Kernel: Some futex improvements

This adds support for FUTEX_WAKE_OP, FUTEX_WAIT_BITSET, FUTEX_WAKE_BITSET,
FUTEX_REQUEUE, and FUTEX_CMP_REQUEUE, as well well as global and private
futex and absolute/relative timeouts against the appropriate clock. This
also changes the implementation so that kernel resources are only used when
a thread is blocked on a futex.

Global futexes are implemented as offsets in VMObjects, so that different
processes can share a futex against the same VMObject despite potentially
being mapped at different virtual addresses.

1 files changed, 8 insertions, 3 deletions

diff --git a/Kernel/API/Syscall.h b/Kernel/API/Syscall.h
index f236616c41..26a14416d1 100644
--- a/Kernel/API/Syscall.h
+++ b/Kernel/API/Syscall.h
@@ -310,10 +310,15 @@ struct SC_getpeername_params {
 };
 
 struct SC_futex_params {
-    const i32* userspace_address;
+    u32* userspace_address;
     int futex_op;
-    i32 val;
-    const timespec* timeout;
+    u32 val;
+    union {
+        const timespec* timeout;
+        u32 val2;
+    };
+    u32* userspace_address2;
+    u32 val3;
 };
 
 struct SC_setkeymap_params {