spu_syscalls.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * SPU file system -- system call stubs
  4 *
  5 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
  6 * (C) Copyright 2006-2007, IBM Corporation
  7 *
  8 * Author: Arnd Bergmann <arndb@de.ibm.com>
  9 */
 10#include <linux/file.h>
 11#include <linux/fs.h>
 12#include <linux/module.h>
 13#include <linux/syscalls.h>
 14#include <linux/rcupdate.h>
 15#include <linux/binfmts.h>
 16
 17#include <asm/spu.h>
 18
 19/* protected by rcu */
 20static struct spufs_calls *spufs_calls;
 21
 22#ifdef CONFIG_SPU_FS_MODULE
 23
 24static inline struct spufs_calls *spufs_calls_get(void)
 25{
 26	struct spufs_calls *calls = NULL;
 27
 28	rcu_read_lock();
 29	calls = rcu_dereference(spufs_calls);
 30	if (calls && !try_module_get(calls->owner))
 31		calls = NULL;
 32	rcu_read_unlock();
 33
 34	return calls;
 35}
 36
 37static inline void spufs_calls_put(struct spufs_calls *calls)
 38{
 39	if (!calls)
 40		return;
 41
 42	BUG_ON(calls != spufs_calls);
 43
 44	/* we don't need to rcu this, as we hold a reference to the module */
 45	module_put(spufs_calls->owner);
 46}
 47
 48#else /* !defined CONFIG_SPU_FS_MODULE */
 49
 50static inline struct spufs_calls *spufs_calls_get(void)
 51{
 52	return spufs_calls;
 53}
 54
 55static inline void spufs_calls_put(struct spufs_calls *calls) { }
 56
 57#endif /* CONFIG_SPU_FS_MODULE */
 58
 59DEFINE_CLASS(spufs_calls, struct spufs_calls *, spufs_calls_put(_T), spufs_calls_get(), void)
 60
 61SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
 62	umode_t, mode, int, neighbor_fd)
 63{
 64	CLASS(spufs_calls, calls)();
 65	if (!calls)
 66		return -ENOSYS;
 67
 68	if (flags & SPU_CREATE_AFFINITY_SPU) {
 69		CLASS(fd, neighbor)(neighbor_fd);
 70		if (fd_empty(neighbor))
 71			return -EBADF;
 72		return calls->create_thread(name, flags, mode, fd_file(neighbor));
 73	} else {
 74		return calls->create_thread(name, flags, mode, NULL);
 75	}
 76}
 77
 78SYSCALL_DEFINE3(spu_run,int, fd, __u32 __user *, unpc, __u32 __user *, ustatus)
 79{
 80	CLASS(spufs_calls, calls)();
 81	if (!calls)
 82		return -ENOSYS;
 83
 84	CLASS(fd, arg)(fd);
 85	if (fd_empty(arg))
 86		return -EBADF;
 87
 88	return calls->spu_run(fd_file(arg), unpc, ustatus);
 89}
 90
 91#ifdef CONFIG_COREDUMP
 92int elf_coredump_extra_notes_size(void)
 93{
 94	CLASS(spufs_calls, calls)();
 95	if (!calls)
 96		return 0;
 97
 98	return calls->coredump_extra_notes_size();
 99}
100
101int elf_coredump_extra_notes_write(struct coredump_params *cprm)
102{
103	CLASS(spufs_calls, calls)();
104	if (!calls)
105		return 0;
106
107	return calls->coredump_extra_notes_write(cprm);
108}
109#endif
110
111void notify_spus_active(void)
112{
113	struct spufs_calls *calls;
114
115	calls = spufs_calls_get();
116	if (!calls)
117		return;
118
119	calls->notify_spus_active();
120	spufs_calls_put(calls);
121
122	return;
123}
124
125int register_spu_syscalls(struct spufs_calls *calls)
126{
127	if (spufs_calls)
128		return -EBUSY;
129
130	rcu_assign_pointer(spufs_calls, calls);
131	return 0;
132}
133EXPORT_SYMBOL_GPL(register_spu_syscalls);
134
135void unregister_spu_syscalls(struct spufs_calls *calls)
136{
137	BUG_ON(spufs_calls->owner != calls->owner);
138	RCU_INIT_POINTER(spufs_calls, NULL);
139	synchronize_rcu();
140}
141EXPORT_SYMBOL_GPL(unregister_spu_syscalls);