[v4,12/21] nptl: sparc: Fix Race conditions in pthread cancellation [BZ#12683]

Message ID 20200403203201.7494-13-adhemerval.zanella@linaro.org
State New
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  • nptl: Fix Race conditions in pthread cancellation [BZ#12683]
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Commit Message

Sergei Trofimovich via Libc-alpha April 3, 2020, 8:31 p.m.
This patch adds the sparc modifications required for the BZ#12683 fix.

Different than other architectures, SPARC passes the sigcontext_t
struct pointer as third argument in the signal handler set with
SA_SIGINFO (some info at [1]) for 64 bits and the pt_regs in 32 bits.
From Linux code:

* arch/sparc/kernel/signal_64.c

428         /* 3. signal handler back-trampoline and parameters */
429         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
430         regs->u_regs[UREG_I0] = ksig->sig;
431         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
432
433         /* The sigcontext is passed in this way because of how it
434          * is defined in GLIBC's /usr/include/bits/sigcontext.h
435          * for sparc64.  It includes the 128 bytes of siginfo_t.
436          */
437         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

* arch/sparc/kernel/signal_32.c:

392         regs->u_regs[UREG_FP] = (unsigned long) sf;
393         regs->u_regs[UREG_I0] = ksig->sig;
394         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
395         regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
396
397         regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
398         regs->npc = (regs->pc + 4);

So it requires an arch-specific ucontext_add_cancel.

Also on sparc interrupted pause syscall returns with a PC indicating a
side-effect and this deviates from other architectures.  The sparc64
pause fall back to ppool syscall.

Checked on sparc64-linux-gnu and sparcv9-linux-gnu.

[1] https://www.spinics.net/lists/sparclinux/msg05037.html
---
 sysdeps/sparc/nptl/tcb-offsets.sym            |  3 +
 .../sysv/linux/sparc/cancellation-sigmask.h   | 39 ++++++++++
 .../sysv/linux/sparc/sparc32/syscall_cancel.S | 71 ++++++++++++++++++
 sysdeps/unix/sysv/linux/sparc/sparc64/pause.c | 25 +++++++
 .../sysv/linux/sparc/sparc64/syscall_cancel.S | 74 +++++++++++++++++++
 5 files changed, 212 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h
 create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S
 create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
 create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S

-- 
2.17.1

Comments

Stepan Golosunov April 12, 2020, 3:33 p.m. | #1
03.04.2020 в 17:31:52 -0300 Adhemerval Zanella написал:
> This patch adds the sparc modifications required for the BZ#12683 fix.

> 

> Different than other architectures, SPARC passes the sigcontext_t

> struct pointer as third argument in the signal handler set with

> SA_SIGINFO (some info at [1]) for 64 bits and the pt_regs in 32 bits.

> >From Linux code:

> 

> * arch/sparc/kernel/signal_64.c

> 

> 428         /* 3. signal handler back-trampoline and parameters */

> 429         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;

> 430         regs->u_regs[UREG_I0] = ksig->sig;

> 431         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;

> 432

> 433         /* The sigcontext is passed in this way because of how it

> 434          * is defined in GLIBC's /usr/include/bits/sigcontext.h

> 435          * for sparc64.  It includes the 128 bytes of siginfo_t.

> 436          */

> 437         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

> 

> * arch/sparc/kernel/signal_32.c:

> 

> 392         regs->u_regs[UREG_FP] = (unsigned long) sf;

> 393         regs->u_regs[UREG_I0] = ksig->sig;

> 394         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;

> 395         regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;

> 396

> 397         regs->pc = (unsigned long) ksig->ka.sa.sa_handler;

> 398         regs->npc = (regs->pc + 4);

> 

> So it requires an arch-specific ucontext_add_cancel.

> 

> Also on sparc interrupted pause syscall returns with a PC indicating a

> side-effect and this deviates from other architectures.  The sparc64

> pause fall back to ppool syscall.


s/ppool/ppoll/

> 

> Checked on sparc64-linux-gnu and sparcv9-linux-gnu.

> 

> [1] https://www.spinics.net/lists/sparclinux/msg05037.html

> ---

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

>  .../sysv/linux/sparc/cancellation-sigmask.h   | 39 ++++++++++

>  .../sysv/linux/sparc/sparc32/syscall_cancel.S | 71 ++++++++++++++++++

>  sysdeps/unix/sysv/linux/sparc/sparc64/pause.c | 25 +++++++

>  .../sysv/linux/sparc/sparc64/syscall_cancel.S | 74 +++++++++++++++++++

>  5 files changed, 212 insertions(+)

>  create mode 100644 sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h

>  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S

>  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/pause.c

>  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S


> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c

> @@ -0,0 +1,25 @@

> +/* Linux pause syscall implementation.  Linux/sparc64.

