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>
This commit is contained in:
Josh Poimboeuf 2017-03-01 12:04:44 -06:00 committed by Ingo Molnar
parent 55149d0653
commit e390f9a968
6 changed files with 10 additions and 8 deletions

View file

@ -200,7 +200,7 @@
#ifdef CONFIG_STACK_VALIDATION
#define annotate_unreachable() ({ \
asm("%c0:\t\n" \
".pushsection __unreachable, \"a\"\t\n" \
".pushsection .discard.unreachable\t\n" \
".long %c0b - .\t\n" \
".popsection\t\n" : : "i" (__LINE__)); \
})