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Subject[PATCH 06/29] 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-coontrol-flow
instances -- consider text range checks, text patching, or return
trampolines etc.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/linkage.h | 11 +++++++++++
include/linux/instruction_pointer.h | 5 +++++
include/linux/objtool.h | 13 +++++++++++++
3 files changed, 29 insertions(+)

--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -78,6 +78,12 @@ 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__ */

/*
@@ -130,6 +136,13 @@ struct unwind_hint {
.popsection
.endm

+.macro ANNOTATE_NOENDBR
+.Lhere_\@:
+ .pushsection .discard.noendbr
+ .quad .Lhere_\@
+ .popsection
+.endm
+
#endif /* __ASSEMBLY__ */

#else /* !CONFIG_STACK_VALIDATION */

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