LXR linux/arch/powerpc/platforms/cell/spu

   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 */
  32static struct spufs_calls *spufs_calls;
  33
  34#ifdef CONFIG_SPU_FS_MODULE
  35
  36static 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
  49static 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
  59static inline struct spufs_calls *spufs_calls_get(void)
  60{
  61        return spufs_calls;
  62}
  63
  64static inline void spufs_calls_put(struct spufs_calls *calls) { }
  65
  66#endif /* CONFIG_SPU_FS_MODULE */
  67
  68SYSCALL_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
  92asmlinkage 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
 113int 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
 129int 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
 145void 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
 159int 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}
 167EXPORT_SYMBOL_GPL(register_spu_syscalls);
 168
 169void 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}
 175EXPORT_SYMBOL_GPL(unregister_spu_syscalls);
 176