On Thu, Jan 7, 2021 at 12:09 PM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
>
>
> On 06/01/2021 14:11, H.J. Lu wrote:
> > Here is the updated patch.  Tested under i686, x32 and x86-64 modes
> > on x86-64-v2, x86-64-v3 and x86-64-v4 machines.
> >
> > OK for master?
> >
> > Thanks.
> >
>
> LGTM with just two clarification below.
>
> Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
>
> > From 6630e06f9bcb361177d46c277cf8e67cbd722429 Mon Sep 17 00:00:00 2001
> > From: "H.J. Lu" <hjl.tools@gmail.com>
> > Date: Fri, 9 Oct 2020 06:06:56 -0700
> > Subject: [PATCH] x86: Support GNU_PROPERTY_X86_ISA_1_V[234] marker [BZ #26717]
> >
> > GCC 11 supports -march=x86-64-v[234] to enable x86 micro-architecture ISA
> > levels:
> >
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97250
> >
> > and -mneeded to emit GNU_PROPERTY_X86_ISA_1_NEEDED property with
> > GNU_PROPERTY_X86_ISA_1_V[234] marker:
> >
> > https://gitlab.com/x86-psABIs/x86-64-ABI/-/merge_requests/13
> >
> > Binutils support for GNU_PROPERTY_X86_ISA_1_V[234] marker were added by
> >
> > commit b0ab06937385e0ae25cebf1991787d64f439bf12
> > Author: H.J. Lu <hjl.tools@gmail.com>
> > Date:   Fri Oct 30 06:49:57 2020 -0700
> >
> >     x86: Support GNU_PROPERTY_X86_ISA_1_BASELINE marker
> >
> > and
> >
> > commit 32930e4edbc06bc6f10c435dbcc63131715df678
> > Author: H.J. Lu <hjl.tools@gmail.com>
> > Date:   Fri Oct 9 05:05:57 2020 -0700
> >
> >     x86: Support GNU_PROPERTY_X86_ISA_1_V[234] marker
> >
> > GNU_PROPERTY_X86_ISA_1_NEEDED property in x86 ELF binaries indicate the
> > micro-architecture ISA level required to execute the binary.  The marker
> > must be added by programmers explicitly in one of 3 ways:
> >
> > 1. Pass -mneeded to GCC.
> > 2. Add the marker in the linker inputs as this patch does.
> > 3. Pass -z x86-64-v[234] to the linker.
> >
> > Add GNU_PROPERTY_X86_ISA_1_BASELINE and GNU_PROPERTY_X86_ISA_1_V[234]
> > marker support to ld.so if binutils 2.32 or newer is used to build glibc:
> >
> > 1. Add GNU_PROPERTY_X86_ISA_1_BASELINE and GNU_PROPERTY_X86_ISA_1_V[234]
> > markers to elf.h.
> > 2. Add GNU_PROPERTY_X86_ISA_1_BASELINE and GNU_PROPERTY_X86_ISA_1_V[234]
> > marker to abi-note.o based on the ISA level used to compile abi-note.o,
> > assuming that the same ISA level is used to compile the whole glibc.
> > 3. Add isa_1 to cpu_features to record the supported x86 ISA level.
> > 4. Rename _dl_process_cet_property_note to _dl_process_property_note and
> > add GNU_PROPERTY_X86_ISA_1_V[234] marker detection.
> > 5. Update _rtld_main_check and _dl_open_check to check loaded objects
> > with the incompatible ISA level.
> > 6. Add a testcase to verify that dlopen an x86-64-v4 shared object fails
> > on lesser platforms.
> > 7. Use <get-isa-level.h> in dl-hwcaps-subdirs.c and tst-glibc-hwcaps.c.
> >
> > Tested under i686, x32 and x86-64 modes on x86-64-v2, x86-64-v3 and
> > x86-64-v4 machines.
> >
> > Marked elf/tst-isa-level-1 with x86-64-v4, ran it on x86-64-v3 machine
> > and got:
> >
> > [hjl@gnu-cfl-2 build-x86_64-linux]$ ./elf/tst-isa-level-1
> > ./elf/tst-isa-level-1: CPU ISA level is lower than required
> > [hjl@gnu-cfl-2 build-x86_64-linux]$
> > ---
> >  config.h.in                                |   3 +
> >  elf/elf.h                                  |  35 +++----
> >  sysdeps/x86/Makefile                       |  30 ++++++
> >  sysdeps/x86/abi-note.c                     |  29 ++++++
> >  sysdeps/x86/configure                      |  79 ++++++++++++++
> >  sysdeps/x86/configure.ac                   |  66 ++++++++++++
> >  sysdeps/x86/cpu-features.c                 |   3 +
> >  sysdeps/x86/dl-cet.c                       |  12 ++-
> >  sysdeps/x86/dl-prop.h                      | 113 +++++++++++++++------
> >  sysdeps/x86/get-isa-level.h                |  66 ++++++++++++
> >  sysdeps/x86/include/cpu-features.h         |   2 +
> >  sysdeps/x86/isa-level.c                    |  97 ++++++++++++++++++
> >  sysdeps/x86/link_map.h                     |  18 ++--
> >  sysdeps/x86/tst-isa-level-1.c              | 104 +++++++++++++++++++
> >  sysdeps/x86/tst-isa-level-mod-1-baseline.c |   1 +
> >  sysdeps/x86/tst-isa-level-mod-1-v2.c       |   1 +
> >  sysdeps/x86/tst-isa-level-mod-1-v3.c       |   1 +
> >  sysdeps/x86/tst-isa-level-mod-1-v4.c       |   1 +
> >  sysdeps/x86/tst-isa-level-mod-1.c          |  25 +++++
> >  sysdeps/x86_64/dl-hwcaps-subdirs.c         |  30 ++----
> >  sysdeps/x86_64/tst-glibc-hwcaps.c          |  41 ++------
> >  21 files changed, 644 insertions(+), 113 deletions(-)
> >  create mode 100644 sysdeps/x86/abi-note.c
> >  create mode 100644 sysdeps/x86/get-isa-level.h
> >  create mode 100644 sysdeps/x86/isa-level.c
> >  create mode 100644 sysdeps/x86/tst-isa-level-1.c
> >  create mode 100644 sysdeps/x86/tst-isa-level-mod-1-baseline.c
> >  create mode 100644 sysdeps/x86/tst-isa-level-mod-1-v2.c
> >  create mode 100644 sysdeps/x86/tst-isa-level-mod-1-v3.c
> >  create mode 100644 sysdeps/x86/tst-isa-level-mod-1-v4.c
> >  create mode 100644 sysdeps/x86/tst-isa-level-mod-1.c
> >
> > diff --git a/config.h.in b/config.h.in
> > index eca2d66a2c..947feeff36 100644
> > --- a/config.h.in
> > +++ b/config.h.in
> > @@ -269,4 +269,7 @@
> >  /* The default value of x86 CET control.  */
> >  #define DEFAULT_DL_X86_CET_CONTROL cet_elf_property
> >
> > +/* Define if x86 ISA level should be included in shared libraries.  */
> > +#undef INCLUDE_X86_ISA_LEVEL
> > +
> >  #endif
> > diff --git a/elf/elf.h b/elf/elf.h
>
> Ok.
