1 files changed, 67 insertions, 0 deletions
diff --git a/sysdeps/arm/pointer_guard.h b/sysdeps/arm/pointer_guard.h
new file mode 100644
index 0000000000..6b90cec2f3
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+++ b/sysdeps/arm/pointer_guard.h
@@ -0,0 +1,67 @@
+/* Pointer guard implementation.  Arm version.
+   Copyright (C) 2013-2022 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/>.  */
+
+#ifndef POINTER_GUARD_H
+#define POINTER_GUARD_H
+
+/* Pointer mangling support.  */
+#if (IS_IN (rtld) \
+     || (!defined SHARED && (IS_IN (libc) || IS_IN (libpthread))))
+# ifdef __ASSEMBLER__
+#  define PTR_MANGLE_LOAD(guard, tmp)                                   \
+  LDR_HIDDEN (guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local), 0)
+#  define PTR_MANGLE(dst, src, guard, tmp)                              \
+  PTR_MANGLE_LOAD(guard, tmp);                                          \
+  PTR_MANGLE2(dst, src, guard)
+/* Use PTR_MANGLE2 for efficiency if guard is already loaded.  */
+#  define PTR_MANGLE2(dst, src, guard)          \
+  eor dst, src, guard
+#  define PTR_DEMANGLE(dst, src, guard, tmp)    \
+  PTR_MANGLE (dst, src, guard, tmp)
+#  define PTR_DEMANGLE2(dst, src, guard)        \
+  PTR_MANGLE2 (dst, src, guard)
+# else
+extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
+#  define PTR_MANGLE(var) \
+  (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
+#  define PTR_DEMANGLE(var)     PTR_MANGLE (var)
+# endif
+#else
+# ifdef __ASSEMBLER__
+#  define PTR_MANGLE_LOAD(guard, tmp)                                   \
+  LDR_GLOBAL (guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard), 0);
+#  define PTR_MANGLE(dst, src, guard, tmp)                              \
+  PTR_MANGLE_LOAD(guard, tmp);                                          \
+  PTR_MANGLE2(dst, src, guard)
+/* Use PTR_MANGLE2 for efficiency if guard is already loaded.  */
+#  define PTR_MANGLE2(dst, src, guard)          \
+  eor dst, src, guard
+#  define PTR_DEMANGLE(dst, src, guard, tmp)    \
+  PTR_MANGLE (dst, src, guard, tmp)
+#  define PTR_DEMANGLE2(dst, src, guard)        \
+  PTR_MANGLE2 (dst, src, guard)
+# else
+#  include <stdint.h>
+extern uintptr_t __pointer_chk_guard attribute_relro;
+#  define PTR_MANGLE(var) \
+  (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
+#  define PTR_DEMANGLE(var)     PTR_MANGLE (var)
+# endif
+#endif
+
+#endif /* POINTER_GUARD_H */