sysdeps/unix/sysv/linux/sh/clone.S

   1 /* Copyright (C) 1999-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 /* clone() is even more special than fork() as it mucks with stacks
  19    and invokes a function in the right context after its all over.  */
  20
  21 #include <sysdep.h>
  22 #define _ERRNO_H        1
  23 #include <bits/errno.h>
  24 #ifdef RESET_PID
  25 #include <tcb-offsets.h>
  26 #endif
  27 /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
  28              pid_t *ptid, void *tls, pid_t *ctid); */
  29
  30         .text
  31 ENTRY(__clone)
  32         /* sanity check arguments.  */
  33         tst     r4, r4
  34         bt/s    0f
  35          tst    r5, r5
  36         bf      1f
  37 0:
  38         bra     .Lsyscall_error
  39          mov    #-EINVAL,r0
  40 1:
  41         /* insert the args onto the new stack */
  42         mov.l   r7, @-r5
  43         /* save the function pointer as the 0th element */
  44         mov.l   r4, @-r5
  45
  46         /* do the system call */
  47         mov     r6, r4
  48         mov.l   @r15, r6
  49         mov.l   @(8,r15), r7
  50         mov.l   @(4,r15), r0
  51         mov     #+SYS_ify(clone), r3
  52         trapa   #0x15
  53         mov     r0, r1
  54         mov     #-12, r2
  55         shad    r2, r1
  56         not     r1, r1                  // r1=0 means r0 = -1 to -4095
  57         tst     r1, r1                  // i.e. error in linux
  58         bf      .Lclone_end
  59 .Lsyscall_error:
  60         SYSCALL_ERROR_HANDLER
  61 .Lclone_end:
  62         tst     r0, r0
  63         bt      2f
  64 .Lpseudo_end:
  65         rts
  66          nop
  67 2:
  68         /* terminate the stack frame */
  69         mov     #0, r14
  70 #ifdef RESET_PID
  71         mov     r4, r0
  72         shlr16  r0
  73         tst     #1, r0                  // CLONE_THREAD = (1 << 16)
  74         bf/s    4f
  75          mov    r4, r0
  76         /* new pid */
  77         shlr8   r0
  78         tst     #1, r0                  // CLONE_VM = (1 << 8)
  79         bf/s    3f
  80          mov    #-1, r0
  81         mov     #+SYS_ify(getpid), r3
  82         trapa   #0x15
  83 3:
  84         stc     gbr, r1
  85         mov.w   .Lpidoff, r2
  86         add     r1, r2
  87         mov.l   r0, @r2
  88         mov.w   .Ltidoff, r2
  89         add     r1, r2
  90         mov.l   r0, @r2
  91 4:
  92 #endif
  93         /* thread starts */
  94         mov.l   @r15, r1
  95         jsr     @r1
  96          mov.l  @(4,r15), r4
  97
  98         /* we are done, passing the return value through r0  */
  99         mov.l   .L3, r1
 100 #ifdef SHARED
 101         mov.l   r12, @-r15
 102         sts.l   pr, @-r15
 103         mov     r0, r4
 104         mova    .LG, r0
 105         mov.l   .LG, r12
 106         add     r0, r12
 107         mova    .L3, r0
 108         add     r0, r1
 109         jsr     @r1
 110          nop
 111         lds.l   @r15+, pr
 112         rts
 113          mov.l  @r15+, r12
 114 #else
 115         jmp     @r1
 116          mov    r0, r4
 117 #endif
 118         .align  2
 119 .LG:
 120         .long   _GLOBAL_OFFSET_TABLE_
 121 .L3:
 122         .long   PLTJMP(C_SYMBOL_NAME(_exit))
 123 #ifdef RESET_PID
 124 .Lpidoff:
 125         .word   PID - TLS_PRE_TCB_SIZE
 126 .Ltidoff:
 127         .word   TID - TLS_PRE_TCB_SIZE
 128 #endif
 129 PSEUDO_END (__clone)
 130
 131 weak_alias (__clone, clone)