diff mbox

[07/08] nptl: aarch64: Fix Race conditions in pthread cancellation (BZ#12683)

Message ID 558DABCC.3020109@linaro.org
State New
Headers show

Commit Message

Adhemerval Zanella Netto June 26, 2015, 7:45 p.m. UTC
This patch adds the aarch64 modifications required for the BZ#12683 fix.
It basically removes the enable_asynccancel/disable_asynccancel function
usage on code, provide a arch-specific symbol that contains global
markers to be used in SIGCANCEL handler.

--

	* sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S: New file.
	* sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h (PSEUDO): Redefine
	to call __syscall_cancel function for cancellable syscalls.
	(__pthread_get_ip): Add implementation.
	* sysdeps/unix/sysv/linux/aarch64/sysdep.h (SYSCALL_CANCEL_ERROR): Add
	definition.
	(SYSCALL_CANCEL_ERRNO): Likewise.

--

Comments

Szabolcs Nagy June 29, 2015, 10:32 a.m. UTC | #1
On 26/06/15 20:45, Adhemerval Zanella wrote:
> +/* long int [r0] __syscall_cancel_arch (int *cancelhandling [x0],
> +                                       long int nr   [x1],
> +                                       long int arg1 [x2],
> +                                       long int arg2 [x3],
> +                                       long int arg3 [x4],
> +                                       long int arg4 [x5],
> +                                       long int arg5 [x6],
> +                                       long int arg6 [x7])  */
> +
> +ENTRY (__syscall_cancel_arch)
> +
> +        stp     x29, x30, [sp, -16]!
> +        cfi_def_cfa_offset (16)
> +        cfi_offset (29, -16)
> +        cfi_offset (30, -8)
> +        add     x29, sp, 0
> +        cfi_def_cfa_register (29)
> +

you save things on the stack here ...

> +       .globl __syscall_cancel_arch_start
> +       .type  __syscall_cancel_arch_start,@function
> +__syscall_cancel_arch_start:
> +
> +       /* if (*cancelhandling & CANCELED_BITMASK)
> +            __syscall_do_cancel()  */
> +       ldr     w0, [x0]
> +       tbnz    w0, 2, 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
> +       .type  __syscall_cancel_arch_end,@function
> +__syscall_cancel_arch_end:
> +
> +        ldp     x29, x30, [sp], 16
> +        cfi_remember_state
> +        cfi_restore (30)
> +        cfi_restore (29)
> +        cfi_def_cfa (31, 0)
> +       ret
> +
> +1:
> +       cfi_restore_state
> +       b       __syscall_do_cancel
> +

... and tail call into a function that does not restore the stack.

i think you can omit saving the frame pointer.
(neither syscall, nor tail call needs it).

> --- a/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h
> +++ b/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h
> @@ -20,42 +20,50 @@
>  #include <tls.h>
>  #ifndef __ASSEMBLER__
>  # include <nptl/pthreadP.h>
> +# include <sys/ucontext.h>
>  #endif
> 
>  #if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
> 
> +# if IS_IN (libc)
> +#  define JMP_SYSCALL_CANCEL HIDDEN_JUMPTARGET(__syscall_cancel)
> +# else
> +#  define JMP_SYSCALL_CANCEL __syscall_cancel
> +# endif
> +
>  # undef PSEUDO
>  # define PSEUDO(name, syscall_name, args)                              \
> -       .section ".text";                                               \
> -ENTRY (__##syscall_name##_nocancel);                                   \
> -.Lpseudo_nocancel:                                                     \
> -       DO_CALL (syscall_name, args);                                   \
> -.Lpseudo_finish:                                                       \
> -       cmn     x0, 4095;                                               \
> -       b.cs    .Lsyscall_error;                                        \
> -       .subsection 2;                                                  \
> -       .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \
> +        .section ".text";                                               \
> +ENTRY (__##syscall_name##_nocancel);                                    \
> +L(pseudo_nocancel):                                                    \
> +        DO_CALL (syscall_name, args);                                   \
> +L(pseudo_finish):                                                      \
> +        cmn     x0, 4095;                                               \
> +        b.cs    L(syscall_error);                                      \
> +        .subsection 2;                                                 \
> +        .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \

i think there is a problem here that may need independent
fix (not a regression, but worth a mention):

a glibc test (debug/tst-backtrace5) checks if 'read' symbol
is found when read is interrupted and the signal handler
calls backtrace_symbols.

