Change the thread ID (thr_id_t) used for 1:1 threading from being a

pointer to the corresponding struct thread to the thread ID (lwpid_t)
assigned to that thread. The primary reason for this change is that
libthr now internally uses the same ID as the debugger and the kernel
when referencing to a kernel thread. This allows us to implement the
support for debugging without additional translations and/or mappings.

To preserve the ABI, the 1:1 threading syscalls, including the umtx
locking API have not been changed to work on a lwpid_t. Instead the
1:1 threading syscalls operate on long and the umtx locking API has
not been changed except for the contested bit. Previously this was
the least significant bit. Now it's the most significant bit. Since
the contested bit should not be tested by userland, this change is
not expected to be visible. Just to be sure, UMTX_CONTESTED has been
removed from <sys/umtx.h>.

Reviewed by: mtm@
ABI preservation tested on: i386, ia64

4 files changed, 9 insertions, 19 deletions

diff --git a/lib/libthr/thread/thr_cond.c b/lib/libthr/thread/thr_cond.c
index dedd3c2..b2cbb83 100644
--- a/lib/libthr/thread/thr_cond.c
+++ b/lib/libthr/thread/thr_cond.c
@@ -439,11 +439,11 @@ cond_queue_enq(pthread_cond_t cond, pthread_t pthread)
 
 	name = pthread->name ? pthread->name : "unknown";
 	if ((pthread->flags & PTHREAD_FLAGS_IN_CONDQ) != 0)
-		_thread_printf(2, "Thread (%s:%u) already on condq\n",
-		    pthread->name, pthread->uniqueid);
+		_thread_printf(2, "Thread (%s:%ld) already on condq\n",
+		    pthread->name, pthread->thr_id);
 	if ((pthread->flags & PTHREAD_FLAGS_IN_MUTEXQ) != 0)
-		_thread_printf(2, "Thread (%s:%u) already on mutexq\n",
-		    pthread->name, pthread->uniqueid);
+		_thread_printf(2, "Thread (%s:%ld) already on mutexq\n",
+		    pthread->name, pthread->thr_id);
 	PTHREAD_ASSERT_NOT_IN_SYNCQ(pthread);
 
 	/*
diff --git a/lib/libthr/thread/thr_create.c b/lib/libthr/thread/thr_create.c
index 8eff861..a6193327 100644
--- a/lib/libthr/thread/thr_create.c
+++ b/lib/libthr/thread/thr_create.c
@@ -43,11 +43,8 @@
 #include "thr_private.h"
 #include "libc_private.h"
 
-static u_int64_t next_uniqueid = 1;
-
 #define OFF(f)	offsetof(struct pthread, f)
 int _thread_next_offset			= OFF(tle.tqe_next);
-int _thread_uniqueid_offset		= OFF(uniqueid);
 int _thread_name_offset			= OFF(name);
 int _thread_ctx_offset			= OFF(ctx);
 #undef OFF
@@ -137,12 +134,6 @@ _pthread_create(pthread_t * thread, const pthread_attr_t * attr,
 	}
 	new_thread->active_priority = new_thread->base_priority;
 
-	/*
-	 * Initialise the unique id which GDB uses to
-	 * track threads.
-	 */
-	new_thread->uniqueid = next_uniqueid++;
-
 	THREAD_LIST_LOCK;
 
 	/* Add the thread to the linked list of all threads: */
diff --git a/lib/libthr/thread/thr_mutex.c b/lib/libthr/thread/thr_mutex.c
index 46a0625..ca16cb6 100644
--- a/lib/libthr/thread/thr_mutex.c
+++ b/lib/libthr/thread/thr_mutex.c
@@ -799,11 +799,11 @@ mutex_queue_enq(pthread_mutex_t mutex, pthread_t pthread)
 
 	name = pthread->name ? pthread->name : "unknown";
 	if ((pthread->flags & PTHREAD_FLAGS_IN_CONDQ) != 0)
-		_thread_printf(2, "Thread (%s:%u) already on condq\n",
-		    pthread->name, pthread->uniqueid);
+		_thread_printf(2, "Thread (%s:%ld) already on condq\n",
+		    pthread->name, pthread->thr_id);
 	if ((pthread->flags & PTHREAD_FLAGS_IN_MUTEXQ) != 0)
-		_thread_printf(2, "Thread (%s:%u) already on mutexq\n",
-		    pthread->name, pthread->uniqueid);
+		_thread_printf(2, "Thread (%s:%ld) already on mutexq\n",
+		    pthread->name, pthread->thr_id);
 	PTHREAD_ASSERT_NOT_IN_SYNCQ(pthread);
 	/*
 	 * For the common case of all threads having equal priority,
diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h
index 4e78de2..e6ba4aa 100644
--- a/lib/libthr/thread/thr_private.h
+++ b/lib/libthr/thread/thr_private.h
@@ -478,8 +478,7 @@ struct pthread {
 #define	PTHREAD_MAGIC		((u_int32_t) 0xd09ba115)
 	u_int32_t		magic;
 	char			*name;
-	u_int64_t		uniqueid; /* for gdb */
-	thr_id_t		thr_id;
+	long			thr_id;
 	sigset_t		savedsig;
 	int			signest; /* blocked signal netsting level */
 	int			ptdflags; /* used by other other threads