| 1 | /* clone() implementation for Nios II. |
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| 2 | Copyright (C) 2008-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | /* clone() is even more special than fork() as it mucks with stacks |
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| 20 | and invokes a function in the right context after its all over. */ |
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| 21 | |
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| 22 | #include <sysdep.h> |
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| 23 | #define _ERRNO_H 1 |
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| 24 | #include <bits/errno.h> |
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| 25 | #include <tcb-offsets.h> |
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| 26 | |
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| 27 | /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, |
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| 28 | void *parent_tidptr, void *tls, void *child_tidptr) */ |
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| 29 | |
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| 30 | .text |
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| 31 | ENTRY(__clone) |
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| 32 | /* Sanity check arguments. */ |
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| 33 | movi r2, EINVAL |
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| 34 | /* No NULL function pointers. */ |
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| 35 | beq r4, zero, SYSCALL_ERROR_LABEL |
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| 36 | /* No NULL stack pointers. */ |
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| 37 | beq r5, zero, SYSCALL_ERROR_LABEL |
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| 38 | |
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| 39 | subi r5, r5, 8 /* Reserve argument save space. */ |
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| 40 | stw r4, 4(r5) /* Save function pointer. */ |
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| 41 | stw r7, 0(r5) /* Save argument pointer. */ |
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| 42 | |
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| 43 | /* Load arguments. */ |
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| 44 | mov r4, r6 |
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| 45 | ldw r6, 0(sp) |
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| 46 | ldw r7, 8(sp) |
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| 47 | ldw r8, 4(sp) |
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| 48 | |
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| 49 | /* Do the system call. */ |
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| 50 | movi r2, SYS_ify (clone) |
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| 51 | |
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| 52 | /* End FDE now, because in the child the unwind info will be |
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| 53 | wrong. */ |
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| 54 | cfi_endproc |
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| 55 | trap |
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| 56 | |
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| 57 | /* Check for errors. */ |
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| 58 | bne r7, zero, SYSCALL_ERROR_LABEL |
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| 59 | /* See if we're on the newly created thread. */ |
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| 60 | beq r2, zero, thread_start |
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| 61 | /* Successful return from the parent */ |
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| 62 | ret |
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| 63 | |
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| 64 | thread_start: |
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| 65 | cfi_startproc |
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| 66 | cfi_undefined (ra) |
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| 67 | |
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| 68 | ldw r5, 4(sp) /* Function pointer. */ |
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| 69 | ldw r4, 0(sp) /* Argument pointer. */ |
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| 70 | addi sp, sp, 8 |
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| 71 | |
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| 72 | /* Call the user's function. */ |
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| 73 | callr r5 |
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| 74 | |
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| 75 | /* exit with the result. */ |
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| 76 | movi r2, SYS_ify (exit) |
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| 77 | trap |
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| 78 | cfi_endproc |
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| 79 | |
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| 80 | cfi_startproc |
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| 81 | PSEUDO_END (__clone) |
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| 82 | libc_hidden_def (__clone) |
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| 83 | weak_alias (__clone, clone) |
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| 84 | |
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