[PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help

[Stephen Warren]

On 9/4/20 3:07 AM, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias at xilinx.com>
> 
> Mention the requirement of 4K aligned load addresses in the
> help section for the POSITION_INDEPENDENT option.
> 
> Suggested-by: Michal Simek <michal.simek at xilinx.com>
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias at xilinx.com>
> ---
>  arch/arm/Kconfig | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index f30c2639ec..c144c08612 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -21,6 +21,9 @@ config POSITION_INDEPENDENT
>  	  information that is embedded in the binary to support U-Boot
>  	  relocating itself to the top-of-RAM later during execution.
>  
> +	  When this option is enabled, U-Boot needs to be loaded at a
> +	  4K aligned address.

I don't believe this restriction should be documented as part of
POSITION_INDEPENDENT; the restriction always exists at least for 64-bit
ARM, since arch/arm/lib/relocate_64.S relocate_code uses the same
assembly sequence that imposes this restriction, and IIUC that code is
unconditionally used.