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 UNWIND_EPILOGUE 100 101#elif defined(__arm__) 102 103#include <arm/arch.h> 104 105 .data 106 .globl __current_pid 107 .align 2 108__current_pid: 109 /* Cached pid. Possible values: 110 * 0: no value cached 111 * > 0: cached PID of current process 112 * < 0: negative number of vforks in progress 113 * INT_MIN: for pre-ARMv6, "looking" value (0x80000000) 114 */ 115 .long 0 116 117MI_ENTRY_POINT(___getpid) 118 ldr r3, L__current_pid 119L1: add r3, pc, r3 // r3 = &__current_pid 120 ldr r0, [r3] // get the cached pid 121 cmp r0, #0 122 bxgt lr // if positive, return it 123 124 SYSCALL_NONAME(getpid, 0, cerror_nocancel) 125 126#ifdef _ARM_ARCH_6 127 ldrex r2, [r3] // see if we can cache it 128 cmp r2, #0 // we can't if there are any... 129 bxlt lr // ...vforks in progress 130 strex r2, r0, [r3] // ignore conflicts 131#else 132 mov r1, #0x80000000 // load "looking" value 133 swp r2, r1, [r3] // look at the value, lock others out 134 cmp r2, r1 // anyone else trying to look? 135 bxeq lr // yes, so return immediately/ 136 cmp r2, #0 // see if we can cache it 137 streq r0, [r3] // if zero, we can 138 strne r2, [r3] // otherwise restore previous value 139#endif 140 141 bx lr 142 143L__current_pid: 144 .long __current_pid - (L1+8) 145 146#elif defined(__arm64__) 147 .data 148 .globl __current_pid 149 .align 2 150__current_pid: 151 /* cached pid. possible values: 152 * 0: no value cached 153 * > 0: cached pid of current process 154 * < 0: negative number of vforks in progress 155 * int_min: for pre-armv6, "looking" value (0x80000000) 156 */ 157 .long 0 158 159MI_ENTRY_POINT(___getpid) 160 MI_GET_ADDRESS(x9, __current_pid) // Get address of cached value 161 ldr w0, [x9] // Load it 162 cmp w0, #0 // See if there's a cached value 163 b.le L_notcached // If not, make syscall 164 ret // Else, we're done 165L_notcached: 166 SYSCALL_NONAME(getpid, 0, cerror_nocancel) 167 ldxr w10, [x9] // Exclusive load 168 cbnz w10, L_done // Unless unset, don't even try 169 stxr wzr, w0, [x9] // Try to store, but don't care if we fail (someone will win, or not) 170L_done: 171 ret // Done 172#else 173#error Unsupported architecture 174#endif 175