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wine-staging/patches/ntdll-NtAlertThreadByThreadId/0007-ntdll-Reimplement-Win32-futexes-on-top-of-thread-ID-.patch

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From 4b2ad3bf49e77c6cb0e541329ac851d054e6f649 Mon Sep 17 00:00:00 2001
From: Zebediah Figura <z.figura12@gmail.com>
Date: Mon, 7 Jun 2021 16:26:18 -0500
Subject: [PATCH] ntdll: Reimplement Win32 futexes on top of thread-ID alerts.
Signed-off-by: Zebediah Figura <z.figura12@gmail.com>
Signed-off-by: Zebediah Figura <zfigura@codeweavers.com>
---
dlls/ntdll/sync.c | 173 ++++++++++++++++++++++++++++++++++++++-
dlls/ntdll/unix/loader.c | 3 -
dlls/ntdll/unix/sync.c | 162 ------------------------------------
dlls/ntdll/unixlib.h | 6 +-
4 files changed, 171 insertions(+), 173 deletions(-)
diff --git a/dlls/ntdll/sync.c b/dlls/ntdll/sync.c
index bfb30661864..adc03c9ff7a 100644
--- a/dlls/ntdll/sync.c
+++ b/dlls/ntdll/sync.c
@@ -34,11 +34,18 @@
#include "windef.h"
#include "winternl.h"
#include "wine/debug.h"
+#include "wine/list.h"
#include "ntdll_misc.h"
WINE_DEFAULT_DEBUG_CHANNEL(sync);
WINE_DECLARE_DEBUG_CHANNEL(relay);
+static const char *debugstr_timeout( const LARGE_INTEGER *timeout )
+{
+ if (!timeout) return "(infinite)";
+ return wine_dbgstr_longlong( timeout->QuadPart );
+}
+
/******************************************************************
* RtlRunOnceInitialize (NTDLL.@)
*/
@@ -863,13 +870,111 @@ NTSTATUS WINAPI RtlSleepConditionVariableSRW( RTL_CONDITION_VARIABLE *variable,
return status;
}
+/* RtlWaitOnAddress() and RtlWakeAddress*(), hereafter referred to as "Win32
+ * futexes", offer futex-like semantics with a variable set of address sizes,
+ * but are limited to a single process. They are also fair—the documentation
+ * specifies this, and tests bear it out.
+ *
+ * On Windows they are implemented using NtAlertThreadByThreadId and
+ * NtWaitForAlertByThreadId, which manipulate a single flag (similar to a
+ * manual-reset event) per thread. This can be tested by attempting to wake a
+ * thread waiting in RtlWaitOnAddress() via NtAlertThreadByThreadId.
+ */
+
+struct futex_entry
+{
+ struct list entry;
+ const void *addr;
+ DWORD tid;
+};
+
+struct futex_queue
+{
+ struct list queue;
+ LONG lock;
+};
+
+static struct futex_queue futex_queues[256];
+
+static struct futex_queue *get_futex_queue( const void *addr )
+{
+ ULONG_PTR val = (ULONG_PTR)addr;
+
+ return &futex_queues[(val >> 4) % ARRAY_SIZE(futex_queues)];
+}
+
+static void spin_wrlock( LONG *lock )
+{
+ while (InterlockedCompareExchange( lock, -1, 0 ))
+ YieldProcessor();
+}
+
+static void spin_wrunlock( LONG *lock )
+{
+ InterlockedExchange( lock, 0 );
+}
+
+static BOOL compare_addr( const void *addr, const void *cmp, SIZE_T size )
+{
+ switch (size)
+ {
+ case 1:
+ return (*(const UCHAR *)addr == *(const UCHAR *)cmp);
+ case 2:
+ return (*(const USHORT *)addr == *(const USHORT *)cmp);
+ case 4:
+ return (*(const ULONG *)addr == *(const ULONG *)cmp);
+ case 8:
+ return (*(const ULONG64 *)addr == *(const ULONG64 *)cmp);
+ }
