platforms/cell/spu_syscalls.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * SPU file system -- system call stubs
0004  *
0005  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
0006  * (C) Copyright 2006-2007, IBM Corporation
0007  *
0008  * Author: Arnd Bergmann <arndb@de.ibm.com>
0009  */
0010 #include <linux/file.h>
0011 #include <linux/fs.h>
0012 #include <linux/module.h>
0013 #include <linux/syscalls.h>
0014 #include <linux/rcupdate.h>
0015 #include <linux/binfmts.h>
0016
0017 #include <asm/spu.h>
0018
0019 /* protected by rcu */
0020 static struct spufs_calls *spufs_calls;
0021
0022 #ifdef CONFIG_SPU_FS_MODULE
0023
0024 static inline struct spufs_calls *spufs_calls_get(void)
0025 {
0026     struct spufs_calls *calls = NULL;
0027
0028     rcu_read_lock();
0029     calls = rcu_dereference(spufs_calls);
0030     if (calls && !try_module_get(calls->owner))
0031         calls = NULL;
0032     rcu_read_unlock();
0033
0034     return calls;
0035 }
0036
0037 static inline void spufs_calls_put(struct spufs_calls *calls)
0038 {
0039     BUG_ON(calls != spufs_calls);
0040
0041     /* we don't need to rcu this, as we hold a reference to the module */
0042     module_put(spufs_calls->owner);
0043 }
0044
0045 #else /* !defined CONFIG_SPU_FS_MODULE */
0046
0047 static inline struct spufs_calls *spufs_calls_get(void)
0048 {
0049     return spufs_calls;
0050 }
0051
0052 static inline void spufs_calls_put(struct spufs_calls *calls) { }
0053
0054 #endif /* CONFIG_SPU_FS_MODULE */
0055
0056 SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
0057     umode_t, mode, int, neighbor_fd)
0058 {
0059     long ret;
0060     struct spufs_calls *calls;
0061
0062     calls = spufs_calls_get();
0063     if (!calls)
0064         return -ENOSYS;
0065
0066     if (flags & SPU_CREATE_AFFINITY_SPU) {
0067         struct fd neighbor = fdget(neighbor_fd);
0068         ret = -EBADF;
0069         if (neighbor.file) {
0070             ret = calls->create_thread(name, flags, mode, neighbor.file);
0071             fdput(neighbor);
0072         }
0073     } else
0074         ret = calls->create_thread(name, flags, mode, NULL);
0075
0076     spufs_calls_put(calls);
0077     return ret;
0078 }
0079
0080 SYSCALL_DEFINE3(spu_run,int, fd, __u32 __user *, unpc, __u32 __user *, ustatus)
0081 {
0082     long ret;
0083     struct fd arg;
0084     struct spufs_calls *calls;
0085
0086     calls = spufs_calls_get();
0087     if (!calls)
0088         return -ENOSYS;
0089
0090     ret = -EBADF;
0091     arg = fdget(fd);
0092     if (arg.file) {
0093         ret = calls->spu_run(arg.file, unpc, ustatus);
0094         fdput(arg);
0095     }
0096
0097     spufs_calls_put(calls);
0098     return ret;
0099 }
0100
0101 #ifdef CONFIG_COREDUMP
0102 int elf_coredump_extra_notes_size(void)
0103 {
0104     struct spufs_calls *calls;
0105     int ret;
0106
0107     calls = spufs_calls_get();
0108     if (!calls)
0109         return 0;
0110
0111     ret = calls->coredump_extra_notes_size();
0112
0113     spufs_calls_put(calls);
0114
0115     return ret;
0116 }
0117
0118 int elf_coredump_extra_notes_write(struct coredump_params *cprm)
0119 {
0120     struct spufs_calls *calls;
0121     int ret;
0122
0123     calls = spufs_calls_get();
0124     if (!calls)
0125         return 0;
0126
0127     ret = calls->coredump_extra_notes_write(cprm);
0128
0129     spufs_calls_put(calls);
0130
0131     return ret;
0132 }
0133 #endif
0134
0135 void notify_spus_active(void)
0136 {
0137     struct spufs_calls *calls;
0138
0139     calls = spufs_calls_get();
0140     if (!calls)
0141         return;
0142
0143     calls->notify_spus_active();
0144     spufs_calls_put(calls);
0145
0146     return;
0147 }
0148
0149 int register_spu_syscalls(struct spufs_calls *calls)
0150 {
0151     if (spufs_calls)
0152         return -EBUSY;
0153
0154     rcu_assign_pointer(spufs_calls, calls);
0155     return 0;
0156 }
0157 EXPORT_SYMBOL_GPL(register_spu_syscalls);
0158
0159 void unregister_spu_syscalls(struct spufs_calls *calls)
0160 {
0161     BUG_ON(spufs_calls->owner != calls->owner);
0162     RCU_INIT_POINTER(spufs_calls, NULL);
0163     synchronize_rcu();
0164 }
0165 EXPORT_SYMBOL_GPL(unregister_spu_syscalls);