Hi, Ryan,
This patch is to fix the issue about a warning for ARMv8 64-bit kernel
you reported before. I have tested on my LayerScape boards. Please review and
try on your boards too.
Thanks.
Best Regards,
Alison Wang
> -----Original Message-----
> From: Alison Wang [mailto:b18...@freescale.com]
> Sent: Friday, January 13, 2017 3:50 PM
> To: york sun <york....@nxp.com>; ryan.har...@linaro.org; ag...@suse.de;
> Scott Wood <scott.w...@nxp.com>; Stuart Yoder <stuart.yo...@nxp.com>;
> Leo Li <leoyang...@nxp.com>; feng...@phytium.com.cn;
> linus.wall...@linaro.org; u-boot@lists.denx.de
> Cc: Jason Jin <jason....@nxp.com>; Alison Wang <alison.w...@nxp.com>
> Subject: [PATCH] armv8: aarch64: Fix the warning about x1-x3 nonzero
> issue
>
> For 64-bit kernel, there is a warning about x1-x3 nonzero in violation
> of boot protocol. x3 should be reset to zero before jumping to the
> kernel.
>
> This patch will adjust the parameters to transfer and make sure x3 is
> zero.
>
> Signed-off-by: Alison Wang <alison.w...@nxp.com>
> ---
> arch/arm/cpu/armv8/transition.S | 44
> +++++++++++++++++++++++++++++++++++++----
> 1 file changed, 40 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/cpu/armv8/transition.S
> b/arch/arm/cpu/armv8/transition.S index adb9f35..06b6664 100644
> --- a/arch/arm/cpu/armv8/transition.S
> +++ b/arch/arm/cpu/armv8/transition.S
> @@ -26,9 +26,27 @@ ENTRY(armv8_switch_to_el2)
> * if CONFIG_ARMV8_SWITCH_TO_EL1 is defined.
> * When running in EL2 now, jump to the
> * address saved in x3.
> + *
> + * For 64-bit kernel, there is a warning about
> + * x1-x3 nonzero in violation of boot protocol.
> + * x3 should be reset to zero before jumping to
> + * the kernel. Use x4 instead of x3 as parameter.
> */
> - br x3
> -1: armv8_switch_to_el2_m x3, x4, x5
> + mov x4, x3
> + mov x3, #0
> + br x4
> +1:
> + /*
> + * For 64-bit kernel, there is a warning about
> + * x1-x3 nonzero in violation of boot protocol.
> + * x3 should be reset to zero before jumping to
> + * the kernel. Use x4, x5, x6 instead of x3, x4,
> + * x5 as parameters.
> + */
> + mov x5, x4
> + mov x4, x3
> + mov x3, #0
> + armv8_switch_to_el2_m x4, x5, x6
> ENDPROC(armv8_switch_to_el2)
>
> ENTRY(armv8_switch_to_el1)
> @@ -36,9 +54,27 @@ ENTRY(armv8_switch_to_el1)
> 0:
> /* x3 is kernel entry point. When running in EL1
> * now, jump to the address saved in x3.
> + *
> + * For 64-bit kernel, there is a warning about
> + * x1-x3 nonzero in violation of boot protocol.
> + * x3 should be reset to zero before jumping to
> + * the kernel. Use x4 instead of x3 as parameter.
> + */
> + mov x4, x3
> + mov x3, #0
> + br x4
> +1:
> + /*
> + * For 64-bit kernel, there is a warning about
> + * x1-x3 nonzero in violation of boot protocol.
> + * x3 should be reset to zero before jumping to
> + * the kernel. Use x4, x5, x6 instead of x3, x4,
> + * x5 as parameters.
> */
> - br x3
> -1: armv8_switch_to_el1_m x3, x4, x5
> + mov x5, x4
> + mov x4, x3
> + mov x3, #0
> + armv8_switch_to_el1_m x4, x5, x6
> ENDPROC(armv8_switch_to_el1)
>
> WEAK(armv8_el2_to_aarch32)
> --
> 2.1.0.27.g96db324
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