diff mbox series

i386: Add the clone3 wrapper

Message ID 20210714133327.3102313-1-hjl.tools@gmail.com
State Committed
Commit 5adb0e14a5cc9e011e58a7aaf193b598ecbd7b07
Headers show
Series i386: Add the clone3 wrapper | expand

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit fail Patch caused testsuite regressions

Commit Message

H.J. Lu July 14, 2021, 1:33 p.m. UTC
extern int clone3 (struct clone_args *__cl_args, size_t __size,
		   int (*__func) (void *__arg), void *__arg);
---
 sysdeps/unix/sysv/linux/i386/clone3.S | 123 ++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/i386/sysdep.h |   2 +
 2 files changed, 125 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/i386/clone3.S

Comments

Noah Goldstein July 14, 2021, 6:19 p.m. UTC | #1
On Wed, Jul 14, 2021 at 9:33 AM H.J. Lu via Libc-alpha <
libc-alpha@sourceware.org> wrote:

> extern int clone3 (struct clone_args *__cl_args, size_t __size,
>                    int (*__func) (void *__arg), void *__arg);
> ---
>  sysdeps/unix/sysv/linux/i386/clone3.S | 123 ++++++++++++++++++++++++++
>  sysdeps/unix/sysv/linux/i386/sysdep.h |   2 +
>  2 files changed, 125 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/i386/clone3.S
>
> diff --git a/sysdeps/unix/sysv/linux/i386/clone3.S
> b/sysdeps/unix/sysv/linux/i386/clone3.S
> new file mode 100644
> index 0000000000..bef3ce0455
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/i386/clone3.S
> @@ -0,0 +1,123 @@
> +/* The clone3 syscall wrapper.  Linux/i386 version.
> +   Copyright (C) 2021 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
> +   <https://www.gnu.org/licenses/>.  */
> +
> +/* clone3() is even more special than fork() as it mucks with stacks
> +   and invokes a function in the right context after its all over.  */
> +
> +#include <sysdep.h>
> +
> +/* The userland implementation is:
> +   int clone3 (struct clone_args *cl_args, size_t size,
> +              int (*func)(void *arg), void *arg);
> +   the kernel entry is:
> +   int clone3 (struct clone_args *cl_args, size_t size);
> +
> +   The parameters are passed on stack from userland:
> +   16(%esp)    arg
> +   12(%esp)    func
> +    8(%esp)    size
> +    4(%esp)    cl_args
> +     (%esp)    Return address
> +
> +   The kernel expects:
> +   eax:                system call number
> +   ebx:                cl_args
> +   ecx:                size
> + */
> +
> +#define CL_ARGS        4
> +#define SIZE   8
> +#define FUNC   12
> +#define ARG    16
> +
> +        .text
> +ENTRY (__clone3)
> +       /* Sanity check arguments.  */
> +       movl    $-EINVAL, %eax
> +       movl    CL_ARGS(%esp), %ecx     /* No NULL cl_args pointer.  */
> +       testl   %ecx, %ecx
> +       jz      SYSCALL_ERROR_LABEL
> +       /* Save the function pointer in EDX which is preserved by the
> +          system call.  */
> +       movl    FUNC(%esp), %edx        /* No NULL function pointer.  */
> +       testl   %edx, %edx
> +       jz      SYSCALL_ERROR_LABEL
> +
> +       /* Save EBX and ESI.  */
> +       pushl   %ebx
> +       cfi_adjust_cfa_offset (4)
> +       pushl   %esi
> +       cfi_adjust_cfa_offset (4)
> +
> +       /* Save the function argument in ESI which is preserved by the
> +          system call.  */
> +       movl    (ARG + 8)(%esp), %esi
> +
> +       /* Put cl_args in EBX.  */
> +       movl    %ecx, %ebx
> +
> +       /* Put size in ECX.  */
> +       movl    (SIZE + 8)(%esp), %ecx
> +
> +       /* Do the system call.  */
> +       movl    $SYS_ify(clone3), %eax
> +
> +       /* End FDE now, because in the child the unwind info will be
> +          wrong.  */
> +       cfi_endproc
> +
> +       int     $0x80
> +       test    %eax, %eax
> +       /* No need to restore EBX and ESI in child.  */
>
does esp need to be adjusted?

