[glibc] x86: In ld.so, diagnose missing APX support in APX-only builds

[glibc] x86: In ld.so, diagnose missing APX support in APX-only builds

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b62928f9070c6f3c5cc43a4cb89b4bfb950d7406

commit b62928f9070c6f3c5cc43a4cb89b4bfb950d7406
Author: Florian Weimer <fweimer@redhat.com>
Date:   Thu Apr 25 17:20:28 2024 +0200

    x86: In ld.so, diagnose missing APX support in APX-only builds
    
    At this point, this is mainly a tool for testing the early ld.so
    CPU compatibility diagnostics: GCC uses the new instructions in most
    functions, so it's easy to spot if some of the early code is not
    built correctly.
    
    Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Diff:
---
 sysdeps/x86/dl-get-cpu-features.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sysdeps/x86/dl-get-cpu-features.c b/sysdeps/x86/dl-get-cpu-features.c
index 4d6c5c59a6..579d02d638 100644
--- a/sysdeps/x86/dl-get-cpu-features.c
+++ b/sysdeps/x86/dl-get-cpu-features.c
@@ -64,6 +64,11 @@ Fatal glibc error: CPU does not support x86-64-v%d\n", 4);
 #    endif /* ISA level 4 */
 #   endif /* ISA level 3 */
 #  endif /* ISA level 2 */
+# ifdef GCCMACRO__APX_F__
+      if (!CPU_FEATURE_USABLE_P (cpu_features, APX_F))
+	_dl_fatal_printf ("\
+Fatal glibc error: CPU does not support APX\n");
+# endif
 # endif /* IS_IN (rtld) */
     }
 }