[PATCH 3/7] riscv: Use NULL as a sentinel value for smp_call_function

[Leo Liang]

On Fri, Sep 11, 2020 at 04:04:13PM +0800, Bin Meng wrote:
> On Tue, Sep 8, 2020 at 2:17 AM Sean Anderson <seanga2 at gmail.com> wrote:
> >
> > Some IPIs may already be pending when U-Boot is started. This could be a
> > problem if a secondary hart tries to handle an IPI before the boot hart has
> > initialized the IPI device.
> >
> > This commit uses NULL as a sentinel for secondary harts so they know when
> > the IPI is initialized, and it is safe to use the IPI API. The smp addr
> > parameter is initialized to NULL by board_init_f_init_reserve. Before this,
> > secondary harts wait in wait_for_gd_init.
> >
> > This imposes a minor restriction because harts may no longer jump to NULL.
> > However, given that the RISC-V debug device is likely to be located at
> > 0x400, it is unlikely for any RISC-V implementation to have usable ram
> > located at 0x0.
> >
> > Signed-off-by: Sean Anderson <seanga2 at gmail.com>
> > ---
> >
> >  arch/riscv/lib/smp.c | 26 ++++++++++++++++++++++----
> >  1 file changed, 22 insertions(+), 4 deletions(-)
> >
> 
> Reviewed-by: Bin Meng <bin.meng at windriver.com>

Hi Bin,

There is a series of follow-up discussion on this patch that you might miss reading.

This current patch will cause AE350 to fail booting,

so maybe we should wait until Sean's next patch comes up to consider a reviewed-by tag.

Best regards,

Leo