arm: Fix Race conditions in pthread cancellation [BZ#12683]

By adding the required syscall_cancel.S.

Checked on arm-linux-gnueabihf.

1 files changed, 78 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/arm/syscall_cancel.S b/sysdeps/unix/sysv/linux/arm/syscall_cancel.S
new file mode 100644
index 0000000000..6b899306e3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arm/syscall_cancel.S
@@ -0,0 +1,78 @@
+/* Cancellable syscall wrapper.  Linux/arm 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 [r0] __syscall_cancel_arch (int *cancelhandling [r0],
+					long int nr   [r1],
+					long int arg1 [r2],
+					long int arg2 [r3],
+					long int arg3 [SP],
+					long int arg4 [SP+4],
+					long int arg5 [SP+8],
+					long int arg6 [SP+12])  */
+
+	.syntax unified
+
+ENTRY (__syscall_cancel_arch)
+	.fnstart
+	mov	ip, sp
+	stmfd	sp!, {r4, r5, r6, r7, lr}
+	.save	{r4, r5, r6, r7, lr}
+
+	cfi_adjust_cfa_offset (20)
+	cfi_rel_offset (r4, 0)
+	cfi_rel_offset (r5, 4)
+	cfi_rel_offset (r6, 8)
+	cfi_rel_offset (r7, 12)
+	cfi_rel_offset (lr, 16)
+
+	.globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+
+	/* if (*cancelhandling & CANCELED_BITMASK)
+	     __syscall_do_cancel()  */
+	ldr	r0, [r0]
+	tst	r0, #TCB_CANCELED_BITMASK
+	bne	1f
+
+	/* Issue a 6 argument syscall, the nr [r1] being the syscall
+	   number.  */
+	mov	r7, r1
+	mov	r0, r2
+	mov	r1, r3
+	ldmfd	ip, {r2, r3, r4, r5, r6}
+	svc	0x0
+
+	.globl __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+	ldmfd	sp!, {r4, r5, r6, r7, lr}
+	cfi_adjust_cfa_offset (-20)
+        cfi_restore (r4)
+        cfi_restore (r5)
+        cfi_restore (r6)
+        cfi_restore (r7)
+        cfi_restore (lr)
+	BX (lr)
+
+1:
+	ldmfd	sp!, {r4, r5, r6, r7, lr}
+	b	__syscall_do_cancel
+	.fnend
+END (__syscall_cancel_arch)