[PATCH] x86: Add Hygon Dhyana support.

[Pawar, Amit]

> -----Original Message-----
> From: Carlos O'Donell <carlos@redhat.com>
> Sent: Tuesday, December 11, 2018 8:45 AM
> To: fanjinke <fanjinke@hygon.cn>; libc-alpha@sourceware.org; Pawar, Amit
> <Amit.Pawar@amd.com>
> Cc: H.J. Lu <hjl.tools@gmail.com>
> Subject: Re: [PATCH] x86: Add Hygon Dhyana support.
> 
> On 12/10/18 5:26 AM, fanjinke wrote:
> > This patch fix Hygon Dhyana processor CPU Vendor ID detection problem
> > in glibc sysdep module, current glibc codes doesn't recognize Dhyana
> > CPU Vendor ID("HygonGenuine") and set kind to arch_kind_other, which
> > result to incorrect zero value for __cache_sysconf() syscall. As Hygon
> > Dhyana share most architecture feature as AMD Family 17h, this patch
> > add Hygon CPU Vendor ID check and setup kind to arch_kind_amd and
> > reuse AMD code path, which lead to correct return value in
> > __cache_sysconf() syscall. we run the glibc test suite for both Hygon
> > Dhyana and AMD EPYC and found no failure case.
> >
> > Background:
> > Chengdu Haiguang IC Design Co., Ltd (Hygon) is a Joint Venture between
> > AMD and Haiguang Information Technology Co.,Ltd., aims at providing
> > high performance x86 processor for China server market. Its first
> > generation processor codename is Dhyana, which originates from AMD
> > technology and shares most of the architecture with AMD's family 17h,
> > but with different CPU Vendor ID("HygonGenuine")/Family series
> number(Family 18h).
> >
> > Related Hygon kernel patch can be found on
> > http://lkml.kernel.org/r/5ce86123a7b9dad925ac583d88d2f921040e859b.
> > 1538583282.git.puwen@hygon.cn
> >
> > Very appreciate everyone who has helped review and fix issues.
> 
> Do you have copyright assignment papers filed with the FSF?
> 
> This one-line change doesn't need copyright papers filed, but if you need to
> make more compilcated changes, then you will need them.
> 
> > *Tested for Hygon:*
> > Before patching the results of hygon's tests:
> > Summary of test results:
> >       6 FAIL
> >    5927 PASS
> >      29 UNSUPPORTED
> >      17 XFAIL
> >       2 XPASS
> > Makefile:403: recipe for target 'tests' failed
> > make[1]: *** [tests] Error 1
> > make[1]: Leaving directory
> > '/home/higon/space/src/opensrc/glibc/glibc/glibc'
> > Makefile:9: recipe for target 'check' failed
> > make: *** [check] Error 2
> >
> > And the result of testing after patching:
> > Summary of test results:
> >    5945 PASS
> >      17 UNSUPPORTED
> >      17 XFAIL
> >       2 XPASS
> > make[1]: Leaving directory
> > '/home/higon/space/src/opensrc/glibc/glibc/glibc'
> >
> > *Tested for AMD:*
> > The test results did not change before and after patching:
> > Summary of test results:
> >    5951 PASS
> >      11 UNSUPPORTED
> >      17 XFAIL
> >       2 XPASS
> > make[1]: Leaving directory '/home/higon/glibc'
> >
> > ChangeLog:
> >
> > 2018-12-10  fanjinke  <fanjinke@hygon.cn>
> >
> >         * sysdeps/x86/cpu-features.c (init_cpu_features):
> > ---
> >  sysdeps/x86/cpu-features.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
> > index 5f9eefd408..86e78bfb78 100644
> > --- a/sysdeps/x86/cpu-features.c
> > +++ b/sysdeps/x86/cpu-features.c
> > @@ -425,8 +425,9 @@ init_cpu_features (struct cpu_features
> *cpu_features)
> >  	cpu_features->feature[index_arch_Prefer_No_AVX512]
> >  	  |= bit_arch_Prefer_No_AVX512;
> >      }
> > -  /* This spells out "AuthenticAMD".  */
> > -  else if (ebx == 0x68747541 && ecx == 0x444d4163 && edx ==
> > 0x69746e65)
> > +  /* This spells out "AuthenticAMD" or "HygonGenuine". */
> > +  else if ((ebx == 0x68747541 && ecx == 0x444d4163 && edx ==
> 0x69746e65)
> > +	|| (ebx == 0x6f677948 && ecx == 0x656e6975 && edx ==
> 0x6e65476e))
> >      {
> >        unsigned int extended_model;
> 
> This looks fine to me, and reuses the AMD code.
> 
> I'd like to hear from Amit if this is OK for him, since he'll have to maintain this
> code as things diverge.
> 
> Amit, Any objections?
No objection from my side.
> 
> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> 
> --
> Cheers,
> Carlos.

Thanks,
Amit Pawar