1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <private/bionic_asm.h> 30 31 // pid_t __bionic_clone(int flags, void* child_stack, pid_t* parent_tid, void* tls, pid_t* child_tid, int (*fn)(void*), void* arg); 32 ENTRY_PRIVATE(__bionic_clone) 33 # Copy 'fn' and 'arg' onto the child stack. 34 movq %r9, -16(%rsi) # fn 35 movq 8(%rsp), %rax # Read 'arg'. 36 movq %rax, -8(%rsi) # Write 'arg'. 37 38 subq $16, %rsi 39 40 # Translate to the kernel calling convention and swap the 'tls' and 'child_tid' arguments. 41 # They're flipped for x86-64 compared to all our other architectures and __bionic_clone. 42 movq %r8, %r10 43 movq %rcx, %r8 44 45 # Make the system call. 46 movl $__NR_clone, %eax 47 syscall 48 49 # Check result. 50 testq %rax, %rax 51 jz .L_bc_child 52 jg .L_bc_parent 53 54 # An error occurred, set errno and return -1. 55 negl %eax 56 movl %eax, %edi 57 call __set_errno_internal 58 ret 59 60 .L_bc_child: 61 # We don't want anyone to unwind past this point. 62 .cfi_undefined %rip 63 .cfi_undefined %rbp 64 65 # We're in the child now, so call __start_thread 66 # with the arguments from the child stack moved into 67 # the appropriate registers. 68 popq %rdi # fn 69 popq %rsi # arg 70 call __start_thread 71 hlt 72 73 .L_bc_parent: 74 # We're the parent; nothing to do. 75 ret 76 END(__bionic_clone) 77
