[U-Boot] [PATCH] arm: Add option to disable code relocation

[Marek Vasut]

> This permits disabling the code relation in U-Boot which is useful when
> debugging with an ICE.
> 
> To use it define CONFIG_SYS_SKIP_ARM_RELOCATION in your board.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>  arch/arm/config.mk                 |    2 ++
>  arch/arm/cpu/armv7/start.S         |    3 +--
>  arch/arm/include/asm/global_data.h |    3 +++
>  arch/arm/lib/board.c               |   10 ++++++++++
>  4 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/config.mk b/arch/arm/config.mk
> index 45f9dca..46b52af 100644
> --- a/arch/arm/config.mk
> +++ b/arch/arm/config.mk
> @@ -79,5 +79,7 @@ endif
> 
>  # needed for relocation
>  ifndef CONFIG_NAND_SPL
> +ifndef CONFIG_SYS_SKIP_ARM_RELOCATION
>  LDFLAGS_u-boot += -pie
>  endif
> +endif
> diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
> index ef08a55..82eac7c 100644
> --- a/arch/arm/cpu/armv7/start.S
> +++ b/arch/arm/cpu/armv7/start.S
> @@ -183,8 +183,7 @@ stack_setup:
>  	mov	sp, r4
> 
>  	adr	r0, _start
> -	cmp	r0, r6
> -	moveq	r9, #0		/* no relocation. relocation offset(r9) = 0 */
> +	subs	r9, r6, r0		/* r9 <- relocation offset */
>  	beq	clear_bss		/* skip relocation */
>  	mov	r1, r6			/* r1 <- scratch for copy_loop */
>  	ldr	r3, _image_copy_end_ofs
> diff --git a/arch/arm/include/asm/global_data.h
> b/arch/arm/include/asm/global_data.h index c3ff789..23a6077 100644
> --- a/arch/arm/include/asm/global_data.h
> +++ b/arch/arm/include/asm/global_data.h
> @@ -77,6 +77,9 @@ typedef	struct	global_data {
>  	unsigned long	tlb_addr;
>  #endif
>  	const void	*fdt_blob;	/* Our device tree, NULL if none */
> +#ifdef CONFIG_SYS_SKIP_ARM_RELOCATION
> +	ulong		malloc_end;	/* End of malloc region (addr + 1) */
> +#endif
>  	void		**jt;		/* jump table */
>  	char		env_buf[32];	/* buffer for getenv() before reloc. */
>  #if defined(CONFIG_POST) || defined(CONFIG_LOGBUFFER)
> diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
> index 3d78274..81293c3 100644
> --- a/arch/arm/lib/board.c
> +++ b/arch/arm/lib/board.c
> @@ -355,6 +355,7 @@ void board_init_f(ulong bootflag)
>  #endif /* CONFIG_FB_ADDR */
>  #endif /* CONFIG_LCD */
> 
> +#ifndef CONFIG_SYS_SKIP_ARM_RELOCATION
>  	/*
>  	 * reserve memory for U-Boot code, data & bss
>  	 * round down to next 4 kB limit
> @@ -363,6 +364,7 @@ void board_init_f(ulong bootflag)
>  	addr &= ~(4096 - 1);
> 
>  	debug("Reserving %ldk for U-Boot at: %08lx\n", gd->mon_len >> 10, addr);
> +#endif
> 
>  #ifndef CONFIG_SPL_BUILD
>  	/*
> @@ -419,6 +421,10 @@ void board_init_f(ulong bootflag)
>  	dram_init_banksize();
>  	display_dram_config();	/* and display it */
> 
> +#ifdef CONFIG_SYS_SKIP_ARM_RELOCATION
> +	gd->malloc_end = addr;
> +	addr = _TEXT_BASE;
> +#endif
>  	gd->relocaddr = addr;
>  	gd->start_addr_sp = addr_sp;
>  	gd->reloc_off = addr - _TEXT_BASE;
> @@ -478,7 +484,11 @@ void board_init_r(gd_t *id, ulong dest_addr)
>  #endif
> 
>  	/* The Malloc area is immediately below the monitor copy in DRAM */
> +#ifdef CONFIG_SYS_SKIP_ARM_RELOCATION
> +	malloc_start = gd->malloc_end - TOTAL_MALLOC_LEN;
> +#else
>  	malloc_start = dest_addr - TOTAL_MALLOC_LEN;
> +#endif
>  	mem_malloc_init (malloc_start, TOTAL_MALLOC_LEN);
> 
>  #if !defined(CONFIG_SYS_NO_FLASH)

Why would you need this one ? Is there any user for this patch?

M