tree deaaf97ea7b97c061f36e10d08463ae78498e864
parent 42b063ad30324f1459915070226e820aabd54336
author Moyang Wang <mw828@cornell.edu> 1522700582 -0400
committer Tuan Ta <qtt2@cornell.edu> 1549639530 +0000

sim, kern: support FUTEX_CMP_REQUEUE

This patch supports FUTEX_CMP_REQUEUE operation. Below is its
description from Linux man page:

futex syscall: int futex(int *uaddr, int futex_op, int val,
                         const struct timespec *timeout,
                         int *uaddr2, int val3);

This operation first checks whether the location uaddr still contains
the value val3.  If not, the operation fails with the error EAGAIN.
Otherwise, the operation wakes up a maximum of val waiters that are
waiting on the futex at uaddr.  If there are more than val waiters, then
the remaining waiters are removed from the wait queue of the source
futex at uaddr and added to the wait queue of the target futex at
uaddr2.  The val2 argument specifies an upper limit on the number of
waiters that are requeued to the futex at uaddr2.

Reference: http://man7.org/linux/man-pages/man2/futex.2.html

Change-Id: I6d2ebd19a935b656d19d8342f7ab450c0d2031f4
Reviewed-on: https://gem5-review.googlesource.com/c/9629
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>