LibC: Implement sched_getcpu

userspace/libraries/LibC/sched.cpp

@@ -2,6 +2,10 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+#include <kernel/API/SharedPage.h>
+
+extern volatile Kernel::API::SharedPage* g_shared_page;
+
 int sched_get_priority_max(int policy)
 {
 	(void)policy;
@@ -18,3 +22,17 @@ int sched_yield(void)
 {
 	return syscall(SYS_YIELD);
 }
+
+int sched_getcpu(void)
+{
+	if (g_shared_page == nullptr)
+		return -1;
+
+	uint8_t cpu;
+#if defined(__x86_64__)
+	asm volatile("movb %%gs:0, %0" : "=r"(cpu));
+#elif defined(__i686__)
+	asm volatile("movb %%fs:0, %0" : "=q"(cpu));
+#endif
+	return cpu;
+}