>
> > index 4a9ae97dfc..9ebd052c8a 100644
> > --- a/elf/elf.h
> > +++ b/elf/elf.h
> > @@ -1324,31 +1324,26 @@ typedef struct
> >
> >  /* The x86 instruction sets indicated by the corresponding bits are
> >     used in program.  Their support in the hardware is optional.  */
> > -#define GNU_PROPERTY_X86_ISA_1_USED          0xc0000000
> > +#define GNU_PROPERTY_X86_ISA_1_USED          0xc0010002
> >  /* The x86 instruction sets indicated by the corresponding bits are
> >     used in program and they must be supported by the hardware.   */
> > -#define GNU_PROPERTY_X86_ISA_1_NEEDED                0xc0000001
> > +#define GNU_PROPERTY_X86_ISA_1_NEEDED                0xc0008002
> >  /* X86 processor-specific features used in program.  */
> >  #define GNU_PROPERTY_X86_FEATURE_1_AND               0xc0000002
> >
> > -#define GNU_PROPERTY_X86_ISA_1_486           (1U << 0)
> > -#define GNU_PROPERTY_X86_ISA_1_586           (1U << 1)
> > -#define GNU_PROPERTY_X86_ISA_1_686           (1U << 2)
> > -#define GNU_PROPERTY_X86_ISA_1_SSE           (1U << 3)
> > -#define GNU_PROPERTY_X86_ISA_1_SSE2          (1U << 4)
> > -#define GNU_PROPERTY_X86_ISA_1_SSE3          (1U << 5)
> > -#define GNU_PROPERTY_X86_ISA_1_SSSE3         (1U << 6)
> > -#define GNU_PROPERTY_X86_ISA_1_SSE4_1                (1U << 7)
> > -#define GNU_PROPERTY_X86_ISA_1_SSE4_2                (1U << 8)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX           (1U << 9)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX2          (1U << 10)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX512F               (1U << 11)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX512CD              (1U << 12)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX512ER              (1U << 13)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX512PF              (1U << 14)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX512VL              (1U << 15)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX512DQ              (1U << 16)
> > -#define GNU_PROPERTY_X86_ISA_1_AVX512BW              (1U << 17)
> > +/* GNU_PROPERTY_X86_ISA_1_BASELINE: CMOV, CX8 (cmpxchg8b), FPU (fld),
> > +   MMX, OSFXSR (fxsave), SCE (syscall), SSE and SSE2.  */
> > +#define GNU_PROPERTY_X86_ISA_1_BASELINE              (1U << 0)
> > +/* GNU_PROPERTY_X86_ISA_1_V2: GNU_PROPERTY_X86_ISA_1_BASELINE,
> > +   CMPXCHG16B (cmpxchg16b), LAHF-SAHF (lahf), POPCNT (popcnt), SSE3,
> > +   SSSE3, SSE4.1 and SSE4.2.  */
> > +#define GNU_PROPERTY_X86_ISA_1_V2            (1U << 1)
> > +/* GNU_PROPERTY_X86_ISA_1_V3: GNU_PROPERTY_X86_ISA_1_V2, AVX, AVX2, BMI1,
> > +   BMI2, F16C, FMA, LZCNT, MOVBE, XSAVE.  */
> > +#define GNU_PROPERTY_X86_ISA_1_V3            (1U << 2)
> > +/* GNU_PROPERTY_X86_ISA_1_V4: GNU_PROPERTY_X86_ISA_1_V3, AVX512F,
> > +   AVX512BW, AVX512CD, AVX512DQ and AVX512VL.  */
> > +#define GNU_PROPERTY_X86_ISA_1_V4            (1U << 3)
> >
> >  /* This indicates that all executable sections are compatible with
> >     IBT.  */
>
> Ok.
>
> > diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> > index 081cc72e93..c814d5a195 100644
> > --- a/sysdeps/x86/Makefile
> > +++ b/sysdeps/x86/Makefile
> > @@ -9,6 +9,36 @@ sysdep_headers += sys/platform/x86.h
> >  tests += tst-get-cpu-features tst-get-cpu-features-static \
> >        tst-cpu-features-cpuinfo tst-cpu-features-supports
> >  tests-static += tst-get-cpu-features-static
> > +ifeq (yes,$(enable-x86-isa-level))
> > +tests += tst-isa-level-1
> > +modules-names += tst-isa-level-mod-1-baseline \
> > +              tst-isa-level-mod-1-v2 \
> > +              tst-isa-level-mod-1-v3 \
> > +              tst-isa-level-mod-1-v4 \
> > +
> > +# X86 ISA level baseline
> > +CFLAGS-tst-isa-level-mod-1-baseline.c += -DINCLUDE_X86_ISA_LEVEL \
> > +                                      -DISA_LEVEL=0x1 \
> > +                                      -march=x86-64
> > +# X86 ISA level v2
> > +CFLAGS-tst-isa-level-mod-1-v2.c += -DINCLUDE_X86_ISA_LEVEL \
> > +                                -DISA_LEVEL=0x3 \
> > +                                -march=x86-64
> > +# X86 ISA level v3
> > +CFLAGS-tst-isa-level-mod-1-v3.c += -DINCLUDE_X86_ISA_LEVEL \
> > +                                -DISA_LEVEL=0x7 \
> > +                                -march=x86-64
> > +# X86 ISA level v4
> > +CFLAGS-tst-isa-level-mod-1-v4.c += -DINCLUDE_X86_ISA_LEVEL \
> > +                                -DISA_LEVEL=0xf \
> > +                                -march=x86-64
> > +
> > +$(objpfx)tst-isa-level-1: $(libdl)
> > +$(objpfx)tst-isa-level-1.out: $(objpfx)tst-isa-level-mod-1-baseline.so \
> > +                           $(objpfx)tst-isa-level-mod-1-v2.so \
> > +                           $(objpfx)tst-isa-level-mod-1-v3.so \
> > +                           $(objpfx)tst-isa-level-mod-1-v4.so
> > +endif
> >  endif
> >
> >  ifeq ($(subdir),math)
>
> Ok.
>
> > diff --git a/sysdeps/x86/abi-note.c b/sysdeps/x86/abi-note.c
> > new file mode 100644
> > index 0000000000..5140e6ab47
> > --- /dev/null
> > +++ b/sysdeps/x86/abi-note.c
> > @@ -0,0 +1,29 @@
> > +/* Special .init and .fini section support.  x86-64 version.
> > +   Copyright (C) 2020 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   In addition to the permissions in the GNU Lesser General Public
> > +   License, the Free Software Foundation gives you unlimited
> > +   permission to link the compiled version of this file with other
> > +   programs, and to distribute those programs without any restriction
> > +   coming from the use of this file.  (The Lesser General Public
> > +   License restrictions do apply in other respects; for example, they
> > +   cover modification of the file, and distribution when not linked
> > +   into another program.)
