[RFC PATCH v4 34/37] arm64: entry: Annotate valid stack in kernel entry

[Chen Zhongjin]

From: Julien Thierry <jthierry@xxxxxxxxxx>

When taking an exception/interrupt, add unwind hints to indicate from
which point the stack pointer is known to be valid.

Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx>
Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
---
 arch/arm64/kernel/entry.S | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 10fac8f13982..eeb576ec97ba 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -68,6 +68,7 @@
 	tbnz	x0, #THREAD_SHIFT, 0f
 	sub	x0, sp, x0			// x0'' = sp' - x0' = (sp + x0) - sp = x0
 	sub	sp, sp, x0			// sp'' = sp' - x0 = (sp + x0) - x0 = sp
+	UNWIND_HINT_FUNC sp_offset=S_FRAME_SIZE
 	b	el\el\ht\()_\regsize\()_\label
 
 0:
@@ -100,6 +101,7 @@
 	sub	sp, sp, x0
 	mrs	x0, tpidrro_el0
 #endif
+	UNWIND_HINT_FUNC sp_offset=S_FRAME_SIZE
 	b	el\el\ht\()_\regsize\()_\label
 .org .Lventry_start\@ + 128	// Did we overflow the ventry slot?
 	.endm
-- 
2.17.1