[PATCH master 1/3] ARM: asm: fix miscompilation of 32-bit ENTRY_FUNCTION_WITHSTACK

[Ahmad Fatoum]

gcc-11.1.1 shipped with OSELAS.Toolchain-2021.07.0 hoists a single
instruction from __ARM_SETUP_STACK in front of __barebox_arm_head
breaking the barebox header format for the Raspberry Pi 3. This can't
happen with ARM64 and the Raspberry Pi entry points are currently the
only 32-bit users.

While the resulting barebox image was still bootable, header detection
would fail. Add an intermediate naked function to work around this.

This is not required for plain ENTRY_FUNCTION, because the
board-supplied entry point is already NAKED. For
ENTRY_FUNCTION_WITH_FUNCTION, that same entry point is intentionally
non-naked to reduce pitfalls for board code authors..

Fixes: 880c9803b95a ("ARM: implement ENTRY_FUNCTION_WITHSTACK")
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 arch/arm/include/asm/barebox-arm.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/barebox-arm.h b/arch/arm/include/asm/barebox-arm.h
index d915cde294a4..bee906f3a97b 100644
--- a/arch/arm/include/asm/barebox-arm.h
+++ b/arch/arm/include/asm/barebox-arm.h
@@ -194,6 +194,7 @@ static inline unsigned long arm_mem_barebox_image(unsigned long membase,
 	void name(ulong r0, ulong r1, ulong r2);			\
 									\
 	static void __##name(ulong, ulong, ulong);			\
+	static void ____##name(ulong, ulong, ulong);			\
 									\
 	void NAKED __section(.text_head_entry_##name)	name		\
 				(ulong r0, ulong r1, ulong r2)		\
@@ -202,7 +203,13 @@ static inline unsigned long arm_mem_barebox_image(unsigned long membase,
 			__ARM_SETUP_STACK(stack_top);			\
 			__##name(r0, r1, r2);				\
 		}							\
-		static void noinline __##name				\
+		static void NAKED noinline __##name			\
+			(ulong r0, ulong r1, ulong r2)			\
+		{							\
+			__ARM_SETUP_STACK(stack_top);			\
+			____##name(r0, r1, r2);				\
+		}							\
+		static void noinline ____##name				\
 			(ulong arg0, ulong arg1, ulong arg2)
 
 
-- 
2.30.2