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| author | Nick Desaulniers <ndesaulniers@google.com> | 2018-08-22 16:37:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-22 17:31:34 -0700 |
| commit | 815f0ddb346c196018d4d8f8f55c12b83da1de3f (patch) | |
| tree | 4805bf7e3cb7ec4e727aba8e62f9211e9001a760 /mm/ksm.c | |
| parent | 899fbc33fd775b9dfa363db28f322272920a2196 (diff) | |
| download | linux-815f0ddb346c196018d4d8f8f55c12b83da1de3f.tar.gz linux-815f0ddb346c196018d4d8f8f55c12b83da1de3f.tar.bz2 linux-815f0ddb346c196018d4d8f8f55c12b83da1de3f.zip | |
include/linux/compiler*.h: make compiler-*.h mutually exclusive
Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6")
recently exposed a brittle part of the build for supporting non-gcc
compilers.
Both Clang and ICC define __GNUC__, __GNUC_MINOR__, and
__GNUC_PATCHLEVEL__ for quick compatibility with code bases that haven't
added compiler specific checks for __clang__ or __INTEL_COMPILER.
This is brittle, as they happened to get compatibility by posing as a
certain version of GCC. This broke when upgrading the minimal version
of GCC required to build the kernel, to a version above what ICC and
Clang claim to be.
Rather than always including compiler-gcc.h then undefining or
redefining macros in compiler-intel.h or compiler-clang.h, let's
separate out the compiler specific macro definitions into mutually
exclusive headers, do more proper compiler detection, and keep shared
definitions in compiler_types.h.
Fixes: cafa0010cd51 ("Raise the minimum required gcc version to 4.6")
Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Suggested-by: Eli Friedman <efriedma@codeaurora.org>
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/ksm.c')
| -rw-r--r-- | mm/ksm.c | 4 |
1 files changed, 2 insertions, 2 deletions
@@ -652,9 +652,9 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node) * list_head to stay clear from the rb_parent_color union * (aligned and different than any node) and also different * from &migrate_nodes. This will verify that future list.h changes - * don't break STABLE_NODE_DUP_HEAD. + * don't break STABLE_NODE_DUP_HEAD. Only recent gcc can handle it. */ -#if GCC_VERSION >= 40903 /* only recent gcc can handle it */ +#if defined(GCC_VERSION) && GCC_VERSION >= 40903 BUILD_BUG_ON(STABLE_NODE_DUP_HEAD <= &migrate_nodes); BUILD_BUG_ON(STABLE_NODE_DUP_HEAD >= &migrate_nodes + 1); #endif |