[v5,4/5] x86-64: Add the clone3 wrapper
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Commit Message
extern int clone3 (struct clone_args *__cl_args,
int (*__func) (void *__arg), void *__arg);
---
sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++++
sysdeps/unix/sysv/linux/x86_64/sysdep.h | 2 +
2 files changed, 94 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S
Comments
* H. J. Lu:
> extern int clone3 (struct clone_args *__cl_args,
> int (*__func) (void *__arg), void *__arg);
> ---
> sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++++
> sysdeps/unix/sysv/linux/x86_64/sysdep.h | 2 +
> 2 files changed, 94 insertions(+)
> create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S
>
> diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> new file mode 100644
> index 0000000000..f7d4036a6a
> + .text
> +ENTRY (__clone3)
> + /* Sanity check arguments. */
> + movq $-EINVAL, %rax
> + testq %rdi, %rdi /* No NULL cl_args pointer. */
> + jz SYSCALL_ERROR_LABEL
> + testq %rsi, %rsi /* No NULL function pointer. */
> + jz SYSCALL_ERROR_LABEL
I think some of these register aren't x32-compatible. Isn't the upper
half undefined?
> + /* Save the function pointer in R8 which is preserved by the
> + syscall. */
> + movq %rsi, %r8
> +
> + /* Put sizeof (struct clone_args) in ESI. */
> + movl $CLONE_ARGS_SIZE , %esi
If this is in preparation of the public wrapper, this should actually be
an argument. Sorry didn't realize this was the direction.
> +L(thread_start):
> + cfi_startproc
> + /* Clearing frame pointer is insufficient, use CFI. */
> + cfi_undefined (rip)
> + /* Clear the frame pointer. The ABI suggests this be done, to mark
> + the outermost frame obviously. */
> + xorl %ebp, %ebp
> +
> + /* Set up arguments for the function call. */
> + movq %rdx, %rdi /* Argument. */
> + call *%r8 /* Call function. */
> + /* Call exit with return value from function call. */
> + movq %rax, %rdi
> + movl $SYS_ify(exit), %eax
> + syscall
> + cfi_endproc
> +
> + cfi_startproc
> +PSEUDO_END (__clone3)
If this is a public wrapper, should it round up %rsp to 16 bytes
at the point of the caller, to follow the x86-64 calling convention?
Thanks,
Florian
On Sat, May 15, 2021 at 9:23 AM H.J. Lu via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> extern int clone3 (struct clone_args *__cl_args,
> int (*__func) (void *__arg), void *__arg);
> ---
> sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++++
> sysdeps/unix/sysv/linux/x86_64/sysdep.h | 2 +
> 2 files changed, 94 insertions(+)
> create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S
>
> diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> new file mode 100644
> index 0000000000..f7d4036a6a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> @@ -0,0 +1,92 @@
> +/* The clone3 syscall wrapper. Linux/x86-64 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>
> +#include <clone-offsets.h>
> +
> +/* The userland implementation is:
> + int clone3 (struct clone_args *cl_args, int (*func)(void *arg),
> + void *arg);
> + the kernel entry is:
> + int clone3 (struct clone_args *cl_args, size_t size);
> +
> + The parameters are passed in registers from userland:
> + rdi: cl_args
> + rsi: func
> + rdx: arg
> +
> + The kernel expects:
> + rax: system call number
> + rdi: cl_args
> + rsi: size */
> +
> + .text
> +ENTRY (__clone3)
> + /* Sanity check arguments. */
> + movq $-EINVAL, %rax
Can this be movl?
> + testq %rdi, %rdi /* No NULL cl_args pointer. */
> + jz SYSCALL_ERROR_LABEL
> + testq %rsi, %rsi /* No NULL function pointer. */
> + jz SYSCALL_ERROR_LABEL
> +
> + /* Save the function pointer in R8 which is preserved by the
> + syscall. */
> + movq %rsi, %r8
> +
> + /* Put sizeof (struct clone_args) in ESI. */
> + movl $CLONE_ARGS_SIZE , %esi
> +
> + /* Do the system call. */
> + movl $SYS_ify(clone3), %eax
> +
> + /* End FDE now, because in the child the unwind info will be
> + wrong. */
> + cfi_endproc
> + syscall
> +
> + test %RAX_LP, %RAX_LP
> + jl SYSCALL_ERROR_LABEL
> + jz L(thread_start)
> +
Is expectation to go to L(thread_start)? If so
think jnz L(ret) and fallthrough is probably
better.
