1/*
2 * Copyright (c) 1999-2007 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29#include "SYS.h"
30
31#if defined(__i386__)
32
33	.data
34	.private_extern __current_pid
35L__current_pid_addr:
36 __current_pid:
37	.long 0
38
39#if defined(__DYNAMIC__)
40#define GET_CURRENT_PID				\
41	call	0f				; \
420:						; \
43	popl	%ecx				; \
44	leal	L__current_pid_addr-0b(%ecx), %ecx
45
46#define __current_pid (%ecx)
47
48#else
49#define GET_CURRENT_PID
50#endif
51
52/*
53 * If __current_pid is > 0, return it, else make syscall.
54 * If __current_pid is 0, cache result of syscall.
55 */
56TEXT
57LEAF(___getpid, 0)
58	GET_CURRENT_PID
59	movl		__current_pid, %eax
60	testl		%eax, %eax
61	jle		1f
62	ret
631:
64	UNIX_SYSCALL_NONAME(getpid, 0, cerror_nocancel)
65	movl		%eax, %edx
66	xorl		%eax, %eax
67	GET_CURRENT_PID
68	lock
69	cmpxchgl	%edx, __current_pid
70	movl		%edx, %eax
71	ret
72
73#elif defined(__x86_64__)
74
75	.data
76	.private_extern __current_pid
77__current_pid:
78	.long 0
79
80/*
81 * If __current_pid is > 0, return it, else make syscall.
82 * If __current_pid is 0, cache result of syscall.
83 */
84TEXT
85LEAF(___getpid, 0)
86	movl	__current_pid(%rip), %eax
87	testl	%eax, %eax
88	jle		1f
89	ret
901:
91	UNIX_SYSCALL_NONAME(getpid, 0, cerror_nocancel)
92	movl		%eax, %edx
93	xorl		%eax, %eax
94	leaq		__current_pid(%rip), %rcx
95	lock
96	cmpxchgl	%edx, (%rcx)
97	movl		%edx, %eax
98	ret
99
100#elif defined(__arm__)
101
102#include <arm/arch.h>
103
104	.data
105	.globl	__current_pid
106	.align 2
107__current_pid:
108	/* Cached pid.  Possible values:
109	 *	0:		no value cached
110	 *	> 0:		cached PID of current process
111	 *	< 0:		negative number of vforks in progress
112	 *	INT_MIN:	for pre-ARMv6, "looking" value (0x80000000)
113	 */
114	.long 0
115
116MI_ENTRY_POINT(___getpid)
117	ldr	r3, L__current_pid
118L1:	add	r3, pc, r3		// r3 = &__current_pid
119	ldr	r0, [r3]		// get the cached pid
120	cmp	r0, #0
121	bxgt	lr			// if positive, return it
122
123	SYSCALL_NONAME(getpid, 0)
124
125#ifdef _ARM_ARCH_6
126	ldrex	r2, [r3]		// see if we can cache it
127	cmp	r2, #0			// we can't if there are any...
128	bxlt	lr			// ...vforks in progress
129	strex	r2, r0, [r3]		// ignore conflicts
130#else
131	mov	r1, #0x80000000		// load "looking" value
132	swp	r2, r1, [r3]		// look at the value, lock others out
133	cmp	r2, r1			// anyone else trying to look?
134	bxeq	lr			// yes, so return immediately/
135	cmp	r2, #0			// see if we can cache it
136	streq	r0, [r3]		// if zero, we can
137	strne	r2, [r3]		// otherwise restore previous value
138#endif
139
140	bx	lr
141
142L__current_pid:
143	.long	__current_pid - (L1+8)
144
145#else
146#error Unsupported architecture
147#endif
148