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authorNick Desaulniers <ndesaulniers@google.com>2020-10-13 16:47:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-13 18:38:26 -0700
commit4c207c50ea35abf98f087bbcda8c95b23c4bb3b1 (patch)
treeb56e20e6b3d410cb5d433ed51d8ec815256fc146 /Makefile
parent1f7a44f63e6c782c9c2aa9f18f40c23914e6b46a (diff)
Revert "kbuild: disable clang's default use of -fmerge-all-constants"
This reverts commit 87e0d4f0f37fb0c8c4aeeac46fff5e957738df79. -fno-merge-all-constants has been the default since clang-6; the minimum supported version of clang in the kernel is clang-10 (10.0.1). Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Marco Elver <elver@google.com> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200902225911.209899-3-ndesaulniers@google.com Link: https://reviews.llvm.org/rL329300. Link: https://github.com/ClangBuiltLinux/linux/issues/9 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile9
1 files changed, 0 insertions, 9 deletions
diff --git a/Makefile b/Makefile
index 51540b291738..342d26432553 100644
--- a/Makefile
+++ b/Makefile
@@ -921,15 +921,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized)
# disable invalid "can't wrap" optimizations for signed / pointers
KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow)
-# clang sets -fmerge-all-constants by default as optimization, but this
-# is non-conforming behavior for C and in fact breaks the kernel, so we
-# need to disable it here generally.
-KBUILD_CFLAGS += $(call cc-option,-fno-merge-all-constants)
-
-# for gcc -fno-merge-all-constants disables everything, but it is fine
-# to have actual conforming behavior enabled.
-KBUILD_CFLAGS += $(call cc-option,-fmerge-constants)
-
# Make sure -fstack-check isn't enabled (like gentoo apparently did)
KBUILD_CFLAGS += $(call cc-option,-fno-stack-check,)