ppc/sys/vfork.s

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /* Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  26  *
  27  *      File:   libc/ppc/sys/vfork.s
  28  *
  29  * HISTORY
  30  * 23-Jun-1998  Umesh Vaishampayan (umeshv@apple.com)
  31  *      Created from fork.s
  32  *
  33  */
  34 #if 0
  35 #import <sys/syscall.h>
  36 #import <architecture/ppc/asm_help.h>
  37 #import <architecture/ppc/pseudo_inst.h>
  38 #import <mach/ppc/syscall_sw.h>
  39
  40 /* We use 8 bytes for LOCAL_VAR(1) and LOCAL_VAR(2) */
  41 NESTED(_vfork, 8, 0, 0, 0)
  42         CALL_EXTERN(__cthread_fork_prepare)
  43 #if defined(__DYNAMIC__)
  44 .cstring
  45 LC1:
  46         .ascii  "__dyld_fork_prepare\0"
  47 .text
  48         .align 2
  49         mflr    r0
  50         bl      1f
  51 1:      mflr    r3
  52         mtlr    r0
  53         addis   r3,r3,ha16(LC1-1b)
  54         addi    r3,r3,lo16(LC1-1b)
  55         addi    r4,r1,LOCAL_VAR(1)
  56         bl      __dyld_func_lookup
  57         lwz     r3,LOCAL_VAR(1)(r1)
  58         mtspr   ctr,r3
  59         bctrl
  60 #endif
  61         li      r0,SYS_vfork
  62         sc
  63         b       Lbotch                  // error return
  64
  65         cmpwi   r4,0
  66         beq     Lparent                 // parent, since a1 == 0 in parent,
  67                                         //                     1 in child
  68 #if defined(__DYNAMIC__)
  69 .cstring
  70 LC3:
  71         .ascii  "__dyld_fork_child\0"
  72 .text
  73         .align 2
  74         mflr    r0
  75         bl      1f
  76 1:      mflr    r3
  77         mtlr    r0
  78         addis   r3,r3,ha16(LC3-1b)
  79         addi    r3,r3,lo16(LC3-1b)
  80         addi    r4,r1,LOCAL_VAR(1)
  81         bl      __dyld_func_lookup
  82         lwz     r3,LOCAL_VAR(1)(r1)
  83         mtspr   ctr,r3
  84         bctrl
  85 #endif
  86         li      r3,0
  87         REG_TO_EXTERN(r3, EXT(_current_pid))
  88         CALL_EXTERN(_fork_mach_init)
  89         CALL_EXTERN(__cthread_fork_child)
  90 #if defined(__DYNAMIC__)
  91 .cstring
  92 LC4:
  93         .ascii  "__dyld_fork_child_final\0"
  94 .text
  95         .align 2
  96         mflr    r0
  97         bl      1f
  98 1:      mflr    r3
  99         mtlr    r0
 100         addis   r3,r3,ha16(LC4-1b)
 101         addi    r3,r3,lo16(LC4-1b)
 102         addi    r4,r1,LOCAL_VAR(1)
 103         bl      __dyld_func_lookup
 104         lwz     r3,LOCAL_VAR(1)(r1)
 105         mtspr   ctr,r3
 106         bctrl
 107 #endif
 108
 109         li      r3,0
 110         b       Lreturn
 111
 112 Lparent:
 113 #if defined(__DYNAMIC__)
 114         stw     r3,LOCAL_VAR(2)(r1)     // save child pid
 115         mflr    r0
 116         bl      1f
 117 1:      mflr    r3
 118         mtlr    r0
 119         addis   r3,r3,ha16(LC2-1b)
 120         addi    r3,r3,lo16(LC2-1b)
 121         addi    r4,r1,LOCAL_VAR(1)
 122         bl      __dyld_func_lookup
 123         lwz     r3,LOCAL_VAR(1)(r1)
 124         mtspr   ctr,r3
 125         bctrl
 126 #endif
 127         CALL_EXTERN(__cthread_fork_parent)
 128 #if defined(__DYNAMIC__)
 129         lwz     r3,LOCAL_VAR(2)(r1)
 130 #endif
 131         b       Lreturn
 132
 133 Lbotch:
 134 #if defined(__DYNAMIC__)
 135 .cstring
 136 LC2:
 137         .ascii  "__dyld_fork_parent\0"
 138 .text
 139         .align 2
 140         stw     r3,LOCAL_VAR(2)(r1)     // save error value
 141         mflr    r0
 142         bl      1f
 143 1:      mflr    r3
 144         mtlr    r0
 145         addis   r3,r3,ha16(LC2-1b)
 146         addi    r3,r3,lo16(LC2-1b)
 147         addi    r4,r1,LOCAL_VAR(1)
 148         bl      __dyld_func_lookup
 149         lwz     r3,LOCAL_VAR(1)(r1)
 150         mtspr   ctr,r3
 151         bctrl
 152         lwz     r3,LOCAL_VAR(2)(r1)     // restore error value for cerror
 153
 154 #endif
 155         CALL_EXTERN(cerror)
 156         /*
 157          * We use cthread_fork_parent() to clean up after a fork error
 158          * (unlock cthreads and mailloc packages) so the parent
 159          * process can Malloc() after fork() errors without
 160          * deadlocking.
 161          */
 162         CALL_EXTERN_AGAIN(__cthread_fork_parent)
 163         li32    r3,-1                   // error return
 164 Lreturn:        RETURN
 165 END(_vfork)
 166 #else
 167 #include "SYS.h"
 168
 169 LEAF(_vfork)
 170 #if defined(__DYNAMIC__)
 171         PICIFY(__current_pid)
 172         mr      r5,PICIFY_REG
 173         NON_LAZY_STUB(__current_pid)
 174 #else
 175         lis     r5,ha16(__current_pid)
 176         ori     r5,r5,lo16(__current_pid)
 177 #endif
 178 2:
 179         lwarx   r6,0,r5                 // dont cache pid across vfork
 180         cmpwi   r6,0
 181         ble-    3f                      // is another vfork in progress
 182         li      r6,0                    // if not, erase the stored pid
 183 3:
 184         addi    r6,r6,-1                // count the parallel vforks in
 185         stwcx.  r6,0,r5                 // negative cached pid values
 186         bne-    2b
 187
 188         li      r0,SYS_vfork
 189         sc
 190         b       Lbotch                  // error return
 191
 192         cmpwi   r4,0
 193         beq     Lparent                 // parent, since a1 == 0 in parent,
 194
 195         li      r3,0                    // child
 196         blr
 197
 198 Lparent:
 199         lwarx   r6,0,r5                 // were back, decrement vfork count
 200         addi    r6,r6,1
 201         stwcx.  r6,0,r5
 202         bne-    Lparent
 203         blr
 204
 205 Lbotch:
 206         lwarx   r6,0,r5                 // never went, decrement vfork count
 207         addi    r6,r6,1
 208         stwcx.  r6,0,r5
 209         bne-    Lbotch
 210
 211         BRANCH_EXTERN(cerror)
 212 END(_vfork)
 213 #endif
 214