libsyscall/custom/__getpid.s

   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(__ppc__) || defined(__ppc64__)
  32
  33         .data
  34         .globl  __current_pid
  35         .align  2
  36 __current_pid:
  37         .long 0
  38
  39 MI_ENTRY_POINT(___getpid)
  40 #if defined(__DYNAMIC__)
  41         mflr    r0              // note we cannot use MI_GET_ADDRESS...
  42         bcl    20,31,1f         // ...because we define __current_pid
  43 1:
  44         mflr    r5
  45         mtlr    r0
  46         addis   r5, r5, ha16(__current_pid - 1b)
  47         addi    r5, r5, lo16(__current_pid - 1b)
  48 #else
  49         lis     r5,hi16(__current_pid)
  50         ori     r5,r5,lo16(__current_pid)
  51 #endif
  52         lwz     r3,0(r5)                // get the cached pid
  53         cmpwi   r3,0                    // if positive,
  54         bgtlr++                 // return it
  55
  56         SYSCALL_NONAME(getpid, 0)
  57
  58         lwarx   r4,0,r5                 // see if we can cache it
  59         cmpwi   r4,0                    // we can't if there are any...
  60         blt--   1f              // ...vforks in progress
  61
  62         stwcx.  r3,0,r5                 // ignore cache conflicts
  63         blr
  64 1:
  65         li      r6,-4           // on 970, cancel the reservation using red zone...
  66         stwcx.  r3,r6,r1        // ...to avoid an errata
  67         blr
  68
  69 #elif defined(__i386__)
  70
  71         .data
  72         .private_extern __current_pid
  73 __current_pid:
  74         .long 0
  75 L__current_pid_addr = __current_pid
  76
  77 #if defined(__DYNAMIC__)
  78 #define GET_CURRENT_PID                         \
  79         call    0f                              ; \
  80 0:                                              ; \
  81         popl    %ecx                            ; \
  82         leal    L__current_pid_addr-0b(%ecx), %ecx
  83
  84 #define __current_pid (%ecx)
  85
  86 #else
  87 #define GET_CURRENT_PID
  88 #endif
  89
  90 /*
  91  * If __current_pid is > 0, return it, else make syscall.
  92  * If __current_pid is 0, cache result of syscall.
  93  */
  94 TEXT
  95 LEAF(___getpid, 0)
  96         GET_CURRENT_PID
  97         movl            __current_pid, %eax
  98         testl           %eax, %eax
  99         jle             1f
 100         ret
 101 1:
 102         UNIX_SYSCALL_NONAME(getpid, 0)
 103         movl            %eax, %edx
 104         xorl            %eax, %eax
 105         GET_CURRENT_PID
 106         lock
 107         cmpxchgl        %edx, __current_pid
 108         movl            %edx, %eax
 109         ret
 110
 111 #elif defined(__x86_64__)
 112
 113         .data
 114         .private_extern __current_pid
 115 __current_pid:
 116         .long 0
 117
 118 /*
 119  * If __current_pid is > 0, return it, else make syscall.
 120  * If __current_pid is 0, cache result of syscall.
 121  */
 122 TEXT
 123 LEAF(___getpid, 0)
 124         movl    __current_pid(%rip), %eax
 125         testl   %eax, %eax
 126         jle             1f
 127         ret
 128 1:
 129         UNIX_SYSCALL_NONAME(getpid, 0)
 130         movl            %eax, %edx
 131         xorl            %eax, %eax
 132         leaq            __current_pid(%rip), %rcx
 133         lock
 134         cmpxchgl        %edx, (%rcx)
 135         movl            %edx, %eax
 136         ret
 137
 138 #else
 139 #error Unsupported architecture
 140 #endif