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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2017-07-24 18:34:14 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-07-25 11:12:45 +0200 |
| commit | 867ac9d737094e46a6c33213f16dd1ec9e8bd5d5 (patch) | |
| tree | 708c868a63e86271f0572ea7120a406bfe7e88a1 /scripts | |
| parent | 9683a64fc3cb67e663859a6bb2e0db5dcee9ed32 (diff) | |
| download | linux-867ac9d737094e46a6c33213f16dd1ec9e8bd5d5.tar.gz linux-867ac9d737094e46a6c33213f16dd1ec9e8bd5d5.tar.bz2 linux-867ac9d737094e46a6c33213f16dd1ec9e8bd5d5.zip | |
objtool: Fix gcov check for older versions of GCC
Objtool tries to silence 'unreachable instruction' warnings when it
detects gcov is enabled, because gcov produces a lot of unreachable
instructions and they don't really matter.
However, the 0-day bot is still reporting some unreachable instruction
warnings with CONFIG_GCOV_KERNEL=y on GCC 4.6.4.
As it turns out, objtool's gcov detection doesn't work with older
versions of GCC because they don't create a bunch of symbols with the
'gcov.' prefix like newer versions of GCC do.
Move the gcov check out of objtool and instead just create a new
'--no-unreachable' flag which can be passed in by the kernel Makefile
when CONFIG_GCOV_KERNEL is defined.
Also rename the 'nofp' variable to 'no_fp' for consistency with the new
'no_unreachable' variable.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 9cfffb116887 ("objtool: Skip all "unreachable instruction" warnings for gcov kernels")
Link: http://lkml.kernel.org/r/c243dc78eb2ffdabb6e927844dea39b6033cd395.1500939244.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/Makefile.build | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 4a9a2cec0a1b..854608d42e85 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -262,6 +262,9 @@ objtool_args = check ifndef CONFIG_FRAME_POINTER objtool_args += --no-fp endif +ifdef CONFIG_GCOV_KERNEL +objtool_args += --no-unreachable +endif # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file |