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 
29 #include <asm/spu.h>
30 
31 /* protected by rcu */
32 static struct spufs_calls *spufs_calls;
33 
34 #ifdef CONFIG_SPU_FS_MODULE
35 
36 static inline struct spufs_calls *spufs_calls_get(void)
37 {
38 	struct spufs_calls *calls = NULL;
39 
40 	rcu_read_lock();
41 	calls = rcu_dereference(spufs_calls);
42 	if (calls && !try_module_get(calls->owner))
43 		calls = NULL;
44 	rcu_read_unlock();
45 
46 	return calls;
47 }
48 
49 static inline void spufs_calls_put(struct spufs_calls *calls)
50 {
51 	BUG_ON(calls != spufs_calls);
52 
53 	/* we don't need to rcu this, as we hold a reference to the module */
54 	module_put(spufs_calls->owner);
55 }
56 
57 #else /* !defined CONFIG_SPU_FS_MODULE */
58 
59 static inline struct spufs_calls *spufs_calls_get(void)
60 {
61 	return spufs_calls;
62 }
63 
64 static inline void spufs_calls_put(struct spufs_calls *calls) { }
65 
66 #endif /* CONFIG_SPU_FS_MODULE */
67 
68 SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
69 	umode_t, mode, int, neighbor_fd)
70 {
71 	long ret;
72 	struct spufs_calls *calls;
73 
74 	calls = spufs_calls_get();
75 	if (!calls)
76 		return -ENOSYS;
77 
78 	if (flags & SPU_CREATE_AFFINITY_SPU) {
79 		struct fd neighbor = fdget(neighbor_fd);
80 		ret = -EBADF;
81 		if (neighbor.file) {
82 			ret = calls->create_thread(name, flags, mode, neighbor.file);
83 			fdput(neighbor);
84 		}
85 	} else
86 		ret = calls->create_thread(name, flags, mode, NULL);
87 
88 	spufs_calls_put(calls);
89 	return ret;
90 }
91 
92 asmlinkage long sys_spu_run(int fd, __u32 __user *unpc, __u32 __user *ustatus)
93 {
94 	long ret;
95 	struct fd arg;
96 	struct spufs_calls *calls;
97 
98 	calls = spufs_calls_get();
99 	if (!calls)
100 		return -ENOSYS;
101 
102 	ret = -EBADF;
103 	arg = fdget(fd);
104 	if (arg.file) {
105 		ret = calls->spu_run(arg.file, unpc, ustatus);
106 		fdput(arg);
107 	}
108 
109 	spufs_calls_put(calls);
110 	return ret;
111 }
112 
113 int elf_coredump_extra_notes_size(void)
114 {
115 	struct spufs_calls *calls;
116 	int ret;
117 
118 	calls = spufs_calls_get();
119 	if (!calls)
120 		return 0;
121 
122 	ret = calls->coredump_extra_notes_size();
123 
124 	spufs_calls_put(calls);
125 
126 	return ret;
127 }
128 
129 int elf_coredump_extra_notes_write(struct file *file, loff_t *foffset)
130 {
131 	struct spufs_calls *calls;
132 	int ret;
133 
134 	calls = spufs_calls_get();
135 	if (!calls)
136 		return 0;
137 
138 	ret = calls->coredump_extra_notes_write(file, foffset);
139 
140 	spufs_calls_put(calls);
141 
142 	return ret;
143 }
144 
145 void notify_spus_active(void)
146 {
147 	struct spufs_calls *calls;
148 
149 	calls = spufs_calls_get();
150 	if (!calls)
151 		return;
152 
153 	calls->notify_spus_active();
154 	spufs_calls_put(calls);
155 
156 	return;
157 }
158 
159 int register_spu_syscalls(struct spufs_calls *calls)
160 {
161 	if (spufs_calls)
162 		return -EBUSY;
163 
164 	rcu_assign_pointer(spufs_calls, calls);
165 	return 0;
166 }
167 EXPORT_SYMBOL_GPL(register_spu_syscalls);
168 
169 void unregister_spu_syscalls(struct spufs_calls *calls)
170 {
171 	BUG_ON(spufs_calls->owner != calls->owner);
172 	rcu_assign_pointer(spufs_calls, NULL);
173 	synchronize_rcu();
174 }
175 EXPORT_SYMBOL_GPL(unregister_spu_syscalls);
176