Re: [PATCH v2] riscv: cancel the limitation that NR_CPUS is less than or equal to 32

[Leo Liang <ycliang@andestech.com>]

Hi Xiang,

On Fri, Feb 03, 2023 at 03:24:37PM +0100, David Abdurachmanov wrote:
> On Mon, Jan 3, 2022 at 1:13 PM Leo Liang <ycliang@andestech.com> wrote:
> >
> > On Thu, Dec 30, 2021 at 01:55:15AM +0800, Xiang W wrote:
> > > 在 2021-12-29星期三的 17:23 +0800，Leo Liang写道：
> > > > Hi Xiang,
> > > > On Wed, Dec 22, 2021 at 07:32:53AM +0800, Xiang W wrote:
> > > > > Various specifications of riscv allow the number of hart to be
> > > > > greater than 32. The limit of 32 is determined by
> > > > > gd->arch.available_harts. We can eliminate this limitation through
> > > > > bitmaps. Currently, the number of hart is limited to 4095, and 4095
> > > > > is the limit of the RISC-V Advanced Core Local Interruptor
> > > > > Specification.
> > > > >
> > > > > Test on sifive unmatched.
> > > > >
> > > > > Signed-off-by: Xiang W <wxjstz@126.com>
> > > > > ---
> > > > > Changes since v1:
> > > > >
> > > > > * When NR_CPUS is very large, the value of GD_AVAILABLE_HARTS will
> > > > >   overflow the immediate range of ld/lw. This patch fixes this
> > > > >   problem
> > > > >
> > > > >  arch/riscv/Kconfig                   |  4 ++--
> > > > >  arch/riscv/cpu/start.S               | 21 ++++++++++++++++-----
> > > > >  arch/riscv/include/asm/global_data.h |  4 +++-
> > > > >  arch/riscv/lib/smp.c                 |  2 +-
> > > > >  4 files changed, 22 insertions(+), 9 deletions(-)
> > > > >
> 
> I noticed that this has never landed in U-Boot. Was this forgotten or
> dropped for some reason (couldn't find anything)?
> 
> The current limit on the Linux kernel side is 512. The default on
> 64-bit (riscv64) is 64.
> 
> david

The patch seems to cause some CI error (timeout on QEMU).
(https://source.denx.de/u-boot/custodians/u-boot-riscv/-/pipelines/15076)
Could you take a look at it if you have time?

Best regards,
Leo