+
+ return FALSE;
+}
+
/***********************************************************************
* RtlWaitOnAddress (NTDLL.@)
*/
NTSTATUS WINAPI RtlWaitOnAddress( const void *addr, const void *cmp, SIZE_T size,
const LARGE_INTEGER *timeout )
{
- return unix_funcs->RtlWaitOnAddress( addr, cmp, size, timeout );
+ struct futex_queue *queue = get_futex_queue( addr );
+ struct futex_entry entry;
+ NTSTATUS ret;
+
+ TRACE("addr %p cmp %p size %#Ix timeout %s\n", addr, cmp, size, debugstr_timeout( timeout ));
+
+ if (size != 1 && size != 2 && size != 4 && size != 8)
+ return STATUS_INVALID_PARAMETER;
+
+ entry.addr = addr;
+ entry.tid = GetCurrentThreadId();
+
+ spin_wrlock( &queue->lock );
+
+ if (!compare_addr( addr, cmp, size ))
+ {
+ spin_wrunlock( &queue->lock );
+ return STATUS_SUCCESS;
+ }
+
+ if (!queue->queue.next)
+ list_init( &queue->queue );
+ list_add_tail( &queue->queue, &entry.entry );
+
+ spin_wrunlock( &queue->lock );
+
+ ret = NtWaitForAlertByThreadId( NULL, timeout );
+
+ spin_wrlock( &queue->lock );
+ /* We may have already been removed by a call to RtlWakeAddressSingle(). */
+ if (entry.addr)
+ list_remove( &entry.entry );
+ spin_wrunlock( &queue->lock );
+
+ TRACE("returning %#x\n", ret);
+
+ if (ret == STATUS_ALERTED) ret = STATUS_SUCCESS;
+ return ret;
}
/***********************************************************************
@@ -877,7 +982,37 @@ NTSTATUS WINAPI RtlWaitOnAddress( const void *addr, const void *cmp, SIZE_T size
*/
void WINAPI RtlWakeAddressAll( const void *addr )
{
- return unix_funcs->RtlWakeAddressAll( addr );
+ struct futex_queue *queue = get_futex_queue( addr );
+ unsigned int count = 0, i;
+ struct futex_entry *entry;
+ DWORD tids[256];
+
+ TRACE("%p\n", addr);
+
+ if (!addr) return;
+
+ spin_wrlock( &queue->lock );
+
+ if (!queue->queue.next)
+ list_init(&queue->queue);
+
+ LIST_FOR_EACH_ENTRY( entry, &queue->queue, struct futex_entry, entry )
+ {
+ if (entry->addr == addr)
+ {
+ /* Try to buffer wakes, so that we don't make a system call while
+ * holding a spinlock. */
+ if (count < ARRAY_SIZE(tids))
+ tids[count++] = entry->tid;
+ else
+ NtAlertThreadByThreadId( (HANDLE)(DWORD_PTR)entry->tid );
+ }
+ }
+
+ spin_wrunlock( &queue->lock );
+
+ for (i = 0; i < count; ++i)
+ NtAlertThreadByThreadId( (HANDLE)(DWORD_PTR)tids[i] );
}
/***********************************************************************
@@ -885,5 +1020,37 @@ void WINAPI RtlWakeAddressAll( const void *addr )
*/
void WINAPI RtlWakeAddressSingle( const void *addr )
{
- return unix_funcs->RtlWakeAddressSingle( addr );
+ struct futex_queue *queue = get_futex_queue( addr );
+ struct futex_entry *entry;
+ DWORD tid = 0;
+
+ TRACE("%p\n", addr);
+
+ if (!addr) return;
+
+ spin_wrlock( &queue->lock );
+
+ if (!queue->queue.next)
+ list_init(&queue->queue);
+
+ LIST_FOR_EACH_ENTRY( entry, &queue->queue, struct futex_entry, entry )
+ {
+ if (entry->addr == addr)
+ {
+ /* Try to buffer wakes, so that we don't make a system call while
+ * holding a spinlock. */
+ tid = entry->tid;
+
+ /* Remove this entry from the queue, so that a simultaneous call to
