From: Arnd Bergmann <arnd@kernel.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Miguel Ojeda <ojeda@kernel.org>,
Fangrui Song <maskray@google.com>,
Michal Marek <michal.lkml@markovi.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Nathan Chancellor <nathan@kernel.org>
Subject: Re: [PATCH 2/2] Makefile: drop CROSS_COMPILE for LLVM=1 LLVM_IAS=1
Date: Thu, 8 Jul 2021 13:44:52 +0200 [thread overview]
Message-ID: <CAK8P3a1MW9hYzDT-iL4CpwaJ5NUuQODT3XgheocrnF7496GKFw@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNAR66iE0w4bjpMVEz6W==mnc59MEnRWm1MXrqApP0aE4Qw@mail.gmail.com>
On Thu, Jul 8, 2021 at 12:23 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
> On Thu, Jul 8, 2021 at 7:43 AM 'Nick Desaulniers' via Clang Built
>
> We must rely on this behavior of Clang because
> --target (which is contained in CLANG_FLAGS)
> must be specified before the Kconfig time.
> Then, a user can toggle CONFIG_64BIT any time
> from menuconfig etc.
>
> With this in mind, using $(ARCH) as if-else
> switches is pointless.
> $(SRCARCH) is the only meaningful input.
>
>
> else ifeq ($(ARCH),i386)
> CLANG_FLAGS += --target=i686-linux-gnu
> else ifeq ($(ARCH),x86)
> CLANG_FLAGS += --target=x86_64-linux-gnu
> else ifeq ($(ARCH),x86_64)
> CLANG_FLAGS += --target=x86_64-linux-gnu
>
> should be replaced with:
>
> else ifeq ($(SRCARCH),x86_64)
> CLANG_FLAGS += --target=x86_64-linux-gnu
I think we usually only have to provide the architecture
name, as in "--target=x86_64", though for arm I get a
warning "clang: warning: unknown platform, assuming
-mfloat-abi=soft" unless I provide the full triple.
> For example for ARCH=arm, which is better
> --target=arm-linux-gnueabi or
> --target=arm-lnux-gnueabihf or something we don't care about?
The kernel is always soft-float itself, so it does not matter either way.
Arnd
next prev parent reply other threads:[~2021-07-08 11:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-07 22:43 [PATCH 0/2] infer CROSS_COMPILE from ARCH for LLVM=1 LLVM_IAS=1 Nick Desaulniers
2021-07-07 22:43 ` [PATCH 1/2] Makefile: move initial clang flag handling into scripts/Makefile.clang Nick Desaulniers
2021-07-07 22:43 ` [PATCH 2/2] Makefile: drop CROSS_COMPILE for LLVM=1 LLVM_IAS=1 Nick Desaulniers
2021-07-08 8:08 ` Geert Uytterhoeven
2021-07-08 8:44 ` Masahiro Yamada
2021-07-08 10:21 ` Masahiro Yamada
2021-07-08 11:44 ` Arnd Bergmann [this message]
2021-07-08 19:06 ` Nick Desaulniers
2021-07-08 19:02 ` Nick Desaulniers
2021-07-08 19:47 ` Masahiro Yamada
2021-07-08 5:49 ` [PATCH 0/2] infer CROSS_COMPILE from ARCH " Christoph Hellwig
2021-07-08 7:27 ` Arnd Bergmann
2021-07-08 18:04 ` Nick Desaulniers
2021-07-09 8:07 ` Arnd Bergmann
2021-07-14 18:09 ` Nick Desaulniers
2021-07-14 20:18 ` Arnd Bergmann
2021-07-19 21:10 ` Nick Desaulniers
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