Merge branch 't/gsync-libc' into refs/top-bases/tschwinge/Roger_Whittaker

8 files changed, 383 insertions, 6 deletions

diff --git a/hurd/Makefile b/hurd/Makefile
index 85c295ac06..59e7d42355 100644
--- a/hurd/Makefile
+++ b/hurd/Makefile
@@ -56,6 +56,7 @@ routines = hurdstartup hurdinit \
 	   ports-get ports-set hurdports hurdmsg \
 	   errno-loc \
 	   sysvshm \
+	   hurdlock \
 	   $(sig) $(dtable) $(inlines) port-cleanup report-wait xattr
 sig	= hurdsig hurdfault siginfo hurd-raise preempt-sig \
 	  trampoline longjmp-ts catch-exc exc2signal hurdkill sigunwind \
diff --git a/hurd/Versions b/hurd/Versions
index b80323293e..7502d32a22 100644
--- a/hurd/Versions
+++ b/hurd/Versions
@@ -152,4 +152,13 @@ libc {
     cthread_keycreate; cthread_getspecific; cthread_setspecific;
     __libc_getspecific;
   }
+
+  GLIBC_PRIVATE {
+    # Used by other libs.
+    lll_xwait; lll_timed_wait; lll_timed_xwait;
+    __lll_abstimed_wait; __lll_abstimed_xwait;
+    __lll_abstimed_lock; lll_robust_lock;
+    __lll_robust_abstimed_lock; lll_robust_trylock;
+    lll_set_wake; lll_robust_unlock; lll_requeue;
+  }
 }
diff --git a/hurd/hurdlock.c b/hurd/hurdlock.c
new file mode 100644
index 0000000000..d6e47316ea
--- /dev/null
+++ b/hurd/hurdlock.c
@@ -0,0 +1,247 @@
+/* Copyright (C) 1999-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "hurdlock.h"
+#include <hurd.h>
+#include <time.h>
+#include <errno.h>
+
+int lll_xwait (void *ptr, int lo, int hi, int flags)
+{
+  return (__gsync_wait (__mach_task_self (),
+    (vm_offset_t)ptr, lo, hi, 0, flags | GSYNC_QUAD));
+}
+
+int lll_timed_wait (void *ptr, int val, int mlsec, int flags)
+{
+  return (__gsync_wait (__mach_task_self (),
+    (vm_offset_t)ptr, val, 0, mlsec, flags | GSYNC_TIMED));
+}
+
+int lll_timed_xwait (void *ptr, int lo,
+  int hi, int mlsec, int flags)
+{
+  return (__gsync_wait (__mach_task_self (), (vm_offset_t)ptr,
+    lo, hi, mlsec, flags | GSYNC_TIMED | GSYNC_QUAD));
+}
+
+/* Convert an absolute timeout in nanoseconds to a relative
+ * timeout in milliseconds. */
+static inline int __attribute__ ((gnu_inline))
+compute_reltime (const struct timespec *abstime, clockid_t clk)
+{
+  struct timespec ts;
+  __clock_gettime (clk, &ts);
+
+  ts.tv_sec = abstime->tv_sec - ts.tv_sec;
+  ts.tv_nsec = abstime->tv_nsec - ts.tv_nsec;
+
+  if (ts.tv_nsec < 0)
+    {
+      --ts.tv_sec;
+      ts.tv_nsec += 1000000000;
+    }
+
+  return (ts.tv_sec < 0 ? -1 :
+    (int)(ts.tv_sec * 1000 + ts.tv_nsec / 1000000));
+}
+
+int __lll_abstimed_wait (void *ptr, int val,
+  const struct timespec *tsp, int flags, int clk)
+{
+  int mlsec = compute_reltime (tsp, clk);
+  return (mlsec < 0 ? KERN_TIMEDOUT :
+    lll_timed_wait (ptr, val, mlsec, flags));
+}
+
+int __lll_abstimed_xwait (void *ptr, int lo, int hi,
+  const struct timespec *tsp, int flags, int clk)
+{
+  int mlsec = compute_reltime (tsp, clk);
+  return (mlsec < 0 ? KERN_TIMEDOUT :
+    lll_timed_xwait (ptr, lo, hi, mlsec, flags));
+}
+
+int __lll_abstimed_lock (void *ptr,
+  const struct timespec *tsp, int flags, int clk)
+{
+  if (lll_trylock (ptr) == 0)
+    return (0);
+
+  while (1)
+    {
+      if (atomic_exchange_acq ((int *)ptr, 2) == 0)
+        return (0);
+      else if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
+        return (EINVAL);
+
+      int mlsec = compute_reltime (tsp, clk);
+      if (mlsec < 0 || lll_timed_wait (ptr,
+          2, mlsec, flags) == KERN_TIMEDOUT)
+        return (ETIMEDOUT);
+    }
+}
+
+void lll_set_wake (void *ptr, int val, int flags)
+{
+  __gsync_wake (__mach_task_self (),
+    (vm_offset_t)ptr, val, flags | GSYNC_MUTATE);
+}
+
+void lll_requeue (void *src, void *dst, int wake_one, int flags)
+{
+  __gsync_requeue (__mach_task_self (), (vm_offset_t)src,
+    (vm_offset_t)dst, (boolean_t)wake_one, flags);
+}
+
+/* Robust locks. */
+
