
Thanks,
~Nick Desaulniers