Commit c8c301ab authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86/ibt: Add ANNOTATE_NOENDBR 



In order to have objtool warn about code references to !ENDBR
instruction, we need an annotation to allow this for non-control-flow
instances -- consider text range checks, text patching, or return
trampolines etc.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.578968224@infradead.org
parent 156ff4a5

include/linux/objtool.h

+16 −0
Original line number Diff line number Diff line
@@ -77,6 +77,12 @@ struct unwind_hint { 
#define STACK_FRAME_NON_STANDARD_FP(func)

#endif



#define ANNOTATE_NOENDBR					\

	"986: \n\t"						\

	".pushsection .discard.noendbr\n\t"			\

	_ASM_PTR " 986b\n\t"					\

	".popsection\n\t"



#else /* __ASSEMBLY__ */



/*
@@ -129,6 +135,13 @@ struct unwind_hint { 
	.popsection

.endm



.macro ANNOTATE_NOENDBR

.Lhere_\@:

	.pushsection .discard.noendbr

	.quad	.Lhere_\@

	.popsection

.endm



#endif /* __ASSEMBLY__ */



#else /* !CONFIG_STACK_VALIDATION */
@@ -139,12 +152,15 @@ struct unwind_hint { 
	"\n\t"

#define STACK_FRAME_NON_STANDARD(func)

#define STACK_FRAME_NON_STANDARD_FP(func)

#define ANNOTATE_NOENDBR

#else

#define ANNOTATE_INTRA_FUNCTION_CALL

.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0

.endm

.macro STACK_FRAME_NON_STANDARD func:req

.endm

.macro ANNOTATE_NOENDBR

.endm

#endif



#endif /* CONFIG_STACK_VALIDATION */

tools/include/linux/objtool.h

+16 −0
Original line number Diff line number Diff line
@@ -77,6 +77,12 @@ struct unwind_hint { 
#define STACK_FRAME_NON_STANDARD_FP(func)

#endif



#define ANNOTATE_NOENDBR					\

	"986: \n\t"						\

	".pushsection .discard.noendbr\n\t"			\

	_ASM_PTR " 986b\n\t"					\

	".popsection\n\t"



#else /* __ASSEMBLY__ */



/*
@@ -129,6 +135,13 @@ struct unwind_hint { 
	.popsection

.endm



.macro ANNOTATE_NOENDBR

.Lhere_\@:

	.pushsection .discard.noendbr

	.quad	.Lhere_\@

	.popsection

.endm



#endif /* __ASSEMBLY__ */



#else /* !CONFIG_STACK_VALIDATION */
@@ -139,12 +152,15 @@ struct unwind_hint { 
	"\n\t"

#define STACK_FRAME_NON_STANDARD(func)

#define STACK_FRAME_NON_STANDARD_FP(func)

#define ANNOTATE_NOENDBR

#else

#define ANNOTATE_INTRA_FUNCTION_CALL

.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0

.endm

.macro STACK_FRAME_NON_STANDARD func:req

.endm

.macro ANNOTATE_NOENDBR

.endm

#endif



#endif /* CONFIG_STACK_VALIDATION */