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <isa-level.c>
> > +#include <csu/abi-note.c>
>
> Ok.
>
> > diff --git a/sysdeps/x86/configure b/sysdeps/x86/configure
> > index 81cc4e80d6..5e32dc62b3 100644
> > --- a/sysdeps/x86/configure
> > +++ b/sysdeps/x86/configure
> > @@ -68,3 +68,82 @@ elif test $enable_cet = permissive; then
> >  fi
> >  config_vars="$config_vars
> >  enable-cet = $enable_cet"
> > +
> > +# Check if linker supports x86 ISA level.
> > +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker x86 ISA level support" >&5
> > +$as_echo_n "checking for linker x86 ISA level support... " >&6; }
> > +if ${libc_cv_include_x86_isa_level+:} false; then :
> > +  $as_echo_n "(cached) " >&6
> > +else
> > +  cat > conftest1.S <<EOF
> > +#ifdef __LP64__
> > +# define P2ALIGN 3
> > +#else
> > +# define P2ALIGN 2
> > +#endif
> > +     .section ".note.gnu.property", "a"
> > +     .p2align P2ALIGN
> > +     .long 1f - 0f           /* name length.  */
> > +     .long 4f - 1f           /* data length.  */
> > +     /* NT_GNU_PROPERTY_TYPE_0 */
> > +     .long 5                 /* note type.  */
> > +0:
> > +     .asciz "GNU"            /* vendor name.  */
> > +1:
> > +     .p2align P2ALIGN
> > +     /* GNU_PROPERTY_X86_ISA_1_NEEDED */
> > +     .long 0xc0008002        /* pr_type.  */
> > +     .long 3f - 2f           /* pr_datasz.  */
> > +2:
> > +     .long 0x1
> > +3:
> > +     .p2align P2ALIGN
> > +4:
> > +EOF
> > +cat > conftest2.S <<EOF
> > +#ifdef __LP64__
> > +# define P2ALIGN 3
> > +#else
> > +# define P2ALIGN 2
> > +#endif
> > +     .section ".note.gnu.property", "a"
> > +     .p2align P2ALIGN
> > +     .long 1f - 0f           /* name length.  */
> > +     .long 4f - 1f           /* data length.  */
> > +     /* NT_GNU_PROPERTY_TYPE_0 */
> > +     .long 5                 /* note type.  */
> > +0:
> > +     .asciz "GNU"            /* vendor name.  */
> > +1:
> > +     .p2align P2ALIGN
> > +     /* GNU_PROPERTY_X86_ISA_1_NEEDED */
> > +     .long 0xc0008002        /* pr_type.  */
> > +     .long 3f - 2f           /* pr_datasz.  */
> > +2:
> > +     .long 0x2
> > +3:
> > +     .p2align P2ALIGN
> > +4:
> > +EOF
> > +libc_cv_include_x86_isa_level=no
> > +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -nostartfiles -nostdlib -r -o conftest conftest1.S conftest2.S'
> > +  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> > +  (eval $ac_try) 2>&5
> > +  ac_status=$?
> > +  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> > +  test $ac_status = 0; }; }; then
> > +  count=`LC_ALL=C $READELF -n conftest | grep NT_GNU_PROPERTY_TYPE_0 | wc -l`
> > +  if test "$count" = 1; then
> > +    libc_cv_include_x86_isa_level=yes
> > +  fi
> > +fi
> > +rm -f conftest*
> > +fi
> > +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_include_x86_isa_level" >&5
> > +$as_echo "$libc_cv_include_x86_isa_level" >&6; }
> > +if test $libc_cv_include_x86_isa_level = yes; then
> > +  $as_echo "#define INCLUDE_X86_ISA_LEVEL 1" >>confdefs.h
> > +
> > +fi
> > +config_vars="$config_vars
> > +enable-x86-isa-level = $libc_cv_include_x86_isa_level"
> > diff --git a/sysdeps/x86/configure.ac b/sysdeps/x86/configure.ac
> > index 8f3e1191f6..f94088f377 100644
> > --- a/sysdeps/x86/configure.ac
> > +++ b/sysdeps/x86/configure.ac
> > @@ -43,3 +43,69 @@ elif test $enable_cet = permissive; then
> >    AC_DEFINE(DEFAULT_DL_X86_CET_CONTROL, cet_permissive)
> >  fi
> >  LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
> > +
> > +# Check if linker supports x86 ISA level.
> > +AC_CACHE_CHECK([for linker x86 ISA level support],
> > +            libc_cv_include_x86_isa_level, [dnl
> > +cat > conftest1.S <<EOF
> > +#ifdef __LP64__
> > +# define P2ALIGN 3
> > +#else
> > +# define P2ALIGN 2
> > +#endif
> > +     .section ".note.gnu.property", "a"
> > +     .p2align P2ALIGN
> > +     .long 1f - 0f           /* name length.  */
> > +     .long 4f - 1f           /* data length.  */
> > +     /* NT_GNU_PROPERTY_TYPE_0 */
> > +     .long 5                 /* note type.  */
> > +0:
> > +     .asciz "GNU"            /* vendor name.  */
> > +1:
> > +     .p2align P2ALIGN
> > +     /* GNU_PROPERTY_X86_ISA_1_NEEDED */
> > +     .long 0xc0008002        /* pr_type.  */
> > +     .long 3f - 2f           /* pr_datasz.  */
> > +2:
> > +     .long 0x1
> > +3:
> > +     .p2align P2ALIGN
> > +4:
> > +EOF
> > +cat > conftest2.S <<EOF
> > +#ifdef __LP64__
> > +# define P2ALIGN 3
> > +#else
> > +# define P2ALIGN 2
> > +#endif
> > +     .section ".note.gnu.property", "a"
> > +     .p2align P2ALIGN
> > +     .long 1f - 0f           /* name length.  */
> > +     .long 4f - 1f           /* data length.  */
> > +     /* NT_GNU_PROPERTY_TYPE_0 */
> > +     .long 5                 /* note type.  */
> > +0:
> > +     .asciz "GNU"            /* vendor name.  */
> > +1:
> > +     .p2align P2ALIGN
> > +     /* GNU_PROPERTY_X86_ISA_1_NEEDED */
> > +     .long 0xc0008002        /* pr_type.  */
> > +     .long 3f - 2f           /* pr_datasz.  */
> > +2:
> > +     .long 0x2
> > +3:
> > +     .p2align P2ALIGN
> > +4:
> > +EOF
> > +libc_cv_include_x86_isa_level=no
> > +if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -nostartfiles -nostdlib -r -o conftest conftest1.S conftest2.S); then
> > +  count=`LC_ALL=C $READELF -n conftest | grep NT_GNU_PROPERTY_TYPE_0 | wc -l`
> > +  if test "$count" = 1; then
> > +    libc_cv_include_x86_isa_level=yes
> > +  fi
> > +fi
> > +rm -f conftest*])
> > +if test $libc_cv_include_x86_isa_level = yes; then
> > +  AC_DEFINE(INCLUDE_X86_ISA_LEVEL)
> > +fi
> > +LIBC_CONFIG_VAR([enable-x86-isa-level], [$libc_cv_include_x86_isa_level])
>
> Skipping autogenerated file.
