Commit-ID: 9a99417acbad99ba6c6a9389b45a53a4d002bb7e Gitweb: http://git.kernel.org/tip/9a99417acbad99ba6c6a9389b45a53a4d002bb7e Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Sun, 28 Feb 2016 22:22:35 -0600 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Mon, 29 Feb 2016 08:35:10 +0100
objtool: Add STACK_FRAME_NON_STANDARD() macro Add a new macro, STACK_FRAME_NON_STANDARD(), which is used to denote a function which does something unusual related to its stack frame. Use of the macro prevents objtool from emitting a false positive warning. Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Andy Lutomirski <l...@kernel.org> Cc: Arnaldo Carvalho de Melo <a...@kernel.org> Cc: Bernd Petrovitsch <be...@petrovitsch.priv.at> Cc: Borislav Petkov <b...@alien8.de> Cc: Chris J Arges <chris.j.ar...@canonical.com> Cc: Jiri Slaby <jsl...@suse.cz> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Michal Marek <mma...@suse.cz> Cc: Namhyung Kim <namhy...@gmail.com> Cc: Pedro Alves <pal...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: live-patch...@vger.kernel.org Link: http://lkml.kernel.org/r/34487a17b23dba43c50941599d47054a9584b219.1456719558.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/vmlinux.lds.S | 5 ++++- include/linux/frame.h | 23 +++++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 92dc211..13fa0ad 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -343,7 +343,10 @@ SECTIONS /* Sections to be discarded */ DISCARDS - /DISCARD/ : { *(.eh_frame) } + /DISCARD/ : { + *(.eh_frame) + *(__func_stack_frame_non_standard) + } } diff --git a/include/linux/frame.h b/include/linux/frame.h new file mode 100644 index 0000000..e6baaba --- /dev/null +++ b/include/linux/frame.h @@ -0,0 +1,23 @@ +#ifndef _LINUX_FRAME_H +#define _LINUX_FRAME_H + +#ifdef CONFIG_STACK_VALIDATION +/* + * This macro marks the given function's stack frame as "non-standard", which + * tells objtool to ignore the function when doing stack metadata validation. + * It should only be used in special cases where you're 100% sure it won't + * affect the reliability of frame pointers and kernel stack traces. + * + * For more information, see tools/objtool/Documentation/stack-validation.txt. + */ +#define STACK_FRAME_NON_STANDARD(func) \ + static void __used __section(__func_stack_frame_non_standard) \ + *__func_stack_frame_non_standard_##func = func + +#else /* !CONFIG_STACK_VALIDATION */ + +#define STACK_FRAME_NON_STANDARD(func) + +#endif /* CONFIG_STACK_VALIDATION */ + +#endif /* _LINUX_FRAME_H */
