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 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);