>
> > diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
> > index 529c586193..e7da682a2e 100644
> > --- a/sysdeps/x86/cpu-features.c
> > +++ b/sysdeps/x86/cpu-features.c
> > @@ -19,6 +19,7 @@
> >  #include <cpuid.h>
> >  #include <dl-hwcap.h>
> >  #include <libc-pointer-arith.h>
> > +#include <get-isa-level.h>
> >  #if IS_IN (libc) && !defined SHARED
> >  # include <assert.h>
> >  # include <unistd.h>
> > @@ -290,6 +291,8 @@ update_usable (struct cpu_features *cpu_features)
> >        CPU_FEATURE_SET_USABLE (cpu_features, KL);
> >        CPU_FEATURE_SET_USABLE (cpu_features, WIDE_KL);
> >      }
> > +
> > +  cpu_features->isa_1 = get_isa_level (cpu_features);
> >  }
> >
> >  static void
>
> Ok.
>
> > diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
> > index b4910f7634..ed7fd6d10d 100644
> > --- a/sysdeps/x86/dl-cet.c
> > +++ b/sysdeps/x86/dl-cet.c
> > @@ -76,10 +76,12 @@ dl_cet_check (struct link_map *m, const char *program)
> >          */
> >         enable_ibt &= (HAS_CPU_FEATURE (IBT)
> >                        && (enable_ibt_type == cet_always_on
> > -                          || (m->l_cet & lc_ibt) != 0));
> > +                          || (m->l_x86_feature_1_and
> > +                              & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0));
> >         enable_shstk &= (HAS_CPU_FEATURE (SHSTK)
> >                          && (enable_shstk_type == cet_always_on
> > -                            || (m->l_cet & lc_shstk) != 0));
> > +                            || (m->l_x86_feature_1_and
> > +                                & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0));
> >       }
> >
> >        /* ld.so is CET-enabled by kernel.  But shared objects may not
>
> Ok.
>
> > @@ -111,7 +113,8 @@ dl_cet_check (struct link_map *m, const char *program)
> >             /* IBT is enabled only if it is enabled in executable as
> >                well as all shared objects.  */
> >             enable_ibt &= (enable_ibt_type == cet_always_on
> > -                          || (l->l_cet & lc_ibt) != 0);
> > +                          || (l->l_x86_feature_1_and
> > +                              & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0);
> >             if (!found_ibt_legacy && enable_ibt != ibt_enabled)
> >               {
> >                 found_ibt_legacy = true;
> > @@ -121,7 +124,8 @@ dl_cet_check (struct link_map *m, const char *program)
> >             /* SHSTK is enabled only if it is enabled in executable as
> >                well as all shared objects.  */
> >             enable_shstk &= (enable_shstk_type == cet_always_on
> > -                            || (l->l_cet & lc_shstk) != 0);
> > +                            || (l->l_x86_feature_1_and
> > +                                & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0);
> >             if (enable_shstk != shstk_enabled)
> >               {
> >                 found_shstk_legacy = true;
>
> Ok.
>
> > diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h
> > index ce1667dc7a..56bd020b3c 100644
> > --- a/sysdeps/x86/dl-prop.h
> > +++ b/sysdeps/x86/dl-prop.h
> > @@ -19,14 +19,54 @@
> >  #ifndef _DL_PROP_H
> >  #define _DL_PROP_H
> >
> > +#include <libintl.h>
> > +
> >  extern void _dl_cet_check (struct link_map *, const char *)
> >      attribute_hidden;
> >  extern void _dl_cet_open_check (struct link_map *)
> >      attribute_hidden;
> >
> > +static void
> > +dl_isa_level_check (struct link_map *m, const char *program)
> > +{
> > +  const struct cpu_features *cpu_features = __get_cpu_features ();
> > +  unsigned int i;
> > +  struct link_map *l;
> > +
> > +  i = m->l_searchlist.r_nlist;
> > +  while (i-- > 0)
> > +    {
> > +      /* Check each shared object to see if ISA level is compatible.  */
> > +      l = m->l_initfini[i];
> > +
> > +      /* Skip ISA level check if functions have been executed.  */
> > +      if (l->l_init_called)
> > +     continue;
> > +
> > +#ifdef SHARED
> > +      /* Skip ISA level check for ld.so since ld.so won't run if its ISA
> > +      level is higher than CPU.  */
> > +      if (l == &GL(dl_rtld_map) || l->l_real == &GL(dl_rtld_map))
> > +     continue;
> > +#endif
> > +
> > +      if ((l->l_x86_isa_1_needed & cpu_features->isa_1)
> > +       != l->l_x86_isa_1_needed)
> > +     {
> > +       if (program)
> > +         _dl_fatal_printf ("%s: CPU ISA level is lower than required\n",
> > +                           *l->l_name != '\0' ? l->l_name : program);
> > +       else
> > +         _dl_signal_error (0, l->l_name, "dlopen",
> > +                           N_("CPU ISA level is lower than required"));
> > +     }
> > +    }
> > +}
> > +
>
> Ok.
>
> >  static inline void __attribute__ ((always_inline))
> >  _rtld_main_check (struct link_map *m, const char *program)
> >  {
> > +  dl_isa_level_check (m, program);
> >  #if CET_ENABLED
> >    _dl_cet_check (m, program);
> >  #endif
> > @@ -35,20 +75,18 @@ _rtld_main_check (struct link_map *m, const char *program)
> >  static inline void __attribute__ ((always_inline))
> >  _dl_open_check (struct link_map *m)
> >  {
> > +  dl_isa_level_check (m, NULL);
> >  #if CET_ENABLED
> >    _dl_cet_open_check (m);
> >  #endif
> >  }
> >
> >  static inline void __attribute__ ((unused))
> > -_dl_process_cet_property_note (struct link_map *l,
> > -                           const ElfW(Nhdr) *note,
> > -                           const ElfW(Addr) size,
> > -                           const ElfW(Addr) align)
> > +_dl_process_property_note (struct link_map *l, const ElfW(Nhdr) *note,
> > +                        const ElfW(Addr) size, const ElfW(Addr) align)
> >  {
> > -#if CET_ENABLED
> >    /* Skip if we have seen a NT_GNU_PROPERTY_TYPE_0 note before.  */
> > -  if (l->l_cet != lc_unknown)
> > +  if (l->l_property != lc_property_unknown)
> >      return;
> >
> >    /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in
>
> Ok.
