From 9f78a7c1d0963282608da836b840f0d5ae1c478e Mon Sep 17 00:00:00 2001
From: Sunil K Pandey <skpgkp2@gmail.com>
Date: Tue, 13 Feb 2024 12:23:14 -0800
Subject: x86_64: Exclude SSE, AVX and FMA4 variants in libm multiarch

When glibc is built with ISA level 3 or higher by default, the resulting
glibc binaries won't run on SSE or FMA4 processors.  Exclude SSE, AVX and
FMA4 variants in libm multiarch when ISA level 3 or higher is enabled by
default.

When glibc is built with ISA level 2 enabled by default, only keep SSE4.1
variant.

Fixes BZ 31335.

NB: elf/tst-valgrind-smoke test fails with ISA level 4, because valgrind
doesn't support AVX512 instructions:

https://bugs.kde.org/show_bug.cgi?id=383010

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
---
 sysdeps/x86/configure.ac | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'sysdeps/x86/configure.ac')

diff --git a/sysdeps/x86/configure.ac b/sysdeps/x86/configure.ac
index 437a506..78ff7c8 100644
--- a/sysdeps/x86/configure.ac
+++ b/sysdeps/x86/configure.ac
@@ -72,6 +72,7 @@ if test $libc_cv_include_x86_isa_level = yes; then
     fi])
   if test $libc_cv_have_x86_lahf_sahf = yes; then
     AC_DEFINE(HAVE_X86_LAHF_SAHF)
+    ISAFLAG="-DHAVE_X86_LAHF_SAHF"
   fi
   AC_CACHE_CHECK([for MOVBE instruction support],
 		 libc_cv_have_x86_movbe, [dnl
@@ -81,8 +82,31 @@ if test $libc_cv_include_x86_isa_level = yes; then
     fi])
   if test $libc_cv_have_x86_movbe = yes; then
     AC_DEFINE(HAVE_X86_MOVBE)
+    ISAFLAG="$ISAFLAG -DHAVE_X86_MOVBE"
   fi
+
+  # Check for ISA level support.
+  AC_CACHE_CHECK([for ISA level support],
+		 libc_cv_have_x86_isa_level, [dnl
+cat > conftest.c <<EOF
+#include <sysdeps/x86/isa-level.h>
+#if MINIMUM_X86_ISA_LEVEL >= 4
+libc_cv_have_x86_isa_level=4
+#elif MINIMUM_X86_ISA_LEVEL == 3
+libc_cv_have_x86_isa_level=3
+#elif MINIMUM_X86_ISA_LEVEL == 2
+libc_cv_have_x86_isa_level=2
+#else
+libc_cv_have_x86_isa_level=baseline
+#endif
+EOF
+		 eval `${CC-cc} $CFLAGS $CPPFLAGS $ISAFLAG -I$srcdir -E conftest.c | grep libc_cv_have_x86_isa_level`
+		 rm -rf conftest*])
+else
+  libc_cv_have_x86_isa_level=baseline
 fi
+LIBC_CONFIG_VAR([have-x86-isa-level], [$libc_cv_have_x86_isa_level])
+LIBC_CONFIG_VAR([x86-isa-level-3-or-above], [3 4])
 LIBC_CONFIG_VAR([enable-x86-isa-level], [$libc_cv_include_x86_isa_level])
 
 dnl Static PIE is supported.
-- 
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