Building an X86_64 kernel with W=1 throws a total of 9,948 lines of warnings of
this form for both 32-bit and 64-bit syscall tables. Given that the entire rest
of the build for my config only generates 8,375 lines of output, this is a big
reduction in the warnings generated.
The warnings follow this pattern:
./arch/x86/include/generated/asm/syscalls_32.h:885:21: warning: initialized field overwritten [-Woverride-init]
__SYSCALL_I386(379, compat_sys_pwritev2, )
^
arch/x86/entry/syscall_32.c:13:46: note: in definition of macro '__SYSCALL_I386'
#define __SYSCALL_I386(nr, sym, qual) [nr] = sym,
^~~
./arch/x86/include/generated/asm/syscalls_32.h:885:21: note: (near initialization for 'ia32_sys_call_table[379]')
__SYSCALL_I386(379, compat_sys_pwritev2, )
^
arch/x86/entry/syscall_32.c:13:46: note: in definition of macro '__SYSCALL_I386'
#define __SYSCALL_I386(nr, sym, qual) [nr] = sym,
Since we intentionally build the syscall tables this way, ignore that one
warning in the two files.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/7464.1470021890@turing-police.cc.vt.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Code which runs outside the kernel's normal mode of operation often does
unusual things which can cause a static analysis tool like objtool to
emit false positive warnings:
- boot image
- vdso image
- relocation
- realmode
- efi
- head
- purgatory
- modpost
Set OBJECT_FILES_NON_STANDARD for their related files and directories,
which will tell objtool to skip checking them. It's ok to skip them
because they don't affect runtime stack traces.
Also skip the following code which does the right thing with respect to
frame pointers, but is too "special" to be validated by a tool:
- entry
- mcount
Also skip the test_nx module because it modifies its exception handling
table at runtime, which objtool can't understand. Fortunately it's
just a test module so it doesn't matter much.
Currently objtool is the only user of OBJECT_FILES_NON_STANDARD, but it
might eventually be useful for other tools.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/366c080e3844e8a5b6a0327dc7e8c2b90ca3baeb.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
