1 | /* Copyright (C) 1996-2024 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library. If not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | /* clone() is even more special than fork() as it mucks with stacks |
19 | and invokes a function in the right context after its all over. */ |
20 | |
21 | #include <sysdep.h> |
22 | #define _ERRNO_H 1 |
23 | #include <bits/errno.h> |
24 | |
25 | /* int clone(int (*fn)(void *arg), void *child_stack, int flags, |
26 | void *arg, pid_t *ptid, void *tls, pid_t *ctid); |
27 | |
28 | Note that everything past ARG is technically optional, based |
29 | on FLAGS, and that CTID is arg 7, and thus is on the stack. |
30 | However, since a load from top-of-stack better be legal always, |
31 | we don't bother checking FLAGS. */ |
32 | |
33 | .text |
34 | .align 4 |
35 | .globl __clone |
36 | .ent __clone |
37 | .usepv __clone, USEPV_PROF |
38 | |
39 | cfi_startproc |
40 | __clone: |
41 | #ifdef PROF |
42 | .set noat |
43 | ldgp gp,0(pv) |
44 | lda AT, _mcount |
45 | jsr AT, (AT), _mcount |
46 | .set at |
47 | #endif |
48 | |
49 | /* Sanity check arguments. */ |
50 | ldiq v0, EINVAL |
51 | beq a0, SYSCALL_ERROR_LABEL /* no NULL function pointers */ |
52 | beq a1, SYSCALL_ERROR_LABEL /* no NULL stack pointers */ |
53 | |
54 | /* Save the fn ptr and arg on the new stack. */ |
55 | subq a1, 32, a1 |
56 | stq a0, 0(a1) |
57 | stq a3, 8(a1) |
58 | stq a2, 16(a1) |
59 | |
60 | /* The syscall is of the form clone(flags, usp, ptid, ctid, tls). |
61 | Shift the flags, ptid, ctid, tls arguments into place; the |
62 | child_stack argument is already correct. */ |
63 | mov a2, a0 |
64 | mov a4, a2 |
65 | ldq a3, 0(sp) |
66 | mov a5, a4 |
67 | |
68 | /* Do the system call. */ |
69 | ldiq v0, __NR_clone |
70 | call_pal PAL_callsys |
71 | |
72 | bne a3, SYSCALL_ERROR_LABEL |
73 | beq v0, thread_start |
74 | |
75 | /* Successful return from the parent. */ |
76 | ret |
77 | |
78 | PSEUDO_END(__clone) |
79 | cfi_endproc |
80 | |
81 | /* Load up the arguments to the function. Put this block of code in |
82 | its own function so that we can terminate the stack trace with our |
83 | debug info. */ |
84 | |
85 | .align 4 |
86 | .ent thread_start |
87 | cfi_startproc |
88 | thread_start: |
89 | mov 0, fp |
90 | cfi_def_cfa_register(fp) |
91 | cfi_undefined(ra) |
92 | |
93 | /* Load up the arguments. */ |
94 | ldq pv, 0(sp) |
95 | ldq a0, 8(sp) |
96 | addq sp, 32, sp |
97 | |
98 | /* Call the user's function. */ |
99 | jsr ra, (pv) |
100 | ldgp gp, 0(ra) |
101 | |
102 | mov v0, a0 |
103 | ldiq v0, __NR_exit |
104 | call_pal PAL_callsys |
105 | |
106 | /* Die horribly. */ |
107 | .align 4 |
108 | halt |
109 | |
110 | .align 4 |
111 | cfi_endproc |
112 | .end thread_start |
113 | |
114 | libc_hidden_def (__clone) |
115 | weak_alias (__clone, clone) |
116 | |