> + ret
> +
> +L(thread_start):
> + cfi_startproc
> + /* Clearing frame pointer is insufficient, use CFI. */
> + cfi_undefined (rip)
> + /* Clear the frame pointer. The ABI suggests this be done, to mark
> + the outermost frame obviously. */
> + xorl %ebp, %ebp
> +
> + /* Set up arguments for the function call. */
> + movq %rdx, %rdi /* Argument. */
> + call *%r8 /* Call function. */
> + /* Call exit with return value from function call. */
> + movq %rax, %rdi
> + movl $SYS_ify(exit), %eax
> + syscall
> + cfi_endproc
> +
> + cfi_startproc
> +PSEUDO_END (__clone3)
> +
> +libc_hidden_def (__clone3)
> +weak_alias (__clone3, clone3)
> diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> index dbad2c788a..f26ffc68ae 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> @@ -377,6 +377,8 @@
> # define HAVE_GETCPU_VSYSCALL "__vdso_getcpu"
> # define HAVE_CLOCK_GETRES64_VSYSCALL "__vdso_clock_getres"
>
> +# define HAVE_CLONE3_WAPPER 1
> +
> # define SINGLE_THREAD_BY_GLOBAL 1
>
> #endif /* __ASSEMBLER__ */
> --
> 2.31.1
>
On Thu, May 20, 2021 at 2:35 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Sat, May 15, 2021 at 9:23 AM H.J. Lu via Libc-alpha
> <libc-alpha@sourceware.org> wrote:
> >
> > extern int clone3 (struct clone_args *__cl_args,
> > int (*__func) (void *__arg), void *__arg);
> > ---
> > sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++++
> > sysdeps/unix/sysv/linux/x86_64/sysdep.h | 2 +
> > 2 files changed, 94 insertions(+)
> > create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S
> >
> > diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> > new file mode 100644
> > index 0000000000..f7d4036a6a
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> > @@ -0,0 +1,92 @@
> > +/* The clone3 syscall wrapper. Linux/x86-64 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>
> > +#include <clone-offsets.h>
> > +
> > +/* The userland implementation is:
> > + int clone3 (struct clone_args *cl_args, int (*func)(void *arg),
> > + void *arg);
> > + the kernel entry is:
> > + int clone3 (struct clone_args *cl_args, size_t size);
> > +
> > + The parameters are passed in registers from userland:
> > + rdi: cl_args
> > + rsi: func
> > + rdx: arg
> > +
> > + The kernel expects:
> > + rax: system call number
> > + rdi: cl_args
> > + rsi: size */
> > +
> > + .text
> > +ENTRY (__clone3)
> > + /* Sanity check arguments. */
> > + movq $-EINVAL, %rax
>
> Can this be movl?
>
> > + testq %rdi, %rdi /* No NULL cl_args pointer. */
> > + jz SYSCALL_ERROR_LABEL
> > + testq %rsi, %rsi /* No NULL function pointer. */
> > + jz SYSCALL_ERROR_LABEL
> > +
> > + /* Save the function pointer in R8 which is preserved by the
> > + syscall. */
> > + movq %rsi, %r8
> > +
> > + /* Put sizeof (struct clone_args) in ESI. */
> > + movl $CLONE_ARGS_SIZE , %esi
> > +
> > + /* Do the system call. */
> > + movl $SYS_ify(clone3), %eax
> > +
> > + /* End FDE now, because in the child the unwind info will be
> > + wrong. */
> > + cfi_endproc
> > + syscall
> > +
> > + test %RAX_LP, %RAX_LP
> > + jl SYSCALL_ERROR_LABEL
> > + jz L(thread_start)
> > +
>
> Is expectation to go to L(thread_start)? If so
> think jnz L(ret) and fallthrough is probably
> better.
Or better take the error check branch off
the critical path with jnz L(error_or_ret) then jl
in L(error_or_ret)
>
> > + ret
> > +
> > +L(thread_start):
> > + cfi_startproc
> > + /* Clearing frame pointer is insufficient, use CFI. */
> > + cfi_undefined (rip)
> > + /* Clear the frame pointer. The ABI suggests this be done, to mark
> > + the outermost frame obviously. */
> > + xorl %ebp, %ebp
> > +
> > + /* Set up arguments for the function call. */
> > + movq %rdx, %rdi /* Argument. */
> > + call *%r8 /* Call function. */
> > + /* Call exit with return value from function call. */
> > + movq %rax, %rdi
> > + movl $SYS_ify(exit), %eax
> > + syscall
> > + cfi_endproc
> > +
> > + cfi_startproc
> > +PSEUDO_END (__clone3)
> > +
> > +libc_hidden_def (__clone3)
> > +weak_alias (__clone3, clone3)
> > diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> > index dbad2c788a..f26ffc68ae 100644
> > --- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> > +++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> > @@ -377,6 +377,8 @@
> > # define HAVE_GETCPU_VSYSCALL "__vdso_getcpu"
> > # define HAVE_CLOCK_GETRES64_VSYSCALL "__vdso_clock_getres"
> >
> > +# define HAVE_CLONE3_WAPPER 1
> > +
> > # define SINGLE_THREAD_BY_GLOBAL 1
> >
> > #endif /* __ASSEMBLER__ */
> > --
> > 2.31.1
> >
On Thu, May 20, 2021 at 7:53 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> > extern int clone3 (struct clone_args *__cl_args,
> > int (*__func) (void *__arg), void *__arg);
> > ---
> > sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++++
> > sysdeps/unix/sysv/linux/x86_64/sysdep.h | 2 +
> > 2 files changed, 94 insertions(+)
> > create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S
> >
> > diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> > new file mode 100644
> > index 0000000000..f7d4036a6a
>
> > + .text
> > +ENTRY (__clone3)
> > + /* Sanity check arguments. */
> > + movq $-EINVAL, %rax
> > + testq %rdi, %rdi /* No NULL cl_args pointer. */
> > + jz SYSCALL_ERROR_LABEL
> > + testq %rsi, %rsi /* No NULL function pointer. */
> > + jz SYSCALL_ERROR_LABEL
>
> I think some of these register aren't x32-compatible. Isn't the upper
> half undefined?
