1 | /* The clone3 syscall wrapper. Linux/arc version. |
2 | Copyright (C) 2023-2024 Free Software Foundation, Inc. |
3 | |
4 | This file is part of the GNU C Library. |
5 | |
6 | The GNU C Library is free software; you can redistribute it and/or |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either |
9 | version 2.1 of the License, or (at your option) any later version. |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | Lesser General Public License for more details. |
15 | |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; if not, see |
18 | <https://www.gnu.org/licenses/>. */ |
19 | |
20 | #include <sysdep.h> |
21 | #define _ERRNO_H 1 |
22 | #include <bits/errno.h> |
23 | |
24 | /* The userland implementation is: |
25 | int clone3 (struct clone_args *cl_args, size_t size, |
26 | int (*func)(void *arg), void *arg); |
27 | |
28 | the kernel entry is: |
29 | int clone3 (struct clone_args *cl_args, size_t size); |
30 | |
31 | The parameters are passed in registers from userland: |
32 | r0: cl_args |
33 | r1: size |
34 | r2: func |
35 | r3: arg */ |
36 | |
37 | ENTRY(__clone3) |
38 | |
39 | /* Save args for the child. */ |
40 | mov r10, r0 /* cl_args */ |
41 | mov r11, r2 /* func */ |
42 | mov r12, r3 /* args */ |
43 | |
44 | /* Sanity check args. */ |
45 | breq r10, 0, L (__sys_err) /* No NULL cl_args pointer. */ |
46 | breq r11, 0, L (__sys_err) /* No NULL function pointer. */ |
47 | |
48 | /* Do the system call, the kernel expects: |
49 | r8: system call number |
50 | r0: cl_args |
51 | r1: size */ |
52 | mov r0, r10 |
53 | mov r8, __NR_clone3 |
54 | ARC_TRAP_INSN |
55 | |
56 | cmp r0, 0 |
57 | beq thread_start_clone3 /* Child returns. */ |
58 | blt L (__sys_err2) |
59 | j [blink] /* Parent returns. */ |
60 | |
61 | L (__sys_err): |
62 | mov r0, -EINVAL |
63 | L (__sys_err2): |
64 | b __syscall_error |
65 | PSEUDO_END (__clone3) |
66 | |
67 | |
68 | .align 4 |
69 | .type thread_start_clone3, %function |
70 | thread_start_clone3: |
71 | cfi_startproc |
72 | /* Terminate call stack by noting ra is undefined. */ |
73 | cfi_undefined (blink) |
74 | |
75 | /* Child jumps off to @fn with @arg as argument. */ |
76 | jl.d [r11] |
77 | mov r0, r12 |
78 | |
79 | /* exit() with result from @fn (already in r0). */ |
80 | mov r8, __NR_exit |
81 | ARC_TRAP_INSN |
82 | |
83 | /* In case it ever came back. */ |
84 | flag 1 |
85 | |
86 | cfi_endproc |
87 | .size thread_start_clone3, .-thread_start_clone3 |
88 | |
89 | libc_hidden_def (__clone3) |
90 | weak_alias (__clone3, clone3) |
91 | |