[v4,08/21] nptl: aarch64: Fix Race conditions in pthread cancellation [BZ#12683]

Message ID 20200403203201.7494-9-adhemerval.zanella@linaro.org
State New
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Series
  • nptl: Fix Race conditions in pthread cancellation [BZ#12683]
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Commit Message

Florian Weimer via Libc-alpha April 3, 2020, 8:31 p.m.
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.
---
 sysdeps/aarch64/nptl/tcb-offsets.sym          |  3 +
 .../unix/sysv/linux/aarch64/syscall_cancel.S  | 59 +++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S

-- 
2.17.1

Comments

Stepan Golosunov April 12, 2020, 3:29 p.m. | #1
03.04.2020 в 17:31:48 -0300 Adhemerval Zanella написал:
> 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.

> ---

>  sysdeps/aarch64/nptl/tcb-offsets.sym          |  3 +

>  .../unix/sysv/linux/aarch64/syscall_cancel.S  | 59 +++++++++++++++++++

>  2 files changed, 62 insertions(+)

>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S


> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S

> @@ -0,0 +1,59 @@

> +/* Cancellable syscall wrapper.  Linux/AArch64 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>

> +

> +/* 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])  */


Looks like this comment was copypasted from 32-bit arm.  Texts in
square brackets obviously do not correspond to reality.  Starting
from the fact that they imply that sizeof (long int) == 4.

> +

> +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)

> -- 

> 2.17.1

>
Florian Weimer via Libc-alpha April 15, 2020, 2:30 p.m. | #2
On 12/04/2020 12:29, Stepan Golosunov wrote:
> 03.04.2020 в 17:31:48 -0300 Adhemerval Zanella написал:

>> 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.

>> ---

>>  sysdeps/aarch64/nptl/tcb-offsets.sym          |  3 +

>>  .../unix/sysv/linux/aarch64/syscall_cancel.S  | 59 +++++++++++++++++++

>>  2 files changed, 62 insertions(+)

>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S

> 

>> --- /dev/null

>> +++ b/sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S

>> @@ -0,0 +1,59 @@

>> +/* Cancellable syscall wrapper.  Linux/AArch64 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>

>> +

>> +/* 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])  */

> 

> Looks like this comment was copypasted from 32-bit arm.  Texts in

> square brackets obviously do not correspond to reality.  Starting

> from the fact that they imply that sizeof (long int) == 4.


Ack, I have fixed the comment to the expected aarch64 ABI.  Thanks
for spotting it.

> 

>> +

>> +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)

>> -- 

>> 2.17.1

>>

Patch

diff --git a/sysdeps/aarch64/nptl/tcb-offsets.sym b/sysdeps/aarch64/nptl/tcb-offsets.sym
index 238647dd47..614ea23034 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 0000000000..fcb7cf66bf
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S
@@ -0,0 +1,59 @@ 
+/* Cancellable syscall wrapper.  Linux/AArch64 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>
+
+/* 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)