[U-Boot] [PATCH v8 1/3] armv8: Support loading 32-bit OS in AArch32 execution state

[york sun]

On 11/09/2016 07:02 PM, Alison Wang wrote:
> To support loading a 32-bit OS, the execution state will change from
> AArch64 to AArch32 when jumping to kernel.
>
> The architecture information will be got through checking FIT image,
> then U-Boot will load 32-bit OS or 64-bit OS automatically.
>
> Signed-off-by: Ebony Zhu <ebony.zhu at nxp.com>
> Signed-off-by: Alison Wang <alison.wang at nxp.com>
> Signed-off-by: Chenhui Zhao <chenhui.zhao at nxp.com>
> ---
> Changes in v8:
> - Fix the issue when U-Boot is running in EL2 or EL1.
>

Alison,

There is a conflict when merging with upstream code. Alex Graf merged 
his change to support EFI booting. See commit 
69bd459d343fe1e5a68a6f187d8c99c78c6fc6ce. Specifically these lines


         if (current_el() == 3) {
                 smp_kick_all_cpus();
                 dcache_disable();
                 armv8_switch_to_el2();
                 dcache_enable();
         }

Function armv8_switch_to_el2() didn't take any argument before you 
change. With your proposed change to support 32-bit OS, you added 
arguments to this function, and presume this function always load OS. 
This may be flawed. Would it be possible to keep armv8_switch_to_el2() 
but introduce another function to carry out switching EL while loading OS?

York