+ * RtlWakeAddressSingle() will not also wake it—two simultaneous
+ * calls must wake at least two waiters if they exist. */
+ entry->addr = NULL;
+ list_remove( &entry->entry );
+ break;
+ }
+ }
+
+ spin_wrunlock( &queue->lock );
+
+ if (tid) NtAlertThreadByThreadId( (HANDLE)(DWORD_PTR)tid );
}
diff --git a/dlls/ntdll/unix/loader.c b/dlls/ntdll/unix/loader.c
index a411b01a389..59bc978022c 100644
--- a/dlls/ntdll/unix/loader.c
+++ b/dlls/ntdll/unix/loader.c
@@ -2146,9 +2146,6 @@ static struct unix_funcs unix_funcs =
NtCurrentTeb,
#endif
RtlGetSystemTimePrecise,
- RtlWaitOnAddress,
- RtlWakeAddressAll,
- RtlWakeAddressSingle,
fast_RtlpWaitForCriticalSection,
fast_RtlpUnWaitCriticalSection,
fast_RtlDeleteCriticalSection,
diff --git a/dlls/ntdll/unix/sync.c b/dlls/ntdll/unix/sync.c
index ce78c11fd4b..c37dbc5e96e 100644
--- a/dlls/ntdll/unix/sync.c
+++ b/dlls/ntdll/unix/sync.c
@@ -74,10 +74,6 @@ WINE_DEFAULT_DEBUG_CHANNEL(sync);
HANDLE keyed_event = 0;
-static const LARGE_INTEGER zero_timeout;
-
-static pthread_mutex_t addr_mutex = PTHREAD_MUTEX_INITIALIZER;
-
static const char *debugstr_timeout( const LARGE_INTEGER *timeout )
{
if (!timeout) return "(infinite)";
@@ -187,24 +183,6 @@ static void timespec_from_timeout( struct timespec *timespec, const LARGE_INTEGE
#endif
-static BOOL compare_addr( const void *addr, const void *cmp, SIZE_T size )
-{
- switch (size)
- {
- case 1:
- return (*(const UCHAR *)addr == *(const UCHAR *)cmp);
- case 2:
- return (*(const USHORT *)addr == *(const USHORT *)cmp);
- case 4:
- return (*(const ULONG *)addr == *(const ULONG *)cmp);
- case 8:
- return (*(const ULONG64 *)addr == *(const ULONG64 *)cmp);
- }
-
- return FALSE;
-}
-
-
/* create a struct security_descriptor and contained information in one contiguous piece of memory */
NTSTATUS alloc_object_attributes( const OBJECT_ATTRIBUTES *attr, struct object_attributes **ret,
data_size_t *ret_len )
@@ -3035,71 +3013,6 @@ NTSTATUS CDECL fast_RtlWakeConditionVariable( RTL_CONDITION_VARIABLE *variable,
return STATUS_SUCCESS;
}
-
-/* We can't map addresses to futex directly, because an application can wait on
- * 8 bytes, and we can't pass all 8 as the compare value to futex(). Instead we
- * map all addresses to a small fixed table of futexes. This may result in
- * spurious wakes, but the application is already expected to handle those. */
-
-static int addr_futex_table[256];
-
-static inline int *hash_addr( const void *addr )
-{
- ULONG_PTR val = (ULONG_PTR)addr;
-
- return &addr_futex_table[(val >> 2) & 255];
-}
-
-static inline NTSTATUS fast_wait_addr( const void *addr, const void *cmp, SIZE_T size,
- const LARGE_INTEGER *timeout )
-{
- int *futex;
- int val;
- struct timespec timespec;
- int ret;
-
- if (!use_futexes())
- return STATUS_NOT_IMPLEMENTED;
-
- futex = hash_addr( addr );
-
- /* We must read the previous value of the futex before checking the value
- * of the address being waited on. That way, if we receive a wake between
- * now and waiting on the futex, we know that val will have changed.