>
> > @@ -59,7 +97,8 @@ _dl_process_cet_property_note (struct link_map *l,
> >
> >    const ElfW(Addr) start = (ElfW(Addr)) note;
> >
> > -  unsigned int feature_1 = 0;
> > +  unsigned int feature_1_and = 0;
> > +  unsigned int isa_1_needed = 0;
> >    unsigned int last_type = 0;
> >
> >    while ((ElfW(Addr)) (note + 1) - start < size)
> > @@ -71,11 +110,11 @@ _dl_process_cet_property_note (struct link_map *l,
> >       {
> >         /* Stop if we see more than one GNU property note which may
> >            be generated by the older linker.  */
> > -       if (l->l_cet != lc_unknown)
> > +       if (l->l_property != lc_property_unknown)
> >           return;
> >
> > -       /* Check CET status now.  */
> > -       l->l_cet = lc_none;
> > +       /* Check CET status and ISA levels now.  */
> > +       l->l_property = lc_property_none;
> >
> >         /* Check for invalid property.  */
> >         if (note->n_descsz < 8
> > @@ -101,26 +140,37 @@ _dl_process_cet_property_note (struct link_map *l,
> >
> >             last_type = type;
> >
> > -           if (type == GNU_PROPERTY_X86_FEATURE_1_AND)
> > +           if (type == GNU_PROPERTY_X86_FEATURE_1_AND
> > +               || type == GNU_PROPERTY_X86_ISA_1_NEEDED)
> >               {
> > -               /* The size of GNU_PROPERTY_X86_FEATURE_1_AND is 4
> > -                  bytes.  When seeing GNU_PROPERTY_X86_FEATURE_1_AND,
> > -                  we stop the search regardless if its size is correct
> > -                  or not.  There is no point to continue if this note
> > -                  is ill-formed.  */
> > +               /* The sizes of types which we are searching for are
> > +                  4 bytes.  There is no point to continue if this
> > +                  note is ill-formed.  */
> >                 if (datasz != 4)
> >                   return;
> >
> > -               feature_1 = *(unsigned int *) ptr;
> > -
> > -               /* Keep searching for the next GNU property note
> > -                  generated by the older linker.  */
> > -               break;
> > +               /* NB: Stop the scan only after seeing all types which
> > +                  we are searching for.  */
> > +               _Static_assert ((GNU_PROPERTY_X86_ISA_1_NEEDED >
> > +                                GNU_PROPERTY_X86_FEATURE_1_AND),
> > +                               "GNU_PROPERTY_X86_ISA_1_NEEDED > "
> > +                               "GNU_PROPERTY_X86_FEATURE_1_AND");
> > +               if (type == GNU_PROPERTY_X86_FEATURE_1_AND)
> > +                 feature_1_and = *(unsigned int *) ptr;
> > +               else
> > +                 {
> > +                   isa_1_needed = *(unsigned int *) ptr;
> > +
> > +                   /* Keep searching for the next GNU property note
> > +                      generated by the older linker.  */
> > +                   break;
> > +                 }
> >               }
> > -           else if (type > GNU_PROPERTY_X86_FEATURE_1_AND)
> > +           else if (type > GNU_PROPERTY_X86_ISA_1_NEEDED)
> >               {
> > -               /* Stop since property type is in ascending order.  */
> > -               return;
> > +               /* Stop the scan since property type is in ascending
> > +                  order.  */
> > +               break;
> >               }
> >
> >             /* Check the next property item.  */
>
> Ok.
>
> > @@ -137,18 +187,21 @@ _dl_process_cet_property_note (struct link_map *l,
> >      }
> >
> >    /* We get here only if there is one or no GNU property note.  */
> > -  if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT))
> > -    l->l_cet |= lc_ibt;
> > -  if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
> > -    l->l_cet |= lc_shstk;
> > -#endif
> > +  if (isa_1_needed != 0 || feature_1_and != 0)
> > +    {
> > +      l->l_property = lc_property_valid;
> > +      l->l_x86_isa_1_needed = isa_1_needed;
> > +      l->l_x86_feature_1_and = feature_1_and;
> > +    }
> > +  else
> > +    l->l_property = lc_property_none;
> >  }
> >
> >  static inline void __attribute__ ((unused))
> >  _dl_process_pt_note (struct link_map *l, int fd, const ElfW(Phdr) *ph)
> >  {
> >    const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
> > -  _dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align);
> > +  _dl_process_property_note (l, note, ph->p_memsz, ph->p_align);
> >  }
> >
> >  static inline int __attribute__ ((always_inline))
>
> Ok.
>
> > diff --git a/sysdeps/x86/get-isa-level.h b/sysdeps/x86/get-isa-level.h
> > new file mode 100644
> > index 0000000000..a86e1e8941
> > --- /dev/null
> > +++ b/sysdeps/x86/get-isa-level.h
> > @@ -0,0 +1,66 @@
> > +/* Get x86 ISA level.
> > +   This file is part of the GNU C Library.
> > +   Copyright (C) 2020 Free Software Foundation, Inc.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <sys/platform/x86.h>
> > +
> > +/* Get GNU_PROPERTY_X86_ISA_1_BASELINE and GNU_PROPERTY_X86_ISA_1_V[234]
> > +   ISA level.  */
> > +
> > +static unsigned int
> > +get_isa_level (const struct cpu_features *cpu_features)
> > +{
> > +  unsigned int isa_level = 0;
> > +
> > +  if (CPU_FEATURE_USABLE_P (cpu_features, CMOV)
> > +      && CPU_FEATURE_USABLE_P (cpu_features, CX8)
> > +      && CPU_FEATURE_CPU_P (cpu_features, FPU)
> > +      && CPU_FEATURE_USABLE_P (cpu_features, FXSR)
> > +      && CPU_FEATURE_USABLE_P (cpu_features, MMX)
> > +      && CPU_FEATURE_USABLE_P (cpu_features, SSE)
> > +      && CPU_FEATURE_USABLE_P (cpu_features, SSE2))
> > +    {
> > +      isa_level = GNU_PROPERTY_X86_ISA_1_BASELINE;
> > +      if (CPU_FEATURE_USABLE_P (cpu_features, CMPXCHG16B)
> > +       && CPU_FEATURE_USABLE_P (cpu_features, LAHF64_SAHF64)
> > +       && CPU_FEATURE_USABLE_P (cpu_features, POPCNT)
> > +       && CPU_FEATURE_USABLE_P (cpu_features, SSE3)
> > +       && CPU_FEATURE_USABLE_P (cpu_features, SSSE3)
> > +       && CPU_FEATURE_USABLE_P (cpu_features, SSE4_1)
> > +       && CPU_FEATURE_USABLE_P (cpu_features, SSE4_2))
> > +     {
> > +       isa_level |= GNU_PROPERTY_X86_ISA_1_V2;
> > +       if (CPU_FEATURE_USABLE_P (cpu_features, AVX)
> > +           && CPU_FEATURE_USABLE_P (cpu_features, AVX2)
> > +           && CPU_FEATURE_USABLE_P (cpu_features, F16C)
> > +           && CPU_FEATURE_USABLE_P (cpu_features, FMA)
> > +           && CPU_FEATURE_USABLE_P (cpu_features, LZCNT)
> > +           && CPU_FEATURE_USABLE_P (cpu_features, MOVBE))
> > +         {
> > +           isa_level |= GNU_PROPERTY_X86_ISA_1_V3;
> > +           if (CPU_FEATURE_USABLE_P (cpu_features, AVX512F)
> > +               && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
> > +               && CPU_FEATURE_USABLE_P (cpu_features, AVX512CD)
> > +               && CPU_FEATURE_USABLE_P (cpu_features, AVX512DQ)
> > +               && CPU_FEATURE_USABLE_P (cpu_features, AVX512VL))
> > +             isa_level |= GNU_PROPERTY_X86_ISA_1_V4;
> > +         }
> > +     }
> > +    }
> > +
> > +  return isa_level;
> > +}
>
> Ok, is there any plan to add the gcc ISA_1_VX for 32-bit ABI as well? I am
> asking because if there is no upcoming plan maybe an option is just to
> return 0 for !__X86_64__.

