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 3/3] efi/libstub: Add $(CLANG_FLAGS) to x86 flags
Date: Thu, 25 Mar 2021 17:04:35 -0700 [thread overview]
Message-ID: <20210326000435.4785-4-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/page_64.h:52:7: error: invalid output constraint
'=D' in asm
This happens because the x86 flags in the EFI stub are not derived from
KBUILD_CFLAGS like the other architectures are and the clang flags that
set the target architecture ('--target=') and the path to the GNU cross
tools ('--prefix=') are not present, meaning that the host architecture
is targeted.
These flags are available as $(CLANG_FLAGS) from the main Makefile so
add them to the cflags for x86 so that cross compiling works as
expected.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
drivers/firmware/efi/libstub/Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index c23466e05e60..d0537573501e 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -13,7 +13,8 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \
-Wno-pointer-sign \
$(call cc-disable-warning, address-of-packed-member) \
$(call cc-disable-warning, gnu) \
- -fno-asynchronous-unwind-tables
+ -fno-asynchronous-unwind-tables \
+ $(CLANG_FLAGS)
# arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
# disable the stackleak plugin
--
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 ` [PATCH 2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS Nathan Chancellor
2021-03-26 13:13 ` [tip: x86/build] " tip-bot2 for Nathan Chancellor
2021-03-26 0:04 ` Nathan Chancellor [this message]
2021-03-26 13:13 ` [tip: x86/build] efi/libstub: Add $(CLANG_FLAGS) to x86 flags 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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