| /* Copyright (C) 1996-2014 Free Software Foundation, Inc. |
| |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* clone() is even more special than fork() as it mucks with stacks |
| and invokes a function in the right context after its all over. */ |
| |
| #include <sysdep.h> |
| #define _ERRNO_H 1 |
| #include <bits/errno.h> |
| |
| #define CLONE_VM_BIT 8 |
| #define CLONE_VM (1 << CLONE_VM_BIT) |
| |
| #define CLONE_THREAD_BIT 16 |
| #define CLONE_THREAD (1 << CLONE_THREAD_BIT) |
| |
| /* int clone(int (*fn)(void *arg), x0 |
| void *child_stack, x1 |
| int flags, x2 |
| void *arg, x3 |
| pid_t *ptid, x4 |
| struct user_desc *tls, x5 |
| pid_t *ctid); x6 |
| */ |
| .text |
| ENTRY(__clone) |
| /* Sanity check args. */ |
| cbz x0, 1f |
| cbz x1, 1f |
| /* Insert the args onto the new stack. */ |
| stp x0, x3, [x1, #-16]! /* Fn, arg. */ |
| |
| /* Do the system call. */ |
| mov x0, x2 /* flags */ |
| |
| /* New sp is already in x1. */ |
| mov x2, x4 /* ptid */ |
| mov x3, x5 /* tls */ |
| mov x4, x6 /* ctid */ |
| |
| #ifdef RESET_PID |
| /* We rely on the kernel preserving the argument regsiters across a |
| each system call so that we can inspect the flags against after |
| the clone call. */ |
| mov x5, x0 |
| #endif |
| |
| mov x8, #SYS_ify(clone) |
| /* X0:flags, x1:newsp, x2:parenttidptr, x3:newtls, x4:childtid. */ |
| svc 0x0 |
| cfi_endproc |
| cmp x0, #0 |
| beq 2f |
| blt 3f |
| RET |
| 1: mov x0, #-EINVAL |
| 3: |
| b syscall_error |
| |
| 2: |
| cfi_startproc |
| cfi_undefined (x30) |
| mov x29, 0 |
| #ifdef RESET_PID |
| tbnz x5, #CLONE_THREAD_BIT, 3f |
| mov x0, #-1 |
| tbnz x5, #CLONE_VM_BIT, 2f |
| mov x8, #SYS_ify(getpid) |
| svc 0x0 |
| 2: |
| mrs x1, tpidr_el0 |
| sub x1, x1, #PTHREAD_SIZEOF |
| str w0, [x1, #PTHREAD_PID_OFFSET] |
| str w0, [x1, #PTHREAD_TID_OFFSET] |
| |
| 3: |
| #endif |
| /* Pick the function arg and call address from the stack and |
| execute. */ |
| ldp x1, x0, [sp], #16 |
| blr x1 |
| |
| /* We are done, pass the return value through x0. */ |
| b HIDDEN_JUMPTARGET(_exit) |
| cfi_endproc |
| cfi_startproc |
| PSEUDO_END (__clone) |
| |
| weak_alias (__clone, clone) |