+extern int __getpid (void) __attribute__ ((const));
+extern task_t __pid2task (int);
+
+/* Test if a given process id is still valid. */
+static inline int valid_pid (int pid)
+{
+  task_t task = __pid2task (pid);
+  if (task == MACH_PORT_NULL)
+    return (0);
+
+  __mach_port_deallocate (__mach_task_self (), task);
+  return (1);
+}
+
+/* Robust locks have currently no support from the kernel; they
+ * are simply implemented with periodic polling. When sleeping, the
+ * maximum blocking time is determined by this constant. */
+#define MAX_WAIT_TIME   1500
+
+int lll_robust_lock (void *ptr, int flags)
+{
+  int *iptr = (int *)ptr;
+  int id = __getpid ();
+  int wait_time = 25;
+  unsigned int val;
+
+  /* Try to set the lock word to our PID if it's clear. Otherwise,
+   * mark it as having waiters. */
+  while (1)
+    {
+      val = *iptr;
+      if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+        return (0);
+      else if (atomic_compare_and_exchange_bool_acq (iptr,
+          val | LLL_WAITERS, val) == 0)
+        break;
+    }
+
+  for (id |= LLL_WAITERS ; ; )
+    {
+      val = *iptr;
+      if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+        return (0);
+      else if (val && !valid_pid (val & LLL_OWNER_MASK))
+        {
+          if (atomic_compare_and_exchange_bool_acq (iptr, id, val) == 0)
+            return (EOWNERDEAD);
+        }
+      else
+        {
+          lll_timed_wait (iptr, val, wait_time, flags);
+          if (wait_time < MAX_WAIT_TIME)
+            wait_time <<= 1;
+        }
+    }
+}
+
+int __lll_robust_abstimed_lock (void *ptr,
+  const struct timespec *tsp, int flags, int clk)
+{
+  int *iptr = (int *)ptr;
+  int id = __getpid ();
+  int wait_time = 25;
+  unsigned int val;
+
+  while (1)
+    {
+      val = *iptr;
+      if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+        return (0);
+      else if (atomic_compare_and_exchange_bool_acq (iptr,
+          val | LLL_WAITERS, val) == 0)
+        break;
+    }
+
+  for (id |= LLL_WAITERS ; ; )
+    {
+      val = *iptr;
+      if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+        return (0);
+      else if (val && !valid_pid (val & LLL_OWNER_MASK))
+        {
+          if (atomic_compare_and_exchange_bool_acq (iptr, id, val) == 0)
+            return (EOWNERDEAD);
+        }
+      else
+        {
+          int mlsec = compute_reltime (tsp, clk);
+          if (mlsec < 0)
+            return (ETIMEDOUT);
+          else if (mlsec > wait_time)
+            mlsec = wait_time;
+
+          int res = lll_timed_wait (iptr, val, mlsec, flags);
+          if (res == KERN_TIMEDOUT)
+            return (ETIMEDOUT);
+          else if (wait_time < MAX_WAIT_TIME)
+            wait_time <<= 1;
+        }
+    }
+}
+
+int lll_robust_trylock (void *ptr)
+{
+  int *iptr = (int *)ptr;
+  int id = __getpid ();
+  unsigned int val = *iptr;
+
+  if (!val)
+    {
+      if (atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+        return (0);
+    }
+  else if (!valid_pid (val & LLL_OWNER_MASK) &&
+      atomic_compare_and_exchange_bool_acq (iptr, id, val) == 0)
+    return (EOWNERDEAD);
+
+  return (EBUSY);
+}
+
+void lll_robust_unlock (void *ptr, int flags)
+{
+  while (1)
+    {
+      unsigned int val = *(unsigned int *)ptr;
+      if (val & LLL_WAITERS)
+        {
+          lll_set_wake (ptr, 0, flags);
+          break;
+        }
+      else if (atomic_compare_and_exchange_bool_rel ((int *)ptr, 0, val) == 0)
+        break;
+    }
+}
+
diff --git a/hurd/hurdlock.h b/hurd/hurdlock.h
new file mode 100644
index 0000000000..405ffaf5f9
--- /dev/null
+++ b/hurd/hurdlock.h
@@ -0,0 +1,117 @@
+/* Copyright (C) 1999-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _HURD_LOCK_H
+#define _HURD_LOCK_H   1
+
+#include <mach/lowlevellock.h>
+
+struct timespec;
+
+/* Flags for robust locks. */
