kernel: do not release a waiter on a zero-count syncOnAddress wake (linux only) (#168)

* kernel: do not release a waiter on a zero-count syncOnAddress wake

sceKernelSyncOnAddressWake with a count of 0 must release no waiters. On
Linux it released exactly one.

WakeLinux passes the count straight to FUTEX_WAKE, which does not treat 0
as "wake nobody": the kernel's wake loop tests `if (++ret >= nr_wake) break`
after waking a waiter, so any waiter present is released before the loop can
break. A standalone futex program confirms it -- FUTEX_WAKE with val = 0
returns 1, and the waiter observes its wait return 0 with the word unchanged.

WakePortable already short-circuits count == 0, so the two backends of the
same ABI disagreed, with only the Linux one wrong.

TestWakeZeroIsNoOp in SyncOnAddressTests covers exactly this and fails on
Linux without the fix (15 consecutive failures on the assertion "zero-count
wake releases no waiters"); with the fix the suite passes 15 consecutive runs.

* kernel: shorten zero-count futex comment

---------

Co-authored-by: nmzik <Nmzik@mail.ru>

src/common/CMakeLists.txt

@@ -24,6 +24,7 @@ target_link_libraries(common
 		Tracy::TracyClient
 	PRIVATE
 		cpuinfo
+		kyty_git_version
 		spdlog::spdlog
 )
 

src/common/assert.cpp

@@ -3,6 +3,7 @@
 #include "common/debug.h"
 #include "common/logging/log.h"
 #include "common/subsystems.h"
+#include "kytyGitVersion.h"
 
 #include <cstdio>
 #include <cstdlib>
@@ -23,7 +24,7 @@ static std::string BuildFatalReport(const char* title, std::string_view text, co
 	DebugStack stack;
 	DebugStack::Trace(&stack);
 
-	std::string report = "--- Stack Trace ---\n";
+	std::string report = "--- Build ---\n" KYTY_BUILD_LABEL "\n--- Stack Trace ---\n";
 	for (int i = PRINT_STACK_FROM; i < stack.depth; i++) {
 		report += fmt::format("[{}] {:016x}\n", i - PRINT_STACK_FROM,
 		                      static_cast<uint64_t>(stack.GetAddr(i)));

src/graphics/presentation/window/window.cpp

@@ -938,13 +938,6 @@ void WindowContext::UpdateTitle() {
 	static constexpr auto build_type = "Unknown";
 #endif
 
-#if defined(KYTY_OFFICIAL_BUILD)
-	static constexpr auto build_label = "Official build " KYTY_RELEASE_TAG;
-#elif defined(KYTY_FORK_BUILD)
-	static constexpr auto build_label = "Fork build " KYTY_BUILD_REPOSITORY " " KYTY_GIT_HASH;
-#else
-	static constexpr auto build_label = "Source build " KYTY_GIT_HASH;
-#endif
 
 	const auto now       = Common::Timer::QueryPerformanceCounter();
 	const auto frequency = Common::Timer::QueryPerformanceFrequency();
@@ -957,7 +950,7 @@ void WindowContext::UpdateTitle() {
 		fps_frames  = 0;
 	}
 
-	auto fps = fmt::format("[{} | {}] {}{}{}{}{}{}[{}] [{}], frame: {}, fps: {:f}", build_label,
+	auto fps = fmt::format("[{} | {}] {}{}{}{}{}{}[{}] [{}], frame: {}, fps: {:f}", KYTY_BUILD_LABEL,
 	                       build_type, (has_title ? title : ""), (has_title ? ", " : ""),
 	                       (has_title_id ? title_id : ""), (has_title_id ? ", " : ""),
 	                       (has_app_ver ? app_ver : ""), (has_app_ver ? " " : ""), device_name,

src/kernel/syncOnAddress.cpp

@@ -119,6 +119,11 @@ int WaitLinux(volatile T* address, T expected, const uint32_t* timeout_micros,
 }
 
 int WakeLinux(volatile void* address, int32_t count) {
+	// The legacy FUTEX_WAKE path may wake one waiter when count is zero.
+	if (count == 0) {
+		return OK;
+	}
+
 	const auto result = syscall(SYS_futex, const_cast<void*>(address), FUTEX_WAKE_PRIVATE, count,
 	                            nullptr, nullptr, 0);
 	return result < 0 ? KERNEL_ERROR_EINVAL : OK;

src/kytyGitVersion.h.in

@@ -1,2 +1,13 @@
+#include "cmake_config.h"
+
 #define KYTY_GIT_VERSION "@KYTY_GIT_VERSION@"
 #define KYTY_GIT_HASH "@KYTY_GIT_HASH@"
+
+/* Build provenance, shown in the window title and in crash reports. */
+#if defined(KYTY_OFFICIAL_BUILD)
+#define KYTY_BUILD_LABEL "Official build " KYTY_RELEASE_TAG
+#elif defined(KYTY_FORK_BUILD)
+#define KYTY_BUILD_LABEL "Fork build " KYTY_BUILD_REPOSITORY " " KYTY_GIT_HASH
+#else
+#define KYTY_BUILD_LABEL "Source build " KYTY_GIT_HASH
+#endif

src/libs/controller.cpp

@@ -208,7 +208,8 @@ void GameController::AddState(const ControllerState& state) {
 void GameController::Button(int id, uint32_t button, bool down) {
 	Common::LockGuard lock(m_mutex);
 
-	if (m_active_id == id) {
+	// The keyboard shares the player-1 pad with the active gamepad.
+	if (m_active_id == id || id == HOST_INPUT_CONTROLLER_ID) {
 		auto state = GetLastState();
 
 		state.time = LibKernel::KernelGetProcessTime();
@@ -226,7 +227,7 @@ void GameController::Button(int id, uint32_t button, bool down) {
 void GameController::Axis(int id, Controller::Axis axis, int value) {
 	Common::LockGuard lock(m_mutex);
 
-	if (m_active_id == id) {
+	if (m_active_id == id || id == HOST_INPUT_CONTROLLER_ID) {
 		auto state = GetLastState();
 
 		state.time = LibKernel::KernelGetProcessTime();