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[glibc/azanella/bz12683] nptl: aarch64: Fix Race conditions in pthread cancellation (BZ#12683)
- From: Adhemerval Zanella <azanella at sourceware dot org>
- To: glibc-cvs at sourceware dot org
- Date: 17 Oct 2019 13:57:28 -0000
- Subject: [glibc/azanella/bz12683] nptl: aarch64: Fix Race conditions in pthread cancellation (BZ#12683)
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=2e797b0c43331a5d720bd674bc321dc13d8c8600
commit 2e797b0c43331a5d720bd674bc321dc13d8c8600
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Mon Jan 7 16:03:04 2019 +0000
nptl: aarch64: Fix Race conditions in pthread cancellation (BZ#12683)
This patch adds the aarch64 modifications required for the BZ#12683 fix
by adding the arch-specific cancellation syscall bridge.
Checked on aarch64-linux-gnu.
Diff:
---
sysdeps/aarch64/nptl/tcb-offsets.sym | 3 ++
sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S | 59 ++++++++++++++++++++++++
2 files changed, 62 insertions(+)
diff --git a/sysdeps/aarch64/nptl/tcb-offsets.sym b/sysdeps/aarch64/nptl/tcb-offsets.sym
index 238647d..614ea23 100644
--- a/sysdeps/aarch64/nptl/tcb-offsets.sym
+++ b/sysdeps/aarch64/nptl/tcb-offsets.sym
@@ -4,3 +4,6 @@
PTHREAD_MULTIPLE_THREADS_OFFSET offsetof (struct pthread, header.multiple_threads)
PTHREAD_TID_OFFSET offsetof (struct pthread, tid)
PTHREAD_SIZEOF sizeof (struct pthread)
+
+-- Not strictly offsets, used on syscall_cancel.S
+TCB_CANCELED_BIT CANCELED_BIT
diff --git a/sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S b/sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S
new file mode 100644
index 0000000..185dfd6
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S
@@ -0,0 +1,59 @@
+/* Cancellable syscall wrapper. Linux/AArch64 version.
+ Copyright (C) 2019 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>
+
+/* 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]) */
+
+ENTRY (__syscall_cancel_arch)
+
+ .globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+
+ /* if (*cancelhandling & CANCELED_BITMASK)
+ __syscall_do_cancel() */
+ ldr w0, [x0]
+ tbnz w0, TCB_CANCELED_BIT, 1f
+
+ /* Issue a 6 argument syscall, the nr [x1] being the syscall
+ number. */
+ mov x8, x1
+ mov x0, x2
+ mov x1, x3
+ mov x2, x4
+ mov x3, x5
+ mov x4, x6
+ mov x5, x7
+ svc 0x0
+
+ .globl __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+ ret
+
+1:
+ b __syscall_do_cancel
+
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)