Support futexes on FreeBSD

libc/runtime/clone.c

@@ -112,7 +112,7 @@ WinThreadEntry(int rdi,                                 // rcx
   // since we didn't indirect this function through NT2SYSV() it's not
   // safe to simply return, and as such, we just call ExitThread().
   __imp_ExitThread(rc);
-  unreachable;
+  notpossible;
 }
 
 static textwindows int CloneWindows(int (*func)(void *, int), char *stk,
@@ -192,7 +192,7 @@ XnuThreadMain(void *pthread,                    // rdi
                : "=m"(*wt->ztid)
                : "a"(0x2000000 | 361), "D"(0), "S"(0), "d"(0)
                : "rcx", "r10", "r11", "memory");
-  unreachable;
+  notpossible;
 }
 
 static int CloneXnu(int (*fn)(void *), char *stk, size_t stksz, int flags,
@@ -239,12 +239,15 @@ static wontreturn void FreebsdThreadMain(void *p) {
   wt->func(wt->arg, wt->tid);
   // we no longer use the stack after this point
   // void thr_exit(%rdi = long *state);
-  asm volatile("movl\t$0,%0\n\t"  // *wt->ztid = 0
+  asm volatile("movl\t$0,%0\n\t"       // *wt->ztid = 0
-               "syscall"          // thr_exit()
+               "syscall\n\t"           // _umtx_op()
+               "movl\t$431,%%eax\n\t"  // thr_exit()
+               "xor\t%%edi,%%edi\n\t"
+               "syscall"
                : "=m"(*wt->ztid)
-               : "a"(431), "D"(0)
+               : "a"(454), "D"(wt->ztid), "S"(UMTX_OP_WAKE)
-               : "rcx", "r11", "memory");
+               : "rcx", "r8", "r9", "r10", "r11", "memory");
-  unreachable;
+  notpossible;
 }
 
 static int CloneFreebsd(int (*func)(void *, int), char *stk, size_t stksz,
@@ -318,7 +321,7 @@ noasan static wontreturn void OpenbsdThreadMain(void *p) {
                : "a"(83), "m"(oldrsp), "D"(wt->ztid), "S"(FUTEX_WAKE),
                  "d"(INT_MAX)
                : "rcx", "r11", "memory");
-  unreachable;
+  notpossible;
 }
 
 static int CloneOpenbsd(int (*func)(void *, int), char *stk, size_t stksz,
@@ -372,7 +375,7 @@ static wontreturn void NetbsdThreadMain(void *arg,                 // rdi
                : "=a"(ax), "=d"(dx), "=m"(*ztid)
                : "0"(310)
                : "rcx", "r11", "memory");
-  unreachable;
+  notpossible;
 }
 
 static int CloneNetbsd(int (*func)(void *, int), char *stk, size_t stksz,

libc/sysv/calls/sys_umtx_op.s

@@ -0,0 +1,2 @@
+.include "o/libc/sysv/macros.internal.inc"
+.scall sys_umtx_op,0xffffff1c6fffffff,globl

libc/sysv/consts.sh

@@ -1316,9 +1316,9 @@ syscon	rusage	RUSAGE_BOTH				-2			99			99			99			99			99			# woop
 #
 #	group	name					GNU/Systemd		XNU's Not UNIX!		FreeBSD			OpenBSD			NetBSD			The New Technology	Commentary
 syscon	futex	FUTEX_WAIT				0			0			0			1			0			0
-syscon	futex	FUTEX_WAKE				1			0			0			2			0			1
+syscon	futex	FUTEX_WAKE				1			0			1			2			0			1
 syscon	futex	FUTEX_REQUEUE				3			0			0			3			0			0
-syscon	futex	FUTEX_PRIVATE_FLAG			128			0			0			128			0			0
+syscon	futex	FUTEX_PRIVATE_FLAG			128			0			128			128			0			0
 
 #	lio_listio() magnums
 #

libc/sysv/consts/FUTEX_PRIVATE_FLAG.s

@@ -1,2 +1,2 @@
 .include "o/libc/sysv/consts/syscon.internal.inc"
-.syscon futex,FUTEX_PRIVATE_FLAG,128,0,0,128,0,0
+.syscon futex,FUTEX_PRIVATE_FLAG,128,0,128,128,0,0

libc/sysv/consts/FUTEX_WAKE.s

@@ -1,2 +1,2 @@
 .include "o/libc/sysv/consts/syscon.internal.inc"
-.syscon futex,FUTEX_WAKE,1,0,0,2,0,1
+.syscon futex,FUTEX_WAKE,1,0,1,2,0,1

libc/sysv/syscalls.sh

@@ -18,6 +18,7 @@
 ╚────────────────────────────────────────────────────────────────'>/dev/null #*/
 dir=libc/sysv/calls
 . libc/sysv/gen.sh
+#include "libc/calls/syscall-sysv.internal.h"
 