All pointers passed in registers are zero-extended to 64 bits.
I changed it to use REG_LP macros to avoid the REX prefix.
> > + /* Save the function pointer in R8 which is preserved by the
> > + syscall. */
> > + movq %rsi, %r8
> > +
> > + /* Put sizeof (struct clone_args) in ESI. */
> > + movl $CLONE_ARGS_SIZE , %esi
>
> If this is in preparation of the public wrapper, this should actually be
> an argument. Sorry didn't realize this was the direction.
Fixed.
> > +L(thread_start):
> > + cfi_startproc
> > + /* Clearing frame pointer is insufficient, use CFI. */
> > + cfi_undefined (rip)
> > + /* Clear the frame pointer. The ABI suggests this be done, to mark
> > + the outermost frame obviously. */
> > + xorl %ebp, %ebp
> > +
> > + /* Set up arguments for the function call. */
> > + movq %rdx, %rdi /* Argument. */
> > + call *%r8 /* Call function. */
> > + /* Call exit with return value from function call. */
> > + movq %rax, %rdi
> > + movl $SYS_ify(exit), %eax
> > + syscall
> > + cfi_endproc
> > +
> > + cfi_startproc
> > +PSEUDO_END (__clone3)
>
> If this is a public wrapper, should it round up %rsp to 16 bytes
Fixed.
> at the point of the caller, to follow the x86-64 calling convention?
>
> Thanks,
> Florian
>
Thanks.
On Thu, May 20, 2021 at 11:39 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Thu, May 20, 2021 at 2:35 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > On Sat, May 15, 2021 at 9:23 AM H.J. Lu via Libc-alpha
> > <libc-alpha@sourceware.org> wrote:
> > >
> > > extern int clone3 (struct clone_args *__cl_args,
> > > int (*__func) (void *__arg), void *__arg);
> > > ---
> > > sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++++
> > > sysdeps/unix/sysv/linux/x86_64/sysdep.h | 2 +
> > > 2 files changed, 94 insertions(+)
> > > create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S
> > >
> > > diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> > > new file mode 100644
> > > index 0000000000..f7d4036a6a
> > > --- /dev/null
> > > +++ b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> > > @@ -0,0 +1,92 @@
> > > +/* The clone3 syscall wrapper. Linux/x86-64 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>
> > > +#include <clone-offsets.h>
> > > +
> > > +/* The userland implementation is:
> > > + int clone3 (struct clone_args *cl_args, int (*func)(void *arg),
> > > + void *arg);
> > > + the kernel entry is:
> > > + int clone3 (struct clone_args *cl_args, size_t size);
> > > +
> > > + The parameters are passed in registers from userland:
> > > + rdi: cl_args
> > > + rsi: func
> > > + rdx: arg
> > > +
> > > + The kernel expects:
> > > + rax: system call number
> > > + rdi: cl_args
> > > + rsi: size */
> > > +
> > > + .text
> > > +ENTRY (__clone3)
> > > + /* Sanity check arguments. */
> > > + movq $-EINVAL, %rax
> >
> > Can this be movl?
Yes. Fixed.
