diff --git a/libitm/Makefile.am b/libitm/Makefile.am
index 09c21ff..ee1822b 100644
--- a/libitm/Makefile.am
+++ b/libitm/Makefile.am
@@ -51,6 +51,9 @@ x86_sse.lo : XCFLAGS += -msse
x86_avx.lo : XCFLAGS += -mavx
endif
+if ARCH_FUTEX
+libitm_la_SOURCES += futex.cc
+endif
# Automake Documentation:
# If your package has Texinfo files in many directories, you can use the
diff --git a/libitm/Makefile.in b/libitm/Makefile.in
index 57f76f6..524753e 100644
--- a/libitm/Makefile.in
+++ b/libitm/Makefile.in
@@ -37,6 +37,7 @@ build_triplet = @build@
host_triplet = @host@
target_triplet = @target@
@ARCH_X86_TRUE@am__append_1 = x86_sse.cc x86_avx.cc
+@ARCH_FUTEX_TRUE@am__append_2 = futex.cc
subdir = .
DIST_COMMON = $(am__configure_deps) $(srcdir)/../config.guess \
$(srcdir)/../config.sub $(srcdir)/../depcomp \
@@ -49,6 +50,7 @@ ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
am__aclocal_m4_deps = $(top_srcdir)/../config/acx.m4 \
$(top_srcdir)/../config/depstand.m4 \
$(top_srcdir)/../config/enable.m4 \
+ $(top_srcdir)/../config/futex.m4 \
$(top_srcdir)/../config/lead-dot.m4 \
$(top_srcdir)/../config/mmap.m4 \
$(top_srcdir)/../config/multi.m4 \
@@ -95,12 +97,14 @@ am__libitm_la_SOURCES_DIST = aatree.cc alloc.cc alloc_c.cc \
alloc_cpp.cc barrier.cc beginend.cc clone.cc cacheline.cc \
cachepage.cc eh_cpp.cc local.cc query.cc retry.cc rwlock.cc \
useraction.cc util.cc sjlj.S tls.cc method-serial.cc \
- x86_sse.cc x86_avx.cc
+ x86_sse.cc x86_avx.cc futex.cc
@ARCH_X86_TRUE@am__objects_1 = x86_sse.lo x86_avx.lo
+@ARCH_FUTEX_TRUE@am__objects_2 = futex.lo
am_libitm_la_OBJECTS = aatree.lo alloc.lo alloc_c.lo alloc_cpp.lo \
barrier.lo beginend.lo clone.lo cacheline.lo cachepage.lo \
eh_cpp.lo local.lo query.lo retry.lo rwlock.lo useraction.lo \
- util.lo sjlj.lo tls.lo method-serial.lo $(am__objects_1)
+ util.lo sjlj.lo tls.lo method-serial.lo $(am__objects_1) \
+ $(am__objects_2)
libitm_la_OBJECTS = $(am_libitm_la_OBJECTS)
DEFAULT_INCLUDES = -I.@am__isrc@
depcomp = $(SHELL) $(top_srcdir)/../depcomp
@@ -369,7 +373,8 @@ libitm_la_LDFLAGS = $(libitm_version_info) $(libitm_version_script) \
libitm_la_SOURCES = aatree.cc alloc.cc alloc_c.cc alloc_cpp.cc \
barrier.cc beginend.cc clone.cc cacheline.cc cachepage.cc \
eh_cpp.cc local.cc query.cc retry.cc rwlock.cc useraction.cc \
- util.cc sjlj.S tls.cc method-serial.cc $(am__append_1)
+ util.cc sjlj.S tls.cc method-serial.cc $(am__append_1) \
+ $(am__append_2)
# Automake Documentation:
# If your package has Texinfo files in many directories, you can use the
@@ -499,6 +504,7 @@ distclean-compile:
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/cachepage.Plo@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/clone.Plo@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/eh_cpp.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/futex.Plo@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/local.Plo@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/method-serial.Plo@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/query.Plo@am__quote@
diff --git a/libitm/aclocal.m4 b/libitm/aclocal.m4
index ff6ddad..6dcccdf 100644
--- a/libitm/aclocal.m4
+++ b/libitm/aclocal.m4
@@ -993,6 +993,7 @@ AC_SUBST([am__untar])
m4_include([../config/acx.m4])
m4_include([../config/depstand.m4])
m4_include([../config/enable.m4])
+m4_include([../config/futex.m4])
m4_include([../config/lead-dot.m4])
m4_include([../config/mmap.m4])
m4_include([../config/multi.m4])
diff --git a/libitm/beginend.cc b/libitm/beginend.cc
index 7863042..e53ea6c 100644
--- a/libitm/beginend.cc
+++ b/libitm/beginend.cc
@@ -23,6 +23,7 @@
. */
#include "libitm_i.h"
+#include
using namespace GTM;
diff --git a/libitm/config/linux/alpha/futex_bits.h b/libitm/config/linux/alpha/futex_bits.h
new file mode 100644
index 0000000..5a7a474
--- /dev/null
+++ b/libitm/config/linux/alpha/futex_bits.h
@@ -0,0 +1,56 @@
+/* Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+ Contributed by Richard Henderson .
