[U-Boot] [PATCH] arm: arm64 32bit address relocation

[Udit Kumar]

Hi Ibai

> -----Original Message-----
> From: Ibai Erkiaga <ibai.erkiaga-elorza at xilinx.com>
> Sent: Wednesday, February 27, 2019 8:18 PM
> To: u-boot at lists.denx.de
> Cc: Ibai Erkiaga <ibai.erkiaga-elorza at xilinx.com>; Udit Kumar
> <udit.kumar at nxp.com>; Tom Rini <trini at konsulko.com>; Albert Aribaud
> <albert.u.boot at aribaud.net>; Meenakshi Aggarwal
> <meenakshi.aggarwal at nxp.com>; Stefan Roese <sr at denx.de>; Prabhakar
> Kushwaha <prabhakar.kushwaha at nxp.com>
> Subject: [U-Boot][PATCH] arm: arm64 32bit address relocation
> 
> Current relocation code is limited to 21bit PC-relative addressing
> which might not be enough for bigger code sizes. The following patch
> increases the addressing to 32bit PC-relative. This feature is
> specially interesting if U-Boot is build without optimiation (-O0) as
> the text section is increased significativelly.
> 
> Signed-off-by: Ibai Erkiaga <ibai.erkiaga-elorza at xilinx.com>
> ---
> 
>  arch/arm/lib/relocate_64.S | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm/lib/relocate_64.S b/arch/arm/lib/relocate_64.S
> index 7603f52..6e9658b 100644
> --- a/arch/arm/lib/relocate_64.S
> +++ b/arch/arm/lib/relocate_64.S
> @@ -26,9 +26,10 @@ ENTRY(relocate_code)
>  	/*
>  	 * Copy u-boot from flash to RAM
>  	 */
> -	adr	x1, __image_copy_start	/* x1 <- Run
> &__image_copy_start */
> -	subs	x9, x0, x1		/* x8 <- Run to copy offset */
> -	b.eq	relocate_done		/* skip relocation */
> +	adrp	x1, __image_copy_start		/* x1 <- address bits
> [31:12] */
> +	add	x1, x1, :lo12:__image_copy_start/* x1 <- address bits [11:00]
> */
> +	subs	x9, x0, x1			/* x8 <- Run to copy offset */

Should be x9 in comments 

> +	b.eq	relocate_done			/* skip relocation */
>  	/*
>  	 * Don't ldr x1, __image_copy_start here, since if the code is already
>  	 * running at an address other than it was linked to, that instruction
> @@ -42,8 +43,10 @@ ENTRY(relocate_code)
>  	ldr	x1, _TEXT_BASE		/* x1 <- Linked
> &__image_copy_start */
>  	subs	x9, x0, x1		/* x9 <- Link to copy offset */
> 
> -	adr	x1, __image_copy_start	/* x1 <- Run
> &__image_copy_start */
> -	adr	x2, __image_copy_end	/* x2 <- Run &__image_copy_end */
> +	adrp	x1, __image_copy_start		/* x1 <- address bits
> [31:12] */
> +	add	x1, x1, :lo12:__image_copy_start/* x1 <- address bits [11:00]
> */
> +	adrp	x2, __image_copy_end		/* x2 <- address bits [31:12]
> */
> +	add	x2, x2, :lo12:__image_copy_end	/* x2 <- address bits
> [11:00] */
>  copy_loop:
>  	ldp	x10, x11, [x1], #16	/* copy from source address [x1] */
>  	stp	x10, x11, [x0], #16	/* copy to   target address [x0] */
> @@ -54,8 +57,10 @@ copy_loop:
>  	/*
>  	 * Fix .rela.dyn relocations
>  	 */
> -	adr	x2, __rel_dyn_start	/* x2 <- Run &__rel_dyn_start */
> -	adr	x3, __rel_dyn_end	/* x3 <- Run &__rel_dyn_end */
> +	adrp	x2, __rel_dyn_start		/* x2 <- address bits [31:12]
> */
> +	add	x2, x2, :lo12:__rel_dyn_start	/* x2 <- address bits [11:00]
> */
> +	adrp	x3, __rel_dyn_end		/* x3 <- address bits [31:12]
> */
> +	add	x3, x3, :lo12:__rel_dyn_end	/* x3 <- address bits [11:00]
> */
>  fixloop:
>  	ldp	x0, x1, [x2], #16	/* (x0,x1) <- (SRC location, fixup) */
>  	ldr	x4, [x2], #8		/* x4 <- addend */
> --
> 1.8.3.1