orbis-kernel: Add SharedAtomic utility

Initial shared atomic implementation for Darwin

orbis-kernel/src/utils/SharedAtomic.cpp

@@ -0,0 +1,95 @@
+#include "utils/SharedAtomic.hpp"
+using namespace orbis;
+
+#ifdef ORBIS_HAS_FUTEX
+#include <linux/futex.h>
+
+std::errc shared_atomic32::wait_impl(std::uint32_t oldValue,
+                                     std::chrono::microseconds usec_timeout) {
+  auto usec_timeout_count = usec_timeout.count();
+  struct timespec timeout{};
+  timeout.tv_nsec = (usec_timeout_count % 1000'000) * 1000;
+  timeout.tv_sec = (usec_timeout_count / 1000'000);
+
+  int result = syscall(
+      SYS_futex, this, FUTEX_WAIT, oldValue,
+      usec_timeout != std::chrono::microseconds::max() ? &timeout : nullptr, 0,
+      0);
+
+  if (result < 0) {
+    return static_cast<std::errc>(errno);
+  }
+
+  return {};
+}
+
+int shared_atomic32::notify_n(int count) const {
+  return syscall(SYS_futex, this, FUTEX_WAKE, count);
+}
+#elif defined(ORBIS_HAS_ULOCK)
+#include <limits>
+
+#define UL_COMPARE_AND_WAIT 1
+#define UL_UNFAIR_LOCK 2
+#define UL_COMPARE_AND_WAIT_SHARED 3
+#define UL_UNFAIR_LOCK64_SHARED 4
+#define UL_COMPARE_AND_WAIT64 5
+#define UL_COMPARE_AND_WAIT64_SHARED 6
+
+#define ULF_WAKE_ALL 0x00000100
+#define ULF_WAKE_THREAD 0x00000200
+#define ULF_WAKE_ALLOW_NON_OWNER 0x00000400
+
+#define ULF_WAIT_WORKQ_DATA_CONTENTION 0x00010000
+#define ULF_WAIT_CANCEL_POINT 0x00020000
+#define ULF_WAIT_ADAPTIVE_SPIN 0x00040000
+
+#define ULF_NO_ERRNO 0x01000000
+
+#define UL_OPCODE_MASK 0x000000FF
+#define UL_FLAGS_MASK 0xFFFFFF00
+#define ULF_GENERIC_MASK 0xFFFF0000
+
+extern int __ulock_wait(uint32_t operation, void *addr, uint64_t value,
+                        uint32_t timeout);
+extern int __ulock_wake(uint32_t operation, void *addr, uint64_t wake_value);
+
+std::errc shared_atomic32::wait_impl(std::uint32_t oldValue,
+                                     std::chrono::microseconds usec_timeout) {
+  int result = __ulock_wait(UL_COMPARE_AND_WAIT_SHARED, (void *)this, oldValue,
+                            usec_timeout.count());
+
+  if (result < 0) {
+    return static_cast<std::errc>(errno);
+  }
+
+  return {};
+}
+
+int shared_atomic32::notify_n(int count) const {
+  int result = 0;
+  uint32_t operation = UL_COMPARE_AND_WAIT_SHARED | ULF_NO_ERRNO;
+  if (count == 1) {
+    result = __ulock_wake(operation, (void *)this, 0);
+  } else if (count == std::numeric_limits<int>::max()) {
+    result = __ulock_wake(ULF_WAKE_ALL | operation, (void *)this, 0);
+  } else {
+    for (int i = 0; i < count; ++i) {
+      auto ret = __ulock_wake(operation, (void *)this, 0);
+      if (ret != 0) {
+        if (result == 0) {
+          result = ret;
+        }
+
+        break;
+      }
+
+      result++;
+    }
+  }
+
+  return result;
+}
+#else
+#error Unimplemented atomic for this platform
+#endif