[PATCH] riscv: Add a 64-bit image type

[Bin Meng]

Hi Leo,

On Mon, Apr 17, 2023 at 1:22 PM Leo Liang <ycliang at andestech.com> wrote:
>
> Hi Bin,
>
> On Thu, Apr 13, 2023 at 06:06:29PM +0800, Bin Meng wrote:
> > On Mon, Apr 10, 2023 at 3:25 PM Rick Chen <rickchen36 at gmail.com> wrote:
> > >
> > > > From: Simon Glass <sjg at chromium.org>
> > > > Sent: Monday, April 03, 2023 4:28 AM
> > > > To: U-Boot Mailing List <u-boot at lists.denx.de>
> > > > Cc: Sean Anderson <seanga2 at gmail.com>; Bin Meng <bmeng.cn at gmail.com>; Rick Jian-Zhi Chen(陳建志) <rick at andestech.com>; Leo Yu-Chi Liang(梁育齊) <ycliang at andestech.com>; Simon Glass <sjg at chromium.org>; Andre Przywara <andre.przywara at arm.com>; Marc Kleine-Budde <mkl at pengutronix.de>; SESA644425 <giojahermann at gmail.com>; Samuel Holland <samuel at sholland.org>; Steven Lawrance <steven.lawrance at softathome.com>
> > > > Subject: [PATCH] riscv: Add a 64-bit image type
> > > >
> > > > At present it is not possible to know whether an image can be booted by a 32- or 64-bit bootloader. This means that U-Boot may attempt to boot the wrong image. This may cause a crash which might be hard to debug.
> > > >
> > > > Add a new property to make this explicit.
> > > >
> > > > The existing 'RISC-V' is now taken to mean 32-bit.
> > > >
> > > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > > ---
> > > >
> > > >  boot/image.c    | 3 ++-
> > > >  include/image.h | 3 ++-
> > > >  2 files changed, 4 insertions(+), 2 deletions(-)
> > >
> > > Reviewed-by: Rick Chen <rick at andestech.com>
> >
> > This might create compatibility issues if the shipped host tool
> > (mkimage) does not match U-Boot version. Any idea how to avoid that?
> >
>
> I am not sure if I understand you correctly.
> Do you mean that there could be compatibility issue
> if one uses 2023.04 release host tool (mkimage) to build images
> that are to be booted by 2023.07 release u-boot (if this patch is merged in 2023.07 u-boot)?

Yes.

>
> If that is the case, I guess there is no easy way to avoid that.
> We could probably have RISCV represent 64 bit riscv architecture
> and RISCV32 32 bit because most of the boards are 64 bit.
>
> If that is not the case, could you elaborate more ?
>
> And Rick has sent out a patch to fix booting issue based on Simon's patch as well.

I believe we should be querying some wider audience other than U-Boot
that if the RISC-V community intends to support 64-bit U-Boot booting
a 32-bit kernel, before we introduce such incompatibility change.

Regards,
Bin