linux/arch/powerpc/platforms/cell/spu_syscalls.c
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   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 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
  94asmlinkage 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
 116int 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
 132int 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
 148void 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
 162int 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}
 170EXPORT_SYMBOL_GPL(register_spu_syscalls);
 171
 172void 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}
 178EXPORT_SYMBOL_GPL(unregister_spu_syscalls);
 179