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>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/kern/linux/linux.hh b/src/kern/linux/linux.hh
index 2da596814..4ed39028b 100644
--- a/src/kern/linux/linux.hh
+++ b/src/kern/linux/linux.hh
@@ -241,6 +241,8 @@ class Linux : public OperatingSystem
     // For futex system call
     static const unsigned TGT_FUTEX_WAIT                = 0;
     static const unsigned TGT_FUTEX_WAKE                = 1;
+    static const unsigned TGT_FUTEX_REQUEUE             = 3;
+    static const unsigned TGT_FUTEX_CMP_REQUEUE         = 4;
     static const unsigned TGT_FUTEX_WAIT_BITSET         = 9;
     static const unsigned TGT_FUTEX_WAKE_BITSET         = 10;
     static const unsigned TGT_EAGAIN                    = 11;