1/* Copyright (C) 1996-2022 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 <sys/asm.h>
22#include <sysdep.h>
23#define _ERRNO_H 1
24#include <bits/errno.h>
25#include <tls.h>
26
27/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
28 void *parent_tidptr, void *tls, void *child_tidptr) */
29
30 .text
31 .set nomips16
32#if _MIPS_SIM == _ABIO32
33# define EXTRA_LOCALS 1
34#else
35# define EXTRA_LOCALS 0
36#endif
37LOCALSZ= 4
38FRAMESZ= (((NARGSAVE+LOCALSZ)*SZREG)+ALSZ)&ALMASK
39GPOFF= FRAMESZ-(1*SZREG)
40NESTED(__clone,4*SZREG,sp)
41#ifdef __PIC__
42 SETUP_GP
43#endif
44 PTR_SUBU sp, FRAMESZ
45 cfi_adjust_cfa_offset (FRAMESZ)
46 SETUP_GP64_STACK (GPOFF, __clone)
47#ifdef __PIC__
48 SAVE_GP (GPOFF)
49#endif
50#ifdef PROF
51 .set noat
52 move $1,ra
53 jal _mcount
54 .set at
55#endif
56
57 /* Align stack to 8/16 bytes per the ABI. */
58#if _MIPS_SIM == _ABIO32
59 li t0,-8
60#else
61 li t0,-16
62#endif
63 and a1,a1,t0
64
65 /* Sanity check arguments. */
66 li v0,EINVAL
67 beqz a0,L(error) /* No NULL function pointers. */
68 beqz a1,L(error) /* No NULL stack pointers. */
69
70 PTR_SUBU a1,32 /* Reserve argument save space. */
71 PTR_S a0,0(a1) /* Save function pointer. */
72 PTR_S a3,PTRSIZE(a1) /* Save argument pointer. */
73 LONG_S a2,(PTRSIZE*2)(a1) /* Save clone flags. */
74
75 move a0,a2
76
77 /* Shuffle in the last three arguments - arguments 5, 6, and 7 to
78 this function, but arguments 3, 4, and 5 to the syscall. */
79#if _MIPS_SIM == _ABIO32
80 PTR_L a2,(FRAMESZ+PTRSIZE+PTRSIZE+16)(sp)
81 PTR_S a2,16(sp)
82 PTR_L a2,(FRAMESZ+16)(sp)
83 PTR_L a3,(FRAMESZ+PTRSIZE+16)(sp)
84#else
85 move a2,a4
86 move a3,a5
87 move a4,a6
88#endif
89
90 /* Do the system call */
91 li v0,__NR_clone
92 cfi_endproc
93 syscall
94
95 bnez a3,L(error)
96 beqz v0,L(thread_start)
97
98 /* Successful return from the parent */
99 cfi_startproc
100 cfi_adjust_cfa_offset (FRAMESZ)
101 SETUP_GP64_STACK_CFI (GPOFF)
102 cfi_remember_state
103 RESTORE_GP64_STACK
104 PTR_ADDU sp, FRAMESZ
105 cfi_adjust_cfa_offset (-FRAMESZ)
106 ret
107
108 /* Something bad happened -- no child created */
109L(error):
110 cfi_restore_state
111#ifdef __PIC__
112 PTR_LA t9,__syscall_error
113 RESTORE_GP64_STACK
114 PTR_ADDU sp, FRAMESZ
115 cfi_adjust_cfa_offset (-FRAMESZ)
116 jr t9
117#else
118 RESTORE_GP64_STACK
119 PTR_ADDU sp, FRAMESZ
120 cfi_adjust_cfa_offset (-FRAMESZ)
121 j __syscall_error
122#endif
123 END(__clone)
124
125/* Load up the arguments to the function. Put this block of code in
126 its own function so that we can terminate the stack trace with our
127 debug info. */
128
129ENTRY(__thread_start)
130L(thread_start):
131 cfi_undefined ($31)
132 /* cp is already loaded. */
133 SAVE_GP (GPOFF)
134 /* The stackframe has been created on entry of clone(). */
135
136 /* Restore the arg for user's function. */
137 PTR_L t9,0(sp) /* Function pointer. */
138 PTR_L a0,PTRSIZE(sp) /* Argument pointer. */
139
140 /* Call the user's function. */
141 jal t9
142
143 move a0,v0
144 li v0,__NR_exit
145 syscall
146
147 END(__thread_start)
148
149libc_hidden_def (__clone)
150weak_alias (__clone, clone)
151

source code of glibc/sysdeps/unix/sysv/linux/mips/clone.S