+#define LLL_WAITERS      (1U << 31)
+#define LLL_DEAD_OWNER   (1U << 30)
+
+#define LLL_OWNER_MASK   ~(LLL_WAITERS | LLL_DEAD_OWNER)
+
+/* Wait on 64-bit address PTR, without blocking if its contents
+ * are different from the pair <LO, HI>. */
+extern int lll_xwait (void *__ptr, int __lo,
+  int __hi, int __flags);
+
+/* Same as 'lll_wait', but only block for MLSEC milliseconds. */
+extern int lll_timed_wait (void *__ptr, int __val,
+  int __mlsec, int __flags);
+
+/* Same as 'lll_xwait', but only block for MLSEC milliseconds. */
+extern int lll_timed_xwait (void *__ptr, int __lo,
+  int __hi, int __mlsec, int __flags);
+
+/* Same as 'lll_wait', but only block until TSP elapses,
+ * using clock CLK. */
+extern int __lll_abstimed_wait (void *__ptr, int __val,
+  const struct timespec *__tsp, int __flags, int __clk);
+
+/* Same as 'lll_xwait', but only block until TSP elapses,
+ * using clock CLK. */
+extern int __lll_abstimed_xwait (void *__ptr, int __lo, int __hi,
+  const struct timespec *__tsp, int __flags, int __clk);
+
+/* Same as 'lll_lock', but return with an error if TSP elapses,
+ * using clock CLK. */
+extern int __lll_abstimed_lock (void *__ptr,
+  const struct timespec *__tsp, int __flags, int __clk);
+
+/* Acquire the lock at PTR, but return with an error if
+ * the process containing the owner thread dies. */
+extern int lll_robust_lock (void *__ptr, int __flags);
+
+/* Same as 'lll_robust_lock', but only block until TSP
+ * elapses, using clock CLK. */
+extern int __lll_robust_abstimed_lock (void *__ptr,
+  const struct timespec *__tsp, int __flags, int __clk);
+
+/* Same as 'lll_robust_lock', but return with an error
+ * if the lock cannot be acquired without blocking. */
+extern int lll_robust_trylock (void *__ptr);
+
+/* Wake one or more threads waiting on address PTR,
+ * setting its value to VAL before doing so. */
+extern void lll_set_wake (void *__ptr, int __val, int __flags);
+
+/* Release the robust lock at PTR. */
+extern void lll_robust_unlock (void *__ptr, int __flags);
+
+/* Rearrange threads waiting on address SRC to instead wait on
+ * DST, waking one of them if WAIT_ONE is non-zero. */
+extern void lll_requeue (void *__src, void *__dst,
+  int __wake_one, int __flags);
+
+/* The following are hacks that allow us to simulate optional
+ * parameters in C, to avoid having to pass the clock id for
+ * every one of these calls, defaulting to CLOCK_REALTIME if
+ * no argument is passed. */
+
+#define lll_abstimed_wait(ptr, val, tsp, flags, ...)   \
+  ({   \
+     const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ };   \
+     __lll_abstimed_wait ((ptr), (val), (tsp), (flags),   \
+       __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]);   \
+   })
+
+#define lll_abstimed_xwait(ptr, lo, hi, tsp, flags, ...)   \
+  ({   \
+     const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ };   \
+     __lll_abstimed_xwait ((ptr), (lo), (hi), (tsp), (flags),   \
+       __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]);   \
+   })
+
+#define lll_abstimed_lock(ptr, tsp, flags, ...)   \
+  ({   \
+     const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ };   \
+     __lll_abstimed_lock ((ptr), (tsp), (flags),   \
+       __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]);   \
+   })
+
+#define lll_robust_abstimed_lock(ptr, tsp, flags, ...)   \
+  ({   \
+     const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ };   \
+     __lll_robust_abstimed_lock ((ptr), (tsp), (flags),   \
+       __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]);   \
+   })
+
+#endif
diff --git a/hurd/hurdpid.c b/hurd/hurdpid.c
index 633ad6db24..56df97c6b8 100644
--- a/hurd/hurdpid.c
+++ b/hurd/hurdpid.c
@@ -16,6 +16,8 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <hurd.h>
+#include <lowlevellock.h>
+
 pid_t _hurd_pid, _hurd_ppid, _hurd_pgrp;
 int _hurd_orphaned;
 