+
+ This file is part of the GNU Transactional Memory Library (libitm).
+
+ Libitm is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libitm 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ . */
+
+/* Provide target-specific access to the futex system call. */
+
+#ifndef SYS_futex
+#define SYS_futex 394
+#endif
+
+static inline long
+sys_futex0 (int *addr, long op, long val)
+{
+ register long sc_0 __asm__("$0");
+ register long sc_16 __asm__("$16");
+ register long sc_17 __asm__("$17");
+ register long sc_18 __asm__("$18");
+ register long sc_19 __asm__("$19");
+ long res;
+
+ sc_0 = SYS_futex;
+ sc_16 = (long) addr;
+ sc_17 = op;
+ sc_18 = val;
+ sc_19 = 0;
+ __asm volatile ("callsys"
+ : "=r" (sc_0), "=r"(sc_19)
+ : "0"(sc_0), "r" (sc_16), "r"(sc_17), "r"(sc_18), "1"(sc_19)
+ : "$1", "$2", "$3", "$4", "$5", "$6", "$7", "$8",
+ "$22", "$23", "$24", "$25", "$27", "$28", "memory");
+
+ res = sc_0;
+ if (__builtin_expect (sc_19, 0))
+ res = -res;
+ return res;
+}
diff --git a/libitm/config/linux/futex.cc b/libitm/config/linux/futex.cc
new file mode 100644
index 0000000..9585108
--- /dev/null
+++ b/libitm/config/linux/futex.cc
@@ -0,0 +1,82 @@
+/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
+ Contributed by Richard Henderson .
+
+ This file is part of the GNU Transactional Memory Library (libitm).
+
+ Libitm is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libitm 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ . */
+
+/* Provide access to the futex system call. */
+
+#include "libitm_i.h"
+#include "futex.h"
+#include
+
+namespace GTM HIDDEN {
+
+#define FUTEX_WAIT 0
+#define FUTEX_WAKE 1
+#define FUTEX_PRIVATE_FLAG 128L
+
+
+static long int gtm_futex_wait = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
+static long int gtm_futex_wake = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
+
+
+void
+futex_wait (int *addr, int val)
+{
+ long res;
+
+ res = sys_futex0 (addr, gtm_futex_wait, val);
+ if (__builtin_expect (res == -ENOSYS, 0))
+ {
+ gtm_futex_wait = FUTEX_WAIT;
+ gtm_futex_wake = FUTEX_WAKE;
+ res = sys_futex0 (addr, FUTEX_WAIT, val);
+ }
+ if (__builtin_expect (res < 0, 0))
+ {
+ if (res == -EWOULDBLOCK || res == -ETIMEDOUT)
+ ;
+ else if (res == -EFAULT)
+ GTM_fatal ("futex failed (EFAULT %p)", addr);
+ else
+ GTM_fatal ("futex failed (%s)", strerror(-res));
+ }
+}
+
+
+long
+futex_wake (int *addr, int count)
+{
+ long res = sys_futex0 (addr, gtm_futex_wake, count);
+ if (__builtin_expect (res == -ENOSYS, 0))
+ {
+ gtm_futex_wait = FUTEX_WAIT;
+ gtm_futex_wake = FUTEX_WAKE;
+ res = sys_futex0 (addr, FUTEX_WAKE, count);
+ }
+ if (__builtin_expect (res < 0, 0))
+ GTM_fatal ("futex failed (%s)", strerror(-res));
+ else
+ return res;
+}
+
+} // namespace GTM
diff --git a/libitm/config/linux/futex.h b/libitm/config/linux/futex.h
new file mode 100644
index 0000000..3471119
--- /dev/null
+++ b/libitm/config/linux/futex.h
@@ -0,0 +1,39 @@
+/* Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+ Contributed by Richard Henderson .
