powerpc: Move cache line size to rtld_global_ro

GCC 10.0 enabled -fno-common by default and this started to point that
__cache_line_size had been implemented in 2 different places: loader and
libc.

In order to avoid this duplication, the libc variable has been removed
and the loader variable is moved to rtld_global_ro.

File sysdeps/unix/sysv/linux/powerpc/dl-auxv.h has been added in order
to reuse code for both static and dynamic linking scenarios.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/sysdeps/powerpc/mod-cache-ppc.c b/sysdeps/powerpc/mod-cache-ppc.c
new file mode 100644
index 0000000000..81fad52078
--- /dev/null
+++ b/sysdeps/powerpc/mod-cache-ppc.c
@@ -0,0 +1,45 @@
+/* Test if an executable can read from rtld_global_ro._dl_cache_line_size.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <sys/auxv.h>
+#include <ldsodefs.h>
+#include <errno.h>
+
+/* errnop is required in order to work around BZ #20802.  */
+int
+test_cache (int *errnop)
+{
+  int cls1 = GLRO (dl_cache_line_size);
+  errno = *errnop;
+  uint64_t cls2 = getauxval (AT_DCACHEBSIZE);
+  *errnop = errno;
+
+  printf ("AT_DCACHEBSIZE      = %" PRIu64 " B\n", cls2);
+  printf ("_dl_cache_line_size = %d B\n", cls1);
+
+  if (cls1 != cls2)
+    {
+      printf ("error: _dl_cache_line_size != AT_DCACHEBSIZE\n");
+      return 1;
+    }
+
+  return 0;
+}