Although there is no official plan to support it in 32-bit,  since the ISA level
support implemented in GCC and binutils is independent of 32-bit or 64-bit,
32-bit also get the same feature:

[hjl@gnu-cfl-2 tmp]$ touch x.c
[hjl@gnu-cfl-2 tmp]$ /usr/gcc-11.0.0-x32/bin/gcc -c -mneeded x.c -mavx2
[hjl@gnu-cfl-2 tmp]$ readelf -n x.o

Displaying notes found in: .note.gnu.property
  Owner                Data size Description
  GNU                  0x00000010 NT_GNU_PROPERTY_TYPE_0
      Properties: x86 ISA needed: x86-64-baseline, x86-64-v2, x86-64-v3
  GNU                  0x00000020 NT_GNU_PROPERTY_TYPE_0
      Properties: x86 ISA used:
x86 feature used: x86
[hjl@gnu-cfl-2 tmp]$ /usr/gcc-11.0.0-x32/bin/gcc -c -mneeded x.c -mavx2 -m32
[hjl@gnu-cfl-2 tmp]$ readelf -n x.o

Displaying notes found in: .note.gnu.property
  Owner                Data size Description
  GNU                  0x0000000c NT_GNU_PROPERTY_TYPE_0
      Properties: x86 ISA needed: x86-64-baseline, x86-64-v2, x86-64-v3
  GNU                  0x00000018 NT_GNU_PROPERTY_TYPE_0
      Properties: x86 ISA used:
x86 feature used: x86
[hjl@gnu-cfl-2 tmp]$

The glibc implementation also works on 32-bit.

> > diff --git a/sysdeps/x86/include/cpu-features.h b/sysdeps/x86/include/cpu-features.h
> > index ffe300c931..99e7ee08cf 100644
> > --- a/sysdeps/x86/include/cpu-features.h
> > +++ b/sysdeps/x86/include/cpu-features.h
> > @@ -123,6 +123,8 @@ struct cpu_features
> >    struct cpu_features_basic basic;
> >    struct cpuid_features features[COMMON_CPUID_INDEX_MAX];
> >    unsigned int preferred[PREFERRED_FEATURE_INDEX_MAX];
> > +  /* X86 micro-architecture ISA levels.  */
> > +  unsigned int isa_1;
> >    /* The state size for XSAVEC or XSAVE.  The type must be unsigned long
> >       int so that we use
> >
>
> Ok.
>
> > diff --git a/sysdeps/x86/isa-level.c b/sysdeps/x86/isa-level.c
> > new file mode 100644
> > index 0000000000..aaf524cb56
> > --- /dev/null
> > +++ b/sysdeps/x86/isa-level.c
> > @@ -0,0 +1,97 @@
> > +/* ELF program property for x86 ISA level.
> > +   Copyright (C) 2020 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   In addition to the permissions in the GNU Lesser General Public
> > +   License, the Free Software Foundation gives you unlimited
> > +   permission to link the compiled version of this file with other
> > +   programs, and to distribute those programs without any restriction
> > +   coming from the use of this file.  (The Lesser General Public
> > +   License restrictions do apply in other respects; for example, they
> > +   cover modification of the file, and distribution when not linked
> > +   into another program.)
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <elf.h>
> > +
> > +/* ELF program property for x86 ISA level.  */
> > +#ifdef INCLUDE_X86_ISA_LEVEL
> > +# if defined __x86_64__ || defined __FXSR__ || !defined _SOFT_FLOAT \
> > +     || defined  __MMX__ || defined __SSE__ || defined __SSE2__
> > +#  define ISA_BASELINE       GNU_PROPERTY_X86_ISA_1_BASELINE
> > +# else
> > +#  define ISA_BASELINE       0
> > +# endif
> > +
> > +# if defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16 \
> > +     || (defined __x86_64__ && defined __LAHF_SAHF__) \
> > +     || defined __POPCNT__ || defined __SSE3__ \
> > +     || defined __SSSE3__ || defined __SSE4_1__ || defined __SSE4_2__
> > +#  define ISA_V2     GNU_PROPERTY_X86_ISA_1_V2
> > +# else
> > +#  define ISA_V2     0
> > +# endif
> > +
> > +# if defined __AVX__ || defined __AVX2__ || defined __F16C__ \
> > +     || defined __FMA__ || defined __LZCNT__ || defined __MOVBE__ \
> > +     || defined __XSAVE__
> > +#  define ISA_V3     GNU_PROPERTY_X86_ISA_1_V3
> > +# else
> > +#  define ISA_V3     0
> > +# endif
> > +
> > +# if defined __AVX512F__ || defined __AVX512BW__ || defined __AVX512CD__ \
> > +     || defined __AVX512DQ__ || defined __AVX512VL__
> > +#  define ISA_V4     GNU_PROPERTY_X86_ISA_1_V4
> > +# else
> > +#  define ISA_V4     0
> > +# endif
> > +
> > +# ifndef ISA_LEVEL
> > +#  define ISA_LEVEL (ISA_BASELINE | ISA_V2 | ISA_V3 | ISA_V4)
> > +# endif
> > +
> > +# if ISA_LEVEL
> > +#  ifdef __LP64__
> > +#   define PROPERTY_ALIGN 3
> > +#  else
> > +#   define PROPERTY_ALIGN 2
> > +#  endif
> > +
> > +#  define note_stringify(arg) note_stringify_1(arg)
> > +#  define note_stringify_1(arg) #arg
> > +
> > +asm(".pushsection \".note.gnu.property\",\"a\",@note\n"
> > +"    .p2align " note_stringify (PROPERTY_ALIGN)
> > +     /* name length.  */
> > +"\n  .long 1f - 0f\n"
> > +     /* data length.  */
> > +"    .long 4f - 1f\n"
> > +     /* note type: NT_GNU_PROPERTY_TYPE_0.  */
> > +"    .long " note_stringify (NT_GNU_PROPERTY_TYPE_0)
> > +     /* vendor name.  */
> > +"\n0:        .asciz \"GNU\"\n"
> > +"1:  .p2align " note_stringify (PROPERTY_ALIGN)
> > +     /* pr_type: GNU_PROPERTY_X86_ISA_1_NEEDED.  */
> > +"\n  .long " note_stringify (GNU_PROPERTY_X86_ISA_1_NEEDED)
> > +     /* pr_datasz.  */
> > +"\n  .long 3f - 2f\n"
> > +     /* GNU_PROPERTY_X86_ISA_1_V[234].  */
> > +"2:\n         .long " note_stringify (ISA_LEVEL)
> > +"\n3:\n      .p2align " note_stringify (PROPERTY_ALIGN)
> > +"\n4:\n .popsection");
> > +# endif /* ISA_LEVEL */
> > +#endif /* INCLUDE_X86_ISA_LEVEL */
>
> Ok.
