Changeset aaa3c457 in mainline for uspace/lib/c/generic/private/futex.h

Timestamp:

2018-11-12T10:36:10Z (5 years ago)

Author:

GitHub <noreply@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

a43dfcb

Parents:

3ce781f4 (diff), 6874bd2 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

git-author:

Jakub Jermář <jakub@…> (2018-11-12 10:36:10)

git-committer:

GitHub <noreply@…> (2018-11-12 10:36:10)

Message:

Merge pull request #56 from jermar/futexremoval

Remove kernel support for futexes in favor of waitq kobjects.

File:

• uspace/lib/c/generic/private/futex.h (modified) (7 diffs)

uspace/lib/c/generic/private/futex.h

@@ -42 +42 @@
 #include <time.h>
 #include <fibril.h>
+#include <abi/cap.h>
+#include <abi/synch.h>
 
 typedef struct futex {
         volatile atomic_int val;
+        volatile cap_waitq_handle_t whandle;
+
 #ifdef CONFIG_DEBUG_FUTEX
         _Atomic(fibril_t *) owner;
@@ -50 +54 @@
 } futex_t;
 
-extern void futex_initialize(futex_t *futex, int value);
+extern errno_t futex_initialize(futex_t *futex, int value);
+
+static inline errno_t futex_destroy(futex_t *futex)
+{
+        if (futex->whandle) {
+                errno_t rc;
+                rc = __SYSCALL1(SYS_WAITQ_DESTROY, (sysarg_t) futex->whandle);
+                futex->whandle = CAP_NIL;
+                return rc;
+        }
+        return EOK;
+}
 
 #ifdef CONFIG_DEBUG_FUTEX
-
-#define FUTEX_INITIALIZE(val) { (val) , NULL }
-#define FUTEX_INITIALIZER     FUTEX_INITIALIZE(1)
 
 void __futex_assert_is_locked(futex_t *, const char *);
@@ -74 +86 @@
 #else
 
-#define FUTEX_INITIALIZE(val) { (val) }
-#define FUTEX_INITIALIZER     FUTEX_INITIALIZE(1)
-
 #define futex_lock(fut)     (void) futex_down((fut))
 #define futex_trylock(fut)  futex_trydown((fut))
@@ -86 +95 @@
 
 #endif
+
+static inline errno_t futex_allocate_waitq(futex_t *futex)
+{
+        return __SYSCALL1(SYS_WAITQ_CREATE, (sysarg_t) &futex->whandle);
+}
 
 /** Down the futex with timeout, composably.
@@ -107 +121 @@
 {
         // TODO: Add tests for this.
+
+        assert(futex->whandle != CAP_NIL);
 
         if (atomic_fetch_sub_explicit(&futex->val, 1, memory_order_acquire) > 0)
@@ -132 +148 @@
         }
 
-        return __SYSCALL2(SYS_FUTEX_SLEEP, (sysarg_t) futex, (sysarg_t) timeout);
+        return __SYSCALL3(SYS_WAITQ_SLEEP, (sysarg_t) futex->whandle,
+            (sysarg_t) timeout, (sysarg_t) SYNCH_FLAGS_FUTEX);
 }
 
@@ -147 +164 @@
 {
         if (atomic_fetch_add_explicit(&futex->val, 1, memory_order_release) < 0)
-                return __SYSCALL1(SYS_FUTEX_WAKEUP, (sysarg_t) futex);
+                return __SYSCALL1(SYS_WAITQ_WAKEUP, (sysarg_t) futex->whandle);
 
         return EOK;