[PATCH] firmware: Do not allow harts with different XLEN to boot

[Xiang W]

在 2021-06-02星期三的 11:51 +0000，Anup Patel写道：
> 
> 
> > -----Original Message-----
> > From: Jessica Clarke <jrtc27 at jrtc27.com>
> > Sent: 02 June 2021 07:25
> > To: Atish Patra <Atish.Patra at wdc.com>
> > Cc: opensbi at lists.infradead.org; Anup Patel <Anup.Patel at wdc.com>
> > Subject: Re: [PATCH] firmware: Do not allow harts with different
> > XLEN to boot
> > 
> > On 2 Jun 2021, at 02:42, Atish Patra <atish.patra at wdc.com> wrote:
> > > 
> > > OpenSBI is built separately for RV32/RV64. Thus, it shouldn't try
> > > to
> > > boot harts with a different XLEN compared to what it is compiled
> > > with.
> > > 
> > > This patch fixes the issue observed in beagleV which has two
> > > U74(RV64)
> > > and one E24 (RV32) harts.
> > 
> > Is this really necessary? Can the different clusters not boot
> > different
> > OpenSBIs? This is a really gross hack for what seems like a stupid
> > hardware
> > decision if they both blindly load and run from the same place.
> 
> Ideally, a platform should boot different OpenSBI firmwares for
> clusters
> with differing XLEN.
> 
> In any case, if a RV32 HART enters RV64 OpenSBI firmware (or vice-
> versa)
> then the HART should enter a WFI hang loop very early.
> 
> This patch is more of a precautionary check for platforms like
> BeagleV
> where HART with differing XLEN jumps to OpenSBI firmware.
> 
> Regards,
> Anup
> 
MXL can be modified, if it does not match, whether to try to modify
MXL, and then continue to run

Regards,
Xiang W