+       jz      L(thread_start)
> +
> +       /* Restore EBX and ESI in parent.  */
> +       pop     %esi
> +       pop     %ebx
> +       jl      SYSCALL_ERROR_LABEL
> +
> +       ret
> +
> +L(thread_start):
> +       cfi_startproc
> +       /* Clearing frame pointer is insufficient, use CFI.  */
> +       cfi_undefined (eip)
> +       xorl    %ebp, %ebp      /* Terminate the stack frame.  */
> +
> +       /* Align stack to 16 bytes per the i386 psABI.  */
> +       andl    $-16, %esp

+
> +       /* The PUSH below will decrement stack pointer by 4 bytes.  */
> +       subl    $12, %esp
> +
> +       /* Set up the argument for the function call.  */
> +       pushl   %esi            /* Argument.  */
>
Can you pushl then align and drop the subl? Or does esp need to be aligned
before
the pushl?

> +       cfi_adjust_cfa_offset (4)
> +       call    *%edx           /* Call function.  */
> +
> +       /* Call exit with return value from function call. */
> +       movl    %eax, %ebx
> +       movl    $SYS_ify(exit), %eax
> +       ENTER_KERNEL
> +       cfi_endproc
> +
> +       cfi_startproc
> +PSEUDO_END (__clone3)
> +
> +libc_hidden_def (__clone3)
> +weak_alias (__clone3, clone3)
> diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h
> b/sysdeps/unix/sysv/linux/i386/sysdep.h
> index 8680b49bf7..3927a1a6e0 100644
> --- a/sysdeps/unix/sysv/linux/i386/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
> @@ -291,6 +291,8 @@ struct libc_do_syscall_args
>  # define HAVE_TIME_VSYSCALL             "__vdso_time"
>  # define HAVE_CLOCK_GETRES_VSYSCALL     "__vdso_clock_getres"
>
> +# define HAVE_CLONE3_WAPPER            1
> +
>  # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
>  # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
>
> --
> 2.31.1
>
>
H.J. Lu July 14, 2021, 6:56 p.m. UTC | #2
On Wed, Jul 14, 2021 at 11:19 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
>
>
> On Wed, Jul 14, 2021 at 9:33 AM H.J. Lu via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>
>> extern int clone3 (struct clone_args *__cl_args, size_t __size,
>>                    int (*__func) (void *__arg), void *__arg);
>> ---
>>  sysdeps/unix/sysv/linux/i386/clone3.S | 123 ++++++++++++++++++++++++++
>>  sysdeps/unix/sysv/linux/i386/sysdep.h |   2 +
>>  2 files changed, 125 insertions(+)
>>  create mode 100644 sysdeps/unix/sysv/linux/i386/clone3.S
>>
>> diff --git a/sysdeps/unix/sysv/linux/i386/clone3.S b/sysdeps/unix/sysv/linux/i386/clone3.S
>> new file mode 100644
>> index 0000000000..bef3ce0455
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/i386/clone3.S
>> @@ -0,0 +1,123 @@
>> +/* The clone3 syscall wrapper.  Linux/i386 version.
>> +   Copyright (C) 2021 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
>> +   <https://www.gnu.org/licenses/>.  */
>> +
>> +/* clone3() is even more special than fork() as it mucks with stacks
>> +   and invokes a function in the right context after its all over.  */
>> +
>> +#include <sysdep.h>
>> +
>> +/* The userland implementation is:
>> +   int clone3 (struct clone_args *cl_args, size_t size,
>> +              int (*func)(void *arg), void *arg);
>> +   the kernel entry is:
>> +   int clone3 (struct clone_args *cl_args, size_t size);
>> +
>> +   The parameters are passed on stack from userland:
>> +   16(%esp)    arg
>> +   12(%esp)    func
>> +    8(%esp)    size
>> +    4(%esp)    cl_args
>> +     (%esp)    Return address
>> +
>> +   The kernel expects:
>> +   eax:                system call number
>> +   ebx:                cl_args
>> +   ecx:                size
>> + */
>> +
>> +#define CL_ARGS        4
>> +#define SIZE   8
>> +#define FUNC   12
>> +#define ARG    16
>> +
>> +        .text
>> +ENTRY (__clone3)
>> +       /* Sanity check arguments.  */
>> +       movl    $-EINVAL, %eax
>> +       movl    CL_ARGS(%esp), %ecx     /* No NULL cl_args pointer.  */
>> +       testl   %ecx, %ecx
>> +       jz      SYSCALL_ERROR_LABEL
>> +       /* Save the function pointer in EDX which is preserved by the
>> +          system call.  */
>> +       movl    FUNC(%esp), %edx        /* No NULL function pointer.  */
>> +       testl   %edx, %edx
>> +       jz      SYSCALL_ERROR_LABEL
>> +
>> +       /* Save EBX and ESI.  */
>> +       pushl   %ebx
>> +       cfi_adjust_cfa_offset (4)
>> +       pushl   %esi
>> +       cfi_adjust_cfa_offset (4)
>> +
>> +       /* Save the function argument in ESI which is preserved by the
>> +          system call.  */
>> +       movl    (ARG + 8)(%esp), %esi
>> +
>> +       /* Put cl_args in EBX.  */
>> +       movl    %ecx, %ebx
>> +
>> +       /* Put size in ECX.  */
>> +       movl    (SIZE + 8)(%esp), %ecx
>> +
>> +       /* Do the system call.  */
>> +       movl    $SYS_ify(clone3), %eax
>> +
>> +       /* End FDE now, because in the child the unwind info will be
>> +          wrong.  */
>> +       cfi_endproc
>> +
>> +       int     $0x80
>> +       test    %eax, %eax
>> +       /* No need to restore EBX and ESI in child.  */
>
> does esp need to be adjusted?

