| 1 | /* The clone3 syscall wrapper. Linux/aarch64 version. |
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| 2 | Copyright (C) 2023-2024 Free Software Foundation, Inc. |
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| 3 | |
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| 4 | This file is part of the GNU C Library. |
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| 5 | |
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| 6 | The GNU C Library is free software; you can redistribute it and/or |
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| 7 | modify it under the terms of the GNU Lesser General Public |
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| 8 | License as published by the Free Software Foundation; either |
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| 9 | version 2.1 of the License, or (at your option) any later version. |
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| 10 | |
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| 11 | The GNU C Library is distributed in the hope that it will be useful, |
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 14 | Lesser General Public License for more details. |
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| 15 | |
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| 16 | You should have received a copy of the GNU Lesser General Public |
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| 17 | License along with the GNU C Library; if not, see |
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| 18 | <https://www.gnu.org/licenses/>. */ |
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| 19 | |
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| 20 | #include <sysdep.h> |
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| 21 | #define _ERRNO_H 1 |
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| 22 | #include <bits/errno.h> |
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| 23 | |
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| 24 | /* The userland implementation is: |
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| 25 | int clone3 (struct clone_args *cl_args, size_t size, |
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| 26 | int (*func)(void *arg), void *arg); |
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| 27 | |
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| 28 | the kernel entry is: |
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| 29 | int clone3 (struct clone_args *cl_args, size_t size); |
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| 30 | |
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| 31 | The parameters are passed in registers from userland: |
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| 32 | x0: cl_args |
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| 33 | x1: size |
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| 34 | x2: func |
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| 35 | x3: arg */ |
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| 36 | |
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| 37 | .text |
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| 38 | ENTRY(__clone3) |
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| 39 | PTR_ARG (0) |
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| 40 | PTR_ARG (1) |
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| 41 | PTR_ARG (3) |
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| 42 | PTR_ARG (4) |
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| 43 | /* Save args for the child. */ |
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| 44 | mov x10, x0 /* cl_args */ |
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| 45 | mov x11, x2 /* func */ |
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| 46 | mov x12, x3 /* args */ |
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| 47 | |
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| 48 | /* Sanity check args. */ |
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| 49 | mov x0, #-EINVAL |
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| 50 | cbz x10, .Lsyscall_error /* No NULL cl_args pointer. */ |
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| 51 | cbz x2, .Lsyscall_error /* No NULL function pointer. */ |
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| 52 | |
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| 53 | /* Do the system call, the kernel expects: |
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| 54 | x8: system call number |
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| 55 | x0: cl_args |
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| 56 | x1: size */ |
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| 57 | mov x0, x10 |
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| 58 | mov x8, #SYS_ify(clone3) |
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| 59 | svc 0x0 |
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| 60 | |
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| 61 | cmp x0, #0 |
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| 62 | beq thread_start |
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| 63 | blt .Lsyscall_error |
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| 64 | RET |
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| 65 | PSEUDO_END (__clone3) |
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| 66 | |
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| 67 | .align 4 |
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| 68 | .type thread_start, %function |
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| 69 | thread_start: |
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| 70 | cfi_startproc |
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| 71 | cfi_undefined (x30) |
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| 72 | mov x29, 0 |
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| 73 | |
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| 74 | /* Pick the function arg and execute. */ |
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| 75 | mov x0, x12 |
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| 76 | blr x11 |
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| 77 | |
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| 78 | /* We are done, pass the return value through x0. */ |
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| 79 | mov x8, #SYS_ify(exit) |
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| 80 | svc 0x0 |
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| 81 | cfi_endproc |
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| 82 | .size thread_start, .-thread_start |
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| 83 | |
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| 84 | libc_hidden_def (__clone3) |
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| 85 | weak_alias (__clone3, clone3) |
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| 86 | |
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