cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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spu_syscalls.c (3155B)

      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	BUG_ON(calls != spufs_calls);
     40
     41	/* we don't need to rcu this, as we hold a reference to the module */
     42	module_put(spufs_calls->owner);
     43}
     44
     45#else /* !defined CONFIG_SPU_FS_MODULE */
     46
     47static inline struct spufs_calls *spufs_calls_get(void)
     48{
     49	return spufs_calls;
     50}
     51
     52static inline void spufs_calls_put(struct spufs_calls *calls) { }
     53
     54#endif /* CONFIG_SPU_FS_MODULE */
     55
     56SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
     57	umode_t, mode, int, neighbor_fd)
     58{
     59	long ret;
     60	struct spufs_calls *calls;
     61
     62	calls = spufs_calls_get();
     63	if (!calls)
     64		return -ENOSYS;
     65
     66	if (flags & SPU_CREATE_AFFINITY_SPU) {
     67		struct fd neighbor = fdget(neighbor_fd);
     68		ret = -EBADF;
     69		if (neighbor.file) {
     70			ret = calls->create_thread(name, flags, mode, neighbor.file);
     71			fdput(neighbor);
     72		}
     73	} else
     74		ret = calls->create_thread(name, flags, mode, NULL);
     75
     76	spufs_calls_put(calls);
     77	return ret;
     78}
     79
     80SYSCALL_DEFINE3(spu_run,int, fd, __u32 __user *, unpc, __u32 __user *, ustatus)
     81{
     82	long ret;
     83	struct fd arg;
     84	struct spufs_calls *calls;
     85
     86	calls = spufs_calls_get();
     87	if (!calls)
     88		return -ENOSYS;
     89
     90	ret = -EBADF;
     91	arg = fdget(fd);
     92	if (arg.file) {
     93		ret = calls->spu_run(arg.file, unpc, ustatus);
     94		fdput(arg);
     95	}
     96
     97	spufs_calls_put(calls);
     98	return ret;
     99}
    100
    101#ifdef CONFIG_COREDUMP
    102int elf_coredump_extra_notes_size(void)
    103{
    104	struct spufs_calls *calls;
    105	int ret;
    106
    107	calls = spufs_calls_get();
    108	if (!calls)
    109		return 0;
    110
    111	ret = calls->coredump_extra_notes_size();
    112
    113	spufs_calls_put(calls);
    114
    115	return ret;
    116}
    117
    118int elf_coredump_extra_notes_write(struct coredump_params *cprm)
    119{
    120	struct spufs_calls *calls;
    121	int ret;
    122
    123	calls = spufs_calls_get();
    124	if (!calls)
    125		return 0;
    126
    127	ret = calls->coredump_extra_notes_write(cprm);
    128
    129	spufs_calls_put(calls);
    130
    131	return ret;
    132}
    133#endif
    134
    135void notify_spus_active(void)
    136{
    137	struct spufs_calls *calls;
    138
    139	calls = spufs_calls_get();
    140	if (!calls)
    141		return;
    142
    143	calls->notify_spus_active();
    144	spufs_calls_put(calls);
    145
    146	return;
    147}
    148
    149int register_spu_syscalls(struct spufs_calls *calls)
    150{
    151	if (spufs_calls)
    152		return -EBUSY;
    153
    154	rcu_assign_pointer(spufs_calls, calls);
    155	return 0;
    156}
    157EXPORT_SYMBOL_GPL(register_spu_syscalls);
    158
    159void unregister_spu_syscalls(struct spufs_calls *calls)
    160{
    161	BUG_ON(spufs_calls->owner != calls->owner);
    162	RCU_INIT_POINTER(spufs_calls, NULL);
    163	synchronize_rcu();
    164}
    165EXPORT_SYMBOL_GPL(unregister_spu_syscalls);