> +   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 <sys/syscall.h>

> +

> +/* On sparc interrupted pause syscall returns with a PC indicating a

> +   side-effect and this deviates from other architectures.  Fall back to

> +   ppool implementation.  */


ditto

> +#undef __NR_pause

> +#include <sysdeps/unix/sysv/linux/pause.c>

> diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S b/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S
Stepan Golosunov April 14, 2020, 4:54 p.m. | #2
12.04.2020 в 19:33:21 +0400 Stepan Golosunov написал:
> 03.04.2020 в 17:31:52 -0300 Adhemerval Zanella написал:

> > This patch adds the sparc modifications required for the BZ#12683 fix.

> > 

> > Different than other architectures, SPARC passes the sigcontext_t

> > struct pointer as third argument in the signal handler set with

> > SA_SIGINFO (some info at [1]) for 64 bits and the pt_regs in 32 bits.

> > >From Linux code:

> > 

> > * arch/sparc/kernel/signal_64.c

> > 

> > 428         /* 3. signal handler back-trampoline and parameters */

> > 429         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;

> > 430         regs->u_regs[UREG_I0] = ksig->sig;

> > 431         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;

> > 432

> > 433         /* The sigcontext is passed in this way because of how it

> > 434          * is defined in GLIBC's /usr/include/bits/sigcontext.h

> > 435          * for sparc64.  It includes the 128 bytes of siginfo_t.

> > 436          */

> > 437         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

> > 

> > * arch/sparc/kernel/signal_32.c:

> > 

> > 392         regs->u_regs[UREG_FP] = (unsigned long) sf;

> > 393         regs->u_regs[UREG_I0] = ksig->sig;

> > 394         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;

> > 395         regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;

> > 396

> > 397         regs->pc = (unsigned long) ksig->ka.sa.sa_handler;

> > 398         regs->npc = (regs->pc + 4);

> > 

> > So it requires an arch-specific ucontext_add_cancel.

> > 

> > Also on sparc interrupted pause syscall returns with a PC indicating a

> > side-effect and this deviates from other architectures.  The sparc64

> > pause fall back to ppool syscall.

> 

> s/ppool/ppoll/

> 

> > 

> > Checked on sparc64-linux-gnu and sparcv9-linux-gnu.

> > 

> > [1] https://www.spinics.net/lists/sparclinux/msg05037.html

> > ---

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

> >  .../sysv/linux/sparc/cancellation-sigmask.h   | 39 ++++++++++

> >  .../sysv/linux/sparc/sparc32/syscall_cancel.S | 71 ++++++++++++++++++

> >  sysdeps/unix/sysv/linux/sparc/sparc64/pause.c | 25 +++++++

> >  .../sysv/linux/sparc/sparc64/syscall_cancel.S | 74 +++++++++++++++++++

> >  5 files changed, 212 insertions(+)

> >  create mode 100644 sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h

> >  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S

> >  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/pause.c

> >  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S

> 

> > --- /dev/null

> > +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c

> > @@ -0,0 +1,25 @@

> > +/* Linux pause syscall implementation.  Linux/sparc64.

> > +   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 <sys/syscall.h>

> > +

> > +/* On sparc interrupted pause syscall returns with a PC indicating a

> > +   side-effect and this deviates from other architectures.  Fall back to

> > +   ppool implementation.  */

> 

> ditto

> 

> > +#undef __NR_pause

> > +#include <sysdeps/unix/sysv/linux/pause.c>


But sysdeps/unix/sysv/linux/sparc/kernel-features.h already contains

#ifdef __arch64__
/* sparc64 defines __NR_pause,  however it is not supported (ENOSYS).
   Undefine so pause.c can use a correct alternative.  */
# undef __NR_pause
#endif
Sergei Trofimovich via Libc-alpha April 15, 2020, 2:48 p.m. | #3
On 14/04/2020 13:54, Stepan Golosunov wrote:
> 12.04.2020 в 19:33:21 +0400 Stepan Golosunov написал:

>> 03.04.2020 в 17:31:52 -0300 Adhemerval Zanella написал:

>>> This patch adds the sparc modifications required for the BZ#12683 fix.

