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1 | /* Copyright (C) 1996, 1997, 2000 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. | |
3 | Contributed by David Huggins-Daines <dhd@debian.org>, 2000. | |
4 | Based on the Alpha version by Richard Henderson <rth@tamu.edu>, 1996. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
3214b89b AJ |
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. | |
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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 | |
3214b89b | 14 | Lesser General Public License for more details. |
b35e2407 | 15 | |
3214b89b AJ |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; if not, write to the Free | |
18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
19 | 02111-1307 USA. */ | |
b35e2407 UD |
20 | |
21 | /* clone() is even more special than fork() as it mucks with stacks | |
22 | and invokes a function in the right context after its all over. */ | |
23 | ||
24 | #include <asm/unistd.h> | |
25 | #include <sysdep.h> | |
26 | #define _ERRNO_H 1 | |
27 | #include <bits/errno.h> | |
28 | ||
a29e6e84 CD |
29 | /* Non-thread code calls __clone with the following parameters: |
30 | int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg) | |
31 | ||
32 | NPTL Code will call __clone with the following parameters: | |
33 | int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, | |
34 | int *parent_tidptr, struct user_desc *newtls, int *child_pidptr) | |
35 | ||
36 | The code should not mangle the extra input registers. | |
37 | Syscall expects: Input to __clone: | |
38 | 4(r25) - function pointer (r26, arg0) | |
39 | 0(r25) - argument (r23, arg3) | |
40 | r26 - clone flags. (r24, arg2) | |
41 | r25+64 - user stack pointer. (r25, arg1) | |
42 | r24 - parent tid pointer. (stack - 52) | |
43 | r23 - struct user_desc newtls pointer. (stack - 56) | |
44 | r22 - child tid pointer. (stack - 60) | |
45 | r20 - clone syscall number (constant) | |
46 | */ | |
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47 | |
48 | .text | |
49 | ENTRY(__clone) | |
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50 | |
51 | /* Sanity check arguments. */ | |
15a25bb6 | 52 | ldi -EINVAL,%ret0 |
a29e6e84 CD |
53 | comib,=,n 0,%arg0,.Lerror /* no NULL function pointers */ |
54 | comib,=,n 0,%arg1,.Lerror /* no NULL stack pointers */ | |
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55 | |
56 | /* Save the fn ptr and arg on the new stack. */ | |
a29e6e84 CD |
57 | stwm %r26,64(%r25) |
58 | stw %r23,-60(%r25) | |
59 | /* Clone arguments are (int flags, void * child_stack) */ | |
60 | copy %r24,%r26 /* flags are first */ | |
61 | /* User stack pointer is in the correct register already */ | |
62 | ||
63 | /* Load args from stack... */ | |
64 | ldw -52(%sp), %r24 /* Load parent_tidptr */ | |
65 | ldw -56(%sp), %r23 /* Load newtls */ | |
66 | ldw -60(%sp), %r22 /* Load child_tidptr */ | |
67 | ||
68 | /* Create frame to get r3 free */ | |
69 | copy %sp, %r21 | |
70 | stwm %r3, 64(%sp) | |
71 | stw %r21, -4(%sp) | |
b35e2407 | 72 | |
46bf1d81 UD |
73 | /* Save the PIC register. */ |
74 | #ifdef PIC | |
a29e6e84 | 75 | copy %r19, %r3 /* parent */ |
46bf1d81 UD |
76 | #endif |
77 | ||
b35e2407 | 78 | /* Do the system call */ |
15a25bb6 | 79 | ble 0x100(%sr2,%r0) |
b35e2407 UD |
80 | ldi __NR_clone,%r20 |
81 | ||
82 | ldi -4096,%r1 | |
83 | comclr,>>= %r1,%ret0,%r0 /* Note: unsigned compare. */ | |
a29e6e84 | 84 | b,n .LerrorRest |
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85 | |
86 | comib,=,n 0,%ret0,thread_start | |
87 | ||
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88 | /* Successful return from the parent |
89 | No need to restore the PIC register, | |
90 | since we return immediately. */ | |
91 | ||
b35e2407 | 92 | bv %r0(%rp) |
a29e6e84 | 93 | ldwm -64(%sp), %r3 |
46bf1d81 | 94 | |
a29e6e84 | 95 | .LerrorRest |
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96 | /* Restore the PIC register on error */ |
97 | #ifdef PIC | |
a29e6e84 | 98 | copy %r3, %r19 /* parent */ |
46bf1d81 UD |
99 | #endif |
100 | ||
a29e6e84 CD |
101 | /* Something bad happened -- no child created */ |
102 | .Lerror: | |
103 | ||
104 | /* Set errno, save ret0 so we return with that value. */ | |
105 | copy %ret0, %r3 | |
b35e2407 | 106 | b __syscall_error |
15a25bb6 | 107 | sub %r0,%ret0,%arg0 |
a29e6e84 CD |
108 | copy %r3, %ret0 |
109 | /* Return after setting errno, and restoring ret0 */ | |
110 | bv %r0(%rp) | |
111 | ldwm -64(%sp), %r3 | |
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112 | |
113 | thread_start: | |
46bf1d81 | 114 | |
b35e2407 | 115 | /* Load up the arguments. */ |
46bf1d81 UD |
116 | ldw -60(%sr0, %sp),%arg0 |
117 | ldw -64(%sr0, %sp),%r22 | |
118 | ||
119 | /* $$dyncall fixes childs PIC register */ | |
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120 | |
121 | /* Call the user's function */ | |
122 | bl $$dyncall,%r31 | |
123 | copy %r31,%rp | |
124 | ||
125 | bl _exit,%rp | |
126 | copy %ret0,%arg0 | |
127 | ||
128 | /* Die horribly. */ | |
a29e6e84 | 129 | iitlbp %r0,(%sr0,%r0) |
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130 | |
131 | PSEUDO_END(__clone) | |
132 | ||
8796ce21 | 133 | weak_alias (__clone, clone) |