[glibc/azanella/pthread-multiple-fixes] nptl: arc: Fix Race conditions in pthread cancellation [BZ #12683]

[glibc/azanella/pthread-multiple-fixes] nptl: arc: Fix Race conditions in pthread cancellation [BZ #12683]

[Adhemerval Zanella]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=314f9c0ce98758deafa0b0a9ce4d0951bfd9f543

commit 314f9c0ce98758deafa0b0a9ce4d0951bfd9f543
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Thu Oct 1 12:30:12 2020 -0300

    nptl: arc: Fix Race conditions in pthread cancellation [BZ #12683]
    
    This patch adds the nios2 modifications required for the BZ #12683 fix
    by adding the arch-specific cancellation syscall bridge.
    
    Checked against a build and make check run-built-tests=no for
    arc-linux-gnu, arc-linux-gnuhf, and arceb-linux-gnu.

Diff:
---
 sysdeps/arc/nptl/tcb-offsets.sym             |  3 ++
 sysdeps/unix/sysv/linux/arc/syscall_cancel.S | 57 ++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/sysdeps/arc/nptl/tcb-offsets.sym b/sysdeps/arc/nptl/tcb-offsets.sym
index 64c432c22e..c60e6213a7 100644
--- a/sysdeps/arc/nptl/tcb-offsets.sym
+++ b/sysdeps/arc/nptl/tcb-offsets.sym
@@ -9,3 +9,6 @@ TLS_PRE_TCB_SIZE		sizeof (struct pthread)
 TLS_TCB_SIZE            	sizeof (tcbhead_t)
 
 PTHREAD_TID			offsetof (struct pthread, tid)
+
+-- Not strictly offsets, used on syscall_cancel.S
+TCB_CANCELED_BIT		CANCELED_BIT
diff --git a/sysdeps/unix/sysv/linux/arc/syscall_cancel.S b/sysdeps/unix/sysv/linux/arc/syscall_cancel.S
new file mode 100644
index 0000000000..d28cf95f4a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/syscall_cancel.S
@@ -0,0 +1,57 @@
+/* Cancellable syscall wrapper.  Linux/ARC version.
+   Copyright (C) 2020 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 <tcb-offsets.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)  */
+
+ENTRY (__syscall_cancel_arch)
+
+	.globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+	ld_s	r12,[r0]
+	bbit1	r12, TCB_CANCELED_BIT, 1f
+	mov_s	r8, r1
+	mov_s	r0, r2
+	mov_s	r1, r3
+	mov_s	r2, r4
+	mov_s	r3, r5
+	mov_s	r4, r6
+	mov_s	r5, r7
+	trap_s	0
+
+	.globl __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+	j_s	[blink]
+
+	.align 4
+1:	push_s	blink
+	cfi_def_cfa_offset (4)
+	cfi_offset (31, -4)
+	bl	@__do_cancel
+
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)