We don't need to adjust ESP in parent and we will set up
the child stack a few lines below.

>> +       jz      L(thread_start)
>> +
>> +       /* Restore EBX and ESI in parent.  */
>> +       pop     %esi
>> +       pop     %ebx
>> +       jl      SYSCALL_ERROR_LABEL
>> +
>> +       ret
>> +
>> +L(thread_start):
>> +       cfi_startproc
>> +       /* Clearing frame pointer is insufficient, use CFI.  */
>> +       cfi_undefined (eip)
>> +       xorl    %ebp, %ebp      /* Terminate the stack frame.  */
>> +
>> +       /* Align stack to 16 bytes per the i386 psABI.  */
>> +       andl    $-16, %esp
>>
>> +
>> +       /* The PUSH below will decrement stack pointer by 4 bytes.  */
>> +       subl    $12, %esp
>> +
>> +       /* Set up the argument for the function call.  */
>> +       pushl   %esi            /* Argument.  */
>
> Can you pushl then align and drop the subl? Or does esp need to be aligned before
> the pushl?

We need to align the child stack to 16 bytes first and then push the argument
onto stack for the child function.

>>
>> +       cfi_adjust_cfa_offset (4)
>> +       call    *%edx           /* Call function.  */
>> +
>> +       /* Call exit with return value from function call. */
>> +       movl    %eax, %ebx
>> +       movl    $SYS_ify(exit), %eax
>> +       ENTER_KERNEL
>> +       cfi_endproc
>> +
>> +       cfi_startproc
>> +PSEUDO_END (__clone3)
>> +
>> +libc_hidden_def (__clone3)
>> +weak_alias (__clone3, clone3)
>> diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
>> index 8680b49bf7..3927a1a6e0 100644
>> --- a/sysdeps/unix/sysv/linux/i386/sysdep.h
>> +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
>> @@ -291,6 +291,8 @@ struct libc_do_syscall_args
>>  # define HAVE_TIME_VSYSCALL             "__vdso_time"
>>  # define HAVE_CLOCK_GETRES_VSYSCALL     "__vdso_clock_getres"
>>
>> +# define HAVE_CLONE3_WAPPER            1
>> +
>>  # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
>>  # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
>>
>> --
>> 2.31.1
>>
Carlos O'Donell July 19, 2021, 2:08 p.m. UTC | #3
On 7/14/21 9:33 AM, H.J. Lu via Libc-alpha wrote:
> extern int clone3 (struct clone_args *__cl_args, size_t __size,
> 		   int (*__func) (void *__arg), void *__arg);

OK for glibc 2.34.

I think this is important for x86 overall. I'd like to see this
in the release.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

> ---
>  sysdeps/unix/sysv/linux/i386/clone3.S | 123 ++++++++++++++++++++++++++
>  sysdeps/unix/sysv/linux/i386/sysdep.h |   2 +
>  2 files changed, 125 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/i386/clone3.S
> 
> diff --git a/sysdeps/unix/sysv/linux/i386/clone3.S b/sysdeps/unix/sysv/linux/i386/clone3.S
> new file mode 100644
> index 0000000000..bef3ce0455
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/i386/clone3.S
> @@ -0,0 +1,123 @@
> +/* The clone3 syscall wrapper.  Linux/i386 version.

