Re: [PATCH 03/19] <sys/platform/x86.h>: Add LA57 support

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Wed, Apr 5, 2023 at 1:39 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Wed, Apr 5, 2023 at 11:20 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > On Wed, Apr 5, 2023 at 11:22 AM H.J. Lu via Libc-alpha
> > <libc-alpha@sourceware.org> wrote:
> > >
> > > Add 57-bit linear addresses and five-level paging (LA57) support to
> > > <sys/platform/x86.h>.
> > > ---
> > >  manual/platform.texi               | 3 +++
> > >  sysdeps/x86/bits/platform/x86.h    | 2 +-
> > >  sysdeps/x86/tst-get-cpu-features.c | 1 +
> > >  3 files changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/manual/platform.texi b/manual/platform.texi
> > > index c1cef570d2..9251b63e47 100644
> > > --- a/manual/platform.texi
> > > +++ b/manual/platform.texi
> > > @@ -394,6 +394,9 @@ the indirect branch predictor barrier (IBPB).
> > >  @item
> > >  @code{L1D_FLUSH} -- IA32_FLUSH_CMD MSR.
> > >
> > > +@item
> > > +@code{LA57} -- 57-bit linear addresses and five-level paging.
> > > +
> > >  @item
> > >  @code{LAHF64_SAHF64} -- LAHF/SAHF available in 64-bit mode.
> > >
> > > diff --git a/sysdeps/x86/bits/platform/x86.h b/sysdeps/x86/bits/platform/x86.h
> > > index 1ed24d7024..c9189fa248 100644
> > > --- a/sysdeps/x86/bits/platform/x86.h
> > > +++ b/sysdeps/x86/bits/platform/x86.h
> > > @@ -182,7 +182,7 @@ enum
> > >    x86_cpu_INDEX_7_ECX_13       = x86_cpu_index_7_ecx + 13,
> > >    x86_cpu_AVX512_VPOPCNTDQ     = x86_cpu_index_7_ecx + 14,
> > >    x86_cpu_INDEX_7_ECX_15       = x86_cpu_index_7_ecx + 15,
> > > -  x86_cpu_INDEX_7_ECX_16       = x86_cpu_index_7_ecx + 16,
> > > +  x86_cpu_LA57                 = x86_cpu_index_7_ecx + 16,
> > >  /* Note: Bits 17-21: The value of MAWAU used by the BNDLDX and BNDSTX
> > >     instructions in 64-bit mode.  */
> > >    x86_cpu_RDPID                        = x86_cpu_index_7_ecx + 22,
> > > diff --git a/sysdeps/x86/tst-get-cpu-features.c b/sysdeps/x86/tst-get-cpu-features.c
> > > index 1954698df8..5f5cd3e448 100644
> > > --- a/sysdeps/x86/tst-get-cpu-features.c
> > > +++ b/sysdeps/x86/tst-get-cpu-features.c
> > > @@ -144,6 +144,7 @@ do_test (void)
> > >    CHECK_CPU_FEATURE_PRESENT (AVX512_VNNI);
> > >    CHECK_CPU_FEATURE_PRESENT (AVX512_BITALG);
> > >    CHECK_CPU_FEATURE_PRESENT (AVX512_VPOPCNTDQ);
> > > +  CHECK_CPU_FEATURE_PRESENT (LA57);
> > >    CHECK_CPU_FEATURE_PRESENT (RDPID);
> > >    CHECK_CPU_FEATURE_PRESENT (KL);
> > >    CHECK_CPU_FEATURE_PRESENT (CLDEMOTE);
> > > --
> > > 2.39.2
> > >
> > Rename:
> > `#define bit_cpu_INDEX_7_ECX_16`
> > in cpu-features.h?
>
> cpu-features.h is used internally in glibc.   Changes in
> cpu-features.h are needed only if we need to use
> CPU_FEATURE_SET_ACTIVE to mark a feature active.
>
> --
> H.J.

LGTM
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>