 #       The Fifth Bell System Interface, Community Edition     ┌─────────────────────────┐
 #	» so many numbers                                      │ legend                  │
@@ -641,7 +642,7 @@ scall	sys_bsdthread_register	0xfffffffff216efff	globl hidden
 #scall	write_nocancel		0xfffffffff218dfff	globl
 #scall	writev_nocancel		0xfffffffff219cfff	globl
 #──────────────────────────FREEBSD───────────────────────────
-#scall	_umtx_op		0xffffff1c6fffffff	globl
+scall	sys_umtx_op		0xffffff1c6fffffff	globl
 #scall	abort2			0xffffff1cffffffff	globl
 #scall	afs3_syscall		0xffffff179fffffff	globl
 #scall	bindat			0xffffff21afffffff	globl

libc/thread/freebsd.internal.h

@@ -1,8 +1,8 @@
 #ifndef COSMOPOLITAN_LIBC_THREAD_FREEBSD_INTERNAL_H_
 #define COSMOPOLITAN_LIBC_THREAD_FREEBSD_INTERNAL_H_
-#include "libc/intrin/asmflag.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/errno.h"
+#include "libc/intrin/asmflag.h"
 
 /**
  * @fileoverview FreeBSD Threading
@@ -11,9 +11,12 @@
  *     maximum legal range is PID_MAX + 2 (100001) through INT_MAX
  */
 
-#define UMTX_OP_MUTEX_WAIT 17
+#define UMTX_OP_WAIT              2
-#define UMTX_OP_MUTEX_WAKE 18
+#define UMTX_OP_WAIT_UINT         11
-#define UMTX_ABSTIME       1
+#define UMTX_OP_WAIT_UINT_PRIVATE 15
+#define UMTX_OP_WAKE              3
+#define UMTX_OP_WAKE_PRIVATE      16
+#define UMTX_ABSTIME              1
 
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
@@ -42,7 +45,7 @@ struct _umtx_time {
   uint32_t _clockid;
 };
 
-int _umtx_op(void *, int, unsigned long, void *, void *);
+int sys_umtx_op(void *, int, unsigned long, void *, void *);
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

libc/thread/pthread_cond_timedwait.c

@@ -27,14 +27,14 @@
  * Waits for condition with optional time limit, e.g.
  *
  *     struct timespec ts;  // one second timeout
- *     ts = _timespec_add(_timespec_mono(), _timespec_frommillis(1000));
+ *     ts = _timespec_add(_timespec_real(), _timespec_frommillis(1000));
  *     if (pthread_cond_timedwait(cond, mutex, &ts) == ETIMEDOUT) {
  *       // handle timeout...
  *     }
  *
  * @param mutex needs to be held by thread when calling this function
  * @param abstime may be null to wait indefinitely and should contain
- *     some arbitrary interval added to a `CLOCK_MONOTONIC` timestamp
+ *     some arbitrary interval added to a `CLOCK_REALTIME` timestamp
  * @return 0 on success, or errno on error
  * @raise ETIMEDOUT if `abstime` was specified and the current time
  *     exceeded its value

libc/thread/wait0.c

@@ -29,6 +29,7 @@
 #include "libc/nt/runtime.h"
 #include "libc/nt/synchronization.h"
 #include "libc/sysv/consts/futex.h"
+#include "libc/thread/freebsd.internal.h"
 #include "libc/thread/wait0.internal.h"
 
 int _futex(atomic_int *, int, int, const struct timespec *);
@@ -64,6 +65,8 @@ static void _wait0_futex(const atomic_int *a, int e) {
     } else {
       rc = -GetLastError();
     }
+  } else if (IsFreebsd()) {
+    rc = sys_umtx_op(a, UMTX_OP_WAIT_UINT, 0, 0, 0);
   } else {
     rc = _futex(a, op, e, 0);
     if (IsOpenbsd() && rc > 0) {

third_party/nsync/futex.c

@@ -25,7 +25,9 @@
 #include "libc/limits.h"
 #include "libc/nt/runtime.h"
 #include "libc/nt/synchronization.h"
+#include "libc/sysv/consts/clock.h"
 #include "libc/sysv/consts/futex.h"
+#include "libc/thread/freebsd.internal.h"
 #include "libc/thread/thread.h"
 #include "third_party/nsync/common.internal.h"
 #include "third_party/nsync/futex.internal.h"
@@ -52,6 +54,14 @@ __attribute__((__constructor__)) static void nsync_futex_init_ (void) {
 		return;
 	}
 
