Consolidate lowlevellock-futex.h

NPTL is already Linux specific, there is no need to parametrize low
level lock futex operations and add a sysdep Linux specific
implementation.  This patch moves the relevant Linux code to nptl one.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 128 insertions, 37 deletions

diff --git a/sysdeps/nptl/lowlevellock-futex.h b/sysdeps/nptl/lowlevellock-futex.h
index 4cceade..392277e 100644
--- a/sysdeps/nptl/lowlevellock-futex.h
+++ b/sysdeps/nptl/lowlevellock-futex.h
@@ -19,14 +19,60 @@
 #ifndef _LOWLEVELLOCK_FUTEX_H
 #define _LOWLEVELLOCK_FUTEX_H   1
 
-#include <errno.h>
-
-
-/* Values for 'private' parameter of locking macros.  Note pthreadP.h
-   optimizes for these exact values, though they are not required.  */
-#define LLL_PRIVATE     0
-#define LLL_SHARED      128
-
+#ifndef __ASSEMBLER__
+# include <sysdep.h>
+# include <sysdep-cancel.h>
+# include <kernel-features.h>
+#endif
+
+#define FUTEX_WAIT		0
+#define FUTEX_WAKE		1
+#define FUTEX_REQUEUE		3
+#define FUTEX_CMP_REQUEUE	4
+#define FUTEX_WAKE_OP		5
+#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE	((4 << 24) | 1)
+#define FUTEX_LOCK_PI		6
+#define FUTEX_UNLOCK_PI		7
+#define FUTEX_TRYLOCK_PI	8
+#define FUTEX_WAIT_BITSET	9
+#define FUTEX_WAKE_BITSET	10
+#define FUTEX_WAIT_REQUEUE_PI   11
+#define FUTEX_CMP_REQUEUE_PI    12
+#define FUTEX_PRIVATE_FLAG	128
+#define FUTEX_CLOCK_REALTIME	256
+
+#define FUTEX_BITSET_MATCH_ANY	0xffffffff
+
+/* Values for 'private' parameter of locking macros.  Yes, the
+   definition seems to be backwards.  But it is not.  The bit will be
+   reversed before passing to the system call.  */
+#define LLL_PRIVATE	0
+#define LLL_SHARED	FUTEX_PRIVATE_FLAG
+
+#ifndef __ASSEMBLER__
+
+# if IS_IN (libc) || IS_IN (rtld)
+/* In libc.so or ld.so all futexes are private.  */
+#  define __lll_private_flag(fl, private)			\
+  ({								\
+    /* Prevent warnings in callers of this macro.  */		\
+    int __lll_private_flag_priv __attribute__ ((unused));	\
+    __lll_private_flag_priv = (private);			\
+    ((fl) | FUTEX_PRIVATE_FLAG);				\
+  })
+# else
+#  define __lll_private_flag(fl, private) \
+  (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
+# endif
+
+# define lll_futex_syscall(nargs, futexp, op, ...)                       \
+  ({                                                                    \
+    INTERNAL_SYSCALL_DECL (__err);                                      \
+    long int __ret = INTERNAL_SYSCALL (futex, __err, nargs, futexp, op, \
+				       __VA_ARGS__);                    \
+    (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err))         \
+     ? -INTERNAL_SYSCALL_ERRNO (__ret, __err) : 0);                     \
+  })
 
 /* For most of these macros, the return value is never really used.
    Nevertheless, the protocol is that each one returns a negated errno
@@ -36,62 +82,107 @@
 
 
 /* Wait while *FUTEXP == VAL for an lll_futex_wake call on FUTEXP.  */
-#define lll_futex_wait(futexp, val, private) \
+# define lll_futex_wait(futexp, val, private) \
   lll_futex_timed_wait (futexp, val, NULL, private)
 
-/* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses.  */
-#define lll_futex_timed_wait(futexp, val, timeout, private)             \
-  -ENOSYS
+# define lll_futex_timed_wait(futexp, val, timeout, private)     \
+  lll_futex_syscall (4, futexp,                                 \
+		     __lll_private_flag (FUTEX_WAIT, private),  \
+		     val, timeout)
 
