nptl: Use <unwind-link.h> for accessing the libgcc_s unwinder

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

2 files changed, 27 insertions, 28 deletions

diff --git a/sysdeps/arm/nptl/unwind-forcedunwind.c b/sysdeps/arm/nptl/unwind-forcedunwind.c
new file mode 100644
index 0000000..61db34c
--- /dev/null
+++ b/sysdeps/arm/nptl/unwind-forcedunwind.c
@@ -0,0 +1,25 @@
+/* Unwinder function forwarders for libpthread.  Arm 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; see the file COPYING.LIB.  If
+   not, see <https://www.gnu.org/licenses/>.  */
+
+#include <sysdeps/nptl/unwind-forcedunwind.c>
+
+void *
+__unwind_link_get_resume (void)
+{
+  return UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_Resume);
+}
diff --git a/sysdeps/arm/pt-arm-unwind-resume.S b/sysdeps/arm/pt-arm-unwind-resume.S
index d579848..c056eb3 100644
--- a/sysdeps/arm/pt-arm-unwind-resume.S
+++ b/sysdeps/arm/pt-arm-unwind-resume.S
@@ -16,31 +16,5 @@
    License along with the GNU C Library.  If not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <sysdep.h>
-
-/* This is just implementing exactly what the C version does.
-   We do it in assembly just to ensure that we get an unmolested tail
-   call to the libgcc function, which is necessary for the ARM unwinder.  */
-
-ENTRY (_Unwind_Resume)
-	LDR_HIDDEN (ip, ip, __libgcc_s_resume, 0)
-	cmp	ip, #0
-	beq	1f
-0:	PTR_DEMANGLE (ip, ip, r2, r3)
-	bx	ip
-
-	/* We need to save and restore LR (for our own return address)
-	   and R0 (for the argument to _Unwind_Resume) around the call.  */
-1:	push	{r0, lr}
-	cfi_adjust_cfa_offset (8)
-	cfi_rel_offset (r0, 0)
-	cfi_rel_offset (lr, 4)
-	bl	pthread_cancel_init
-	pop	{r0, lr}
-	cfi_adjust_cfa_offset (-8)
-	cfi_restore (r0)
-	cfi_restore (lr)
-
-	LDR_HIDDEN (ip, ip, __libgcc_s_resume, 0)
-	b	0b
-END (_Unwind_Resume)
+/* The implementation in libpthread is identical to the one in libc.  */
+#include <sysdeps/arm/arm-unwind-resume.S>