+
+ This file is part of the GNU Transactional Memory Library (libitm).
+
+ Libitm is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libitm 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ . */
+
+/* Provide access to the futex system call. */
+
+#ifndef GTM_FUTEX_H
+#define GTM_FUTEX_H 1
+
+namespace GTM HIDDEN {
+
+#include "futex_bits.h"
+
+extern void futex_wait (int *addr, int val);
+extern long futex_wake (int *addr, int count);
+
+}
+
+#endif /* GTM_FUTEX_H */
diff --git a/libitm/config/linux/rwlock.cc b/libitm/config/linux/rwlock.cc
new file mode 100644
index 0000000..ea5427d
--- /dev/null
+++ b/libitm/config/linux/rwlock.cc
@@ -0,0 +1,235 @@
+/* Copyright (C) 2011 Free Software Foundation, Inc.
+ Contributed by Torvald Riegel .
+
+ This file is part of the GNU Transactional Memory Library (libitm).
+
+ Libitm is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libitm 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ . */
+
+#include "libitm_i.h"
+#include "futex.h"
+#include
+
+namespace GTM HIDDEN {
+
+// Acquire a RW lock for reading.
+
+void
+gtm_rwlock::read_lock (gtm_thread *tx)
+{
+ for (;;)
+ {
+ // Fast path: first announce our intent to read, then check for
+ // conflicting intents to write. The barrier makes sure that this
+ // happens in exactly this order.
+ tx->shared_state = 0;
+ __sync_synchronize();
+ if (likely(writers == 0))
+ return;
+
+ // There seems to be an active, waiting, or confirmed writer, so enter
+ // the futex-based slow path.
+
+ // Before waiting, we clear our read intent check whether there are any
+ // writers that might potentially wait for readers. If so, wake them.
+ // We need the barrier here for the same reason that we need it in
+ // read_unlock().
+ // TODO Potentially too many wake-ups. See comments in read_unlock().
+ tx->shared_state = ~(typeof tx->shared_state)0;
+ __sync_synchronize();
+ if (writer_readers > 0)
+ {
+ writer_readers = 0;
+ futex_wake(&writer_readers, 1);
+ }
+
+ // Signal that there are waiting readers and wait until there is no
+ // writer anymore.
+ // TODO Spin here on writers for a while. Consider whether we woke
+ // any writers before?
+ while (writers)
+ {
+ // An active writer. Wait until it has finished. To avoid lost
+ // wake-ups, we need to use Dekker-like synchronization.
+ // Note that we cannot reset readers to zero when we see that there
+ // are no writers anymore after the barrier because this pending
+ // store could then lead to lost wake-ups at other readers.
+ readers = 1;
+ __sync_synchronize();
+ if (writers)
+ futex_wait(&readers, 1);
+ }
+
+ // And we try again to acquire a read lock.
+ }
+}
+
+
+// Acquire a RW lock for writing. Generic version that also works for
+// upgrades.
+// Note that an upgrade might fail (and thus waste previous work done during
+// this transaction) if there is another thread that tried to go into serial
+// mode earlier (i.e., upgrades do not have higher priority than pure writers).
