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 #include <linux/binfmts.h>
  29
  30 #include <asm/spu.h>
  31
  32 /* protected by rcu */
  33 static struct spufs_calls *spufs_calls;
  34
  35 #ifdef CONFIG_SPU_FS_MODULE
  36
  37 static inline struct spufs_calls *spufs_calls_get(void)
  38 {
  39         struct spufs_calls *calls = NULL;
  40
  41         rcu_read_lock();
  42         calls = rcu_dereference(spufs_calls);
  43         if (calls && !try_module_get(calls->owner))
  44                 calls = NULL;
  45         rcu_read_unlock();
  46
  47         return calls;
  48 }
  49
  50 static inline void spufs_calls_put(struct spufs_calls *calls)
  51 {
  52         BUG_ON(calls != spufs_calls);
  53
  54         /* we don't need to rcu this, as we hold a reference to the module */
  55         module_put(spufs_calls->owner);
  56 }
  57
  58 #else /* !defined CONFIG_SPU_FS_MODULE */
  59
  60 static inline struct spufs_calls *spufs_calls_get(void)
  61 {
  62         return spufs_calls;
  63 }
  64
  65 static inline void spufs_calls_put(struct spufs_calls *calls) { }
  66
  67 #endif /* CONFIG_SPU_FS_MODULE */
  68
  69 SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
  70         umode_t, mode, int, neighbor_fd)
  71 {
  72         long ret;
  73         struct spufs_calls *calls;
  74
  75         calls = spufs_calls_get();
  76         if (!calls)
  77                 return -ENOSYS;
  78
  79         if (flags & SPU_CREATE_AFFINITY_SPU) {
  80                 struct fd neighbor = fdget(neighbor_fd);
  81                 ret = -EBADF;
  82                 if (neighbor.file) {
  83                         ret = calls->create_thread(name, flags, mode, neighbor.file);
  84                         fdput(neighbor);
  85                 }
  86         } else
  87                 ret = calls->create_thread(name, flags, mode, NULL);
  88
  89         spufs_calls_put(calls);
  90         return ret;
  91 }
  92
  93 asmlinkage long sys_spu_run(int fd, __u32 __user *unpc, __u32 __user *ustatus)
  94 {
  95         long ret;
  96         struct fd arg;
  97         struct spufs_calls *calls;
  98
  99         calls = spufs_calls_get();
 100         if (!calls)
 101                 return -ENOSYS;
 102
 103         ret = -EBADF;
 104         arg = fdget(fd);
 105         if (arg.file) {
 106                 ret = calls->spu_run(arg.file, unpc, ustatus);
 107                 fdput(arg);
 108         }
 109
 110         spufs_calls_put(calls);
 111         return ret;
 112 }
 113
 114 int elf_coredump_extra_notes_size(void)
 115 {
 116         struct spufs_calls *calls;
 117         int ret;
 118
 119         calls = spufs_calls_get();
 120         if (!calls)
 121                 return 0;
 122
 123         ret = calls->coredump_extra_notes_size();
 124
 125         spufs_calls_put(calls);
 126
 127         return ret;
 128 }
 129
 130 int elf_coredump_extra_notes_write(struct coredump_params *cprm)
 131 {
 132         struct spufs_calls *calls;
 133         int ret;
 134
 135         calls = spufs_calls_get();
 136         if (!calls)
 137                 return 0;
 138
 139         ret = calls->coredump_extra_notes_write(cprm);
 140
 141         spufs_calls_put(calls);
 142
 143         return ret;
 144 }
 145
 146 void notify_spus_active(void)
 147 {
 148         struct spufs_calls *calls;
 149
 150         calls = spufs_calls_get();
 151         if (!calls)
 152                 return;
 153
 154         calls->notify_spus_active();
 155         spufs_calls_put(calls);
 156
 157         return;
 158 }
 159
 160 int register_spu_syscalls(struct spufs_calls *calls)
 161 {
 162         if (spufs_calls)
 163                 return -EBUSY;
 164
 165         rcu_assign_pointer(spufs_calls, calls);
 166         return 0;
 167 }
 168 EXPORT_SYMBOL_GPL(register_spu_syscalls);
 169
 170 void unregister_spu_syscalls(struct spufs_calls *calls)
 171 {
 172         BUG_ON(spufs_calls->owner != calls->owner);
 173         rcu_assign_pointer(spufs_calls, NULL);
 174         synchronize_rcu();
 175 }
 176 EXPORT_SYMBOL_GPL(unregister_spu_syscalls);