OK.

> +   Copyright (C) 2021 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
> +   <https://www.gnu.org/licenses/>.  */
> +
> +/* clone3() is even more special than fork() as it mucks with stacks
> +   and invokes a function in the right context after its all over.  */

OK.

> +
> +#include <sysdep.h>
> +
> +/* The userland implementation is:
> +   int clone3 (struct clone_args *cl_args, size_t size,
> +	       int (*func)(void *arg), void *arg);
> +   the kernel entry is:
> +   int clone3 (struct clone_args *cl_args, size_t size);
> +
> +   The parameters are passed on stack from userland:
> +   16(%esp)	arg
> +   12(%esp)	func
> +    8(%esp)	size
> +    4(%esp)	cl_args
> +     (%esp)	Return address
> +
> +   The kernel expects:
> +   eax:		system call number
> +   ebx:		cl_args
> +   ecx:		size
> + */

OK. Nice comment.

> +
> +#define CL_ARGS	4
> +#define SIZE	8
> +#define FUNC	12
> +#define ARG	16
> +
> +        .text
> +ENTRY (__clone3)
> +	/* Sanity check arguments.  */
> +	movl	$-EINVAL, %eax
> +	movl	CL_ARGS(%esp), %ecx	/* No NULL cl_args pointer.  */
> +	testl	%ecx, %ecx
> +	jz	SYSCALL_ERROR_LABEL
> +	/* Save the function pointer in EDX which is preserved by the
> +	   system call.  */
> +	movl	FUNC(%esp), %edx	/* No NULL function pointer.  */
> +	testl	%edx, %edx
> +	jz	SYSCALL_ERROR_LABEL
> +
> +	/* Save EBX and ESI.  */
> +	pushl	%ebx
> +	cfi_adjust_cfa_offset (4)
> +	pushl	%esi
> +	cfi_adjust_cfa_offset (4)
> +
> +	/* Save the function argument in ESI which is preserved by the
> +	   system call.  */
> +	movl	(ARG + 8)(%esp), %esi
> +
> +	/* Put cl_args in EBX.  */
> +	movl	%ecx, %ebx
> +
> +	/* Put size in ECX.  */
> +	movl	(SIZE + 8)(%esp), %ecx
> +
> +	/* Do the system call.  */
> +	movl	$SYS_ify(clone3), %eax

OK.

> +
> +	/* End FDE now, because in the child the unwind info will be
> +	   wrong.  */
> +	cfi_endproc
> +
> +	int	$0x80
> +	test	%eax, %eax
> +	/* No need to restore EBX and ESI in child.  */
> +	jz	L(thread_start)
> +
> +	/* Restore EBX and ESI in parent.  */
> +	pop	%esi
> +	pop	%ebx
> +	jl	SYSCALL_ERROR_LABEL
> +
> +	ret
> +
> +L(thread_start):
> +	cfi_startproc
> +	/* Clearing frame pointer is insufficient, use CFI.  */
> +	cfi_undefined (eip)
> +	xorl	%ebp, %ebp	/* Terminate the stack frame.  */
> +
> +	/* Align stack to 16 bytes per the i386 psABI.  */
> +	andl	$-16, %esp
> +
> +	/* The PUSH below will decrement stack pointer by 4 bytes.  */
> +	subl	$12, %esp
> +
> +	/* Set up the argument for the function call.  */
> +	pushl	%esi		/* Argument.  */
> +	cfi_adjust_cfa_offset (4)
> +	call	*%edx		/* Call function.  */
> +
> +	/* Call exit with return value from function call. */
> +	movl	%eax, %ebx
> +	movl	$SYS_ify(exit), %eax
> +	ENTER_KERNEL
> +	cfi_endproc
> +
> +	cfi_startproc
> +PSEUDO_END (__clone3)
> +
> +libc_hidden_def (__clone3)
> +weak_alias (__clone3, clone3)
> diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
> index 8680b49bf7..3927a1a6e0 100644
> --- a/sysdeps/unix/sysv/linux/i386/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
> @@ -291,6 +291,8 @@ struct libc_do_syscall_args
>  # define HAVE_TIME_VSYSCALL             "__vdso_time"
>  # define HAVE_CLOCK_GETRES_VSYSCALL     "__vdso_clock_getres"
>  
> +# define HAVE_CLONE3_WAPPER		1

OK.

