linux-kernel - [PATCH] LoongArch: Drop -ffreestanding from CFLAGS

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Date:   Fri,  4 Aug 2023 20:56:09 +0800
From:   WANG Xuerui <kernel@...0n.name>
To:     Huacai Chen <chenhuacai@...nel.org>
Cc:     Nathan Chancellor <nathan@...nel.org>, loongarch@...ts.linux.dev,
        llvm@...ts.linux.dev, linux-kernel@...r.kernel.org,
        WANG Xuerui <git@...0n.name>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: [PATCH] LoongArch: Drop -ffreestanding from CFLAGS

From: WANG Xuerui <git@...0n.name>

As explained by Nick in the original issue: the kernel usually does a
good job of providing library helpers that have similar semantics as
their ordinary userspace libc equivalents, but -ffreestanding disables
such libcall optimization and other related features in the compiler,
which can lead to unexpected things such as CONFIG_FORTIFY_SOURCE not
working (!).

As it turns out to be the case, removing the flag does not impact the
LoongArch kernel's normal operation at all; so just remove it to
restore expected libcall semantics globally on this architecture.

Closes: https://github.com/ClangBuiltLinux/linux/issues/1897
Reported-by: Nathan Chancellor <nathan@...nel.org>
Suggested-by: Nick Desaulniers <ndesaulniers@...gle.com>
Signed-off-by: WANG Xuerui <git@...0n.name>
---
 arch/loongarch/Makefile | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index b1e5db51b61c..db0d7210272d 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -83,7 +83,6 @@ KBUILD_CFLAGS_KERNEL		+= -fPIE
 LDFLAGS_vmlinux			+= -static -pie --no-dynamic-linker -z notext
 endif

-cflags-y += -ffreestanding
 cflags-y += $(call cc-option, -mno-check-zero-division)

 load-y		= 0x9000000000200000
-- 
2.40.0