elf: Make dl-rseq-symbols Linux only

And avoid a Hurd build failures.

Checked on x86_64-linux-gnu.

(cherry picked from commit 9fc639f654dc004736836613be703e6bed0c36a8)

2 files changed, 68 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 415aa1f..6ab9b90 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -615,6 +615,10 @@ tests += \
 endif
 
 ifeq ($(subdir),elf)
+dl-routines += \
+  dl-rseq-symbols \
+  # dl-routines
+
 sysdep-rtld-routines += \
   dl-brk \
   dl-getcwd \
diff --git a/sysdeps/unix/sysv/linux/dl-rseq-symbols.S b/sysdeps/unix/sysv/linux/dl-rseq-symbols.S
new file mode 100644
index 0000000..b4bba06
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/dl-rseq-symbols.S
@@ -0,0 +1,64 @@
+/* Define symbols used by rseq.
+   Copyright (C) 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/>.  */
+
+#include <sysdep.h>
+
+#if __WORDSIZE == 64
+#define RSEQ_OFFSET_SIZE	8
+#else
+#define RSEQ_OFFSET_SIZE	4
+#endif
+
+/* Some targets define a macro to denote the zero register.  */
+#undef zero
+
+/* Define 2 symbols: '__rseq_size' is public const and '_rseq_size' (an
+   alias of '__rseq_size') is hidden and writable for internal use by the
+   dynamic linker which will initialize the value both symbols point to
+   before copy relocations take place. */
+
+	.globl	__rseq_size
+	.type	__rseq_size, %object
+	.size	__rseq_size, 4
+	.hidden _rseq_size
+	.globl	_rseq_size
+	.type	_rseq_size, %object
+	.size	_rseq_size, 4
+	.section .data.rel.ro
+	.balign 4
+__rseq_size:
+_rseq_size:
+	.zero	4
+
+/* Define 2 symbols: '__rseq_offset' is public const and '_rseq_offset' (an
+   alias of '__rseq_offset') is hidden and writable for internal use by the
+   dynamic linker which will initialize the value both symbols point to
+   before copy relocations take place. */
+
+	.globl	__rseq_offset
+	.type	__rseq_offset, %object
+	.size	__rseq_offset, RSEQ_OFFSET_SIZE
+	.hidden _rseq_offset
+	.globl	_rseq_offset
+	.type	_rseq_offset, %object
+	.size	_rseq_offset, RSEQ_OFFSET_SIZE
+	.section .data.rel.ro
+	.balign RSEQ_OFFSET_SIZE
+__rseq_offset:
+_rseq_offset:
+	.zero	RSEQ_OFFSET_SIZE