From: David Gow <davidgow@google.com>
To: Kees Cook <keescook@chromium.org>
Cc: Jeff Dike <jdike@addtoit.com>,
Richard Weinberger <richard@nod.at>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <nathan@kernel.org>,
linux-um <linux-um@lists.infradead.org>,
linux-kbuild@vger.kernel.org,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
KUnit Development <kunit-dev@googlegroups.com>,
llvm@lists.linux.dev,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
x86@kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] um: Allow builds with Clang
Date: Thu, 17 Feb 2022 10:59:27 +0800 [thread overview]
Message-ID: <CABVgOSk=oFxsbSbQE-v65VwR2+mXeGXDDjzq8t7FShwjJ3+kUg@mail.gmail.com> (raw)
In-Reply-To: <20220217002843.2312603-1-keescook@chromium.org>
On Thu, Feb 17, 2022 at 8:28 AM Kees Cook <keescook@chromium.org> wrote:
>
> Add x86-64 target for Clang+um and update user-offsets.c to use
> Clang-friendly assembler, similar to the fix from commit cf0c3e68aa81
> ("kbuild: fix asm-offset generation to work with clang").
>
> This lets me run KUnit tests with Clang:
>
> $ ./tools/testing/kunit/kunit.py config --make_options LLVM=1
> ...
> $ ./tools/testing/kunit/kunit.py run --make_options LLVM=1
> ...
>
> Cc: Jeff Dike <jdike@addtoit.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: David Gow <davidgow@google.com>
> Cc: linux-um@lists.infradead.org
> Cc: linux-kbuild@vger.kernel.org
> Cc: linux-kselftest@vger.kernel.org
> Cc: kunit-dev@googlegroups.com
> Cc: llvm@lists.linux.dev
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
Thanks, this worked fine for me, with one small note:
I get the following warning with clang (13.0.1) under UML (but not
under x86_64):
clang: warning: argument unused during compilation:
'-mno-global-merge' [-Wunused-command-line-argument]
It's not really a problem unless -Werror is enabled, though, so this
is still definitely an improvement over clang not working at all.
With that caveat, this is:
Tested-by: David Gow <davidgow@google.com>
Cheers,
-- David
> arch/x86/um/user-offsets.c | 4 ++--
> scripts/Makefile.clang | 1 +
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
> index bae61554abcc..d9071827b515 100644
> --- a/arch/x86/um/user-offsets.c
> +++ b/arch/x86/um/user-offsets.c
> @@ -10,10 +10,10 @@
> #include <asm/types.h>
>
> #define DEFINE(sym, val) \
> - asm volatile("\n->" #sym " %0 " #val : : "i" (val))
> + asm volatile("\n.ascii \"->" #sym " %0 " #val "\"": : "i" (val))
>
> #define DEFINE_LONGS(sym, val) \
> - asm volatile("\n->" #sym " %0 " #val : : "i" (val/sizeof(unsigned long)))
> + asm volatile("\n.ascii \"->" #sym " %0 " #val "\"": : "i" (val/sizeof(unsigned long)))
>
> void foo(void)
> {
> diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang
> index 51fc23e2e9e5..857b23de51c6 100644
> --- a/scripts/Makefile.clang
> +++ b/scripts/Makefile.clang
> @@ -10,6 +10,7 @@ CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu
> CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu
> CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu
> CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu
> +CLANG_TARGET_FLAGS_um := x86_64-linux-gnu
> CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH))
>
> ifeq ($(CROSS_COMPILE),)
> --
> 2.30.2
>
> --
> You received this message because you are subscribed to the Google Groups "KUnit Development" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kunit-dev+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kunit-dev/20220217002843.2312603-1-keescook%40chromium.org.
next prev parent reply other threads:[~2022-02-17 2:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 0:28 [PATCH] um: Allow builds with Clang Kees Cook
2022-02-17 0:37 ` Nathan Chancellor
2022-02-17 2:59 ` David Gow [this message]
2022-02-17 4:54 ` Masahiro Yamada
2022-02-17 17:41 ` Nathan Chancellor
2022-02-18 2:19 ` Masahiro Yamada
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