[U-Boot] [PATCH v3] armv8: spl: Call spl_relocate_stack_gd for ARMv8

[André Przywara]

Hi Tom, Simon,

can we merge this patch for 2017.03 still?
This fixes an SD card boot regression for arm64 SPLs for me, introduced
shortly before -rc1.

Commit b3d2861eb20a ("spl: Remove overwrite of relocated malloc limit"),
introduced just a few commits before -rc1, broke MMC boot for arm64
(because malloc fails): The patch moves the simple_malloc setup into
spl_relocate_stack_gd(), which so far wasn't actually called on arm64
(see the patch below). So the malloc buffer was 0 bytes, malloc failed,
the MMC driver couldn't find a boot device and gave up:
U-Boot SPL 2017.03-rc2-00040-gb7b8021 (Feb 28 2017 - 00:41:35)
DRAM: 1024 MiB
Trying to boot from MMC1
MMC Device 0 not found
spl: could not find mmc device. error: -19
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###
This is the current situation since -rc1 for the Pine64, for instance.

Now one solution to fix this is to actually revert b3d2861eb20a, which
would move back to the old behaviour of using the SRAM malloc buffer for
the whole of the SPL, which is fine for the MMC driver.

But since Andrew's patch is correct, I'd rather merge Philipp's patch
now, which solves a TODO and just calls spl_relocate_stack_gd(), so that
we now get access to the proper (and much bigger) DRAM malloc buffer.

Does that make sense?
Can we merge Philipp's patch here (fixing the commenting style issue on
the fly) to fix the regression?

Cheers,
Andre.

> As part of the startup process for boards using the SPL, we need to
> call spl_relocate_stack_gd. This is needed to set up malloc with its
> DRAM buffer.
> 
> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> Reviewed-by: Andre Przywara <andre.przywara at arm.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> ---
>  arch/arm/lib/crt0_64.S | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S
> index 19c6a98..a7cead5 100644
> --- a/arch/arm/lib/crt0_64.S
> +++ b/arch/arm/lib/crt0_64.S
> @@ -109,8 +109,17 @@ relocation_return:
>   */
>  	bl	c_runtime_cpu_setup		/* still call old routine */
>  #endif /* !CONFIG_SPL_BUILD */
> -
> -/* TODO: For SPL, call spl_relocate_stack_gd() to alloc stack relocation */
> +#if defined(CONFIG_SPL_BUILD)
> +	bl	spl_relocate_stack_gd           /* may return NULL */
> +	/* Perform 'sp = (x0 != NULL) ? x0 : sp' while working
> +	 * around the constraint that conditional moves can not
> +	 * have 'sp' as an operand
> +	 */
> +	mov	x1, sp
> +	cmp	x0, #0
> +	csel	x0, x0, x1, ne
> +	mov	sp, x0
> +#endif
>  
>  /*
>   * Clear BSS section
>