however the interrupt will be in __read_nocancel and that
name is not exported so backtrace does not find it in the
dynamic symbol table so the check fails. (on some other
archs the test pass because the nocancel code is within
the read code, not a separate function).

it's a silly issue so i haven't got around proposing a fix
for this yet.
Adhemerval Zanella Netto June 29, 2015, 10:16 p.m. UTC | #2
Hi Szabolcs,

Thanks for the review, comments below:

On 29-06-2015 07:32, Szabolcs Nagy wrote:
> On 26/06/15 20:45, Adhemerval Zanella wrote:
>> +ENTRY (__syscall_cancel_arch)
>> +
>> +        stp     x29, x30, [sp, -16]!
>> +        cfi_def_cfa_offset (16)
>> +        cfi_offset (29, -16)
>> +        cfi_offset (30, -8)
>> +        add     x29, sp, 0
>> +        cfi_def_cfa_register (29)
>> +
> 
> you save things on the stack here ...
> 
> 
> ... and tail call into a function that does not restore the stack.
> 
> i think you can omit saving the frame pointer.
> (neither syscall, nor tail call needs it).

My first though was the FP save-restore was required to correct create
unwind information for cancellation handlers, but on a second though
they are not necessary indeed. I have removed them and cancellation
handlers works as intended, right now the syscall wrappers looks like:

ENTRY (__syscall_cancel_arch)

        .globl __syscall_cancel_arch_start
        .type  __syscall_cancel_arch_start,@function
__syscall_cancel_arch_start:

        /* if (*cancelhandling & CANCELED_BITMASK)
             __syscall_do_cancel()  */
        ldr     w0, [x0]
        tbnz    w0, 2, 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
        .type  __syscall_cancel_arch_end,@function
__syscall_cancel_arch_end:
        ret

1:
        b       __syscall_do_cancel

END (__syscall_cancel_arch)

> 
>> --- a/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h
>> +++ b/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h
>> @@ -20,42 +20,50 @@
>>  #include <tls.h>
>>  #ifndef __ASSEMBLER__
>>  # include <nptl/pthreadP.h>
>> +# include <sys/ucontext.h>
>>  #endif
>>
>>  #if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
>>
>> +# if IS_IN (libc)
>> +#  define JMP_SYSCALL_CANCEL HIDDEN_JUMPTARGET(__syscall_cancel)
>> +# else
>> +#  define JMP_SYSCALL_CANCEL __syscall_cancel
>> +# endif
>> +
>>  # undef PSEUDO
>>  # define PSEUDO(name, syscall_name, args)                              \
>> -       .section ".text";                                               \
>> -ENTRY (__##syscall_name##_nocancel);                                   \
>> -.Lpseudo_nocancel:                                                     \
>> -       DO_CALL (syscall_name, args);                                   \
>> -.Lpseudo_finish:                                                       \
>> -       cmn     x0, 4095;                                               \
>> -       b.cs    .Lsyscall_error;                                        \
>> -       .subsection 2;                                                  \
>> -       .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \
>> +        .section ".text";                                               \
>> +ENTRY (__##syscall_name##_nocancel);                                    \
>> +L(pseudo_nocancel):                                                    \
>> +        DO_CALL (syscall_name, args);                                   \
>> +L(pseudo_finish):                                                      \
>> +        cmn     x0, 4095;                                               \
>> +        b.cs    L(syscall_error);                                      \
>> +        .subsection 2;                                                 \
>> +        .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \
> 
> i think there is a problem here that may need independent
> fix (not a regression, but worth a mention):
> 
> a glibc test (debug/tst-backtrace5) checks if 'read' symbol
> is found when read is interrupted and the signal handler
> calls backtrace_symbols.
> 
> however the interrupt will be in __read_nocancel and that
> name is not exported so backtrace does not find it in the
> dynamic symbol table so the check fails. (on some other
> archs the test pass because the nocancel code is within
> the read code, not a separate function).
> 
> it's a silly issue so i haven't got around proposing a fix
> for this yet.
> 