>
> > diff --git a/sysdeps/x86/link_map.h b/sysdeps/x86/link_map.h
> > index 8074739b47..4c46a25f83 100644
> > --- a/sysdeps/x86/link_map.h
> > +++ b/sysdeps/x86/link_map.h
> > @@ -16,12 +16,16 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > -/* If this object is enabled with CET.  */
> > +/* if this object has GNU property.  */
> >  enum
> >    {
> > -    lc_unknown = 0,                   /* Unknown CET status.  */
> > -    lc_none = 1 << 0,                         /* Not enabled with CET.  */
> > -    lc_ibt = 1 << 1,                  /* Enabled with IBT.  */
> > -    lc_shstk = 1 << 2,                        /* Enabled with STSHK.  */
> > -    lc_ibt_and_shstk = lc_ibt | lc_shstk /* Enabled with both.  */
> > -  } l_cet:3;
> > +    lc_property_unknown = 0,         /* Unknown property status.  */
> > +    lc_property_none = 1 << 0,               /* No property.  */
> > +    lc_property_valid = 1 << 1               /* Has valid property.  */
> > +  } l_property:2;
> > +
> > +/* GNU_PROPERTY_X86_FEATURE_1_AND of this object.  */
> > +unsigned int l_x86_feature_1_and;
> > +
> > +/* GNU_PROPERTY_X86_ISA_1_NEEDED of this object.  */
> > +unsigned int l_x86_isa_1_needed;
>
> Ok.
>
> > diff --git a/sysdeps/x86/tst-isa-level-1.c b/sysdeps/x86/tst-isa-level-1.c
> > new file mode 100644
> > index 0000000000..dc31d71ad2
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-isa-level-1.c
> > @@ -0,0 +1,104 @@
> > +/* Check ISA level on dlopened shared object.
> > +   Copyright (C) 2020 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <stdlib.h>
> > +#include <stdbool.h>
> > +#include <string.h>
> > +#include <elf.h>
> > +#include <get-isa-level.h>
> > +#include <support/xdlfcn.h>
> > +#include <support/check.h>
> > +#include <support/test-driver.h>
> > +
> > +static void
> > +do_test_1 (const char *modname, bool fail)
> > +{
> > +  int (*fp) (void);
> > +  void *h;
> > +
> > +  h = dlopen (modname, RTLD_LAZY);
> > +  if (h == NULL)
> > +    {
> > +      const char *err = dlerror ();
> > +      if (fail)
> > +     {
> > +       if (strstr (err, "CPU ISA level is lower than required") == NULL)
> > +         FAIL_EXIT1 ("incorrect dlopen '%s' error: %s\n", modname, err);
> > +
> > +       return;
> > +     }
> > +
> > +      FAIL_EXIT1 ("cannot open '%s': %s\n", modname, err);
> > +    }
> > +
> > +  if (fail)
> > +    FAIL_EXIT1 ("dlopen '%s' should have failed\n", modname);
> > +
> > +  fp = xdlsym (h, "test");
> > +
> > +  if (fp () != 0)
> > +    FAIL_EXIT1 ("test () != 0\n");
> > +
> > +  dlclose (h);
> > +}
> > +
> > +static int
> > +do_test (void)
> > +{
> > +  const struct cpu_features *cpu_features
> > +    = __x86_get_cpu_features (COMMON_CPUID_INDEX_MAX);
> > +  unsigned int isa_level = get_isa_level (cpu_features);
> > +  bool has_isa_baseline = ((isa_level & GNU_PROPERTY_X86_ISA_1_BASELINE)
> > +                        == GNU_PROPERTY_X86_ISA_1_BASELINE);
> > +  bool has_isa_v2 = ((isa_level & GNU_PROPERTY_X86_ISA_1_V2)
> > +                        == GNU_PROPERTY_X86_ISA_1_V2);
> > +  bool has_isa_v3 = ((isa_level & GNU_PROPERTY_X86_ISA_1_V3)
> > +                        == GNU_PROPERTY_X86_ISA_1_V3);
> > +  bool has_isa_v4 = ((isa_level & GNU_PROPERTY_X86_ISA_1_V4)
> > +                        == GNU_PROPERTY_X86_ISA_1_V4);
> > +
> > +  if (!has_isa_baseline)
> > +    {
> > +      do_test_1 ("tst-isa-level-mod-1-baseline.so", true);
> > +      return EXIT_SUCCESS;
> > +    }
> > +
> > +  do_test_1 ("tst-isa-level-mod-1-baseline.so", false);
> > +
> > +  /* Skip on x86-64-v4 platforms since dlopen v4 module always works.  */
> > +  if (has_isa_v4)
> > +    return EXIT_UNSUPPORTED;
>
> Not sure if unsupported is the right error code here, since the isa
> selection is just ignored (not really not supported).

I will change it to EXIT_SUCCESS.

> > +
> > +  do_test_1 ("tst-isa-level-mod-1-v4.so", true);
> > +
> > +  /* Skip on x86-64-v3 platforms since dlopen v3 module always works.  */
> > +  if (has_isa_v3)
> > +    return EXIT_SUCCESS;
> > +
> > +  do_test_1 ("tst-isa-level-mod-1-v3.so", true);
> > +
> > +  /* Skip on x86-64-v2 platforms since dlopen v2 module always works.  */
> > +  if (has_isa_v2)
> > +    return EXIT_SUCCESS;
> > +
> > +  do_test_1 ("tst-isa-level-mod-1-v2.so", true);
> > +
> > +  return EXIT_SUCCESS;
> > +}
> > +
> > +#include <support/test-driver.c>
> > diff --git a/sysdeps/x86/tst-isa-level-mod-1-baseline.c b/sysdeps/x86/tst-isa-level-mod-1-baseline.c
> > new file mode 100644
> > index 0000000000..d6fe0685a4
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-isa-level-mod-1-baseline.c
> > @@ -0,0 +1 @@
> > +#include "tst-isa-level-mod-1.c"
> > diff --git a/sysdeps/x86/tst-isa-level-mod-1-v2.c b/sysdeps/x86/tst-isa-level-mod-1-v2.c
> > new file mode 100644
> > index 0000000000..d6fe0685a4
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-isa-level-mod-1-v2.c
> > @@ -0,0 +1 @@
> > +#include "tst-isa-level-mod-1.c"
> > diff --git a/sysdeps/x86/tst-isa-level-mod-1-v3.c b/sysdeps/x86/tst-isa-level-mod-1-v3.c
> > new file mode 100644
> > index 0000000000..d6fe0685a4
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-isa-level-mod-1-v3.c
> > @@ -0,0 +1 @@
> > +#include "tst-isa-level-mod-1.c"
> > diff --git a/sysdeps/x86/tst-isa-level-mod-1-v4.c b/sysdeps/x86/tst-isa-level-mod-1-v4.c
> > new file mode 100644
> > index 0000000000..d6fe0685a4
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-isa-level-mod-1-v4.c
> > @@ -0,0 +1 @@
> > +#include "tst-isa-level-mod-1.c"
>
> Ok.