>>>

>>> Different than other architectures, SPARC passes the sigcontext_t

>>> struct pointer as third argument in the signal handler set with

>>> SA_SIGINFO (some info at [1]) for 64 bits and the pt_regs in 32 bits.

>>> >From Linux code:

>>>

>>> * arch/sparc/kernel/signal_64.c

>>>

>>> 428         /* 3. signal handler back-trampoline and parameters */

>>> 429         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;

>>> 430         regs->u_regs[UREG_I0] = ksig->sig;

>>> 431         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;

>>> 432

>>> 433         /* The sigcontext is passed in this way because of how it

>>> 434          * is defined in GLIBC's /usr/include/bits/sigcontext.h

>>> 435          * for sparc64.  It includes the 128 bytes of siginfo_t.

>>> 436          */

>>> 437         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

>>>

>>> * arch/sparc/kernel/signal_32.c:

>>>

>>> 392         regs->u_regs[UREG_FP] = (unsigned long) sf;

>>> 393         regs->u_regs[UREG_I0] = ksig->sig;

>>> 394         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;

>>> 395         regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;

>>> 396

>>> 397         regs->pc = (unsigned long) ksig->ka.sa.sa_handler;

>>> 398         regs->npc = (regs->pc + 4);

>>>

>>> So it requires an arch-specific ucontext_add_cancel.

>>>

>>> Also on sparc interrupted pause syscall returns with a PC indicating a

>>> side-effect and this deviates from other architectures.  The sparc64

>>> pause fall back to ppool syscall.

>>

>> s/ppool/ppoll/

>>

>>>

>>> Checked on sparc64-linux-gnu and sparcv9-linux-gnu.

>>>

>>> [1] https://www.spinics.net/lists/sparclinux/msg05037.html

>>> ---

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

>>>  .../sysv/linux/sparc/cancellation-sigmask.h   | 39 ++++++++++

>>>  .../sysv/linux/sparc/sparc32/syscall_cancel.S | 71 ++++++++++++++++++

>>>  sysdeps/unix/sysv/linux/sparc/sparc64/pause.c | 25 +++++++

>>>  .../sysv/linux/sparc/sparc64/syscall_cancel.S | 74 +++++++++++++++++++

>>>  5 files changed, 212 insertions(+)

>>>  create mode 100644 sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h

>>>  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S

>>>  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/pause.c

>>>  create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S

>>

>>> --- /dev/null

>>> +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c

>>> @@ -0,0 +1,25 @@

>>> +/* Linux pause syscall implementation.  Linux/sparc64.

>>> +   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 <sys/syscall.h>

>>> +

>>> +/* On sparc interrupted pause syscall returns with a PC indicating a

>>> +   side-effect and this deviates from other architectures.  Fall back to

>>> +   ppool implementation.  */

>>

>> ditto

>>

>>> +#undef __NR_pause

>>> +#include <sysdeps/unix/sysv/linux/pause.c>

> 

> But sysdeps/unix/sysv/linux/sparc/kernel-features.h already contains

> 

> #ifdef __arch64__

> /* sparc64 defines __NR_pause,  however it is not supported (ENOSYS).

>    Undefine so pause.c can use a correct alternative.  */

> # undef __NR_pause

> #endif

> 


Indeed, I already has pushed this fix on generic implementation. I have
removed the new pause implementation and fixed the commit message
accordingly.

