arch/powerpc/platforms/cell/spu_syscalls.c

   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 asmlinkage long sys_spu_create(const char __user *name,
  69                 unsigned int flags, mode_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
  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
 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
 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
 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
 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
 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);