+// However, this seems rare enough to not consider it further as we need both
+// a non-upgrade writer and a writer to happen to switch to serial mode
+// concurrently. If we'd want to handle this, a writer waiting for readers
+// would have to coordinate with later arriving upgrades and hand over the
+// lock to them, including the the reader-waiting state. We can try to support
+// this if this will actually happen often enough in real workloads.
+
+bool
+gtm_rwlock::write_lock_generic (gtm_thread *tx)
+{
+ // Try to acquire the write lock.
+ unsigned int w;
+ if (unlikely((w = __sync_val_compare_and_swap(&writers, 0, 1)) != 0))
+ {
+ // If this is an upgrade, we must not wait for other writers or
+ // upgrades.
+ if (tx != 0)
+ return false;
+
+ // There is already a writer. If there are no other waiting writers,
+ // switch to contended mode.
+ // Note that this is actually an atomic exchange, not a TAS. Also,
+ // it's only guaranteed to have acquire semantics, whereas we need a
+ // full barrier to make the Dekker-style synchronization work. However,
+ // we rely on the xchg being a full barrier on the architectures that we
+ // consider here.
+ // ??? Use C++0x atomics as soon as they are available.
+ if (w != 2)
+ w = __sync_lock_test_and_set(&writers, 2);
+ while (w != 0)
+ {
+ futex_wait(&writers, 2);
+ w = __sync_lock_test_and_set(&writers, 2);
+ }
+ }
+
+ // We have acquired the writer side of the R/W lock. Now wait for any
+ // readers that might still be active.
+ // We don't need an extra barrier here because the CAS and the xchg
+ // operations have full barrier semantics already.
+
+ // If this is an upgrade, we are not a reader anymore. This is only safe to
+ // do after we have acquired the writer lock.
+ // TODO In the worst case, this requires one wait/wake pair for each
+ // active reader. Reduce this!
+ if (tx != 0)
+ tx->shared_state = ~(typeof tx->shared_state)0;
+
+ for (gtm_thread *it = gtm_thread::list_of_threads; it != 0;
+ it = it->next_thread)
+ {
+ // Use a loop here to check reader flags again after waiting.
+ while (it->shared_state != ~(typeof it->shared_state)0)
+ {
+ // An active reader. Wait until it has finished. To avoid lost
+ // wake-ups, we need to use Dekker-like synchronization.
+ // Note that we can reset writer_readers to zero when we see after
+ // the barrier that the reader has finished in the meantime;
+ // however, this is only possible because we are the only writer.
+ // TODO Spin for a while on this reader flag.
+ writer_readers = 1;
+ __sync_synchronize();
+ if (it->shared_state != ~(typeof it->shared_state)0)
+ futex_wait(&writer_readers, 1);
+ else
+ writer_readers = 0;
+ }
+ }
+
+ return true;
+}
+
+// Acquire a RW lock for writing.
+
+void
+gtm_rwlock::write_lock ()
+{
+ write_lock_generic (0);
+}
+
+
+// Upgrade a RW lock that has been locked for reading to a writing lock.
+// Do this without possibility of another writer incoming. Return false
+// if this attempt fails (i.e. another thread also upgraded).
+
+bool
+gtm_rwlock::write_upgrade (gtm_thread *tx)
+{
+ return write_lock_generic (tx);
+}
+
+
+// Release a RW lock from reading.
+
+void
+gtm_rwlock::read_unlock (gtm_thread *tx)
+{
+ tx->shared_state = ~(typeof tx->shared_state)0;
+
+ // If there is a writer waiting for readers, wake it up. We need the barrier
+ // to avoid lost wake-ups.
+ // ??? We might not be the last active reader, so the wake-up might happen
+ // too early. How do we avoid this without slowing down readers too much?
+ // Each reader could scan the list of txns for other active readers but
+ // this can result in many cache misses. Use combining instead?
+ // TODO Sends out one wake-up for each reader in the worst case.
+ __sync_synchronize();
+ if (unlikely(writer_readers > 0))
+ {
+ writer_readers = 0;
+ futex_wake(&writer_readers, 1);
+ }
+}
+
+
+// Release a RW lock from writing.
