linux-kernel - Re: [PATCH] MIPS: Provide Kconfig option for default IEEE754 conformance mode

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Message-ID: <CAAhV-H5PyXZDpysbjhF9EL0iNKeDM7WWPRgjJB2WW0kVdj+w-Q@mail.gmail.com>
Date:   Fri, 31 Jul 2020 14:54:12 +0800
From:   Huacai Chen <chenhc@...ote.com>
To:     Serge Semin <Sergey.Semin@...kalelectronics.ru>
Cc:     Jiaxun Yang <jiaxun.yang@...goat.com>,
        Serge Semin <fancer.lancer@...il.com>,
        "open list:MIPS" <linux-mips@...r.kernel.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Paul Burton <paulburton@...nel.org>,
        Zhou Yanjie <zhouyanjie@...o.com>,
        周琰杰 (Zhou Yanjie) 
        <zhouyanjie@...yeetech.com>,
        Liangliang Huang <huanglllzu@...il.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] MIPS: Provide Kconfig option for default IEEE754
 conformance mode

Reviewed-by: Huacai Chen <chenhc@...ote.com>

On Fri, Jul 31, 2020 at 2:18 PM Serge Semin
<Sergey.Semin@...kalelectronics.ru> wrote:
>
> On Fri, Jul 31, 2020 at 12:10:16PM +0800, Jiaxun Yang wrote:
> > Requested by downstream distros, a Kconfig option for default
> > IEEE754 conformance mode allows them to set their mode to
> > relaxed by default.
>
> That's what should have been here in the first place. Thanks!
> Reviewed-by: Serge Semin <fancer.lancer@...il.com>
>
> >
> > Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
> > ---
> >  arch/mips/Kconfig            | 21 +++++++++++++++++++++
> >  arch/mips/kernel/cpu-probe.c | 12 +++++++++++-
> >  2 files changed, 32 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> > index f6bb446d30f0..ef5b2a177b1b 100644
> > --- a/arch/mips/Kconfig
> > +++ b/arch/mips/Kconfig
> > @@ -2877,6 +2877,27 @@ config MIPS_NR_CPU_NR_MAP
> >       default 1024 if MIPS_NR_CPU_NR_MAP_1024
> >       default NR_CPUS if !MIPS_NR_CPU_NR_MAP_1024
> >
> > +choice
> > +     prompt "Default IEEE Std 754 conformance mode"
> > +     default IEEE754_DEFAULT_STRICT
> > +     help
> > +       Default IEEE Std 754 conformance mode, see ieee754= kernel parameter
> > +       for detail.
> > +
> > +     config IEEE754_DEFAULT_STRICT
> > +             bool "Strict"
> > +
> > +     config IEEE754_DEFAULT_LEGACY
> > +             bool "Legacy"
> > +
> > +     config IEEE754_DEFAULT_STD2008
> > +             bool "2008"
> > +
> > +     config IEEE754_DEFAULT_RELAXED
> > +             bool "Relaxed"
> > +
> > +endchoice
> > +
> >  #
> >  # Timer Interrupt Frequency Configuration
> >  #
> > diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
> > index d9e8d39a7289..03adeed58efb 100644
> > --- a/arch/mips/kernel/cpu-probe.c
> > +++ b/arch/mips/kernel/cpu-probe.c
> > @@ -157,7 +157,17 @@ static void cpu_set_fpu_2008(struct cpuinfo_mips *c)
> >   * IEEE 754 conformance mode to use.  Affects the NaN encoding and the
> >   * ABS.fmt/NEG.fmt execution mode.
> >   */
> > -static enum { STRICT, LEGACY, STD2008, RELAXED } ieee754 = STRICT;
> > +enum ieee754_mode { STRICT, LEGACY, STD2008, RELAXED };
> > +
> > +#if defined(CONFIG_IEEE754_DEFAULT_STRICT)
> > +static enum ieee754_mode ieee754 = STRICT;
> > +#elif defined(CONFIG_IEEE754_DEFAULT_LEGACY)
> > +static enum ieee754_mode ieee754 = LEGACY;
> > +#elif defined(CONFIG_IEEE754_DEFAULT_STD2008)
> > +static enum ieee754_mode ieee754 = STD2008;
> > +#elif defined(CONFIG_IEEE754_DEFAULT_RELAXED)
> > +static enum ieee754_mode ieee754 = RELAXED;
> > +#endif
> >
> >  /*
> >   * Set the IEEE 754 NaN encodings and the ABS.fmt/NEG.fmt execution modes
> > --
> > 2.28.0
> >