[glibc/azanella/bz12683] csky: Fix Race conditions in pthread cancellation [BZ#12683]

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f63c37ef1faa4d343e11f57b5300338951af435c

commit f63c37ef1faa4d343e11f57b5300338951af435c
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Apr 3 11:30:01 2023 -0300

    csky: Fix Race conditions in pthread cancellation [BZ#12683]
    
    By adding the required syscall_cancel.S.
    
    Checked against a build and make check run-built-tests=no for
    csky-linux-gnuabiv2.

Diff:
---
 sysdeps/unix/sysv/linux/csky/syscall_cancel.S | 114 ++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)

diff --git a/sysdeps/unix/sysv/linux/csky/syscall_cancel.S b/sysdeps/unix/sysv/linux/csky/syscall_cancel.S
new file mode 100644
index 0000000000..2989765f8c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/csky/syscall_cancel.S
@@ -0,0 +1,114 @@
+/* Cancellable syscall wrapper.  Linux/csky version.
+   Copyright (C) 2023 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <descr-const.h>
+
+/* long int __syscall_cancel_arch (int *cancelhandling,
+				   __syscall_arg_t nr,
+				   __syscall_arg_t arg1,
+				   __syscall_arg_t arg2,
+				   __syscall_arg_t arg3,
+				   __syscall_arg_t arg4,
+				   __syscall_arg_t arg5,
+				   __syscall_arg_t arg6)  */
+
+#ifdef SHARED
+# define STACK_ADJ 4
+#else
+# define STACK_ADJ 0
+#endif
+
+ENTRY (__syscall_cancel_arch)
+	subi	sp, sp, 16 + STACK_ADJ
+	cfi_def_cfa_offset (16 + STACK_ADJ)
+#ifdef SHARED
+	st.w	gb, (sp, 16)
+	lrw	t1, 1f@GOTPC
+	cfi_offset (gb, -4)
+	grs	gb, 1f
+1:
+#endif
+	st.w	lr, (sp, 12)
+	st.w	l3, (sp, 8)
+	st.w	l1, (sp, 4)
+	st.w	l0, (sp, 0)
+#ifdef SHARED
+	addu	gb, gb, t1
+#endif
+	subi	sp, sp, 16
+	cfi_def_cfa_offset (32 + STACK_ADJ)
+	cfi_offset (lr, -( 4 + STACK_ADJ))
+	cfi_offset (l3, -( 8 + STACK_ADJ))
+	cfi_offset (l1, -(12 + STACK_ADJ))
+	cfi_offset (l0, -(16 + STACK_ADJ))
+
+	mov	l3, a1
+	mov	a1, a3
+	ld.w	a3, (sp, 32 + STACK_ADJ)
+	st.w	a3, (sp, 0)
+	ld.w	a3, (sp, 36 + STACK_ADJ)
+	st.w	a3, (sp, 4)
+	ld.w	a3, (sp, 40 + STACK_ADJ)
+	st.w	a3, (sp, 8)
+	ld.w	a3, (sp, 44 + STACK_ADJ)
+	st.w	a3, (sp, 12)
+
+	.globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+	ld.w	t0, (a0, 0)
+	andi	t0, t0, TCB_CANCELED_BITMASK
+	jbnez	t0, 2f
+	mov	a0, a2
+	ld.w	a3, (sp, 4)
+	ld.w	a2, (sp, 0)
+	ld.w	l0, (sp, 8)
+	ld.w	l1, (sp, 12)
+	trap	0
+
+	.globl __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+	addi	sp, sp, 16
+	cfi_remember_state
+	cfi_def_cfa_offset (16 + STACK_ADJ)
+#ifdef SHARED
+	ld.w	gb, (sp, 16)
+	cfi_restore (gb)
+#endif
+	ld.w	lr, (sp, 12)
+	cfi_restore (lr)
+	ld.w	l3, (sp, 8)
+	cfi_restore (l3)
+	ld.w	l1, (sp, 4)
+	cfi_restore (l1)
+	ld.w	l0, (sp, 0)
+	cfi_restore (l0)
+	addi	sp, sp, 16
+	cfi_def_cfa_offset (0)
+	rts
+
+2:
+	cfi_restore_state
+#ifdef SHARED
+	lrw	a3, __syscall_do_cancel@GOTOFF
+	addu	a3, a3, gb
+	jsr	a3
+#else
+	jbsr	__syscall_do_cancel
+#endif
+END (__syscall_cancel_arch)