+
+void
+gtm_rwlock::write_unlock ()
+{
+ // This is supposed to be a full barrier.
+ if (__sync_fetch_and_sub(&writers, 1) == 2)
+ {
+ // There might be waiting writers, so wake them.
+ writers = 0;
+ if (futex_wake(&writers, 1) == 0)
+ {
+ // If we did not wake any waiting writers, we might indeed be the
+ // last writer (this can happen because write_lock_generic()
+ // exchanges 0 or 1 to 2 and thus might go to contended mode even if
+ // no other thread holds the write lock currently). Therefore, we
+ // have to wake up readers here as well.
+ futex_wake(&readers, INT_MAX);
+ }
+ return;
+ }
+ // No waiting writers, so wake up all waiting readers.
+ // Because the fetch_and_sub is a full barrier already, we don't need
+ // another barrier here (as in read_unlock()).
+ if (readers > 0)
+ {
+ readers = 0;
+ futex_wake(&readers, INT_MAX);
+ }
+}
+
+} // namespace GTM
diff --git a/libitm/config/linux/rwlock.h b/libitm/config/linux/rwlock.h
new file mode 100644
index 0000000..7e6229b
--- /dev/null
+++ b/libitm/config/linux/rwlock.h
@@ -0,0 +1,66 @@
+/* Copyright (C) 2011 Free Software Foundation, Inc.
+ Contributed by Torvald Riegel .
+
+ This file is part of the GNU Transactional Memory Library (libitm).
+
+ Libitm is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libitm 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ . */
+
+#ifndef GTM_RWLOCK_H
+#define GTM_RWLOCK_H
+
+#include "common.h"
+
+namespace GTM HIDDEN {
+
+struct gtm_thread;
+
+// This datastructure is the blocking, futex-based version of the Dekker-style
+// reader-writer lock used to provide mutual exclusion between active and
+// serial transactions.
+// See libitm's documentation for further details.
+//
+// In this implementation, writers are given highest priority access but
+// read-to-write upgrades do not have a higher priority than writers.
+
+class gtm_rwlock
+{
+ // TODO Put futexes on different cachelines?
+ int writers; // Writers' futex.
+ int writer_readers; // A confirmed writer waits here for readers.
+ int readers; // Readers wait here for writers (iff true).
+
+ public:
+ gtm_rwlock() : writers(0), writer_readers(0), readers(0) {};
+
+ void read_lock (gtm_thread *tx);
+ void read_unlock (gtm_thread *tx);
+
+ void write_lock ();
+ void write_unlock ();
+
+ bool write_upgrade (gtm_thread *tx);
+
+ protected:
+ bool write_lock_generic (gtm_thread *tx);
+};
+
+} // namespace GTM
+
+#endif // GTM_RWLOCK_H
diff --git a/libitm/config/linux/x86/futex_bits.h b/libitm/config/linux/x86/futex_bits.h
new file mode 100644
index 0000000..9362107
--- /dev/null
+++ b/libitm/config/linux/x86/futex_bits.h
@@ -0,0 +1,82 @@
+/* Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+ Contributed by Richard Henderson .
+
+ This file is part of the GNU Transactional Memory Library (libitm).
