[PATCH master v2 1/3] ARM: asm: fix miscompilation of 32-bit ENTRY_FUNCTION_WITHSTACK

[Ahmad Fatoum]

On 25.04.22 08:25, Ahmad Fatoum wrote:
> 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 | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/include/asm/barebox-arm.h b/arch/arm/include/asm/barebox-arm.h
> index d915cde294a4..8b0c00633277 100644
> --- a/arch/arm/include/asm/barebox-arm.h
> +++ b/arch/arm/include/asm/barebox-arm.h
> @@ -194,15 +194,21 @@ 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)		\
>  		{							\
>  			__barebox_arm_head();				\
> -			__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				\

I see now I could just make it call ENTRY_FUNCTION on arm32 with stack setup
and leave it unchanged for ARM64. Will do so for v3.

>  			(ulong arg0, ulong arg1, ulong arg2)
>  
>  


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