Commit 9a99417a authored Feb 28, 2016 by Josh Poimboeuf Committed by Ingo Molnar Feb 29, 2016

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 <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/34487a17b23dba43c50941599d47054a9584b219.1456719558.git.jpoimboe@redhat.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent c0dd6716

arch/x86/kernel/vmlinux.lds.S

+4 −1

Original line number	Diff line number	Diff line
		@@ -343,7 +343,10 @@ SECTIONS

		/* Sections to be discarded */
		DISCARDS
		/DISCARD/ : { *(.eh_frame) }
		/DISCARD/ : {
		*(.eh_frame)
		*(__func_stack_frame_non_standard)
		}
		}

include/linux/frame.h

0 → 100644

+23 −0

Original line number	Diff line number	Diff line
		#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 */