+
+ Libitm is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libitm 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ . */
+
+#ifdef __LP64__
+# ifndef SYS_futex
+# define SYS_futex 202
+# endif
+
+static inline long
+sys_futex0 (int *addr, long op, long val)
+{
+ register long r10 __asm__("%r10") = 0;
+ long res;
+
+ __asm volatile ("syscall"
+ : "=a" (res)
+ : "0" (SYS_futex), "D" (addr), "S" (op), "d" (val), "r" (r10)
+ : "r11", "rcx", "memory");
+
+ return res;
+}
+
+#else
+# ifndef SYS_futex
+# define SYS_futex 240
+# endif
+
+# ifdef __PIC__
+
+static inline long
+sys_futex0 (int *addr, int op, int val)
+{
+ long res;
+
+ __asm volatile ("xchgl\t%%ebx, %2\n\t"
+ "int\t$0x80\n\t"
+ "xchgl\t%%ebx, %2"
+ : "=a" (res)
+ : "0"(SYS_futex), "r" (addr), "c"(op),
+ "d"(val), "S"(0)
+ : "memory");
+ return res;
+}
+
+# else
+
+static inline long
+sys_futex0 (int *addr, int op, int val)
+{
+ long res;
+
+ __asm volatile ("int $0x80"
+ : "=a" (res)
+ : "0"(SYS_futex), "b" (addr), "c"(op),
+ "d"(val), "S"(0)
+ : "memory");
+ return res;
+}
+
+# endif /* __PIC__ */
+#endif /* __LP64__ */
diff --git a/libitm/config/posix/cachepage.cc b/libitm/config/posix/cachepage.cc
index 240d09f..3965a9e 100644
--- a/libitm/config/posix/cachepage.cc
+++ b/libitm/config/posix/cachepage.cc
@@ -23,6 +23,7 @@
. */
#include "libitm_i.h"
+#include
//
// We have three possibilities for alloction: mmap, memalign, posix_memalign
diff --git a/libitm/configure b/libitm/configure
index fe7f15b..6d18d87 100755
--- a/libitm/configure
+++ b/libitm/configure
@@ -601,6 +601,8 @@ ac_subst_vars='am__EXEEXT_FALSE
am__EXEEXT_TRUE
LTLIBOBJS
LIBOBJS
+ARCH_FUTEX_FALSE
+ARCH_FUTEX_TRUE
ARCH_X86_FALSE
ARCH_X86_TRUE
link_itm
@@ -762,6 +764,7 @@ enable_fast_install
with_gnu_ld
enable_libtool_lock
enable_maintainer_mode
+enable_linux_futex
enable_tls
enable_symvers
'
@@ -1412,6 +1415,7 @@ Optional Features:
--disable-libtool-lock avoid locking (might break parallel builds)
--enable-maintainer-mode enable make rules and dependencies not useful
(and sometimes confusing) to the casual installer
+ --enable-linux-futex use the Linux futex system call [default=default]
--enable-tls Use thread-local storage [default=yes]
--enable-symvers=STYLE enables symbol versioning of the shared library
[default=yes]
@@ -11811,7 +11815,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 11814 "configure"
+#line 11818 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -11917,7 +11921,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 11920 "configure"
+#line 11924 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -19139,6 +19143,113 @@ $as_echo "#define HAVE_BROKEN_POSIX_SEMAPHORES 1" >>confdefs.h
;;
esac
+ # Check whether --enable-linux-futex was given.
+if test "${enable_linux_futex+set}" = set; then :
+ enableval=$enable_linux_futex;
+ case "$enableval" in
+ yes|no|default) ;;
+ *) as_fn_error "Unknown argument to enable/disable linux-futex" "$LINENO" 5 ;;
+ esac
+
+else
+ enable_linux_futex=default
+fi
+
+
+case "$target" in
+ *-linux*)
+ case "$enable_linux_futex" in
+ default)
+ # If headers don't have gettid/futex syscalls definition, then
+ # default to no, otherwise there will be compile time failures.
+ # Otherwise, default to yes. If we don't detect we are
+ # compiled/linked against NPTL and not cross-compiling, check
+ # if programs are run by default against NPTL and if not, issue
+ # a warning.
+ enable_linux_futex=no
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+#include
+ int lk;
+int
+main ()
+{
+syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ save_LIBS="$LIBS"
+ LIBS="-lpthread $LIBS"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+#ifndef _GNU_SOURCE
+ #define _GNU_SOURCE 1
+ #endif
+ #include
+ pthread_t th; void *status;
+int
+main ()
+{
+pthread_tryjoin_np (th, &status);
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ enable_linux_futex=yes
+else
+ if test x$cross_compiling = xno; then
+ if getconf GNU_LIBPTHREAD_VERSION 2>/dev/null \
+ | LC_ALL=C grep -i NPTL > /dev/null 2>/dev/null; then :; else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: The kernel might not support futex or gettid syscalls.
