| Elliott Hughes | ebc19a9 | 2022-10-14 23:25:36 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2020 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 <platform/bionic/tls_defines.h> |
| 30 | #include <private/bionic_asm.h> |
| 31 | #include <asm/signal.h> |
| 32 | #include <linux/sched.h> |
| 33 | |
| 34 | ENTRY(vfork) |
| 35 | // t0 = __get_tls()[TLS_SLOT_THREAD_ID] |
| 36 | mv t0, tp |
| 37 | ld t0, TLS_SLOT_THREAD_ID * 8(t0) |
| 38 | |
| 39 | // Set cached_pid_ to 0, vforked_ to 1, and stash the previous value. |
| 40 | li t1, 0x80000000 |
| 41 | lw t2, 20(t0) |
| 42 | sw t1, 20(t0) |
| 43 | |
| 44 | li a0, (CLONE_VM | CLONE_VFORK | SIGCHLD) |
| 45 | li a1, 0 //uses a duplicate of the parent's stack |
| 46 | li a2, 0 |
| 47 | li a3, 0 |
| 48 | li a4, 0 |
| 49 | |
| 50 | li a7, __NR_clone |
| 51 | ecall |
| 52 | |
| 53 | // if (rc == 0) we're the child, and finished... |
| 54 | beqz a0, .L_success |
| 55 | |
| 56 | // else if (rc != 0): reset cached_pid_ and vforked_... |
| 57 | sw t2, 20(t0) |
| 58 | // ...and work out whether we succeeded or failed. |
| 59 | bltz a0, .L_failure |
| 60 | .L_success: |
| 61 | ret |
| 62 | |
| 63 | .L_failure: |
| 64 | neg a0, a0 |
| 65 | j __set_errno_internal |
| 66 | END(vfork) |