diff mbox series

[v2] nptl: Add <thread_pointer.h> for sparc

Message ID 20241101160546.113259-1-mjeanson@efficios.com
State New
Headers show
Series [v2] nptl: Add <thread_pointer.h> for sparc | expand

Commit Message

Michael Jeanson Nov. 1, 2024, 4:05 p.m. UTC 
This will be required by the rseq extensible ABI implementation on all
Linux architectures exposing the '__rseq_size' and '__rseq_offset'
symbols to set the initial value of the 'cpu_id' field which can be used
by applications to test if rseq is available and registered. As long as
the symbols are exposed it is valid for an application to perform this
test even if rseq is not yet implemented in libc for this architecture.

Compile tested with build-many-glibcs.py but I don't have access to any
hardware to run the tests.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
---
Changes since v1:
- Remove the __builtin_thread_pointer code path, __has_builtin can't
  reliably check if the builtin is implemented in the backend and
  the latest GCC doesn't implement it.
---
Cc: Florian Weimer <fweimer@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Andreas K. Hüttel <dilfridge@gentoo.org>
Cc: Arjun Shankar <arjun@redhat.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
---
 sysdeps/sparc/nptl/thread_pointer.h | 30 +++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 sysdeps/sparc/nptl/thread_pointer.h
diff mbox series

Patch

diff --git a/sysdeps/sparc/nptl/thread_pointer.h b/sysdeps/sparc/nptl/thread_pointer.h
new file mode 100644
index 0000000000..a526198057
--- /dev/null
+++ b/sysdeps/sparc/nptl/thread_pointer.h
@@ -0,0 +1,30 @@ 
+/* __thread_pointer definition.  sparc version.
+   Copyright (C) 2021-2024 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)
+{
+  void *__thread_register;
+  __asm__ ("mov %%g7, %0" : "=r" (__thread_register));
+  return __thread_register;
+}
+
+#endif /* _SYS_THREAD_POINTER_H */