projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| d4697bc9 | 1 | /* Copyright (C) 1996-2014 Free Software Foundation, Inc. |
| 554066b8 MS |
2 | |
| 3 | This file is part of the GNU C Library. | |
| 4 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | |
| 6 | modify it under the terms of the GNU Lesser General Public | |
| 7 | License as published by the Free Software Foundation; either | |
| 8 | version 2.1 of the License, or (at your option) any later version. | |
| 9 | ||
| 10 | The GNU C Library is distributed in the hope that it will be useful, | |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 | Lesser General Public License for more details. | |
| 14 | ||
| 15 | You should have received a copy of the GNU Lesser General Public | |
| 16 | License along with the GNU C Library; if not, see | |
| 17 | <http://www.gnu.org/licenses/>. */ | |
| 18 | ||
| 19 | /* clone() is even more special than fork() as it mucks with stacks | |
| 20 | and invokes a function in the right context after its all over. */ | |
| 21 | ||
| 22 | #include <sysdep.h> | |
| 23 | #define _ERRNO_H 1 | |
| 24 | #include <bits/errno.h> | |
| 25 | ||
| 26 | #define CLONE_VM_BIT 8 | |
| 27 | #define CLONE_VM (1 << CLONE_VM_BIT) | |
| 28 | ||
| 29 | #define CLONE_THREAD_BIT 16 | |
| 30 | #define CLONE_THREAD (1 << CLONE_THREAD_BIT) | |
| 31 | ||
| 32 | /* int clone(int (*fn)(void *arg), x0 | |
| 33 | void *child_stack, x1 | |
| 34 | int flags, x2 | |
| 35 | void *arg, x3 | |
| 36 | pid_t *ptid, x4 | |
| 37 | struct user_desc *tls, x5 | |
| 38 | pid_t *ctid); x6 | |
| 39 | */ | |
| 40 | .text | |
| 41 | ENTRY(__clone) | |
| 42 | /* Sanity check args. */ | |
| 43 | cbz x0, 1f | |
| 44 | cbz x1, 1f | |
| 45 | /* Insert the args onto the new stack. */ | |
| 46 | stp x0, x3, [x1, #-16]! /* Fn, arg. */ | |
| 47 | ||
| 48 | /* Do the system call. */ | |
| 49 | mov x0, x2 /* flags */ | |
| 50 | ||
| 51 | /* New sp is already in x1. */ | |
| 52 | mov x2, x4 /* ptid */ | |
| 53 | mov x3, x5 /* tls */ | |
| 54 | mov x4, x6 /* ctid */ | |
| 55 | ||
| 56 | #ifdef RESET_PID | |
| 57 | /* We rely on the kernel preserving the argument regsiters across a | |
| 58 | each system call so that we can inspect the flags against after | |
| 59 | the clone call. */ | |
| 60 | mov x5, x0 | |
| 61 | #endif | |
| 62 | ||
| 63 | mov x8, #SYS_ify(clone) | |
| 64 | /* X0:flags, x1:newsp, x2:parenttidptr, x3:newtls, x4:childtid. */ | |
| 65 | svc 0x0 | |
| 3a3acb6a | 66 | cfi_endproc |
| 554066b8 MS |
67 | cmp x0, #0 |
| 68 | beq 2f | |
| d842b144 | 69 | blt 3f |
| 554066b8 MS |
70 | RET |
| 71 | 1: mov x0, #-EINVAL | |
| d842b144 | 72 | 3: |
| 554066b8 MS |
73 | b syscall_error |
| 74 | ||
| 75 | 2: | |
| 3a3acb6a TT |
76 | cfi_startproc |
| 77 | cfi_undefined (x30) | |
| 78 | mov x29, 0 | |
| 554066b8 MS |
79 | #ifdef RESET_PID |
| 80 | tbnz x5, #CLONE_THREAD_BIT, 3f | |
| 81 | mov x0, #-1 | |
| 82 | tbnz x5, #CLONE_VM_BIT, 2f | |
| 83 | mov x8, #SYS_ify(getpid) | |
| 84 | svc 0x0 | |
| 85 | 2: | |
| 86 | mrs x1, tpidr_el0 | |
| 87 | sub x1, x1, #PTHREAD_SIZEOF | |
| 88 | str w0, [x1, #PTHREAD_PID_OFFSET] | |
| 89 | str w0, [x1, #PTHREAD_TID_OFFSET] | |
| 90 | ||
| 91 | 3: | |
| 92 | #endif | |
| 93 | /* Pick the function arg and call address from the stack and | |
| 94 | execute. */ | |
| 95 | ldp x1, x0, [sp], #16 | |
| 96 | blr x1 | |
| 97 | ||
| 98 | /* We are done, pass the return value through x0. */ | |
| 99 | b HIDDEN_JUMPTARGET(_exit) | |
| 3a3acb6a TT |
100 | cfi_endproc |
| 101 | cfi_startproc | |
| 554066b8 MS |
102 | PSEUDO_END (__clone) |
| 103 | ||
| 104 | weak_alias (__clone, clone) |