[PATCH] include: sbi_platform: Increase default stack size

[Anirudh Srinivasan]

Hi Aurelien,

On Tue, Jun 2, 2026 at 2:12 PM Aurelien Jarno <aurelien at aurel32.net> wrote:
>
> On 2026-05-24 13:53, Vivian Wang wrote:
> > sbi_misaligned_v_ld_emulator() has a local buffer (namely mask) which is
> > 8192 bytes in size, so the default stack size is not enough. Double it
> > to 16384.
> >
> > This stack overflow can be observed by any S-mode software and leads to
> > M-mode crash or unexpected behavior, as long as the S-mode software does
> > not enable FWFT misaligned delegation [1]. This may be considered a
> > temporary fix until further fixes are made to misaligned handling [2].
> >
> > Link: https://lore.kernel.org/linux-riscv/nrvt74qnojaubiwjo37ums4lnclu466hovwrhmtbag6f5uhrql@q6msoe2oto4b # [1]
> > Link: https://lore.kernel.org/opensbi/20260210094044.72591-1-ganboing@gmail.com # [2]
> > Signed-off-by: Vivian Wang <wangruikang at iscas.ac.cn>
> > ---
> >  include/sbi/sbi_platform.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Tested-by: Aurelien Jarno <aurelien at aurel32.net>
>
> I can confirm that this fix is required to boot a 7.1-rc6 kernel on a
> CPU with vector instructions (in my case SpacemiT K1).

Are you sure that this is needed for the K1? It seemed like this was
only an issue on boards with large vlen (512 like the x280)? Do you
mind sharing any kernel boot logs with/without this patch?

I was able to boot 7.1.0-rc6-next-20260603 defconfig without issue on
a MilkV Jupiter. Only caveat is that my board is  running an old
vendor opensbi (version k1-bl-v2.2.4 that may be based on upstream
v1.3) that the board shipped with, and not sure if that's
helping/hurting in any manner.


>
> Regards
> Aurelien
>
> --
> Aurelien Jarno                          GPG: 4096R/1DDD8C9B
> aurelien at aurel32.net                     http://aurel32.net