aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
blob: f1a55e64dbb7f0d08cb86add450b5af186141b64 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/* Wrapper around clone system call.  PowerPC64 version.
   Copyright (C) 1997,98,99,2000,02,04, 2006 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, write to the Free
   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA
   02110-1301 USA.  */

#include <sysdep.h>
#define _ERRNO_H	1
#include <bits/errno.h>
#include <bp-sym.h>
#include <bp-asm.h>

#define CLONE_VM	0x00000100
#define CLONE_THREAD	0x00010000

/* This is the only really unusual system call in PPC linux, but not
   because of any weirdness in the system call itself; because of
   all the freaky stuff we have to do to make the call useful.  */

/* int [r3] clone(int (*fn)(void *arg) [r3], void *child_stack [r4],
                  int flags [r5], void *arg [r6], void *parent_tid [r7],
                  void *tls [r8], void *child_tid [r9]); */

ENTRY (BP_SYM (__clone))
	CALL_MCOUNT 7
	/* GKM FIXME: add bounds checks, where sensible.  */
	DISCARD_BOUNDS (r4)
	DISCARD_BOUNDS (r6)

	/* Check for child_stack == NULL || fn == NULL.  */
	cmpdi	cr0,r4,0
	cmpdi	cr1,r3,0
	cror	cr0*4+eq,cr1*4+eq,cr0*4+eq
	beq-	cr0,L(badargs)

	/* Set up stack frame for parent.  */
	stdu	r1,-80(r1)
	cfi_adjust_cfa_offset (80)
	std	r29,56(r1)
	std	r30,64(r1)
	std	r31,72(r1)
	cfi_offset(r29,-56)
	cfi_offset(r30,-64)
	cfi_offset(r31,-72)
#ifdef RESET_PID
	std	r28,48(r1)
	cfi_offset(r28,-48)
#endif

	/* Set up stack frame for child.  */
	clrrdi	r4,r4,4
	li	r0,0
	stdu	r0,-48(r4) /* min stack frame is 48 bytes per ABI */

	/* Save fn, args, stack across syscall.  */
	mr	r29,r3			/* Function in r29.  */
	mr	r30,r4			/* Stack pointer in r30.  */
#ifdef RESET_PID
	mr	r28,r5			/* Flags in r28.  */
#endif
	mr	r31,r6			/* Argument in r31.  */

	/* 'flags' argument is first parameter to clone syscall. (The other
	   argument is the stack pointer, already in r4.)  */
	mr	r3,r5
  /* Move the parent_tid, child_tid and tls arguments. */
	mr	r5,r7
	mr	r6,r8
	mr	r7,r9

	/* End FDE now, because in the child the unwind info will be
	   wrong.  */
	cfi_endproc

	/* Do the call.  */
	DO_CALL(SYS_ify(clone))

	/* Check for child process.  */
	cmpdi	cr1,r3,0
	crandc	cr1*4+eq,cr1*4+eq,cr0*4+so
	bne-	cr1,L(parent)		/* The '-' is to minimise the race.  */

#ifdef RESET_PID
	andis.	r0,r28,CLONE_THREAD>>16
	bne+	cr0,L(oldpid)
	andi.	r0,r28,CLONE_VM
	li	r3,-1
	bne-	cr0,L(nomoregetpid)
	DO_CALL(SYS_ify(getpid))
L(nomoregetpid):
	stw	r3,TID(r13)
	stw	r3,PID(r13)
L(oldpid):
#endif

	std	r2,40(r1)
	/* Call procedure.  */
	ld	r0,0(r29)
	ld	r2,8(r29)
	mtctr	r0
	mr	r3,r31
	bctrl
	ld	r2,40(r1)
	/* Call _exit with result from procedure.  */
#ifdef SHARED
	b	JUMPTARGET(__GI__exit)
#else
	b	JUMPTARGET(_exit)
#endif

L(parent):
	/* Parent.  Restore registers & return.  */
#ifdef RESET_PID
	ld	r28,48(r1)
#endif
	ld	r31,72(r1)
	ld	r30,64(r1)
	ld	r29,56(r1)
	addi	r1,r1,80
	bnslr+
	b	JUMPTARGET(__syscall_error)

L(badargs):
	li	r3,EINVAL
	b	JUMPTARGET(__syscall_error)

	cfi_startproc
END (BP_SYM (__clone))

weak_alias (BP_SYM (__clone), BP_SYM (clone))