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

[Florian Weimer <fweimer@redhat.com>]

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.  (No such problems were flagged for the current
tree.)

---
 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) */
     }
 }

base-commit: 3a3a4497421422aa854c855cbe5110ca7d598ffc