Indeed it would be much better to add more cleanup in this macros.
I have simplified to:

# if IS_IN (libc)
#  define JMP_SYSCALL_CANCEL HIDDEN_JUMPTARGET(__syscall_cancel)
# else
#  define JMP_SYSCALL_CANCEL __syscall_cancel
# endif

# undef PSEUDO
# define PSEUDO(name, syscall_name, args)                               \
ENTRY (name);                                                           \
        SINGLE_THREAD_P(16);                                            \
        cbnz    w16, L(pseudo_cancel);                                  \
        DO_CALL (syscall_name, args);                                   \
        b       L(pseudo_finish);                                       \
L(pseudo_cancel):                                                       \
        stp     x29, x30, [sp, -16]!;                                   \
        cfi_def_cfa_offset (16);                                        \
        cfi_offset (29, -16);                                           \
        cfi_offset (30, -8);                                            \
        add     x29, sp, 0;                                             \
        cfi_def_cfa_register (29);                                      \
        mov     x6, x5;                                                 \
        mov     x5, x4;                                                 \
        mov     x4, x3;                                                 \
        mov     x3, x2;                                                 \
        mov     x2, x1;                                                 \
        mov     x1, x0;                                                 \
        mov     x0, SYS_ify (syscall_name);                             \
        bl      JMP_SYSCALL_CANCEL;                                     \
        ldp     x29, x30, [sp], 16;                                     \
        cfi_restore (30);                                               \
        cfi_restore (29);                                               \
        cfi_def_cfa (31, 0);                                            \
L(pseudo_finish):                                                       \
        cmn     x0, 4095;                                               \
        b.cs    L(syscall_error);

# undef PSEUDO_END
# define PSEUDO_END(name)                                               \
        SYSCALL_ERROR_HANDLER;                                          \
        cfi_endproc;                                                    \
        .size   name, .-name;

And debug/tst-backtrace{5-6} work as intended as well. What do you think?
Szabolcs Nagy June 30, 2015, 8:46 a.m. UTC | #3
On 29/06/15 23:16, Adhemerval Zanella wrote:
> they are not necessary indeed. I have removed them and cancellation
> handlers works as intended, right now the syscall wrappers looks like:
> 
> ENTRY (__syscall_cancel_arch)
> 
>         .globl __syscall_cancel_arch_start
>         .type  __syscall_cancel_arch_start,@function
> __syscall_cancel_arch_start:
> 
>         /* if (*cancelhandling & CANCELED_BITMASK)
>              __syscall_do_cancel()  */
>         ldr     w0, [x0]
>         tbnz    w0, 2, 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
>         .type  __syscall_cancel_arch_end,@function
> __syscall_cancel_arch_end:
>         ret
> 
> 1:
>         b       __syscall_do_cancel
> 
> END (__syscall_cancel_arch)
> 

looks good.

> Indeed it would be much better to add more cleanup in this macros.
> I have simplified to:
> 
> # if IS_IN (libc)
> #  define JMP_SYSCALL_CANCEL HIDDEN_JUMPTARGET(__syscall_cancel)
> # else
> #  define JMP_SYSCALL_CANCEL __syscall_cancel
> # endif
> 
> # undef PSEUDO
> # define PSEUDO(name, syscall_name, args)                               \
> ENTRY (name);                                                           \
>         SINGLE_THREAD_P(16);                                            \
>         cbnz    w16, L(pseudo_cancel);                                  \
>         DO_CALL (syscall_name, args);                                   \
>         b       L(pseudo_finish);                                       \
> L(pseudo_cancel):                                                       \
>         stp     x29, x30, [sp, -16]!;                                   \
>         cfi_def_cfa_offset (16);                                        \
>         cfi_offset (29, -16);                                           \
>         cfi_offset (30, -8);                                            \
>         add     x29, sp, 0;                                             \
>         cfi_def_cfa_register (29);                                      \
>         mov     x6, x5;                                                 \
>         mov     x5, x4;                                                 \
>         mov     x4, x3;                                                 \
>         mov     x3, x2;                                                 \
>         mov     x2, x1;                                                 \
>         mov     x1, x0;                                                 \
>         mov     x0, SYS_ify (syscall_name);                             \
>         bl      JMP_SYSCALL_CANCEL;                                     \
>         ldp     x29, x30, [sp], 16;                                     \
>         cfi_restore (30);                                               \
>         cfi_restore (29);                                               \
>         cfi_def_cfa (31, 0);                                            \
> L(pseudo_finish):                                                       \
>         cmn     x0, 4095;                                               \
>         b.cs    L(syscall_error);
> 
> # undef PSEUDO_END
> # define PSEUDO_END(name)                                               \
>         SYSCALL_ERROR_HANDLER;                                          \
>         cfi_endproc;                                                    \
>         .size   name, .-name;
> 
> And debug/tst-backtrace{5-6} work as intended as well. What do you think?
> 

