/* Copyright (C) 2014 Stony Brook University
This file is part of Graphene Library OS.
Graphene Library OS is free software: you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License
as published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
Graphene Library OS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see . */
/*
* shim_sched.c
*
* Implementation of system call "sched_yield".
*/
#include
#include
#include
#include
#include
int shim_do_sched_yield(void) {
DkThreadYieldExecution();
return 0;
}
int shim_do_sched_getaffinity(pid_t pid, size_t len, __kernel_cpu_set_t* user_mask_ptr) {
__UNUSED(pid);
int ncpus = PAL_CB(cpu_info.cpu_num);
/* Check that user_mask_ptr is valid; if not, should return -EFAULT */
if (test_user_memory(user_mask_ptr, len, 1))
return -EFAULT;
/* Linux kernel bitmap is based on long. So according to its
* implementation, round up the result to sizeof(long) */
size_t bitmask_long_count = (ncpus + sizeof(long) * 8 - 1) / (sizeof(long) * 8);
size_t bitmask_size_in_bytes = bitmask_long_count * sizeof(long);
if (len < bitmask_size_in_bytes)
return -EINVAL;
/* Linux kernel also rejects non-natural size */
if (len & (sizeof(long) - 1))
return -EINVAL;
memset(user_mask_ptr, 0, len);
for (int i = 0; i < ncpus; i++) {
((uint8_t*)user_mask_ptr)[i / 8] |= 1 << (i % 8);
}
/* imitate the Linux kernel implementation
* See SYSCALL_DEFINE3(sched_getaffinity) */
return bitmask_size_in_bytes;
}