From dd2bbe458849a9e9adf44377d13c767b7dd946e9 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Thu, 2 Apr 2026 15:39:36 +0300
Subject: [PATCH] LibC: Implement sched_getcpu

---
 userspace/libraries/LibC/include/sched.h |  2 ++
 userspace/libraries/LibC/sched.cpp       | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/userspace/libraries/LibC/include/sched.h b/userspace/libraries/LibC/include/sched.h
index ffbc41f1..a9625302 100644
--- a/userspace/libraries/LibC/include/sched.h
+++ b/userspace/libraries/LibC/include/sched.h
@@ -28,6 +28,8 @@ int sched_setparam(pid_t pid, const struct sched_param* param);
 int sched_setscheduler(pid_t pid, int, const struct sched_param* param);
 int sched_yield(void);
 
+int sched_getcpu(void);
+
 __END_DECLS
 
 #endif
diff --git a/userspace/libraries/LibC/sched.cpp b/userspace/libraries/LibC/sched.cpp
index f1eac3e6..736ca6c4 100644
--- a/userspace/libraries/LibC/sched.cpp
+++ b/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;
+}