alistair23-linux/include/linux/frame.h
Josh Poimboeuf e390f9a968 objtool, modules: Discard objtool annotation sections for modules
The '__unreachable' and '__func_stack_frame_non_standard' sections are
only used at compile time.  They're discarded for vmlinux but they
should also be discarded for modules.

Since this is a recurring pattern, prefix the section names with
".discard.".  It's a nice convention and vmlinux.lds.h already discards
such sections.

Also remove the 'a' (allocatable) flag from the __unreachable section
since it doesn't make sense for a discarded section.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: d1091c7fa3 ("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-01 20:32:25 +01:00

24 lines
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C

#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(.discard.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 */