From: Nathan Chancellor <nathan@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, Ard Biesheuvel <ardb@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com,
Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH 2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS
Date: Thu, 25 Mar 2021 17:04:34 -0700 [thread overview]
Message-ID: <20210326000435.4785-3-nathan@kernel.org> (raw)
In-Reply-To: <20210326000435.4785-1-nathan@kernel.org>
When cross compiling x86 on an ARM machine with clang, there are several
errors along the lines of:
arch/x86/include/asm/string_64.h:27:10: error: invalid output constraint
'=&c' in asm
This happens because the compressed boot Makefile reassigns KBUILD_CFLAGS
and drops the clang flags that set the target architecture ('--target=')
and the path to the GNU cross tools ('--prefix='), meaning that the host
architecture is targeted.
These flags are available as $(CLANG_FLAGS) from the main Makefile so
add them to the compressed boot folder's KBUILD_CFLAGS so that cross
compiling works as expected.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
arch/x86/boot/compressed/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index e0bc3988c3fa..6e5522aebbbd 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -46,6 +46,7 @@ KBUILD_CFLAGS += -D__DISABLE_EXPORTS
# Disable relocation relaxation in case the link is not PIE.
KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no)
KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h
+KBUILD_CFLAGS += $(CLANG_FLAGS)
# sev-es.c indirectly inludes inat-table.h which is generated during
# compilation and stored in $(objtree). Add the directory to the includes so
--
2.31.0
next prev parent reply other threads:[~2021-03-26 0:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 0:04 [PATCH 0/3] Fix cross compiling x86 with clang Nathan Chancellor
2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor
2021-03-26 8:42 ` Sedat Dilek
2021-03-26 13:13 ` [tip: x86/build] x86/build: " tip-bot2 for John Millikin
2021-03-26 13:38 ` [PATCH 1/3] x86: " John Millikin
2021-03-26 0:04 ` Nathan Chancellor [this message]
2021-03-26 13:13 ` [tip: x86/build] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS tip-bot2 for Nathan Chancellor
2021-03-26 0:04 ` [PATCH 3/3] efi/libstub: Add $(CLANG_FLAGS) to x86 flags Nathan Chancellor
2021-03-26 13:13 ` [tip: x86/build] " tip-bot2 for Nathan Chancellor
2021-03-26 8:43 ` [PATCH 0/3] Fix cross compiling x86 with clang Ard Biesheuvel
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