aarch64: Add the clone3 wrapper

It follow the internal signature:

  extern int clone3 (struct clone_args *__cl_args, size_t __size,
 int (*__func) (void *__arg), void *__arg);

Checked on aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

diff --git a/sysdeps/unix/sysv/linux/aarch64/clone3.S b/sysdeps/unix/sysv/linux/aarch64/clone3.S
new file mode 100644 (file)
index 0000000..88a1fa1
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/clone3.S
@@ -0,0 +1,85 @@
+/* The clone3 syscall wrapper.  Linux/aarch64 version.
+   Copyright (C) 2023 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/>.  */
+
+#include <sysdep.h>
+#define _ERRNO_H        1
+#include <bits/errno.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 in registers from userland:
+   x0: cl_args
+   x1: size
+   x2: func
+   x3: arg  */
+
+        .text
+ENTRY(__clone3)
+       PTR_ARG (0)
+       PTR_ARG (1)
+       PTR_ARG (3)
+       PTR_ARG (4)
+       /* Save args for the child.  */
+       mov     x10, x0         /* cl_args  */
+       mov     x11, x2         /* func  */
+       mov     x12, x3         /* args  */
+
+       /* Sanity check args.  */
+       mov     x0, #-EINVAL
+       cbz     x10, .Lsyscall_error    /* No NULL cl_args pointer.  */
+       cbz     x2, .Lsyscall_error     /* No NULL function pointer.  */
+
+       /* Do the system call, the kernel expects:
+          x8: system call number
+          x0: cl_args
+          x1: size  */
+       mov     x0, x10
+       mov     x8, #SYS_ify(clone3)
+       svc     0x0
+
+       cmp     x0, #0
+       beq     thread_start
+       blt     .Lsyscall_error
+       RET
+PSEUDO_END (__clone3)
+
+       .align 4
+       .type thread_start, %function
+thread_start:
+       cfi_startproc
+       cfi_undefined (x30)
+       mov     x29, 0
+
+       /* Pick the function arg and execute.  */
+       mov     x0, x12
+       blr     x11
+
+       /* We are done, pass the return value through x0.  */
+       mov     x8, #SYS_ify(exit)
+       svc     0x0
+       cfi_endproc
+       .size thread_start, .-thread_start
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)

diff --git a/sysdeps/unix/sysv/linux/aarch64/sysdep.h b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
index 6520fa15da0d8211e4f41ed61ce24ed7ea77331d..e94d1703ada12b5ac1e1357aaaf7f35e33e9159e 100644 (file)
--- a/sysdeps/unix/sysv/linux/aarch64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
@@ -165,6 +165,8 @@
 # define HAVE_CLOCK_GETTIME64_VSYSCALL "__kernel_clock_gettime"
 # define HAVE_GETTIMEOFDAY_VSYSCALL    "__kernel_gettimeofday"
 
+# define HAVE_CLONE3_WRAPPER           1
+
 # undef INTERNAL_SYSCALL_RAW
 # define INTERNAL_SYSCALL_RAW(name, nr, args...)               \
   ({ long _sys_result;                                         \