From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> [ Upstream commit c8c301abeae58ec756b8fcb2178a632bd3c9e284 ] 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: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220308154317.578968224@xxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/linux/objtool.h | 16 ++++++++++++++++ tools/include/linux/objtool.h | 16 ++++++++++++++++ 2 files changed, 32 insertions(+) --- a/include/linux/objtool.h +++ b/include/linux/objtool.h @@ -82,6 +82,12 @@ 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__ */ /* @@ -128,6 +134,13 @@ struct unwind_hint { .popsection .endm +.macro ANNOTATE_NOENDBR +.Lhere_\@: + .pushsection .discard.noendbr + .quad .Lhere_\@ + .popsection +.endm + #endif /* __ASSEMBLY__ */ #else /* !CONFIG_STACK_VALIDATION */ @@ -138,10 +151,13 @@ 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 type:req sp_reg=0 sp_offset=0 end=0 .endm +.macro ANNOTATE_NOENDBR +.endm #endif #endif /* CONFIG_STACK_VALIDATION */ --- a/tools/include/linux/objtool.h +++ b/tools/include/linux/objtool.h @@ -82,6 +82,12 @@ 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__ */ /* @@ -128,6 +134,13 @@ struct unwind_hint { .popsection .endm +.macro ANNOTATE_NOENDBR +.Lhere_\@: + .pushsection .discard.noendbr + .quad .Lhere_\@ + .popsection +.endm + #endif /* __ASSEMBLY__ */ #else /* !CONFIG_STACK_VALIDATION */ @@ -138,10 +151,13 @@ 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 type:req sp_reg=0 sp_offset=0 end=0 .endm +.macro ANNOTATE_NOENDBR +.endm #endif #endif /* CONFIG_STACK_VALIDATION */
