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1da177e4 LT |
1 | /* kernel_thread.S: kernel thread creation |
2 | * | |
3 | * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/linkage.h> | |
13 | #include <asm/unistd.h> | |
14 | ||
15 | #define CLONE_VM 0x00000100 /* set if VM shared between processes */ | |
16 | #define KERN_ERR "<3>" | |
17 | ||
18 | .section .rodata | |
19 | kernel_thread_emsg: | |
20 | .asciz KERN_ERR "failed to create kernel thread: error=%d\n" | |
21 | ||
22 | .text | |
23 | .balign 4 | |
24 | ||
25 | ############################################################################### | |
26 | # | |
27 | # Create a kernel thread | |
28 | # | |
29 | # int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) | |
30 | # | |
31 | ############################################################################### | |
32 | .globl kernel_thread | |
33 | .type kernel_thread,@function | |
34 | kernel_thread: | |
35 | or.p gr8,gr0,gr4 | |
36 | or gr9,gr0,gr5 | |
37 | ||
38 | # start by forking the current process, but with shared VM | |
39 | setlos.p #__NR_clone,gr7 ; syscall number | |
40 | ori gr10,#CLONE_VM,gr8 ; first syscall arg [clone_flags] | |
41 | sethi.p #0xe4e4,gr9 ; second syscall arg [newsp] | |
42 | setlo #0xe4e4,gr9 | |
43 | setlos.p #0,gr10 ; third syscall arg [parent_tidptr] | |
44 | setlos #0,gr11 ; fourth syscall arg [child_tidptr] | |
45 | tira gr0,#0 | |
46 | setlos.p #4095,gr7 | |
47 | andcc gr8,gr8,gr0,icc0 | |
48 | addcc.p gr8,gr7,gr0,icc1 | |
49 | bnelr icc0,#2 | |
50 | bc icc1,#0,kernel_thread_error | |
51 | ||
52 | # now invoke the work function | |
53 | or gr5,gr0,gr8 | |
54 | calll @(gr4,gr0) | |
55 | ||
56 | # and finally exit the thread | |
57 | setlos #__NR_exit,gr7 ; syscall number | |
58 | tira gr0,#0 | |
59 | ||
60 | kernel_thread_error: | |
61 | subi sp,#8,sp | |
62 | movsg lr,gr4 | |
63 | sti gr8,@(sp,#0) | |
64 | sti.p gr4,@(sp,#4) | |
65 | ||
66 | or gr8,gr0,gr9 | |
67 | sethi.p %hi(kernel_thread_emsg),gr8 | |
68 | setlo %lo(kernel_thread_emsg),gr8 | |
69 | ||
70 | call printk | |
71 | ||
72 | ldi @(sp,#4),gr4 | |
73 | ldi @(sp,#0),gr8 | |
74 | subi sp,#8,sp | |
75 | jmpl @(gr4,gr0) | |
76 | ||
77 | .size kernel_thread,.-kernel_thread |