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-rw-r--r--sysdeps/aarch64/__mtag_new_tag.S38
1 files changed, 38 insertions, 0 deletions
diff --git a/sysdeps/aarch64/__mtag_new_tag.S b/sysdeps/aarch64/__mtag_new_tag.S
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+++ b/sysdeps/aarch64/__mtag_new_tag.S
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+/* 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+	.arch armv8.5-a
+	.arch_extension memtag
+
+/* NB, only supported on variants with 64-bit pointers.  */
+
+/* FIXME: This is a minimal implementation.  We could do better than
+   this for larger values of COUNT.  */
+
+#define ptr x0
+#define xset x1
+
+ENTRY(__libc_mtag_new_tag)
+	// Guarantee that the new tag is not the same as now.
+	gmi	xset, ptr, xzr
+	irg	ptr, ptr, xset
+	ret
+END (__libc_mtag_new_tag)
+libc_hidden_builtin_def (__libc_mtag_new_tag)