> > > + testq %rdi, %rdi /* No NULL cl_args pointer. */
> > > + jz SYSCALL_ERROR_LABEL
> > > + testq %rsi, %rsi /* No NULL function pointer. */
> > > + jz SYSCALL_ERROR_LABEL
> > > +
> > > + /* Save the function pointer in R8 which is preserved by the
> > > + syscall. */
> > > + movq %rsi, %r8
> > > +
> > > + /* Put sizeof (struct clone_args) in ESI. */
> > > + movl $CLONE_ARGS_SIZE , %esi
> > > +
> > > + /* Do the system call. */
> > > + movl $SYS_ify(clone3), %eax
> > > +
> > > + /* End FDE now, because in the child the unwind info will be
> > > + wrong. */
> > > + cfi_endproc
> > > + syscall
> > > +
> > > + test %RAX_LP, %RAX_LP
> > > + jl SYSCALL_ERROR_LABEL
> > > + jz L(thread_start)
> > > +
> >
> > Is expectation to go to L(thread_start)? If so
> > think jnz L(ret) and fallthrough is probably
> > better.
>
> Or better take the error check branch off
> the critical path with jnz L(error_or_ret) then jl
> in L(error_or_ret)
I don't think the clone wrapper is on the critical path.
Since the same code is executed by both child and parent.
I check the error return first.
> >
> > > + ret
> > > +
> > > +L(thread_start):
> > > + cfi_startproc
> > > + /* Clearing frame pointer is insufficient, use CFI. */
> > > + cfi_undefined (rip)
> > > + /* Clear the frame pointer. The ABI suggests this be done, to mark
> > > + the outermost frame obviously. */
> > > + xorl %ebp, %ebp
> > > +
> > > + /* Set up arguments for the function call. */
> > > + movq %rdx, %rdi /* Argument. */
> > > + call *%r8 /* Call function. */
> > > + /* Call exit with return value from function call. */
> > > + movq %rax, %rdi
> > > + movl $SYS_ify(exit), %eax
> > > + syscall
> > > + cfi_endproc
> > > +
> > > + cfi_startproc
> > > +PSEUDO_END (__clone3)
> > > +
> > > +libc_hidden_def (__clone3)
> > > +weak_alias (__clone3, clone3)
> > > diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> > > index dbad2c788a..f26ffc68ae 100644
> > > --- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> > > +++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
> > > @@ -377,6 +377,8 @@
> > > # define HAVE_GETCPU_VSYSCALL "__vdso_getcpu"
> > > # define HAVE_CLOCK_GETRES64_VSYSCALL "__vdso_clock_getres"
> > >
> > > +# define HAVE_CLONE3_WAPPER 1
> > > +
> > > # define SINGLE_THREAD_BY_GLOBAL 1
> > >
> > > #endif /* __ASSEMBLER__ */
> > > --
> > > 2.31.1
> > >
Thanks.
new file mode 100644
@@ -0,0 +1,92 @@
+/* The clone3 syscall wrapper. Linux/x86-64 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>
+#include <clone-offsets.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, int (*func)(void *arg),
+ void *arg);
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ rdi: cl_args
+ rsi: func
+ rdx: arg
+
+ The kernel expects:
+ rax: system call number
+ rdi: cl_args
+ rsi: size */
+
+ .text
+ENTRY (__clone3)
+ /* Sanity check arguments. */
+ movq $-EINVAL, %rax
+ testq %rdi, %rdi /* No NULL cl_args pointer. */
+ jz SYSCALL_ERROR_LABEL
+ testq %rsi, %rsi /* No NULL function pointer. */
+ jz SYSCALL_ERROR_LABEL
+
+ /* Save the function pointer in R8 which is preserved by the
+ syscall. */
+ movq %rsi, %r8
+
+ /* Put sizeof (struct clone_args) in ESI. */
+ movl $CLONE_ARGS_SIZE , %esi
+
+ /* Do the system call. */
+ movl $SYS_ify(clone3), %eax
+
+ /* End FDE now, because in the child the unwind info will be
+ wrong. */
+ cfi_endproc
+ syscall
+
+ test %RAX_LP, %RAX_LP
+ jl SYSCALL_ERROR_LABEL
+ jz L(thread_start)
+
+ ret
+
+L(thread_start):
+ cfi_startproc
+ /* Clearing frame pointer is insufficient, use CFI. */
+ cfi_undefined (rip)
+ /* Clear the frame pointer. The ABI suggests this be done, to mark
+ the outermost frame obviously. */
+ xorl %ebp, %ebp
+
+ /* Set up arguments for the function call. */
+ movq %rdx, %rdi /* Argument. */
+ call *%r8 /* Call function. */
+ /* Call exit with return value from function call. */
+ movq %rax, %rdi
+ movl $SYS_ify(exit), %eax
+ syscall
+ cfi_endproc
+
+ cfi_startproc
+PSEUDO_END (__clone3)
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
@@ -377,6 +377,8 @@
# define HAVE_GETCPU_VSYSCALL "__vdso_getcpu"
# define HAVE_CLOCK_GETRES64_VSYSCALL "__vdso_clock_getres"
+# define HAVE_CLONE3_WAPPER 1
+
# define SINGLE_THREAD_BY_GLOBAL 1
#endif /* __ASSEMBLER__ */