+If so, please configure with --disable-linux-futex" >&5
+$as_echo "$as_me: WARNING: The kernel might not support futex or gettid syscalls.
+If so, please configure with --disable-linux-futex" >&2;}
+ fi
+ fi
+ enable_linux_futex=yes
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ LIBS="$save_LIBS"
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ ;;
+ yes)
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+#include
+ int lk;
+int
+main ()
+{
+syscall (SYS_gettid); syscall (SYS_futex, &lk, 0, 0, 0);
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+else
+ as_fn_error "SYS_gettid and SYS_futex required for --enable-linux-futex" "$LINENO" 5
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ ;;
+ esac
+ ;;
+ *)
+ enable_linux_futex=no
+ ;;
+esac
+if test x$enable_linux_futex = xyes; then
+ :
+fi
+
+
# See if we support thread-local storage.
@@ -20078,6 +20189,14 @@ else
ARCH_X86_FALSE=
fi
+ if test $enable_linux_futex = yes; then
+ ARCH_FUTEX_TRUE=
+ ARCH_FUTEX_FALSE='#'
+else
+ ARCH_FUTEX_TRUE='#'
+ ARCH_FUTEX_FALSE=
+fi
+
ac_config_files="$ac_config_files Makefile testsuite/Makefile libitm.spec"
@@ -20223,6 +20342,10 @@ if test -z "${ARCH_X86_TRUE}" && test -z "${ARCH_X86_FALSE}"; then
as_fn_error "conditional \"ARCH_X86\" was never defined.
Usually this means the macro was only invoked conditionally." "$LINENO" 5
fi
+if test -z "${ARCH_FUTEX_TRUE}" && test -z "${ARCH_FUTEX_FALSE}"; then
+ as_fn_error "conditional \"ARCH_FUTEX\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
: ${CONFIG_STATUS=./config.status}
ac_write_fail=0
diff --git a/libitm/configure.ac b/libitm/configure.ac
index c6892d6..f2c7ce6 100644
--- a/libitm/configure.ac
+++ b/libitm/configure.ac
@@ -196,6 +196,8 @@ case "$host" in
;;
esac
+GCC_LINUX_FUTEX(:)
+
# See if we support thread-local storage.
GCC_CHECK_TLS
@@ -255,6 +257,7 @@ fi
AC_SUBST(link_itm)
AM_CONDITIONAL([ARCH_X86], [test "$ARCH" = x86])
+AM_CONDITIONAL([ARCH_FUTEX], [test $enable_linux_futex = yes])
AC_CONFIG_FILES(Makefile testsuite/Makefile libitm.spec)
AC_OUTPUT
diff --git a/libitm/configure.tgt b/libitm/configure.tgt
index 68c81d4..853c082 100644
--- a/libitm/configure.tgt
+++ b/libitm/configure.tgt
@@ -89,6 +89,12 @@ config_path="$ARCH posix generic"
# Other system configury
case "${target}" in
+ *-*-linux*)
+ if test $enable_linux_futex = yes; then
+ config_path="linux/$ARCH linux $config_path"
+ fi
+ ;;
+
*-*-hpux11*)
# HPUX v11.x requires -lrt to resolve sem_init in libgomp.la
XLDFLAGS="${XLDFLAGS} -lrt"
diff --git a/libitm/testsuite/Makefile.in b/libitm/testsuite/Makefile.in
index 88ee292..ed1f314 100644
--- a/libitm/testsuite/Makefile.in
+++ b/libitm/testsuite/Makefile.in
@@ -40,6 +40,7 @@ ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
am__aclocal_m4_deps = $(top_srcdir)/../config/acx.m4 \
$(top_srcdir)/../config/depstand.m4 \
$(top_srcdir)/../config/enable.m4 \
+ $(top_srcdir)/../config/futex.m4 \
$(top_srcdir)/../config/lead-dot.m4 \
$(top_srcdir)/../config/mmap.m4 \
$(top_srcdir)/../config/multi.m4 \