Re: [PATCH v6 07/24] RISC-V: Use the minor version mask while computing sbi version

[Andrew Jones]

On Tue, Apr 16, 2024 at 01:31:27AM -0700, Atish Patra wrote:
> On 4/15/24 06:06, Andrew Jones wrote:
> > On Wed, Apr 10, 2024 at 05:07:35PM -0700, Atish Patra wrote:
> > > As per the SBI specification, minor version is encoded in the
> > > lower 24 bits only. Make sure that the SBI version is computed
> > > with the appropriate mask.
> > > 
> > > Currently, there is no minor version in use. Thus, it doesn't
> > > change anything functionality but it is good to be compliant with
> > > the specification.
> > > 
> > > Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
> > > ---
> > >   arch/riscv/include/asm/sbi.h | 4 ++--
> > >   1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> > > index f31650b10899..935b082d6a6c 100644
> > > --- a/arch/riscv/include/asm/sbi.h
> > > +++ b/arch/riscv/include/asm/sbi.h
> > > @@ -367,8 +367,8 @@ static inline unsigned long sbi_minor_version(void)
> > >   static inline unsigned long sbi_mk_version(unsigned long major,
> > >   					    unsigned long minor)
> > >   {
> > > -	return ((major & SBI_SPEC_VERSION_MAJOR_MASK) <<
> > > -		SBI_SPEC_VERSION_MAJOR_SHIFT) | minor;
> > > +	return ((major & SBI_SPEC_VERSION_MAJOR_MASK) << SBI_SPEC_VERSION_MAJOR_SHIFT
> > > +		| (minor & SBI_SPEC_VERSION_MINOR_MASK));
> > 
> > The previous version had ((major & major_mask) << major_shift) | minor
> > (parentheses around all the major bits before the OR). Now we have
> > parentheses around everything, which aren't necessary, and no longer
> 
> We have to use parentheses around | to avoid compiler warnings
> (-Wparentheses)
> 
> Are you only concerned about the outer parentheses ? I have removed it.
> 
> > have them around all the major bits before the OR. We don't need the
> > parentheses around the major bits, since shift has higher precedence
> > than OR, but I'd probably keep them.
> > 
> 
> Is this what you prefer?
> 
> return ((major & SBI_SPEC_VERSION_MAJOR_MASK) <<
> SBI_SPEC_VERSION_MAJOR_SHIFT) | (minor & SBI_SPEC_VERSION_MINOR_MASK);

Yup

Thanks,
drew

> 
> 
> 
> 
> > Otherwise,
> > 
> > Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
> > 
> > >   }
> > >   int sbi_err_map_linux_errno(int err);
> > > -- 
> > > 2.34.1
> > > 
> > 
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