1 /*
2  * SPU file system -- system call stubs
3  *
4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
5  * (C) Copyright 2006-2007, IBM Corporation
6  *
7  * Author: Arnd Bergmann <arndb@de.ibm.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2, or (at your option)
12  * any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22  */
23 #include <linux/file.h>
24 #include <linux/fs.h>
25 #include <linux/module.h>
26 #include <linux/syscalls.h>
27 #include <linux/rcupdate.h>
28 #include <linux/binfmts.h>
29 
30 #include <asm/spu.h>
31 
32 /* protected by rcu */
33 static struct spufs_calls *spufs_calls;
34 
35 #ifdef CONFIG_SPU_FS_MODULE
36 
37 static inline struct spufs_calls *spufs_calls_get(void)
38 {
39 	struct spufs_calls *calls = NULL;
40 
41 	rcu_read_lock();
42 	calls = rcu_dereference(spufs_calls);
43 	if (calls && !try_module_get(calls->owner))
44 		calls = NULL;
45 	rcu_read_unlock();
46 
47 	return calls;
48 }
49 
50 static inline void spufs_calls_put(struct spufs_calls *calls)
51 {
52 	BUG_ON(calls != spufs_calls);
53 
54 	/* we don't need to rcu this, as we hold a reference to the module */
55 	module_put(spufs_calls->owner);
56 }
57 
58 #else /* !defined CONFIG_SPU_FS_MODULE */
59 
60 static inline struct spufs_calls *spufs_calls_get(void)
61 {
62 	return spufs_calls;
63 }
64 
65 static inline void spufs_calls_put(struct spufs_calls *calls) { }
66 
67 #endif /* CONFIG_SPU_FS_MODULE */
68 
69 SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
70 	umode_t, mode, int, neighbor_fd)
71 {
72 	long ret;
73 	struct spufs_calls *calls;
74 
75 	calls = spufs_calls_get();
76 	if (!calls)
77 		return -ENOSYS;
78 
79 	if (flags & SPU_CREATE_AFFINITY_SPU) {
80 		struct fd neighbor = fdget(neighbor_fd);
81 		ret = -EBADF;
82 		if (neighbor.file) {
83 			ret = calls->create_thread(name, flags, mode, neighbor.file);
84 			fdput(neighbor);
85 		}
86 	} else
87 		ret = calls->create_thread(name, flags, mode, NULL);
88 
89 	spufs_calls_put(calls);
90 	return ret;
91 }
92 
93 asmlinkage long sys_spu_run(int fd, __u32 __user *unpc, __u32 __user *ustatus)
94 {
95 	long ret;
96 	struct fd arg;
97 	struct spufs_calls *calls;
98 
99 	calls = spufs_calls_get();
100 	if (!calls)
101 		return -ENOSYS;
102 
103 	ret = -EBADF;
104 	arg = fdget(fd);
105 	if (arg.file) {
106 		ret = calls->spu_run(arg.file, unpc, ustatus);
107 		fdput(arg);
108 	}
109 
110 	spufs_calls_put(calls);
111 	return ret;
112 }
113 
114 int elf_coredump_extra_notes_size(void)
115 {
116 	struct spufs_calls *calls;
117 	int ret;
118 
119 	calls = spufs_calls_get();
120 	if (!calls)
121 		return 0;
122 
123 	ret = calls->coredump_extra_notes_size();
124 
125 	spufs_calls_put(calls);
126 
127 	return ret;
128 }
129 
130 int elf_coredump_extra_notes_write(struct coredump_params *cprm)
131 {
132 	struct spufs_calls *calls;
133 	int ret;
134 
135 	calls = spufs_calls_get();
136 	if (!calls)
137 		return 0;
138 
139 	ret = calls->coredump_extra_notes_write(cprm);
140 
141 	spufs_calls_put(calls);
142 
143 	return ret;
144 }
145 
146 void notify_spus_active(void)
147 {
148 	struct spufs_calls *calls;
149 
150 	calls = spufs_calls_get();
151 	if (!calls)
152 		return;
153 
154 	calls->notify_spus_active();
155 	spufs_calls_put(calls);
156 
157 	return;
158 }
159 
160 int register_spu_syscalls(struct spufs_calls *calls)
161 {
162 	if (spufs_calls)
163 		return -EBUSY;
164 
165 	rcu_assign_pointer(spufs_calls, calls);
166 	return 0;
167 }
168 EXPORT_SYMBOL_GPL(register_spu_syscalls);
169 
170 void unregister_spu_syscalls(struct spufs_calls *calls)
171 {
172 	BUG_ON(spufs_calls->owner != calls->owner);
173 	RCU_INIT_POINTER(spufs_calls, NULL);
174 	synchronize_rcu();
175 }
176 EXPORT_SYMBOL_GPL(unregister_spu_syscalls);
177