[RFC v5 48/57] arm64: sleep: Prevent stack frame warnings from objtool

From: Julien Thierry
Date: Thu Jan 09 2020 - 11:09:03 EST


From: Raphael Gault <raphael.gault@xxxxxxx>

This code doesn't respect the Arm PCS but it is intended this
way. Adapting it to respect the PCS would result in altering the
behaviour.

In order to suppress objtool's warnings, we setup a stack frame
for __cpu_suspend_enter and annotate cpu_resume and _cpu_resume
as having non-standard stack frames.

Signed-off-by: Raphael Gault <raphael.gault@xxxxxxx>
Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx>
---
arch/arm64/kernel/sleep.S | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index f5b04dd8a710..55c7c099d32c 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -1,5 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/errno.h>
+#include <linux/frame.h>
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
@@ -90,6 +91,7 @@ ENTRY(__cpu_suspend_enter)
str x0, [x1]
add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS
stp x29, lr, [sp, #-16]!
+ mov x29, sp
bl cpu_do_suspend
ldp x29, lr, [sp], #16
mov x0, #1
@@ -146,3 +148,6 @@ ENTRY(_cpu_resume)
mov x0, #0
ret
ENDPROC(_cpu_resume)
+
+ asm_stack_frame_non_standard cpu_resume
+ asm_stack_frame_non_standard _cpu_resume
--
2.21.0