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- /* 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 <http://www.gnu.org/licenses/>. */
- /*
- * shim_sched.c
- *
- * Implementation of system call "sched_yield".
- */
- #include <api.h>
- #include <errno.h>
- #include <pal.h>
- #include <shim_internal.h>
- #include <shim_table.h>
- 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;
- }
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