[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / aarch64 / clone.S

/* Copyright (C) 1996-2015 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/>.  */

/* 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 <sysdep.h>
#define _ERRNO_H	1
#include <bits/errno.h>

#define CLONE_VM_BIT      8
#define CLONE_VM          (1 << CLONE_VM_BIT)

#define CLONE_THREAD_BIT  16
#define CLONE_THREAD      (1 << CLONE_THREAD_BIT)

/* int clone(int (*fn)(void *arg),            x0
	     void *child_stack,               x1
	     int flags,                       x2
	     void *arg,                       x3
	     pid_t *ptid,                     x4
	     struct user_desc *tls,           x5
             pid_t *ctid);                    x6
 */
        .text
ENTRY(__clone)
	/* Save args for the child.  */
	mov	x10, x0
	mov	x11, x2
	mov	x12, x3

	/* Sanity check args.  */
	mov	x0, #-EINVAL
	cbz	x10, .Lsyscall_error
	cbz	x1, .Lsyscall_error

	/* Do the system call.  */
	/* X0:flags, x1:newsp, x2:parenttidptr, x3:newtls, x4:childtid.  */
	mov	x0, x2                  /* flags  */
	/* New sp is already in x1.  */
	mov	x2, x4			/* ptid  */
	mov	x3, x5			/* tls  */
	mov	x4, x6			/* ctid  */
	mov	x8, #SYS_ify(clone)
	svc	0x0

	cmp	x0, #0
	beq	thread_start
	blt	.Lsyscall_error
	RET
PSEUDO_END (__clone)

	.align 4
	.type thread_start, %function
thread_start:
	cfi_startproc
	cfi_undefined (x30)
	mov	x29, 0

	tbnz	x11, #CLONE_THREAD_BIT, 3f
	mov	x0, #-1
	tbnz	x11, #CLONE_VM_BIT, 2f
	mov	x8, #SYS_ify(getpid)
	svc	0x0
2:
	mrs	x1, tpidr_el0
	sub	x1, x1, #PTHREAD_SIZEOF
	str	w0, [x1, #PTHREAD_PID_OFFSET]
	str	w0, [x1, #PTHREAD_TID_OFFSET]
3:

	/* Pick the function arg and execute.  */
	mov	x0, x12
	blr	x10

	/* We are done, pass the return value through x0.  */
	b	HIDDEN_JUMPTARGET(_exit)
	cfi_endproc
	.size thread_start, .-thread_start

weak_alias (__clone, clone)
Commit	Line	Data
b168057a	1	/* Copyright (C) 1996-2015 Free Software Foundation, Inc.
554066b8 MS	2
	3	This file is part of the GNU C Library.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
	16	License along with the GNU C Library; if not, see
	17	<http://www.gnu.org/licenses/>. */
	18
	19	/* clone() is even more special than fork() as it mucks with stacks
	20	and invokes a function in the right context after its all over. */
	21
	22	#include <sysdep.h>
	23	#define _ERRNO_H 1
	24	#include <bits/errno.h>
	25
	26	#define CLONE_VM_BIT 8
	27	#define CLONE_VM (1 << CLONE_VM_BIT)
	28
	29	#define CLONE_THREAD_BIT 16
	30	#define CLONE_THREAD (1 << CLONE_THREAD_BIT)
	31
	32	/* int clone(int (fn)(void arg), x0
	33	void *child_stack, x1
	34	int flags, x2
	35	void *arg, x3
	36	pid_t *ptid, x4
	37	struct user_desc *tls, x5
	38	pid_t *ctid); x6
	39	*/
	40	.text
	41	ENTRY(__clone)
111cc714 RH	42	/* Save args for the child. */
	43	mov x10, x0
	44	mov x11, x2
	45	mov x12, x3
	46
554066b8	47	/* Sanity check args. */
111cc714 RH	48	mov x0, #-EINVAL
	49	cbz x10, .Lsyscall_error
	50	cbz x1, .Lsyscall_error
554066b8 MS	51
554066b8 MS	52	/* Do the system call. */
111cc714	53	/* X0:flags, x1:newsp, x2:parenttidptr, x3:newtls, x4:childtid. */
554066b8	54	mov x0, x2 /* flags */
554066b8 MS	55	/* New sp is already in x1. */
	56	mov x2, x4 /* ptid */
	57	mov x3, x5 /* tls */
	58	mov x4, x6 /* ctid */
554066b8	59	mov x8, #SYS_ify(clone)
554066b8	60	svc 0x0
111cc714	61
554066b8	62	cmp x0, #0
111cc714 RH	63	beq thread_start
111cc714 RH	64	blt .Lsyscall_error
554066b8	65	RET
111cc714	66	PSEUDO_END (__clone)
554066b8	67
111cc714 RH	68	.align 4
	69	.type thread_start, %function
	70	thread_start:
3a3acb6a TT	71	cfi_startproc
	72	cfi_undefined (x30)
	73	mov x29, 0
111cc714 RH	74
111cc714 RH	75	tbnz x11, #CLONE_THREAD_BIT, 3f
554066b8	76	mov x0, #-1
111cc714	77	tbnz x11, #CLONE_VM_BIT, 2f
554066b8 MS	78	mov x8, #SYS_ify(getpid)
	79	svc 0x0
	80	2:
	81	mrs x1, tpidr_el0
	82	sub x1, x1, #PTHREAD_SIZEOF
	83	str w0, [x1, #PTHREAD_PID_OFFSET]
	84	str w0, [x1, #PTHREAD_TID_OFFSET]
554066b8	85	3:
111cc714 RH	86
	87	/* Pick the function arg and execute. */
	88	mov x0, x12
	89	blr x10
554066b8 MS	90
	91	/* We are done, pass the return value through x0. */
	92	b HIDDEN_JUMPTARGET(_exit)
3a3acb6a	93	cfi_endproc
111cc714	94	.size thread_start, .-thread_start
554066b8 MS	95
554066b8 MS	96	weak_alias (__clone, clone)