is it ok to remove the __<syscall>_nocancel internal symbols?

otherwise it looks good.

thanks.
Adhemerval Zanella Netto June 30, 2015, 2:12 p.m. UTC | #4
On 30-06-2015 05:46, Szabolcs Nagy wrote:
> On 29/06/15 23:16, Adhemerval Zanella wrote:
>> they are not necessary indeed. I have removed them and cancellation
>> handlers works as intended, right now the syscall wrappers looks like:
>>
>> ENTRY (__syscall_cancel_arch)
>>
>>         .globl __syscall_cancel_arch_start
>>         .type  __syscall_cancel_arch_start,@function
>> __syscall_cancel_arch_start:
>>
>>         /* if (*cancelhandling & CANCELED_BITMASK)
>>              __syscall_do_cancel()  */
>>         ldr     w0, [x0]
>>         tbnz    w0, 2, 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
>>         .type  __syscall_cancel_arch_end,@function
>> __syscall_cancel_arch_end:
>>         ret
>>
>> 1:
>>         b       __syscall_do_cancel
>>
>> END (__syscall_cancel_arch)
>>
> 
> looks good.
> 
>> Indeed it would be much better to add more cleanup in this macros.
>> I have simplified to:
>>
>> # if IS_IN (libc)
>> #  define JMP_SYSCALL_CANCEL HIDDEN_JUMPTARGET(__syscall_cancel)
>> # else
>> #  define JMP_SYSCALL_CANCEL __syscall_cancel
>> # endif
>>
>> # undef PSEUDO
>> # define PSEUDO(name, syscall_name, args)                               \
>> ENTRY (name);                                                           \
>>         SINGLE_THREAD_P(16);                                            \
>>         cbnz    w16, L(pseudo_cancel);                                  \
>>         DO_CALL (syscall_name, args);                                   \
>>         b       L(pseudo_finish);                                       \
>> L(pseudo_cancel):                                                       \
>>         stp     x29, x30, [sp, -16]!;                                   \
>>         cfi_def_cfa_offset (16);                                        \
>>         cfi_offset (29, -16);                                           \
>>         cfi_offset (30, -8);                                            \
>>         add     x29, sp, 0;                                             \
>>         cfi_def_cfa_register (29);                                      \
>>         mov     x6, x5;                                                 \
>>         mov     x5, x4;                                                 \
>>         mov     x4, x3;                                                 \
>>         mov     x3, x2;                                                 \
>>         mov     x2, x1;                                                 \
>>         mov     x1, x0;                                                 \
>>         mov     x0, SYS_ify (syscall_name);                             \
>>         bl      JMP_SYSCALL_CANCEL;                                     \
>>         ldp     x29, x30, [sp], 16;                                     \
>>         cfi_restore (30);                                               \
>>         cfi_restore (29);                                               \
>>         cfi_def_cfa (31, 0);                                            \
>> L(pseudo_finish):                                                       \
>>         cmn     x0, 4095;                                               \
>>         b.cs    L(syscall_error);
>>
>> # undef PSEUDO_END
>> # define PSEUDO_END(name)                                               \
>>         SYSCALL_ERROR_HANDLER;                                          \
>>         cfi_endproc;                                                    \
>>         .size   name, .-name;
>>
>> And debug/tst-backtrace{5-6} work as intended as well. What do you think?
>>
> 
> is it ok to remove the __<syscall>_nocancel internal symbols?
> 
> otherwise it looks good.

Yes, the idea of 34caaafd1ae38c9295325a1da491d75a92b205b0 is exactly to
remove __<syscall>_nocancel usage.