 /* Verify whether the supplied clockid is supported by
    lll_futex_clock_wait_bitset.  */
-#define lll_futex_supported_clockid(clockid)				\
-  (0)
-
-/* Wait until a lll_futex_wake call on FUTEXP, or the absolute TIMEOUT
-   measured against CLOCKID elapses. CLOCKID may be CLOCK_REALTIME or
-   CLOCK_MONOTONIC.  */
-#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
-  -ENOSYS
+# define lll_futex_supported_clockid(clockid)			\
+  ((clockid) == CLOCK_REALTIME || (clockid) == CLOCK_MONOTONIC)
+
+/* The kernel currently only supports CLOCK_MONOTONIC or
+   CLOCK_REALTIME timeouts for FUTEX_WAIT_BITSET.  We could attempt to
+   convert others here but currently do not.  */
+# define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
+  ({									\
+    long int __ret;							\
+    if (lll_futex_supported_clockid (clockid))                          \
+      {                                                                 \
+        const unsigned int clockbit =                                   \
+          (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0;       \
+        const int op =                                                  \
+          __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private);   \
+                                                                        \
+        __ret = lll_futex_syscall (6, futexp, op, val,                  \
+                                   timeout, NULL /* Unused.  */,	\
+                                   FUTEX_BITSET_MATCH_ANY);		\
+      }                                                                 \
+    else                                                                \
+      __ret = -EINVAL;							\
+    __ret;								\
+  })
 
 /* Wake up up to NR waiters on FUTEXP.  */
-#define lll_futex_wake(futexp, nr, private)                             \
-  -ENOSYS
+# define lll_futex_wake(futexp, nr, private)                             \
+  lll_futex_syscall (4, futexp,                                         \
+		     __lll_private_flag (FUTEX_WAKE, private), nr, 0)
 
 /* Wake up up to NR_WAKE waiters on FUTEXP.  Move up to NR_MOVE of the
-   rest from waiting on FUTEXP to waiting on MUTEX (a different futex).  */
-#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
-  -ENOSYS
+   rest from waiting on FUTEXP to waiting on MUTEX (a different futex).
+   Returns non-zero if error happened, zero if success.  */
+# define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
+  lll_futex_syscall (6, futexp,                                         \
+		     __lll_private_flag (FUTEX_CMP_REQUEUE, private),   \
+		     nr_wake, nr_move, mutex, val)
+
+/* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2.
+   Returns non-zero if error happened, zero if success.  */
+# define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
+  lll_futex_syscall (6, futexp,                                         \
+		     __lll_private_flag (FUTEX_WAKE_OP, private),       \
+		     nr_wake, nr_wake2, futexp2,                        \
+		     FUTEX_OP_CLEAR_WAKE_IF_GT_ONE)
 
-/* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2.  */
-#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
-  -ENOSYS
 
+/* Priority Inheritance support.  */
 
 /* Like lll_futex_wait (FUTEXP, VAL, PRIVATE) but with the expectation
    that lll_futex_cmp_requeue_pi (FUTEXP, _, _, MUTEX, _, PRIVATE) will
    be used to do the wakeup.  Confers priority-inheritance behavior on
    the waiter.  */
-#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
+# define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
   lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
 
 /* Like lll_futex_wait_requeue_pi, but with a timeout.  */
-#define lll_futex_timed_wait_requeue_pi(futexp, val, timeout, clockbit, \
+# define lll_futex_timed_wait_requeue_pi(futexp, val, timeout, clockbit, \
                                         mutex, private)                 \
-  -ENOSYS
+  lll_futex_syscall (5, futexp,                                         \
+		     __lll_private_flag (FUTEX_WAIT_REQUEUE_PI          \
+					 | (clockbit), private),        \
+		     val, timeout, mutex)
 
 /* Like lll_futex_requeue, but pairs with lll_futex_wait_requeue_pi
    and inherits priority from the waiter.  */
-#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex,       \
+# define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex,       \
                                  val, private)                          \
-  -ENOSYS
+  lll_futex_syscall (6, futexp,                                         \
+		     __lll_private_flag (FUTEX_CMP_REQUEUE_PI,          \
+					 private),                      \
+		     nr_wake, nr_move, mutex, val)
 
 /* Like lll_futex_wait, but acting as a cancellable entrypoint.  */
-#define lll_futex_wait_cancel(futexp, val, private) \
-  -ENOSYS
+# define lll_futex_wait_cancel(futexp, val, private) \
+  ({                                                                   \
+    int __oldtype = CANCEL_ASYNC ();				       \
+    long int __err = lll_futex_wait (futexp, val, LLL_SHARED);	       \
+    CANCEL_RESET (__oldtype);					       \
+    __err;							       \
+  })
 
 /* Like lll_futex_timed_wait, but acting as a cancellable entrypoint.  */
-#define lll_futex_timed_wait_cancel(futexp, val, timeout, private) \
-  -ENOSYS
+# define lll_futex_timed_wait_cancel(futexp, val, timeout, private) \
+  ({									   \
+    int __oldtype = CANCEL_ASYNC ();				       	   \
+    long int __err = lll_futex_timed_wait (futexp, val, timeout, private); \
+    CANCEL_RESET (__oldtype);						   \
+    __err;								   \
+  })
+
+#endif  /* !__ASSEMBLER__  */
 
 #endif  /* lowlevellock-futex.h */