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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 
spufs_calls_get(void)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 
spufs_calls_put(struct spufs_calls * calls)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 
spufs_calls_get(void)59 static inline struct spufs_calls *spufs_calls_get(void)
60 {
61 	return spufs_calls;
62 }
63 
spufs_calls_put(struct spufs_calls * calls)64 static inline void spufs_calls_put(struct spufs_calls *calls) { }
65 
66 #endif /* CONFIG_SPU_FS_MODULE */
67 
SYSCALL_DEFINE4(spu_create,const char __user *,name,unsigned int,flags,umode_t,mode,int,neighbor_fd)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 file *neighbor;
73 	int fput_needed;
74 	struct spufs_calls *calls;
75 
76 	calls = spufs_calls_get();
77 	if (!calls)
78 		return -ENOSYS;
79 
80 	if (flags & SPU_CREATE_AFFINITY_SPU) {
81 		ret = -EBADF;
82 		neighbor = fget_light(neighbor_fd, &fput_needed);
83 		if (neighbor) {
84 			ret = calls->create_thread(name, flags, mode, neighbor);
85 			fput_light(neighbor, fput_needed);
86 		}
87 	} else
88 		ret = calls->create_thread(name, flags, mode, NULL);
89 
90 	spufs_calls_put(calls);
91 	return ret;
92 }
93 
sys_spu_run(int fd,__u32 __user * unpc,__u32 __user * ustatus)94 asmlinkage long sys_spu_run(int fd, __u32 __user *unpc, __u32 __user *ustatus)
95 {
96 	long ret;
97 	struct file *filp;
98 	int fput_needed;
99 	struct spufs_calls *calls;
100 
101 	calls = spufs_calls_get();
102 	if (!calls)
103 		return -ENOSYS;
104 
105 	ret = -EBADF;
106 	filp = fget_light(fd, &fput_needed);
107 	if (filp) {
108 		ret = calls->spu_run(filp, unpc, ustatus);
109 		fput_light(filp, fput_needed);
110 	}
111 
112 	spufs_calls_put(calls);
113 	return ret;
114 }
115 
elf_coredump_extra_notes_size(void)116 int elf_coredump_extra_notes_size(void)
117 {
118 	struct spufs_calls *calls;
119 	int ret;
120 
121 	calls = spufs_calls_get();
122 	if (!calls)
123 		return 0;
124 
125 	ret = calls->coredump_extra_notes_size();
126 
127 	spufs_calls_put(calls);
128 
129 	return ret;
130 }
131 
elf_coredump_extra_notes_write(struct file * file,loff_t * foffset)132 int elf_coredump_extra_notes_write(struct file *file, loff_t *foffset)
133 {
134 	struct spufs_calls *calls;
135 	int ret;
136 
137 	calls = spufs_calls_get();
138 	if (!calls)
139 		return 0;
140 
141 	ret = calls->coredump_extra_notes_write(file, foffset);
142 
143 	spufs_calls_put(calls);
144 
145 	return ret;
146 }
147 
notify_spus_active(void)148 void notify_spus_active(void)
149 {
150 	struct spufs_calls *calls;
151 
152 	calls = spufs_calls_get();
153 	if (!calls)
154 		return;
155 
156 	calls->notify_spus_active();
157 	spufs_calls_put(calls);
158 
159 	return;
160 }
161 
register_spu_syscalls(struct spufs_calls * calls)162 int register_spu_syscalls(struct spufs_calls *calls)
163 {
164 	if (spufs_calls)
165 		return -EBUSY;
166 
167 	rcu_assign_pointer(spufs_calls, calls);
168 	return 0;
169 }
170 EXPORT_SYMBOL_GPL(register_spu_syscalls);
171 
unregister_spu_syscalls(struct spufs_calls * calls)172 void unregister_spu_syscalls(struct spufs_calls *calls)
173 {
174 	BUG_ON(spufs_calls->owner != calls->owner);
175 	rcu_assign_pointer(spufs_calls, NULL);
176 	synchronize_rcu();
177 }
178 EXPORT_SYMBOL_GPL(unregister_spu_syscalls);
179