> 
> thanks.
>
diff mbox

Patch

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..33c51c3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/syscall_cancel.S
@@ -0,0 +1,75 @@ 
+/* Cancellable syscall wrapper - aarch64 version.
+   Copyright (C) 2015 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 [x0],
+					long int nr   [x1],
+					long int arg1 [x2],
+					long int arg2 [x3],
+					long int arg3 [x4],
+					long int arg4 [x5],
+					long int arg5 [x6],
+					long int arg6 [x7])  */
+
+ENTRY (__syscall_cancel_arch)
+
+        stp     x29, x30, [sp, -16]!
+        cfi_def_cfa_offset (16)
+        cfi_offset (29, -16)
+        cfi_offset (30, -8)
+        add     x29, sp, 0
+        cfi_def_cfa_register (29)
+
+	.globl __syscall_cancel_arch_start
+	.type  __syscall_cancel_arch_start,@function
+__syscall_cancel_arch_start:
+
+	/* if (*cancelhandling & CANCELED_BITMASK)
+	     __syscall_do_cancel()  */
+	ldr	w0, [x0]
+	tbnz    w0, 2, 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
+	.type  __syscall_cancel_arch_end,@function
+__syscall_cancel_arch_end:
+
+        ldp     x29, x30, [sp], 16
+        cfi_remember_state
+        cfi_restore (30)
+        cfi_restore (29)
+        cfi_def_cfa (31, 0)
+	ret
+
+1:
+	cfi_restore_state
+	b	__syscall_do_cancel
+
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)
diff --git a/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h b/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h
index 36e8e39..ba91268 100644
--- a/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h
+++ b/sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h
@@ -20,42 +20,50 @@ 
 #include <tls.h>
 #ifndef __ASSEMBLER__
 # include <nptl/pthreadP.h>
+# include <sys/ucontext.h>
 #endif
 
 #if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
 
+# if IS_IN (libc)
+#  define JMP_SYSCALL_CANCEL HIDDEN_JUMPTARGET(__syscall_cancel)
+# else
+#  define JMP_SYSCALL_CANCEL __syscall_cancel
+# endif
+
 # undef PSEUDO
 # define PSEUDO(name, syscall_name, args)				\
-	.section ".text";						\
-ENTRY (__##syscall_name##_nocancel);					\
-.Lpseudo_nocancel:							\
-	DO_CALL (syscall_name, args);					\
-.Lpseudo_finish:							\
-	cmn	x0, 4095;						\
-	b.cs	.Lsyscall_error;					\
-	.subsection 2;							\
-	.size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \
+        .section ".text";                                               \
+ENTRY (__##syscall_name##_nocancel);                                    \
+L(pseudo_nocancel):							\
+        DO_CALL (syscall_name, args);                                   \
+L(pseudo_finish):							\
+        cmn     x0, 4095;                                               \
+        b.cs    L(syscall_error);					\
+        .subsection 2;							\
+        .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \
 ENTRY (name);								\
 	SINGLE_THREAD_P(16);						\
-	cbz	w16, .Lpseudo_nocancel;					\
-	/* Setup common stack frame no matter the number of args.	\
-	   Also save the first arg, since it's basically free.  */	\
-	stp	x30, x0, [sp, -64]!;					\
-	cfi_adjust_cfa_offset (64);					\
-	cfi_rel_offset (x30, 0);					\
-	DOCARGS_##args;		/* save syscall args around CENABLE.  */ \
-	CENABLE;							\
-	mov	x16, x0;	/* save mask around syscall.  */	\
-	UNDOCARGS_##args;	/* restore syscall args.  */		\
-	DO_CALL (syscall_name, args);					\
-	str	x0, [sp, 8];	/* save result around CDISABLE.  */	\
-	mov	x0, x16;	/* restore mask for CDISABLE.  */	\
-	CDISABLE;							\
-	/* Break down the stack frame, restoring result at once.  */	\
-	ldp	x30, x0, [sp], 64;					\
-	cfi_adjust_cfa_offset (-64);					\
-	cfi_restore (x30);						\
-	b	.Lpseudo_finish;					\
+	cbz	w16, L(pseudo_nocancel);				\
+        stp     x29, x30, [sp, -16]!;					\
+        cfi_def_cfa_offset (16);					\
+        cfi_offset (29, -16);						\
+        cfi_offset (30, -8);						\
+	add	x29, sp, 0;						\
+	cfi_def_cfa_register (29);					\
+	mov	x6, x5;							\
+	mov	x5, x4;							\
+	mov	x4, x3;							\
+	mov	x3, x2;							\
+	mov	x2, x1;							\
+	mov	x1, x0;							\
+	mov	x0, SYS_ify (syscall_name);				\
+	bl	JMP_SYSCALL_CANCEL;					\
+        ldp     x29, x30, [sp], 16;					\
+        cfi_restore (30);                                              \
+        cfi_restore (29);						\
+        cfi_def_cfa (31, 0);						\
+	b       L(pseudo_finish);					\
 	cfi_endproc;							\
 	.size	name, .-name;						\
 	.previous
@@ -65,35 +73,10 @@  ENTRY (name);								\
 	SYSCALL_ERROR_HANDLER;						\
 	cfi_endproc
 
