1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * SPU file system -- system call stubs
4  *
5  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
6  * (C) Copyright 2006-2007, IBM Corporation
7  *
8  * Author: Arnd Bergmann <arndb@de.ibm.com>
9  */
10 #include <linux/file.h>
11 #include <linux/fs.h>
12 #include <linux/module.h>
13 #include <linux/syscalls.h>
14 #include <linux/rcupdate.h>
15 #include <linux/binfmts.h>
16 
17 #include <asm/spu.h>
18 
19 /* protected by rcu */
20 static struct spufs_calls *spufs_calls;
21 
22 #ifdef CONFIG_SPU_FS_MODULE
23 
24 static inline struct spufs_calls *spufs_calls_get(void)
25 {
26 	struct spufs_calls *calls = NULL;
27 
28 	rcu_read_lock();
29 	calls = rcu_dereference(spufs_calls);
30 	if (calls && !try_module_get(calls->owner))
31 		calls = NULL;
32 	rcu_read_unlock();
33 
34 	return calls;
35 }
36 
37 static inline void spufs_calls_put(struct spufs_calls *calls)
38 {
39 	BUG_ON(calls != spufs_calls);
40 
41 	/* we don't need to rcu this, as we hold a reference to the module */
42 	module_put(spufs_calls->owner);
43 }
44 
45 #else /* !defined CONFIG_SPU_FS_MODULE */
46 
47 static inline struct spufs_calls *spufs_calls_get(void)
48 {
49 	return spufs_calls;
50 }
51 
52 static inline void spufs_calls_put(struct spufs_calls *calls) { }
53 
54 #endif /* CONFIG_SPU_FS_MODULE */
55 
56 SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
57 	umode_t, mode, int, neighbor_fd)
58 {
59 	long ret;
60 	struct spufs_calls *calls;
61 
62 	calls = spufs_calls_get();
63 	if (!calls)
64 		return -ENOSYS;
65 
66 	if (flags & SPU_CREATE_AFFINITY_SPU) {
67 		struct fd neighbor = fdget(neighbor_fd);
68 		ret = -EBADF;
69 		if (neighbor.file) {
70 			ret = calls->create_thread(name, flags, mode, neighbor.file);
71 			fdput(neighbor);
72 		}
73 	} else
74 		ret = calls->create_thread(name, flags, mode, NULL);
75 
76 	spufs_calls_put(calls);
77 	return ret;
78 }
79 
80 SYSCALL_DEFINE3(spu_run,int, fd, __u32 __user *, unpc, __u32 __user *, ustatus)
81 {
82 	long ret;
83 	struct fd arg;
84 	struct spufs_calls *calls;
85 
86 	calls = spufs_calls_get();
87 	if (!calls)
88 		return -ENOSYS;
89 
90 	ret = -EBADF;
91 	arg = fdget(fd);
92 	if (arg.file) {
93 		ret = calls->spu_run(arg.file, unpc, ustatus);
94 		fdput(arg);
95 	}
96 
97 	spufs_calls_put(calls);
98 	return ret;
99 }
100 
101 #ifdef CONFIG_COREDUMP
102 int elf_coredump_extra_notes_size(void)
103 {
104 	struct spufs_calls *calls;
105 	int ret;
106 
107 	calls = spufs_calls_get();
108 	if (!calls)
109 		return 0;
110 
111 	ret = calls->coredump_extra_notes_size();
112 
113 	spufs_calls_put(calls);
114 
115 	return ret;
116 }
117 
118 int elf_coredump_extra_notes_write(struct coredump_params *cprm)
119 {
120 	struct spufs_calls *calls;
121 	int ret;
122 
123 	calls = spufs_calls_get();
124 	if (!calls)
125 		return 0;
126 
127 	ret = calls->coredump_extra_notes_write(cprm);
128 
129 	spufs_calls_put(calls);
130 
131 	return ret;
132 }
133 #endif
134 
135 void notify_spus_active(void)
136 {
137 	struct spufs_calls *calls;
138 
139 	calls = spufs_calls_get();
140 	if (!calls)
141 		return;
142 
143 	calls->notify_spus_active();
144 	spufs_calls_put(calls);
145 
146 	return;
147 }
148 
149 int register_spu_syscalls(struct spufs_calls *calls)
150 {
151 	if (spufs_calls)
152 		return -EBUSY;
153 
154 	rcu_assign_pointer(spufs_calls, calls);
155 	return 0;
156 }
157 EXPORT_SYMBOL_GPL(register_spu_syscalls);
158 
159 void unregister_spu_syscalls(struct spufs_calls *calls)
160 {
161 	BUG_ON(spufs_calls->owner != calls->owner);
162 	RCU_INIT_POINTER(spufs_calls, NULL);
163 	synchronize_rcu();
164 }
165 EXPORT_SYMBOL_GPL(unregister_spu_syscalls);
166