[PATCH] sbi: fwft: clear the config lock when warm boot

[Xiang W]

在 2024-11-21四的 21:24 -0600，Samuel Holland写道：
> Hi Xiang,
> 
> On 2024-11-21 8:45 PM, Xiang W wrote:
> > 在 2024-11-15五的 15:33 +0800，Nick Hu写道：
> > > The hotplug cpu should clear the fwft config's SBI_FWFT_SET_FLAG_LOCK
> > > in the warm boot flow otherwise the cpu can't set the menvcfg.sse by
> > > SBI_EXT_FWFT_SET sbi call and cause the illegal instruction when
> > > accessing the CSR_SSP in kernel.
> > > 
> > > Signed-off-by: Nick Hu <nick.hu at sifive.com>
> > 
> > In sbi_fwft_init, the memory for fwft_hart_state is allocated by 
> > sbi_zalloc, which ensures that flags is 0. So no additional code
> > is needed to clear the SBI_FWFT_SET_FLAG_LOCK bit.
> 
> That allocation only occurs the first time a hart is started. After a
> sbi_hsm_hart_stop() and sbi_hsm_hart_start(), the FWFT features will be reset to
> their default values per the SBI spec, and the flags need to be reset as well.
> 
Yes, you are right, I ignored the situation you mentioned.

Regards,
Xiang W
> Regards,
> Samuel
> 
> > > ---
> > >  lib/sbi/sbi_fwft.c | 15 +++++++++++++++
> > >  1 file changed, 15 insertions(+)
> > > 
> > > diff --git a/lib/sbi/sbi_fwft.c b/lib/sbi/sbi_fwft.c
> > > index 9cf14c16..0cb165b4 100644
> > > --- a/lib/sbi/sbi_fwft.c
> > > +++ b/lib/sbi/sbi_fwft.c
> > > @@ -311,6 +311,18 @@ static int fwft_get_feature(enum sbi_fwft_feature_t feature,
> > >  	return SBI_SUCCESS;
> > >  }
> > >  
> > > +static void fwft_clear_config_lock(enum sbi_fwft_feature_t feature)
> > > +{
> > > +	int ret;
> > > +	struct fwft_config *conf;
> > > +
> > > +	ret = fwft_get_feature(feature, &conf);
> > > +	if (ret)
> > > +		return;
> > > +
> > > +	conf->flags &= ~SBI_FWFT_SET_FLAG_LOCK;
> > > +}
> > > +
> > >  int sbi_fwft_set(enum sbi_fwft_feature_t feature, unsigned long value,
> > >  		 unsigned long flags)
> > >  {
> > > @@ -414,5 +426,8 @@ int sbi_fwft_init(struct sbi_scratch *scratch, bool cold_boot)
> > >  		fwft_set_hart_state_ptr(scratch, fhs);
> > >  	}
> > >  
> > > +	for (i = 0; i < array_size(features); i++)
> > > +		fwft_clear_config_lock(features[i].id);
> > > +
> > >  	return 0;
> > >  }
> > > -- 
> > > 2.34.1
> > > 
> > > 
> > 
> > 
> 
>