-# define DOCARGS_0
-# define DOCARGS_1
-# define DOCARGS_2	str x1, [sp, 16]
-# define DOCARGS_3	stp x1, x2, [sp, 16]
-# define DOCARGS_4	DOCARGS_3; str x3, [sp, 32]
-# define DOCARGS_5	DOCARGS_3; stp x3, x4, [sp, 32]
-# define DOCARGS_6	DOCARGS_5; str x5, [sp, 48]
-
-# define UNDOCARGS_0
-# define UNDOCARGS_1	ldr x0, [sp, 8]
-# define UNDOCARGS_2	ldp x0, x1, [sp, 8]
-# define UNDOCARGS_3	UNDOCARGS_1; ldp x1, x2, [sp, 16]
-# define UNDOCARGS_4	UNDOCARGS_2; ldp x2, x3, [sp, 24]
-# define UNDOCARGS_5	UNDOCARGS_3; ldp x3, x4, [sp, 32]
-# define UNDOCARGS_6	UNDOCARGS_4; ldp x4, x5, [sp, 40]
-
 # if IS_IN (libpthread)
-#  define CENABLE	bl __pthread_enable_asynccancel
-#  define CDISABLE	bl __pthread_disable_asynccancel
 #  define __local_multiple_threads __pthread_multiple_threads
 # elif IS_IN (libc)
-#  define CENABLE	bl __libc_enable_asynccancel
-#  define CDISABLE	bl __libc_disable_asynccancel
 #  define __local_multiple_threads __libc_multiple_threads
-# elif IS_IN (librt)
-#  define CENABLE	bl __librt_enable_asynccancel
-#  define CDISABLE	bl __librt_disable_asynccancel
-# else
-#  error Unsupported library
 # endif
 
 # if IS_IN (libpthread) || IS_IN (libc)
@@ -131,4 +114,10 @@  extern int __local_multiple_threads attribute_hidden;
 # define RTLD_SINGLE_THREAD_P \
   __builtin_expect (THREAD_GETMEM (THREAD_SELF, \
 				   header.multiple_threads) == 0, 1)
+
+static inline
+long int __pthread_get_ip (const struct ucontext *uc)
+{
+  return uc->uc_mcontext.pc;
+}
 #endif
diff --git a/sysdeps/unix/sysv/linux/aarch64/sysdep.h b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
index fe94a50..5f73b9e 100644
--- a/sysdeps/unix/sysv/linux/aarch64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
@@ -199,6 +199,14 @@ 
 # undef INTERNAL_SYSCALL_ERRNO
 # define INTERNAL_SYSCALL_ERRNO(val, err)	(-(val))
 
+#undef SYSCALL_CANCEL_ERROR
+#define SYSCALL_CANCEL_ERROR(__val) \
+  ((unsigned long) (__val) >= (unsigned long) -4095)
+
+#undef SYSCALL_CANCEL_ERRNO
+#define SYSCALL_CANCEL_ERRNO(__val) \
+  (-(__val))
+
 # define LOAD_ARGS_0()				\
   register long _x0 asm ("x0");
 # define LOAD_ARGS_1(x0)			\