+	if (IsFreebsd ()) {
+		FUTEX_IS_SUPPORTED = true;
+		FUTEX_WAIT_ = FUTEX_WAIT;
+		FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
+		FUTEX_TIMEOUT_IS_ABSOLUTE = true;
+		return;
+	}
+
         if (!(FUTEX_IS_SUPPORTED = IsLinux () || IsOpenbsd ())) {
 		// we're using sched_yield() so let's
 		// avoid needless clock_gettime calls
@@ -75,14 +85,14 @@ __attribute__((__constructor__)) static void nsync_futex_init_ (void) {
 		FUTEX_WAIT_ = FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME;
 		FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
 		FUTEX_TIMEOUT_IS_ABSOLUTE = true;
-	} else if (IsLinux () && 
+	} else if (!IsTiny () && IsLinux () &&
 		   _futex (&x, FUTEX_WAIT_BITSET, 1, 0, 0,
 			   FUTEX_BITSET_MATCH_ANY) == -EAGAIN) {
 		FUTEX_WAIT_ = FUTEX_WAIT_BITSET;
 		FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
 		FUTEX_TIMEOUT_IS_ABSOLUTE = true;
 	} else if (IsOpenbsd () ||
-		   (IsLinux () && 
+		   (!IsTiny () && IsLinux () &&
 		    !_futex (&x, FUTEX_WAKE_PRIVATE, 1, 0, 0, 0))) {
 		FUTEX_WAIT_ = FUTEX_WAIT;
 		FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
@@ -92,8 +102,9 @@ __attribute__((__constructor__)) static void nsync_futex_init_ (void) {
 }
 
 int nsync_futex_wait_ (int *p, int expect, char pshare, struct timespec *timeout) {
-	int rc, op;
+	size_t size;
 	uint32_t ms;
+	int rc, op, fop;
 
 	if (!FUTEX_IS_SUPPORTED) {
 		nsync_yield_ ();
@@ -105,6 +116,10 @@ int nsync_futex_wait_ (int *p, int expect, char pshare, struct timespec *timeout
 	}
 
 	op = FUTEX_WAIT_;
+	if (pshare == PTHREAD_PROCESS_PRIVATE) {
+		op |= FUTEX_PRIVATE_FLAG_;
+	}
+
 	if (NSYNC_FUTEX_WIN32 && IsWindows ()) {
 		if (timeout) {
 			ms = _timespec_tomillis (*timeout);
@@ -116,10 +131,25 @@ int nsync_futex_wait_ (int *p, int expect, char pshare, struct timespec *timeout
 		} else {
 			rc = -GetLastError ();
 		}
-	} else {
+	} else if (IsFreebsd ()) {
-		if (pshare == PTHREAD_PROCESS_PRIVATE) {
+		struct _umtx_time *put, ut;
-			op |= FUTEX_PRIVATE_FLAG_;
+		if (!timeout) {
+			put = 0;
+			size = 0;
+		} else {
+			ut._flags = UMTX_ABSTIME;
+			ut._clockid = CLOCK_REALTIME;
+			ut._timeout = *timeout;
+			put = &ut;
+			size = sizeof(ut);
 		}
+		if (pshare) {
+			fop = UMTX_OP_WAIT_UINT;
+		} else {
+			fop = UMTX_OP_WAIT_UINT_PRIVATE;
+		}
+		rc = sys_umtx_op (p, fop, 0, &size, put);
+	} else {
 		rc = _futex (p, op, expect, timeout, 0, FUTEX_WAIT_BITS_);
 		if (IsOpenbsd() && rc > 0) {
 			// [jart] openbsd does this without setting carry flag
@@ -136,7 +166,7 @@ int nsync_futex_wait_ (int *p, int expect, char pshare, struct timespec *timeout
 }
 
 int nsync_futex_wake_ (int *p, int count, char pshare) {
-	int rc, op;
+	int rc, op, fop;
 	int wake (void *, int, int) asm ("_futex");
 
 	ASSERT (count == 1 || count == INT_MAX);
@@ -147,6 +177,10 @@ int nsync_futex_wake_ (int *p, int count, char pshare) {
 	}
 
 	op = FUTEX_WAKE;
+	if (pshare == PTHREAD_PROCESS_PRIVATE) {
+		op |= FUTEX_PRIVATE_FLAG_;
+	}
+
 	if (NSYNC_FUTEX_WIN32 && IsWindows ()) {
 		if (count == 1) {
 			WakeByAddressSingle (p);
@@ -154,10 +188,14 @@ int nsync_futex_wake_ (int *p, int count, char pshare) {
 			WakeByAddressAll (p);
 		}
 		rc = 0;
-	} else {
+	} else if (IsFreebsd ()) {
-		if (pshare == PTHREAD_PROCESS_PRIVATE) {
+		if (pshare) {
-			op |= FUTEX_PRIVATE_FLAG_;
+			fop = UMTX_OP_WAKE;
+		} else {
+			fop = UMTX_OP_WAKE_PRIVATE;
 		}
+		rc = sys_umtx_op (p, fop, count, 0, 0);
+	} else {
 		rc = wake (p, op, count);
 	}