[glibc/release/2.39/master] x86: Define MINIMUM_X86_ISA_LEVEL in config.h [BZ #31676]

[glibc/release/2.39/master] x86: Define MINIMUM_X86_ISA_LEVEL in config.h [BZ #31676]

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=2f8f157eb0cc7f1d8d9a3fcaa8c55bed53b092a8

commit 2f8f157eb0cc7f1d8d9a3fcaa8c55bed53b092a8
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Apr 23 13:59:50 2024 -0700

    x86: Define MINIMUM_X86_ISA_LEVEL in config.h [BZ #31676]
    
    Define MINIMUM_X86_ISA_LEVEL at configure time to avoid
    
    /usr/bin/ld: …/build/elf/librtld.os: in function `init_cpu_features':
    …/git/elf/../sysdeps/x86/cpu-features.c:1202: undefined reference to `_dl_runtime_resolve_fxsave'
    /usr/bin/ld: …/build/elf/librtld.os: relocation R_X86_64_PC32 against undefined hidden symbol `_dl_runtime_resolve_fxsave' can not be used when making a shared object
    /usr/bin/ld: final link failed: bad value
    collect2: error: ld returned 1 exit status
    
    when glibc is built with -march=x86-64-v3 and configured with
    --with-rtld-early-cflags=-march=x86-64, which is used to allow ld.so to
    print an error message on unsupported CPUs:
    
    Fatal glibc error: CPU does not support x86-64-v3
    
    This fixes BZ #31676.
    Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
    
    (cherry picked from commit 46c999741340ea559784c20a45077955b50aca43)

Diff:
---
 config.h.in              | 3 +++
 sysdeps/x86/configure    | 7 +++++++
 sysdeps/x86/configure.ac | 5 +++++
 sysdeps/x86/isa-level.h  | 4 +++-
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/config.h.in b/config.h.in
index 4d33c63a84..1e647de585 100644
--- a/config.h.in
+++ b/config.h.in
@@ -286,6 +286,9 @@
 /* Define if x86 ISA level should be included in shared libraries.  */
 #undef INCLUDE_X86_ISA_LEVEL
 
+/* The x86 ISA level.  1 for baseline.  Undefined on non-x86.  */
+#undef MINIMUM_X86_ISA_LEVEL
+
 /* Define if -msahf is enabled by default on x86.  */
 #undef HAVE_X86_LAHF_SAHF
 
diff --git a/sysdeps/x86/configure b/sysdeps/x86/configure
index 2a5421bb31..d28d9bcb29 100644
--- a/sysdeps/x86/configure
+++ b/sysdeps/x86/configure
@@ -151,6 +151,13 @@ printf "%s\n" "$libc_cv_have_x86_isa_level" >&6; }
 else
   libc_cv_have_x86_isa_level=baseline
 fi
+if test $libc_cv_have_x86_isa_level = baseline; then
+  printf "%s\n" "#define MINIMUM_X86_ISA_LEVEL 1" >>confdefs.h
+
+else
+  printf "%s\n" "#define MINIMUM_X86_ISA_LEVEL $libc_cv_have_x86_isa_level" >>confdefs.h
+
+fi
 config_vars="$config_vars
 have-x86-isa-level = $libc_cv_have_x86_isa_level"
 config_vars="$config_vars
diff --git a/sysdeps/x86/configure.ac b/sysdeps/x86/configure.ac
index 78ff7c8f41..5b0acd03d2 100644
--- a/sysdeps/x86/configure.ac
+++ b/sysdeps/x86/configure.ac
@@ -105,6 +105,11 @@ EOF
 else
   libc_cv_have_x86_isa_level=baseline
 fi
+if test $libc_cv_have_x86_isa_level = baseline; then
+  AC_DEFINE_UNQUOTED(MINIMUM_X86_ISA_LEVEL, 1)
+else
+  AC_DEFINE_UNQUOTED(MINIMUM_X86_ISA_LEVEL, $libc_cv_have_x86_isa_level)
+fi
 LIBC_CONFIG_VAR([have-x86-isa-level], [$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])
diff --git a/sysdeps/x86/isa-level.h b/sysdeps/x86/isa-level.h
index 11fe1ca90c..2c7f74212b 100644
--- a/sysdeps/x86/isa-level.h
+++ b/sysdeps/x86/isa-level.h
@@ -61,8 +61,10 @@
 # define __X86_ISA_V4 0
 #endif
 
-#define MINIMUM_X86_ISA_LEVEL                                                 \
+#ifndef MINIMUM_X86_ISA_LEVEL
+# define MINIMUM_X86_ISA_LEVEL                                                 \
   (__X86_ISA_V1 + __X86_ISA_V2 + __X86_ISA_V3 + __X86_ISA_V4)
+#endif
 
 /* Depending on the minimum ISA level, a feature check result can be a
    compile-time constant.. */