[U-Boot] [PATCH 0/4] AE350 support SMP boot from flash

[Rick Chen]

Hi Lukas

Auer, Lukas <lukas.auer at aisec.fraunhofer.de> 於 2019年4月25日 週四 上午5:18寫道：
>
> Hi Rick,
>
> On Wed, 2019-04-24 at 09:35 +0800, Rick Chen wrote:
> > Hi Lukas
> >
> > Auer, Lukas <lukas.auer at aisec.fraunhofer.de> 於 2019年4月24日 週三 上午3:58寫道：
> > > Hi Rick,
> > >
> > > On Tue, 2019-04-23 at 13:42 +0800, Andes wrote:
> > > > From: Rick Chen <rick at andestech.com>
> > > >
> > > > In current RISC-V SMP flow, AE350 will encounter the the write
> > > > failure problem since hart_lottery and available_harts_lock was
> > > > not in ram address but in flash address when booing from flash.
> > > >
> > > > This patch can help to fix the failure problem when AE350 was
> > > > booting from flash by disable this two features.
> > > >
> > >
> > > Can you describe the issue you are seeing a bit more. The write
> > > failures are both to variables in the .data section, which should be
> > > writable. Perhaps the write failures can be avoided by moving the .data
> > > section or just the variable to RAM?
> > >
> >
> > When I compile AE350's CONFIG_SYS_TEXT_BASE=0x80000000 which is spi flash base.
> > And burn u-boot.bin into AE350 spi flash. Power off / on, U-Boot will
> > run in XIP mode.
> > At this time prior_stage_fdt_address will be in flash address(0x8004e9e8)
> > So it is not writable.
> >
> > 80000042:       16021563                bnez    tp,800001ac
> > <secondary_hart_loop>
> > 80000046:       0004f297                auipc   t0,0x4f
> > 8000004a:       9a22a283                lw      t0,-1630(t0) #
> > 8004e9e8 <prior_stage_fdt_address+0x3f74>
> > 8000004e:       0092a023                sw      s1,0(t0)
> >
>
> Ok, that makes sense.
> Another option would be to move the variable to RAM or some other
> location, which is write-accessible when U-Boot starts. Would this
> work?
> I think it would be good to support the hart lottery and the available
> harts mask in all configurations.
>

Actually I have tried to move them to gd, but it fail.
Because it need some requirements :
hart_lottery need equal to 0 and available_harts_lock equal to 1 at
compile time.
It is hard to achieve this at run time.
That is why I add a CONFIG_XXX to remove this two features simply.

Thanks
Rick

> Thanks,
> Lukas