>
> > diff --git a/sysdeps/x86/tst-isa-level-mod-1.c b/sysdeps/x86/tst-isa-level-mod-1.c
> > new file mode 100644
> > index 0000000000..40a2e1d99f
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-isa-level-mod-1.c
> > @@ -0,0 +1,25 @@
> > +/* Check ISA level on dlopened shared object.
> > +   Copyright (C) 2019-2020 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <isa-level.c>
> > +
> > +int
> > +test (void)
> > +{
> > +  return 0;
> > +}
>
> Ok.
>
> > diff --git a/sysdeps/x86_64/dl-hwcaps-subdirs.c b/sysdeps/x86_64/dl-hwcaps-subdirs.c
> > index 0aaa635a00..e030534f1b 100644
> > --- a/sysdeps/x86_64/dl-hwcaps-subdirs.c
> > +++ b/sysdeps/x86_64/dl-hwcaps-subdirs.c
> > @@ -18,6 +18,7 @@
> >
> >  #include <dl-hwcaps.h>
> >  #include <cpu-features.h>
> > +#include <get-isa-level.h>
> >
> >  const char _dl_hwcaps_subdirs[] = "x86-64-v4:x86-64-v3:x86-64-v2";
> >  enum { subdirs_count = 3 }; /* Number of components in _dl_hwcaps_subdirs.  */
> > @@ -25,40 +26,25 @@ enum { subdirs_count = 3 }; /* Number of components in _dl_hwcaps_subdirs.  */
> >  uint32_t
> >  _dl_hwcaps_subdirs_active (void)
> >  {
> > +  const struct cpu_features *cpu_features
> > +    = __x86_get_cpu_features (COMMON_CPUID_INDEX_MAX);
> > +  unsigned int isa_level = get_isa_level (cpu_features);
> >    int active = 0;
> >
> >    /* Test in reverse preference order.  */
> >
> >    /* x86-64-v2.  */
> > -  if (!(CPU_FEATURE_USABLE (CMPXCHG16B)
> > -        && CPU_FEATURE_USABLE (LAHF64_SAHF64)
> > -        && CPU_FEATURE_USABLE (POPCNT)
> > -        && CPU_FEATURE_USABLE (SSE3)
> > -        && CPU_FEATURE_USABLE (SSE4_1)
> > -        && CPU_FEATURE_USABLE (SSE4_2)
> > -        && CPU_FEATURE_USABLE (SSSE3)))
> > +  if (!(isa_level & GNU_PROPERTY_X86_ISA_1_V2))
> >      return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
> >    ++active;
> >
> >    /* x86-64-v3.  */
> > -  if (!(CPU_FEATURE_USABLE (AVX)
> > -        && CPU_FEATURE_USABLE (AVX2)
> > -        && CPU_FEATURE_USABLE (BMI1)
> > -        && CPU_FEATURE_USABLE (BMI2)
> > -        && CPU_FEATURE_USABLE (F16C)
> > -        && CPU_FEATURE_USABLE (FMA)
> > -        && CPU_FEATURE_USABLE (LZCNT)
> > -        && CPU_FEATURE_USABLE (MOVBE)
> > -        && CPU_FEATURE_USABLE (OSXSAVE)))
> > +  if (!(isa_level & GNU_PROPERTY_X86_ISA_1_V3))
> >      return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
> >    ++active;
> >
> > - /* x86-64-v4.  */
> > -  if (!(CPU_FEATURE_USABLE (AVX512F)
> > -        && CPU_FEATURE_USABLE (AVX512BW)
> > -        && CPU_FEATURE_USABLE (AVX512CD)
> > -        && CPU_FEATURE_USABLE (AVX512DQ)
> > -        && CPU_FEATURE_USABLE (AVX512VL)))
> > +  /* x86-64-v4.  */
> > +  if (!(isa_level & GNU_PROPERTY_X86_ISA_1_V4))
> >      return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
> >    ++active;
> >
> > diff --git a/sysdeps/x86_64/tst-glibc-hwcaps.c b/sysdeps/x86_64/tst-glibc-hwcaps.c
> > index 8bdcb91db0..37b61d3c84 100644
> > --- a/sysdeps/x86_64/tst-glibc-hwcaps.c
> > +++ b/sysdeps/x86_64/tst-glibc-hwcaps.c
> > @@ -19,7 +19,8 @@
> >  #include <stdio.h>
> >  #include <support/check.h>
> >  #include <sys/param.h>
> > -#include <sys/platform/x86.h>
> > +#include <elf.h>
> > +#include <get-isa-level.h>
> >
> >  extern int marker2 (void);
> >  extern int marker3 (void);
> > @@ -31,35 +32,15 @@ compute_level (void)
> >  {
> >    const struct cpu_features *cpu_features
> >      = __x86_get_cpu_features (COMMON_CPUID_INDEX_MAX);
> > -
> > - if (!(CPU_FEATURE_USABLE_P (cpu_features, CMPXCHG16B)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, LAHF64_SAHF64)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, POPCNT)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, MMX)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, SSE)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, SSE2)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, SSE3)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, SSSE3)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, SSE4_1)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, SSE4_2)))
> > -   return 1;
> > - if (!(CPU_FEATURE_USABLE_P (cpu_features, AVX)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, AVX2)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, BMI1)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, BMI2)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, F16C)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, FMA)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, LZCNT)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, MOVBE)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, OSXSAVE)))
> > -   return 2;
> > - if (!(CPU_FEATURE_USABLE_P (cpu_features, AVX512F)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, AVX512CD)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, AVX512DQ)
> > -       && CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)))
> > -   return 3;
> > - return 4;
> > +  unsigned int isa_level = get_isa_level (cpu_features);
> > +
> > +  if (!(isa_level & GNU_PROPERTY_X86_ISA_1_V2))
> > +    return 1;
> > +  if (!(isa_level & GNU_PROPERTY_X86_ISA_1_V3))
> > +    return 2;
> > +  if (!(isa_level & GNU_PROPERTY_X86_ISA_1_V4))
> > +    return 3;
> > +  return 4;
> >  }
> >
> >  static int
> > --
> > 2.29.2
>
> Ok.

This is the patch I am checking in.

Thanks.

-- 
H.J.