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]$

1 files changed, 66 insertions, 0 deletions

diff --git a/sysdeps/x86/configure.ac b/sysdeps/x86/configure.ac
index 8f3e119..f94088f 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])