- * Use an atomic load so that memory accesses are ordered between this read
- * and the increment below. */
- val = InterlockedCompareExchange( futex, 0, 0 );
- if (!compare_addr( addr, cmp, size ))
- return STATUS_SUCCESS;
-
- if (timeout)
- {
- timespec_from_timeout( &timespec, timeout );
- ret = futex_wait( futex, val, &timespec );
- }
- else
- ret = futex_wait( futex, val, NULL );
-
- if (ret == -1 && errno == ETIMEDOUT)
- return STATUS_TIMEOUT;
- return STATUS_SUCCESS;
-}
-
-static inline NTSTATUS fast_wake_addr( const void *addr )
-{
- int *futex;
-
- if (!use_futexes())
- return STATUS_NOT_IMPLEMENTED;
-
- futex = hash_addr( addr );
-
- InterlockedIncrement( futex );
-
- futex_wake( futex, INT_MAX );
- return STATUS_SUCCESS;
-}
-
#else
NTSTATUS CDECL fast_RtlTryAcquireSRWLockExclusive( RTL_SRWLOCK *lock )
@@ -3142,79 +3055,4 @@ NTSTATUS CDECL fast_wait_cv( RTL_CONDITION_VARIABLE *variable, const void *value
return STATUS_NOT_IMPLEMENTED;
}
-static inline NTSTATUS fast_wait_addr( const void *addr, const void *cmp, SIZE_T size,
- const LARGE_INTEGER *timeout )
-{
- return STATUS_NOT_IMPLEMENTED;
-}
-
-static inline NTSTATUS fast_wake_addr( const void *addr )
-{
- return STATUS_NOT_IMPLEMENTED;
-}
-
#endif
-
-
-/***********************************************************************
- * RtlWaitOnAddress (NTDLL.@)
- */
-NTSTATUS WINAPI RtlWaitOnAddress( const void *addr, const void *cmp, SIZE_T size,
- const LARGE_INTEGER *timeout )
-{
- select_op_t select_op;
- NTSTATUS ret;
- timeout_t abs_timeout = timeout ? timeout->QuadPart : TIMEOUT_INFINITE;
-
- if (size != 1 && size != 2 && size != 4 && size != 8)
- return STATUS_INVALID_PARAMETER;
-
- if ((ret = fast_wait_addr( addr, cmp, size, timeout )) != STATUS_NOT_IMPLEMENTED)
- return ret;
-
- mutex_lock( &addr_mutex );
- if (!compare_addr( addr, cmp, size ))
- {
- mutex_unlock( &addr_mutex );
- return STATUS_SUCCESS;
- }
-
- if (abs_timeout < 0)
- {
- LARGE_INTEGER now;
-
- NtQueryPerformanceCounter( &now, NULL );
- abs_timeout -= now.QuadPart;
- }
-
- select_op.keyed_event.op = SELECT_KEYED_EVENT_WAIT;
- select_op.keyed_event.handle = wine_server_obj_handle( keyed_event );
- select_op.keyed_event.key = wine_server_client_ptr( addr );
-
- return server_select( &select_op, sizeof(select_op.keyed_event), SELECT_INTERRUPTIBLE,
- abs_timeout, NULL, &addr_mutex, NULL );
-}
-
-/***********************************************************************
- * RtlWakeAddressAll (NTDLL.@)
- */
-void WINAPI RtlWakeAddressAll( const void *addr )
-{
- if (fast_wake_addr( addr ) != STATUS_NOT_IMPLEMENTED) return;
-
- mutex_lock( &addr_mutex );
- while (NtReleaseKeyedEvent( 0, addr, 0, &zero_timeout ) == STATUS_SUCCESS) {}
- mutex_unlock( &addr_mutex );
-}
-
-/***********************************************************************
- * RtlWakeAddressSingle (NTDLL.@)
- */
-void WINAPI RtlWakeAddressSingle( const void *addr )
-{
- if (fast_wake_addr( addr ) != STATUS_NOT_IMPLEMENTED) return;
-
- mutex_lock( &addr_mutex );
- NtReleaseKeyedEvent( 0, addr, 0, &zero_timeout );
- mutex_unlock( &addr_mutex );
-}
diff --git a/dlls/ntdll/unixlib.h b/dlls/ntdll/unixlib.h
index 62030d91cdb..ded05c40e17 100644
--- a/dlls/ntdll/unixlib.h
+++ b/dlls/ntdll/unixlib.h
@@ -26,7 +26,7 @@
struct _DISPATCHER_CONTEXT;
/* increment this when you change the function table */
-#define NTDLL_UNIXLIB_VERSION 128
+#define NTDLL_UNIXLIB_VERSION 129
struct unix_funcs
{
@@ -37,10 +37,6 @@ struct unix_funcs
/* other Win32 API functions */
LONGLONG (WINAPI *RtlGetSystemTimePrecise)(void);
- NTSTATUS (WINAPI *RtlWaitOnAddress)( const void *addr, const void *cmp, SIZE_T size,
- const LARGE_INTEGER *timeout );
- void (WINAPI *RtlWakeAddressAll)( const void *addr );
- void (WINAPI *RtlWakeAddressSingle)( const void *addr );
/* fast locks */
NTSTATUS (CDECL *fast_RtlpWaitForCriticalSection)( RTL_CRITICAL_SECTION *crit, int timeout );
--
2.33.0
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