Patch

diff --git a/sysdeps/sparc/nptl/tcb-offsets.sym b/sysdeps/sparc/nptl/tcb-offsets.sym
index f75d02065e..8112290d88 100644
--- a/sysdeps/sparc/nptl/tcb-offsets.sym
+++ b/sysdeps/sparc/nptl/tcb-offsets.sym
@@ -4,3 +4,6 @@ 
 MULTIPLE_THREADS_OFFSET		offsetof (tcbhead_t, multiple_threads)
 POINTER_GUARD			offsetof (tcbhead_t, pointer_guard)
 TID				offsetof (struct pthread, tid)
+
+-- Not strictly offsets, used on syscall_cancel.S
+TCB_CANCELED_BITMASK		CANCELED_BITMASK
diff --git a/sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h b/sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h
new file mode 100644
index 0000000000..8086228828
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h
@@ -0,0 +1,39 @@ 
+/* Architecture specific bits for cancellation handling.
+   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/>.  */
+
+#ifndef _NPTL_CANCELLATION_SIGMASK_H
+#define _NPTL_CANCELLATION_SIGMASK_H 1
+
+/* Add the SIGCANCEL signal on sigmask set at the ucontext CTX obtained from
+   the sigaction handler.  */
+static void
+ucontext_block_sigcancel (void *ctx)
+{
+  sigset_t *set;
+#ifdef __arch64__
+  struct pt_regs *regs = (struct pt_regs*) ((siginfo_t *)(ctx) + 1);
+  __siginfo_fpu_t *f = (__siginfo_fpu_t *)(regs + 1);
+  set = (sigset_t *) ((stack_t *)(f + 1) + 1);
+#else
+  struct pt_regs32 *ptregs = (struct pt_regs32 *) (ctx);
+  set = (sigset_t *) (ptregs + 1);
+#endif
+  __sigaddset (set, SIGCANCEL);
+}
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S b/sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S
new file mode 100644
index 0000000000..2393bf9be0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S
@@ -0,0 +1,71 @@ 
+/* Cancellable syscall wrapper.  Linux/sparc32 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 __syscall_cancel_arch (int *cancelhandling,
+				   long int nr,
+				   long int arg1,
+				   long int arg2,
+				   long int arg3,
+				   long int arg4,
+				   long int arg5,
+				   long int arg6)  */
+
+ENTRY (__syscall_cancel_arch)
+	save	%sp, -96, %sp
+
+	cfi_window_save
+	cfi_register (%o7, %i7)
+	cfi_def_cfa_register (%fp)
+
+	.globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+
+	/* if (*cancelhandling & CANCELED_BITMASK)
+	     __syscall_do_cancel()  */
+	ld	[%i0], %g2
+	andcc	%g2, TCB_CANCELED_BITMASK, %g0
+	bne,pn	%icc, 2f
+	/* Issue a 6 argument syscall.  */
+	 mov	%i1, %g1
+	mov	%i2, %o0
+	mov	%i3, %o1
+	mov	%i4, %o2
+	mov	%i5, %o3
+	ld	[%fp+92], %o4
+	ld	[%fp+96], %o5
+	ta	0x10
+
+	.globl __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+	bcc	1f
+	 nop
+	sub	%g0, %o0, %o0
+1:
+	mov	%o0, %i0
+	return	%i7+8
+	 nop
+
+2:
+	call	__syscall_do_cancel, 0
+	 nop
+	nop
+
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
new file mode 100644
index 0000000000..4fae573091
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
@@ -0,0 +1,25 @@ 
+/* Linux pause syscall implementation.  Linux/sparc64.
+   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 <sys/syscall.h>
+
+/* On sparc interrupted pause syscall returns with a PC indicating a
+   side-effect and this deviates from other architectures.  Fall back to
+   ppool implementation.  */
+#undef __NR_pause
+#include <sysdeps/unix/sysv/linux/pause.c>
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S b/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S
new file mode 100644
index 0000000000..f9ecb4a851
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S
@@ -0,0 +1,74 @@ 
+/* Cancellable syscall wrapper.  Linux/sparc64 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>
+
+	.register       %g2, #scratch
+
+/* long int __syscall_cancel_arch (int *cancelhandling,
+				   long int nr,
+				   long int arg1,
+				   long int arg2,
+				   long int arg3,
+				   long int arg4,
+				   long int arg5,
+				   long int arg6)  */
+
+ENTRY (__syscall_cancel_arch)
+	save	%sp, -176, %sp
+
+	cfi_window_save
+	cfi_register (%o7, %i7)
+	cfi_def_cfa_register (%fp)
+
+	.globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+
+	/* if (*cancelhandling & CANCELED_BITMASK)
+	     __syscall_do_cancel()  */
+	lduw	[%i0], %g2
+	andcc	%g2, TCB_CANCELED_BITMASK, %g0
+	bne,pn	%xcc, 2f
+	/* Issue a 6 argument syscall.  */
+	 mov	%i1, %g1
+	mov	%i2, %o0
+	mov	%i3, %o1
+	mov	%i4, %o2
+	mov	%i5, %o3
+	ldx	[%fp + STACK_BIAS + 176], %o4
+	ldx	[%fp + STACK_BIAS + 184], %o5
+	ta	0x6d
+
+	.global __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+
+	bcc,pt	%xcc, 1f
+	 nop
+	sub	%g0, %o0, %o0
+1:
+	mov	%o0, %i0
+	return	%i7+8
+	 nop
+
+2:
+	call	__syscall_do_cancel, 0
+	 nop
+	nop
+
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)