Re: [PATCH 2.6.32 35/62] MIPS: Fix cpu_has_mips_r2_exec_hazard.

[Willy Tarreau <w@1wt.eu>]

On Tue, Sep 15, 2015 at 04:02:25AM +0100, Ben Hutchings wrote:
> On Sun, 2015-09-13 at 00:56 +0200, Willy Tarreau wrote:
> > 2.6.32-longterm review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Ralf Baechle <ralf@linux-mips.org>
> > 
> > commit 9cdf30bd3bac697fc533988f44a117434a858f69 upstream.
> > 
> > Returns a non-zero value if the current processor implementation requires
> > an IHB instruction to deal with an instruction hazard as per MIPS R2
> > architecture specification, zero otherwise.
> > 
> > For a discussion, see http://patchwork.linux-mips.org/patch/9539/.
> > 
> > Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
> > [bwh: Backported to 3.2: trim the CPU type list]
> > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> > (cherry picked from commit 8feb2a714b3478b2cde5c576fd9f47ef44b60e8d)
> > 
> > Signed-off-by: Willy Tarreau <w@1wt.eu>
> > ---
> >  arch/mips/include/asm/cpu-features.h | 26 +++++++++++++++++++++++++-
> >  1 file changed, 25 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h
> > index 1f4df64..a3dbb59 100644
> > --- a/arch/mips/include/asm/cpu-features.h
> > +++ b/arch/mips/include/asm/cpu-features.h
> > @@ -150,8 +150,32 @@
> >  #define cpu_has_mips_r	(cpu_has_mips32r1 | cpu_has_mips32r2 | \
> >  			 cpu_has_mips64r1 | cpu_has_mips64r2)
> >  
> > +/*
> > + * cpu_has_mips_r2_exec_hazard - return if IHB is required on current processor
> > + *
> > + * Returns non-zero value if the current processor implementation requires
> > + * an IHB instruction to deal with an instruction hazard as per MIPS R2
> > + * architecture specification, zero otherwise.
> > + */
> >  #ifndef cpu_has_mips_r2_exec_hazard
> > -#define cpu_has_mips_r2_exec_hazard cpu_has_mips_r2
> > +#define cpu_has_mips_r2_exec_hazard					\
> > +({									\
> > +	int __res;							\
> > +									\
> > +	switch (current_cpu_type()) {					\
> > +	case CPU_74K:							\
> > +	case CPU_CAVIUM_OCTEON:						\
> > +	case CPU_CAVIUM_OCTEON_PLUS:					\
> > +	case CPU_CAVIUM_OCTEON2:					\
> [...]
> 
> These last two constants aren't defined in 2.6.32, so they would need to
> be removed too.  But I don't think this is needed at all.

Ah thanks, I only built x86_64 and i386. OK I'm dropping the whole patch.

Thanks,
Willy