aarch64: Fix tests not compatible with targets supporting GCS

- Add GCS marking to some of the tests when target supports GCS
 - Fix tst-ro-dynamic-mod.map linker script to avoid removing
   GNU properties
 - Add header with macros for GNU properties

Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>

elf/tst-asm-helper.h

@@ -0,0 +1,49 @@
+/* Test header that defines macros for GNU properties that need to be
+   used in some test assembly files where sysdep.h cannot be included
+   for some reason.
+   Copyright (C) 2024-2025 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 <config.h>
+
+/* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code.  */
+#define FEATURE_1_AND 0xc0000000
+#define FEATURE_1_BTI 1
+#define FEATURE_1_PAC 2
+#define FEATURE_1_GCS 4
+
+/* Add a NT_GNU_PROPERTY_TYPE_0 note.  */
+#define GNU_PROPERTY(type, value)	\
+  .section .note.gnu.property, "a";	\
+  .p2align 3;				\
+  .word 4;				\
+  .word 16;				\
+  .word 5;				\
+  .asciz "GNU";				\
+  .word type;				\
+  .word 4;				\
+  .word value;				\
+  .word 0;				\
+  .text
+
+/* Add GNU property note with the supported features to all asm code
+   where sysdep.h is included.  */
+#if HAVE_AARCH64_BTI && HAVE_AARCH64_PAC_RET
+GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI|FEATURE_1_PAC|FEATURE_1_GCS)
+#elif HAVE_AARCH64_BTI
+GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI|FEATURE_1_GCS)
+#endif

elf/tst-big-note-lib.S

@@ -20,6 +20,8 @@
    On a typical Linux system with 8MiB "ulimit -s", that was enough
    to trigger stack overflow in open_verify.  */
 
+#include "tst-asm-helper.h"
+
 #define NOTE_SIZE 8*1024*1024
 
 .pushsection .note.big,"a"

elf/tst-ro-dynamic-mod.map

@@ -3,14 +3,13 @@ SECTIONS
  . = SIZEOF_HEADERS;
  .dynamic : { *(.dynamic) } :text :dynamic
  .rodata : { *(.data*) *(.bss*) } :text
- /DISCARD/ : {
-  *(.note.gnu.property)
- }
- .note : { *(.note.*) } :text :note
+ .note : { *(.note) } :text :note
+ .note.gnu.property : { *(.note.gnu.property) } :text :gnu_property
 }
 PHDRS
 {
  text PT_LOAD FLAGS(5) FILEHDR PHDRS;
  dynamic PT_DYNAMIC FLAGS(4);
  note PT_NOTE FLAGS(4);
+ gnu_property PT_GNU_PROPERTY FLAGS(4);
 }

sysdeps/aarch64/tst-vpcs-mod.S

@@ -17,6 +17,8 @@
    License along with the GNU C Library.  If not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include "tst-asm-helper.h"
+
 	.variant_pcs	vpcs_call
 	.global	vpcs_call
 	.type	vpcs_call, %function
@@ -121,7 +123,7 @@ vpcs_call_regs:
 	/* Emulate a BL using B, but save x30 before the branch.  */
 	adr	x30, .L_return_addr
 	stp	x30, x29, [x1, 240]
-	b	vpcs_call
+	bl	vpcs_call
 .L_return_addr:
 
 	/* Restore callee-saved registers.  */