[RFC v5 47/57] arm64: assembler: Add macro to annotate asm function having non standard stack-frame.

From: Julien Thierry
Date: Thu Jan 09 2020 - 11:09:02 EST


From: Raphael Gault <raphael.gault@xxxxxxx>

Some functions don't have standard stack-frames but are intended
this way. In order for objtool to ignore those particular cases
we add a macro that enables us to annotate the cases we chose
to mark as particular.

Signed-off-by: Raphael Gault <raphael.gault@xxxxxxx>
Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx>
---
include/linux/frame.h | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/include/linux/frame.h b/include/linux/frame.h
index 02d3ca2d9598..1e35e58ab259 100644
--- a/include/linux/frame.h
+++ b/include/linux/frame.h
@@ -11,14 +11,31 @@
*
* For more information, see tools/objtool/Documentation/stack-validation.txt.
*/
+#ifndef __ASSEMBLY__
#define STACK_FRAME_NON_STANDARD(func) \
static void __used __section(.discard.func_stack_frame_non_standard) \
*__func_stack_frame_non_standard_##func = func
+#else
+ /*
+ * This macro is the arm64 assembler equivalent of the
+ * macro STACK_FRAME_NON_STANDARD define at
+ * ~/include/linux/frame.h
+ */
+ .macro asm_stack_frame_non_standard func
+ .pushsection ".discard.func_stack_frame_non_standard"
+ .quad \func
+ .popsection
+ .endm

+#endif /* __ASSEMBLY__ */
#else /* !CONFIG_STACK_VALIDATION */

+#ifndef __ASSEMBLY__
#define STACK_FRAME_NON_STANDARD(func)
-
+#else
+ .macro asm_stack_frame_non_standard func
+ .endm
+#endif /* __ASSEMBLY__ */
#endif /* CONFIG_STACK_VALIDATION */

#endif /* _LINUX_FRAME_H */
--
2.21.0