@@ -66,6 +68,7 @@ _S_msg_proc_newids (mach_port_t me,
 
   /* Notify any waiting user threads that the id change as been completed.  */
   ++_hurd_pids_changed_stamp;
+  lll_wake (&_hurd_pids_changed_stamp, GSYNC_BROADCAST);
 
   return 0;
 }
diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
index 5ed63b900a..072a870337 100644
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -1572,14 +1572,14 @@ reauth_proc (mach_port_t new)
   __mach_port_destroy (__mach_task_self (), ref);
 
   /* Set the owner of the process here too. */
-  mutex_lock (&_hurd_id.lock);
+  __mutex_lock (&_hurd_id.lock);
   if (!_hurd_check_ids ())
     HURD_PORT_USE (&_hurd_ports[INIT_PORT_PROC],
 		   __proc_setowner (port,
 				    (_hurd_id.gen.nuids
 				     ? _hurd_id.gen.uids[0] : 0),
 				    !_hurd_id.gen.nuids));
-  mutex_unlock (&_hurd_id.lock);
+  __mutex_unlock (&_hurd_id.lock);
 
   (void) &reauth_proc;		/* Silence compiler warning.  */
 }
diff --git a/hurd/setauth.c b/hurd/setauth.c
index 916772f21b..b835c0a80a 100644
--- a/hurd/setauth.c
+++ b/hurd/setauth.c
@@ -18,14 +18,13 @@
 #include <hurd.h>
 #include <hurd/port.h>
 #include <hurd/id.h>
+#include <hurdlock.h>
 #include "set-hooks.h"
 
 /* Things in the library which want to be run when the auth port changes.  */
 DEFINE_HOOK (_hurd_reauth_hook, (auth_t new_auth));
 
-#include <cthreads.h>
-static struct mutex reauth_lock = MUTEX_INITIALIZER;
-
+static unsigned int reauth_lock = LLL_INITIALIZER;
 
 /* Set the auth port to NEW, and reauthenticate
    everything used by the library.  */
diff --git a/hurd/sysvshm.c b/hurd/sysvshm.c
index 5d538a6373..e049345135 100644
--- a/hurd/sysvshm.c
+++ b/hurd/sysvshm.c
@@ -26,6 +26,7 @@
 #include <dirent.h>
 #include <sys/stat.h>
 #include <sys/shm.h>
+#include <hurdlock.h>
 
 
 /* Description of an shm attachment.  */
@@ -45,7 +46,7 @@ struct sysvshm_attach
 static struct sysvshm_attach *sysvshm_list;
 
 /* A lock to protect the linked list of shared memory attachments.  */
-static struct mutex sysvshm_lock = MUTEX_INITIALIZER;
+static unsigned int sysvshm_lock = LLL_INITIALIZER;
 
 
 /* Adds a segment attachment.  */