nptl: Add <thread_pointer.h> for defining __thread_pointer

<tls.h> already contains a definition that is quite similar,
but it is not consistent across architectures.

Only architectures for which rseq support is added are covered.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

3 files changed, 99 insertions, 0 deletions

diff --git a/sysdeps/nptl/thread_pointer.h b/sysdeps/nptl/thread_pointer.h
new file mode 100644
index 0000000000..92f2f3093e
--- /dev/null
+++ b/sysdeps/nptl/thread_pointer.h
@@ -0,0 +1,28 @@
+/* __thread_pointer definition.  Generic version.
+   Copyright (C) 2021 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 _SYS_THREAD_POINTER_H
+#define _SYS_THREAD_POINTER_H
+
+static inline void *
+__thread_pointer (void)
+{
+  return __builtin_thread_pointer ();
+}
+
+#endif /* _SYS_THREAD_POINTER_H */
diff --git a/sysdeps/powerpc/nptl/thread_pointer.h b/sysdeps/powerpc/nptl/thread_pointer.h
new file mode 100644
index 0000000000..8fd5ba671f
--- /dev/null
+++ b/sysdeps/powerpc/nptl/thread_pointer.h
@@ -0,0 +1,33 @@
+/* __thread_pointer definition.  powerpc version.
+   Copyright (C) 2021 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 _SYS_THREAD_POINTER_H
+#define _SYS_THREAD_POINTER_H
+
+static inline void *
+__thread_pointer (void)
+{
+#ifdef __powerpc64__
+  register void *__result asm ("r13");
+#else
+  register void *__result asm ("r2");
+#endif
+  return __result;
+}
+
+#endif /* _SYS_THREAD_POINTER_H */
diff --git a/sysdeps/x86/nptl/thread_pointer.h b/sysdeps/x86/nptl/thread_pointer.h
new file mode 100644
index 0000000000..6b71b6f7e1
--- /dev/null
+++ b/sysdeps/x86/nptl/thread_pointer.h
@@ -0,0 +1,38 @@
+/* __thread_pointer definition.  x86 version.
+   Copyright (C) 2021 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 _SYS_THREAD_POINTER_H
+#define _SYS_THREAD_POINTER_H
+
+static inline void *
+__thread_pointer (void)
+{
+#if __GNUC_PREREQ (11, 1)
+  return __builtin_thread_pointer ();
+#else
+  void *__result;
+# ifdef __x86_64__
+  __asm__ ("mov %%fs:0, %0" : "=r" (__result));
+# else
+  __asm__ ("mov %%gs:0, %0" : "=r" (__result));
+# endif
+  return __result;
+#endif /* !GCC 11 */
+}
+
+#endif /* _SYS_THREAD_POINTER_H */