/* Wrapper around clone system call.  RISC-V version.

   Copyright (C) 1996-2018 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/>.  */

/* clone() is even more special than fork() as it mucks with stacks

   and invokes a function in the right context after its all over.  */

#include <sys/asm.h>

#include <sysdep.h>

#define _ERRNO_H	1

#include <bits/errno.h>

#include <tls.h>

#include "tcb-offsets.h"

/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,

	     void *parent_tidptr, void *tls, void *child_tidptr) */

	.text

LEAF (__clone)

	/* Sanity check arguments.  */

	beqz		a0,L (invalid)	/* No NULL function pointers.  */

	beqz		a1,L (invalid)	/* No NULL stack pointers.  */

	addi		a1,a1,-16	/* Reserve argument save space.  */

	REG_S		a0,0(a1)	/* Save function pointer.  */

	REG_S		a3,SZREG(a1)	/* Save argument pointer.  */

	/* The syscall expects the args to be in different slots.  */

	mv		a0,a2

	mv		a2,a4

	mv		a3,a5

	mv		a4,a6

	/* Do the system call.  */

	li		a7,__NR_clone

	scall

	bltz		a0,L (error)

	beqz		a0,L (thread_start)

	/* Successful return from the parent.  */

	ret

L (invalid):

	li		a0, -EINVAL

	/* Something bad happened -- no child created.  */

L (error):

	j		__syscall_error

	END (__clone)

/* Load up the arguments to the function.  Put this block of code in

   its own function so that we can terminate the stack trace with our

   debug info.  */

ENTRY (__thread_start)

L (thread_start):

	/* Restore the arg for user's function.  */

	REG_L		a1,0(sp)	/* Function pointer.  */

	REG_L		a0,SZREG(sp)	/* Argument pointer.  */

	/* Call the user's function.  */

	jalr		a1

	/* Call exit with the function's return value.  */

	li		a7, __NR_exit

	scall

	END (__thread_start)

libc_hidden_def (__clone)

weak_alias (__clone, clone)