> +
>  # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
>  # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
>  
>
diff mbox series

Patch

diff --git a/sysdeps/unix/sysv/linux/i386/clone3.S b/sysdeps/unix/sysv/linux/i386/clone3.S
new file mode 100644
index 0000000000..bef3ce0455
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/clone3.S
@@ -0,0 +1,123 @@ 
+/* The clone3 syscall wrapper.  Linux/i386 version.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+/* clone3() is even more special than fork() as it mucks with stacks
+   and invokes a function in the right context after its all over.  */
+
+#include <sysdep.h>
+
+/* The userland implementation is:
+   int clone3 (struct clone_args *cl_args, size_t size,
+	       int (*func)(void *arg), void *arg);
+   the kernel entry is:
+   int clone3 (struct clone_args *cl_args, size_t size);
+
+   The parameters are passed on stack from userland:
+   16(%esp)	arg
+   12(%esp)	func
+    8(%esp)	size
+    4(%esp)	cl_args
+     (%esp)	Return address
+
+   The kernel expects:
+   eax:		system call number
+   ebx:		cl_args
+   ecx:		size
+ */
+
+#define CL_ARGS	4
+#define SIZE	8
+#define FUNC	12
+#define ARG	16
+
+        .text
+ENTRY (__clone3)
+	/* Sanity check arguments.  */
+	movl	$-EINVAL, %eax
+	movl	CL_ARGS(%esp), %ecx	/* No NULL cl_args pointer.  */
+	testl	%ecx, %ecx
+	jz	SYSCALL_ERROR_LABEL
+	/* Save the function pointer in EDX which is preserved by the
+	   system call.  */
+	movl	FUNC(%esp), %edx	/* No NULL function pointer.  */
+	testl	%edx, %edx
+	jz	SYSCALL_ERROR_LABEL
+
+	/* Save EBX and ESI.  */
+	pushl	%ebx
+	cfi_adjust_cfa_offset (4)
+	pushl	%esi
+	cfi_adjust_cfa_offset (4)
+
+	/* Save the function argument in ESI which is preserved by the
+	   system call.  */
+	movl	(ARG + 8)(%esp), %esi
+
+	/* Put cl_args in EBX.  */
+	movl	%ecx, %ebx
+
+	/* Put size in ECX.  */
+	movl	(SIZE + 8)(%esp), %ecx
+
+	/* Do the system call.  */
+	movl	$SYS_ify(clone3), %eax
+
+	/* End FDE now, because in the child the unwind info will be
+	   wrong.  */
+	cfi_endproc
+
+	int	$0x80
+	test	%eax, %eax
+	/* No need to restore EBX and ESI in child.  */
+	jz	L(thread_start)
+
+	/* Restore EBX and ESI in parent.  */
+	pop	%esi
+	pop	%ebx
+	jl	SYSCALL_ERROR_LABEL
+
+	ret
+
+L(thread_start):
+	cfi_startproc
+	/* Clearing frame pointer is insufficient, use CFI.  */
+	cfi_undefined (eip)
+	xorl	%ebp, %ebp	/* Terminate the stack frame.  */
+
+	/* Align stack to 16 bytes per the i386 psABI.  */
+	andl	$-16, %esp
+
+	/* The PUSH below will decrement stack pointer by 4 bytes.  */
+	subl	$12, %esp
+
+	/* Set up the argument for the function call.  */
+	pushl	%esi		/* Argument.  */
+	cfi_adjust_cfa_offset (4)
+	call	*%edx		/* Call function.  */
+
+	/* Call exit with return value from function call. */
+	movl	%eax, %ebx
+	movl	$SYS_ify(exit), %eax
+	ENTER_KERNEL
+	cfi_endproc
+
+	cfi_startproc
+PSEUDO_END (__clone3)
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
index 8680b49bf7..3927a1a6e0 100644
--- a/sysdeps/unix/sysv/linux/i386/sysdep.h
+++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
@@ -291,6 +291,8 @@  struct libc_do_syscall_args
 # define HAVE_TIME_VSYSCALL             "__vdso_time"
 # define HAVE_CLOCK_GETRES_VSYSCALL     "__vdso_clock_getres"
 
+# define HAVE_CLONE3_WAPPER		1
+
 # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
 # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1